summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--externals/CMakeLists.txt2
-rw-r--r--externals/stb/stb_image.cpp7529
-rw-r--r--externals/stb/stb_image.h7218
-rw-r--r--externals/stb/stb_image_resize.cpp2282
-rw-r--r--externals/stb/stb_image_resize.h2213
5 files changed, 9813 insertions, 9431 deletions
diff --git a/externals/CMakeLists.txt b/externals/CMakeLists.txt
index 9eebc7d65..b1fd3ac62 100644
--- a/externals/CMakeLists.txt
+++ b/externals/CMakeLists.txt
@@ -168,7 +168,7 @@ if (NOT TARGET LLVM::Demangle)
168 add_library(LLVM::Demangle ALIAS demangle) 168 add_library(LLVM::Demangle ALIAS demangle)
169endif() 169endif()
170 170
171add_library(stb stb/stb_dxt.cpp) 171add_library(stb stb/stb_dxt.cpp stb/stb_image.cpp stb/stb_image_resize.cpp)
172target_include_directories(stb PUBLIC ./stb) 172target_include_directories(stb PUBLIC ./stb)
173 173
174add_library(bc_decoder bc_decoder/bc_decoder.cpp) 174add_library(bc_decoder bc_decoder/bc_decoder.cpp)
diff --git a/externals/stb/stb_image.cpp b/externals/stb/stb_image.cpp
new file mode 100644
index 000000000..dbf26f7c5
--- /dev/null
+++ b/externals/stb/stb_image.cpp
@@ -0,0 +1,7529 @@
1// SPDX-FileCopyrightText: stb http://nothings.org/stb
2// SPDX-License-Identifier: MIT
3
4/* stb_image - v2.28 - public domain image loader - http://nothings.org/stb
5 no warranty implied; use at your own risk
6
7LICENSE
8
9 See end of file for license information.
10
11RECENT REVISION HISTORY:
12
13 2.28 (2023-01-29) many error fixes, security errors, just tons of stuff
14 2.27 (2021-07-11) document stbi_info better, 16-bit PNM support, bug fixes
15 2.26 (2020-07-13) many minor fixes
16 2.25 (2020-02-02) fix warnings
17 2.24 (2020-02-02) fix warnings; thread-local failure_reason and flip_vertically
18 2.23 (2019-08-11) fix clang static analysis warning
19 2.22 (2019-03-04) gif fixes, fix warnings
20 2.21 (2019-02-25) fix typo in comment
21 2.20 (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
22 2.19 (2018-02-11) fix warning
23 2.18 (2018-01-30) fix warnings
24 2.17 (2018-01-29) bugfix, 1-bit BMP, 16-bitness query, fix warnings
25 2.16 (2017-07-23) all functions have 16-bit variants; optimizations; bugfixes
26 2.15 (2017-03-18) fix png-1,2,4; all Imagenet JPGs; no runtime SSE detection on GCC
27 2.14 (2017-03-03) remove deprecated STBI_JPEG_OLD; fixes for Imagenet JPGs
28 2.13 (2016-12-04) experimental 16-bit API, only for PNG so far; fixes
29 2.12 (2016-04-02) fix typo in 2.11 PSD fix that caused crashes
30 2.11 (2016-04-02) 16-bit PNGS; enable SSE2 in non-gcc x64
31 RGB-format JPEG; remove white matting in PSD;
32 allocate large structures on the stack;
33 correct channel count for PNG & BMP
34 2.10 (2016-01-22) avoid warning introduced in 2.09
35 2.09 (2016-01-16) 16-bit TGA; comments in PNM files; STBI_REALLOC_SIZED
36
37 See end of file for full revision history.
38
39
40 ============================ Contributors =========================
41
42 Image formats Extensions, features
43 Sean Barrett (jpeg, png, bmp) Jetro Lauha (stbi_info)
44 Nicolas Schulz (hdr, psd) Martin "SpartanJ" Golini (stbi_info)
45 Jonathan Dummer (tga) James "moose2000" Brown (iPhone PNG)
46 Jean-Marc Lienher (gif) Ben "Disch" Wenger (io callbacks)
47 Tom Seddon (pic) Omar Cornut (1/2/4-bit PNG)
48 Thatcher Ulrich (psd) Nicolas Guillemot (vertical flip)
49 Ken Miller (pgm, ppm) Richard Mitton (16-bit PSD)
50 github:urraka (animated gif) Junggon Kim (PNM comments)
51 Christopher Forseth (animated gif) Daniel Gibson (16-bit TGA)
52 socks-the-fox (16-bit PNG)
53 Jeremy Sawicki (handle all ImageNet JPGs)
54 Optimizations & bugfixes Mikhail Morozov (1-bit BMP)
55 Fabian "ryg" Giesen Anael Seghezzi (is-16-bit query)
56 Arseny Kapoulkine Simon Breuss (16-bit PNM)
57 John-Mark Allen
58 Carmelo J Fdez-Aguera
59
60 Bug & warning fixes
61 Marc LeBlanc David Woo Guillaume George Martins Mozeiko
62 Christpher Lloyd Jerry Jansson Joseph Thomson Blazej Dariusz Roszkowski
63 Phil Jordan Dave Moore Roy Eltham
64 Hayaki Saito Nathan Reed Won Chun
65 Luke Graham Johan Duparc Nick Verigakis the Horde3D community
66 Thomas Ruf Ronny Chevalier github:rlyeh
67 Janez Zemva John Bartholomew Michal Cichon github:romigrou
68 Jonathan Blow Ken Hamada Tero Hanninen github:svdijk
69 Eugene Golushkov Laurent Gomila Cort Stratton github:snagar
70 Aruelien Pocheville Sergio Gonzalez Thibault Reuille github:Zelex
71 Cass Everitt Ryamond Barbiero github:grim210
72 Paul Du Bois Engin Manap Aldo Culquicondor github:sammyhw
73 Philipp Wiesemann Dale Weiler Oriol Ferrer Mesia github:phprus
74 Josh Tobin Neil Bickford Matthew Gregan github:poppolopoppo
75 Julian Raschke Gregory Mullen Christian Floisand github:darealshinji
76 Baldur Karlsson Kevin Schmidt JR Smith github:Michaelangel007
77 Brad Weinberger Matvey Cherevko github:mosra
78 Luca Sas Alexander Veselov Zack Middleton [reserved]
79 Ryan C. Gordon [reserved] [reserved]
80 DO NOT ADD YOUR NAME HERE
81
82 Jacko Dirks
83
84 To add your name to the credits, pick a random blank space in the middle and fill it.
85 80% of merge conflicts on stb PRs are due to people adding their name at the end
86 of the credits.
87*/
88
89#include <stb_image.h>
90
91#if defined(STBI_ONLY_JPEG) || defined(STBI_ONLY_PNG) || defined(STBI_ONLY_BMP) \
92 || defined(STBI_ONLY_TGA) || defined(STBI_ONLY_GIF) || defined(STBI_ONLY_PSD) \
93 || defined(STBI_ONLY_HDR) || defined(STBI_ONLY_PIC) || defined(STBI_ONLY_PNM) \
94 || defined(STBI_ONLY_ZLIB)
95 #ifndef STBI_ONLY_JPEG
96 #define STBI_NO_JPEG
97 #endif
98 #ifndef STBI_ONLY_PNG
99 #define STBI_NO_PNG
100 #endif
101 #ifndef STBI_ONLY_BMP
102 #define STBI_NO_BMP
103 #endif
104 #ifndef STBI_ONLY_PSD
105 #define STBI_NO_PSD
106 #endif
107 #ifndef STBI_ONLY_TGA
108 #define STBI_NO_TGA
109 #endif
110 #ifndef STBI_ONLY_GIF
111 #define STBI_NO_GIF
112 #endif
113 #ifndef STBI_ONLY_HDR
114 #define STBI_NO_HDR
115 #endif
116 #ifndef STBI_ONLY_PIC
117 #define STBI_NO_PIC
118 #endif
119 #ifndef STBI_ONLY_PNM
120 #define STBI_NO_PNM
121 #endif
122#endif
123
124#if defined(STBI_NO_PNG) && !defined(STBI_SUPPORT_ZLIB) && !defined(STBI_NO_ZLIB)
125#define STBI_NO_ZLIB
126#endif
127
128
129#include <stdarg.h>
130#include <stddef.h> // ptrdiff_t on osx
131#include <stdlib.h>
132#include <string.h>
133#include <limits.h>
134
135#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
136#include <math.h> // ldexp, pow
137#endif
138
139#ifndef STBI_NO_STDIO
140#include <stdio.h>
141#endif
142
143#ifndef STBI_ASSERT
144#include <assert.h>
145#define STBI_ASSERT(x) assert(x)
146#endif
147
148#ifdef __cplusplus
149#define STBI_EXTERN extern "C"
150#else
151#define STBI_EXTERN extern
152#endif
153
154
155#ifndef _MSC_VER
156 #ifdef __cplusplus
157 #define stbi_inline inline
158 #else
159 #define stbi_inline
160 #endif
161#else
162 #define stbi_inline __forceinline
163#endif
164
165#ifndef STBI_NO_THREAD_LOCALS
166 #if defined(__cplusplus) && __cplusplus >= 201103L
167 #define STBI_THREAD_LOCAL thread_local
168 #elif defined(__GNUC__) && __GNUC__ < 5
169 #define STBI_THREAD_LOCAL __thread
170 #elif defined(_MSC_VER)
171 #define STBI_THREAD_LOCAL __declspec(thread)
172 #elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_THREADS__)
173 #define STBI_THREAD_LOCAL _Thread_local
174 #endif
175
176 #ifndef STBI_THREAD_LOCAL
177 #if defined(__GNUC__)
178 #define STBI_THREAD_LOCAL __thread
179 #endif
180 #endif
181#endif
182
183#if defined(_MSC_VER) || defined(__SYMBIAN32__)
184typedef unsigned short stbi__uint16;
185typedef signed short stbi__int16;
186typedef unsigned int stbi__uint32;
187typedef signed int stbi__int32;
188#else
189#include <stdint.h>
190typedef uint16_t stbi__uint16;
191typedef int16_t stbi__int16;
192typedef uint32_t stbi__uint32;
193typedef int32_t stbi__int32;
194#endif
195
196// should produce compiler error if size is wrong
197typedef unsigned char validate_uint32[sizeof(stbi__uint32)==4 ? 1 : -1];
198
199#ifdef _MSC_VER
200#define STBI_NOTUSED(v) (void)(v)
201#else
202#define STBI_NOTUSED(v) (void)sizeof(v)
203#endif
204
205#ifdef _MSC_VER
206#define STBI_HAS_LROTL
207#endif
208
209#ifdef STBI_HAS_LROTL
210 #define stbi_lrot(x,y) _lrotl(x,y)
211#else
212 #define stbi_lrot(x,y) (((x) << (y)) | ((x) >> (-(y) & 31)))
213#endif
214
215#if defined(STBI_MALLOC) && defined(STBI_FREE) && (defined(STBI_REALLOC) || defined(STBI_REALLOC_SIZED))
216// ok
217#elif !defined(STBI_MALLOC) && !defined(STBI_FREE) && !defined(STBI_REALLOC) && !defined(STBI_REALLOC_SIZED)
218// ok
219#else
220#error "Must define all or none of STBI_MALLOC, STBI_FREE, and STBI_REALLOC (or STBI_REALLOC_SIZED)."
221#endif
222
223#ifndef STBI_MALLOC
224#define STBI_MALLOC(sz) malloc(sz)
225#define STBI_REALLOC(p,newsz) realloc(p,newsz)
226#define STBI_FREE(p) free(p)
227#endif
228
229#ifndef STBI_REALLOC_SIZED
230#define STBI_REALLOC_SIZED(p,oldsz,newsz) STBI_REALLOC(p,newsz)
231#endif
232
233// x86/x64 detection
234#if defined(__x86_64__) || defined(_M_X64)
235#define STBI__X64_TARGET
236#elif defined(__i386) || defined(_M_IX86)
237#define STBI__X86_TARGET
238#endif
239
240#if defined(__GNUC__) && defined(STBI__X86_TARGET) && !defined(__SSE2__) && !defined(STBI_NO_SIMD)
241// gcc doesn't support sse2 intrinsics unless you compile with -msse2,
242// which in turn means it gets to use SSE2 everywhere. This is unfortunate,
243// but previous attempts to provide the SSE2 functions with runtime
244// detection caused numerous issues. The way architecture extensions are
245// exposed in GCC/Clang is, sadly, not really suited for one-file libs.
246// New behavior: if compiled with -msse2, we use SSE2 without any
247// detection; if not, we don't use it at all.
248#define STBI_NO_SIMD
249#endif
250
251#if defined(__MINGW32__) && defined(STBI__X86_TARGET) && !defined(STBI_MINGW_ENABLE_SSE2) && !defined(STBI_NO_SIMD)
252// Note that __MINGW32__ doesn't actually mean 32-bit, so we have to avoid STBI__X64_TARGET
253//
254// 32-bit MinGW wants ESP to be 16-byte aligned, but this is not in the
255// Windows ABI and VC++ as well as Windows DLLs don't maintain that invariant.
256// As a result, enabling SSE2 on 32-bit MinGW is dangerous when not
257// simultaneously enabling "-mstackrealign".
258//
259// See https://github.com/nothings/stb/issues/81 for more information.
260//
261// So default to no SSE2 on 32-bit MinGW. If you've read this far and added
262// -mstackrealign to your build settings, feel free to #define STBI_MINGW_ENABLE_SSE2.
263#define STBI_NO_SIMD
264#endif
265
266#if !defined(STBI_NO_SIMD) && (defined(STBI__X86_TARGET) || defined(STBI__X64_TARGET))
267#define STBI_SSE2
268#include <emmintrin.h>
269
270#ifdef _MSC_VER
271
272#if _MSC_VER >= 1400 // not VC6
273#include <intrin.h> // __cpuid
274static int stbi__cpuid3(void)
275{
276 int info[4];
277 __cpuid(info,1);
278 return info[3];
279}
280#else
281static int stbi__cpuid3(void)
282{
283 int res;
284 __asm {
285 mov eax,1
286 cpuid
287 mov res,edx
288 }
289 return res;
290}
291#endif
292
293#define STBI_SIMD_ALIGN(type, name) __declspec(align(16)) type name
294
295#if !defined(STBI_NO_JPEG) && defined(STBI_SSE2)
296static int stbi__sse2_available(void)
297{
298 int info3 = stbi__cpuid3();
299 return ((info3 >> 26) & 1) != 0;
300}
301#endif
302
303#else // assume GCC-style if not VC++
304#define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))
305
306#if !defined(STBI_NO_JPEG) && defined(STBI_SSE2)
307static int stbi__sse2_available(void)
308{
309 // If we're even attempting to compile this on GCC/Clang, that means
310 // -msse2 is on, which means the compiler is allowed to use SSE2
311 // instructions at will, and so are we.
312 return 1;
313}
314#endif
315
316#endif
317#endif
318
319// ARM NEON
320#if defined(STBI_NO_SIMD) && defined(STBI_NEON)
321#undef STBI_NEON
322#endif
323
324#ifdef STBI_NEON
325#include <arm_neon.h>
326#ifdef _MSC_VER
327#define STBI_SIMD_ALIGN(type, name) __declspec(align(16)) type name
328#else
329#define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))
330#endif
331#endif
332
333#ifndef STBI_SIMD_ALIGN
334#define STBI_SIMD_ALIGN(type, name) type name
335#endif
336
337#ifndef STBI_MAX_DIMENSIONS
338#define STBI_MAX_DIMENSIONS (1 << 24)
339#endif
340
341///////////////////////////////////////////////
342//
343// stbi__context struct and start_xxx functions
344
345// stbi__context structure is our basic context used by all images, so it
346// contains all the IO context, plus some basic image information
347typedef struct
348{
349 stbi__uint32 img_x, img_y;
350 int img_n, img_out_n;
351
352 stbi_io_callbacks io;
353 void *io_user_data;
354
355 int read_from_callbacks;
356 int buflen;
357 stbi_uc buffer_start[128];
358 int callback_already_read;
359
360 stbi_uc *img_buffer, *img_buffer_end;
361 stbi_uc *img_buffer_original, *img_buffer_original_end;
362} stbi__context;
363
364
365static void stbi__refill_buffer(stbi__context *s);
366
367// initialize a memory-decode context
368static void stbi__start_mem(stbi__context *s, stbi_uc const *buffer, int len)
369{
370 s->io.read = NULL;
371 s->read_from_callbacks = 0;
372 s->callback_already_read = 0;
373 s->img_buffer = s->img_buffer_original = (stbi_uc *) buffer;
374 s->img_buffer_end = s->img_buffer_original_end = (stbi_uc *) buffer+len;
375}
376
377// initialize a callback-based context
378static void stbi__start_callbacks(stbi__context *s, stbi_io_callbacks *c, void *user)
379{
380 s->io = *c;
381 s->io_user_data = user;
382 s->buflen = sizeof(s->buffer_start);
383 s->read_from_callbacks = 1;
384 s->callback_already_read = 0;
385 s->img_buffer = s->img_buffer_original = s->buffer_start;
386 stbi__refill_buffer(s);
387 s->img_buffer_original_end = s->img_buffer_end;
388}
389
390#ifndef STBI_NO_STDIO
391
392static int stbi__stdio_read(void *user, char *data, int size)
393{
394 return (int) fread(data,1,size,(FILE*) user);
395}
396
397static void stbi__stdio_skip(void *user, int n)
398{
399 int ch;
400 fseek((FILE*) user, n, SEEK_CUR);
401 ch = fgetc((FILE*) user); /* have to read a byte to reset feof()'s flag */
402 if (ch != EOF) {
403 ungetc(ch, (FILE *) user); /* push byte back onto stream if valid. */
404 }
405}
406
407static int stbi__stdio_eof(void *user)
408{
409 return feof((FILE*) user) || ferror((FILE *) user);
410}
411
412static stbi_io_callbacks stbi__stdio_callbacks =
413{
414 stbi__stdio_read,
415 stbi__stdio_skip,
416 stbi__stdio_eof,
417};
418
419static void stbi__start_file(stbi__context *s, FILE *f)
420{
421 stbi__start_callbacks(s, &stbi__stdio_callbacks, (void *) f);
422}
423
424//static void stop_file(stbi__context *s) { }
425
426#endif // !STBI_NO_STDIO
427
428static void stbi__rewind(stbi__context *s)
429{
430 // conceptually rewind SHOULD rewind to the beginning of the stream,
431 // but we just rewind to the beginning of the initial buffer, because
432 // we only use it after doing 'test', which only ever looks at at most 92 bytes
433 s->img_buffer = s->img_buffer_original;
434 s->img_buffer_end = s->img_buffer_original_end;
435}
436
437enum
438{
439 STBI_ORDER_RGB,
440 STBI_ORDER_BGR
441};
442
443typedef struct
444{
445 int bits_per_channel;
446 int num_channels;
447 int channel_order;
448} stbi__result_info;
449
450#ifndef STBI_NO_JPEG
451static int stbi__jpeg_test(stbi__context *s);
452static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
453static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp);
454#endif
455
456#ifndef STBI_NO_PNG
457static int stbi__png_test(stbi__context *s);
458static void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
459static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp);
460static int stbi__png_is16(stbi__context *s);
461#endif
462
463#ifndef STBI_NO_BMP
464static int stbi__bmp_test(stbi__context *s);
465static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
466static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp);
467#endif
468
469#ifndef STBI_NO_TGA
470static int stbi__tga_test(stbi__context *s);
471static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
472static int stbi__tga_info(stbi__context *s, int *x, int *y, int *comp);
473#endif
474
475#ifndef STBI_NO_PSD
476static int stbi__psd_test(stbi__context *s);
477static void *stbi__psd_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc);
478static int stbi__psd_info(stbi__context *s, int *x, int *y, int *comp);
479static int stbi__psd_is16(stbi__context *s);
480#endif
481
482#ifndef STBI_NO_HDR
483static int stbi__hdr_test(stbi__context *s);
484static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
485static int stbi__hdr_info(stbi__context *s, int *x, int *y, int *comp);
486#endif
487
488#ifndef STBI_NO_PIC
489static int stbi__pic_test(stbi__context *s);
490static void *stbi__pic_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
491static int stbi__pic_info(stbi__context *s, int *x, int *y, int *comp);
492#endif
493
494#ifndef STBI_NO_GIF
495static int stbi__gif_test(stbi__context *s);
496static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
497static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp);
498static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp);
499#endif
500
501#ifndef STBI_NO_PNM
502static int stbi__pnm_test(stbi__context *s);
503static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
504static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp);
505static int stbi__pnm_is16(stbi__context *s);
506#endif
507
508static
509#ifdef STBI_THREAD_LOCAL
510STBI_THREAD_LOCAL
511#endif
512const char *stbi__g_failure_reason;
513
514STBIDEF const char *stbi_failure_reason(void)
515{
516 return stbi__g_failure_reason;
517}
518
519#ifndef STBI_NO_FAILURE_STRINGS
520static int stbi__err(const char *str)
521{
522 stbi__g_failure_reason = str;
523 return 0;
524}
525#endif
526
527static void *stbi__malloc(size_t size)
528{
529 return STBI_MALLOC(size);
530}
531
532// stb_image uses ints pervasively, including for offset calculations.
533// therefore the largest decoded image size we can support with the
534// current code, even on 64-bit targets, is INT_MAX. this is not a
535// significant limitation for the intended use case.
536//
537// we do, however, need to make sure our size calculations don't
538// overflow. hence a few helper functions for size calculations that
539// multiply integers together, making sure that they're non-negative
540// and no overflow occurs.
541
542// return 1 if the sum is valid, 0 on overflow.
543// negative terms are considered invalid.
544static int stbi__addsizes_valid(int a, int b)
545{
546 if (b < 0) return 0;
547 // now 0 <= b <= INT_MAX, hence also
548 // 0 <= INT_MAX - b <= INTMAX.
549 // And "a + b <= INT_MAX" (which might overflow) is the
550 // same as a <= INT_MAX - b (no overflow)
551 return a <= INT_MAX - b;
552}
553
554// returns 1 if the product is valid, 0 on overflow.
555// negative factors are considered invalid.
556static int stbi__mul2sizes_valid(int a, int b)
557{
558 if (a < 0 || b < 0) return 0;
559 if (b == 0) return 1; // mul-by-0 is always safe
560 // portable way to check for no overflows in a*b
561 return a <= INT_MAX/b;
562}
563
564#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
565// returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow
566static int stbi__mad2sizes_valid(int a, int b, int add)
567{
568 return stbi__mul2sizes_valid(a, b) && stbi__addsizes_valid(a*b, add);
569}
570#endif
571
572// returns 1 if "a*b*c + add" has no negative terms/factors and doesn't overflow
573static int stbi__mad3sizes_valid(int a, int b, int c, int add)
574{
575 return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a*b, c) &&
576 stbi__addsizes_valid(a*b*c, add);
577}
578
579// returns 1 if "a*b*c*d + add" has no negative terms/factors and doesn't overflow
580#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
581static int stbi__mad4sizes_valid(int a, int b, int c, int d, int add)
582{
583 return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a*b, c) &&
584 stbi__mul2sizes_valid(a*b*c, d) && stbi__addsizes_valid(a*b*c*d, add);
585}
586#endif
587
588#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
589// mallocs with size overflow checking
590static void *stbi__malloc_mad2(int a, int b, int add)
591{
592 if (!stbi__mad2sizes_valid(a, b, add)) return NULL;
593 return stbi__malloc(a*b + add);
594}
595#endif
596
597static void *stbi__malloc_mad3(int a, int b, int c, int add)
598{
599 if (!stbi__mad3sizes_valid(a, b, c, add)) return NULL;
600 return stbi__malloc(a*b*c + add);
601}
602
603#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
604static void *stbi__malloc_mad4(int a, int b, int c, int d, int add)
605{
606 if (!stbi__mad4sizes_valid(a, b, c, d, add)) return NULL;
607 return stbi__malloc(a*b*c*d + add);
608}
609#endif
610
611// returns 1 if the sum of two signed ints is valid (between -2^31 and 2^31-1 inclusive), 0 on overflow.
612static int stbi__addints_valid(int a, int b)
613{
614 if ((a >= 0) != (b >= 0)) return 1; // a and b have different signs, so no overflow
615 if (a < 0 && b < 0) return a >= INT_MIN - b; // same as a + b >= INT_MIN; INT_MIN - b cannot overflow since b < 0.
616 return a <= INT_MAX - b;
617}
618
619// returns 1 if the product of two signed shorts is valid, 0 on overflow.
620static int stbi__mul2shorts_valid(short a, short b)
621{
622 if (b == 0 || b == -1) return 1; // multiplication by 0 is always 0; check for -1 so SHRT_MIN/b doesn't overflow
623 if ((a >= 0) == (b >= 0)) return a <= SHRT_MAX/b; // product is positive, so similar to mul2sizes_valid
624 if (b < 0) return a <= SHRT_MIN / b; // same as a * b >= SHRT_MIN
625 return a >= SHRT_MIN / b;
626}
627
628// stbi__err - error
629// stbi__errpf - error returning pointer to float
630// stbi__errpuc - error returning pointer to unsigned char
631
632#ifdef STBI_NO_FAILURE_STRINGS
633 #define stbi__err(x,y) 0
634#elif defined(STBI_FAILURE_USERMSG)
635 #define stbi__err(x,y) stbi__err(y)
636#else
637 #define stbi__err(x,y) stbi__err(x)
638#endif
639
640#define stbi__errpf(x,y) ((float *)(size_t) (stbi__err(x,y)?NULL:NULL))
641#define stbi__errpuc(x,y) ((unsigned char *)(size_t) (stbi__err(x,y)?NULL:NULL))
642
643STBIDEF void stbi_image_free(void *retval_from_stbi_load)
644{
645 STBI_FREE(retval_from_stbi_load);
646}
647
648#ifndef STBI_NO_LINEAR
649static float *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp);
650#endif
651
652#ifndef STBI_NO_HDR
653static stbi_uc *stbi__hdr_to_ldr(float *data, int x, int y, int comp);
654#endif
655
656static int stbi__vertically_flip_on_load_global = 0;
657
658STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip)
659{
660 stbi__vertically_flip_on_load_global = flag_true_if_should_flip;
661}
662
663#ifndef STBI_THREAD_LOCAL
664#define stbi__vertically_flip_on_load stbi__vertically_flip_on_load_global
665#else
666static STBI_THREAD_LOCAL int stbi__vertically_flip_on_load_local, stbi__vertically_flip_on_load_set;
667
668STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip)
669{
670 stbi__vertically_flip_on_load_local = flag_true_if_should_flip;
671 stbi__vertically_flip_on_load_set = 1;
672}
673
674#define stbi__vertically_flip_on_load (stbi__vertically_flip_on_load_set \
675 ? stbi__vertically_flip_on_load_local \
676 : stbi__vertically_flip_on_load_global)
677#endif // STBI_THREAD_LOCAL
678
679static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
680{
681 memset(ri, 0, sizeof(*ri)); // make sure it's initialized if we add new fields
682 ri->bits_per_channel = 8; // default is 8 so most paths don't have to be changed
683 ri->channel_order = STBI_ORDER_RGB; // all current input & output are this, but this is here so we can add BGR order
684 ri->num_channels = 0;
685
686 // test the formats with a very explicit header first (at least a FOURCC
687 // or distinctive magic number first)
688 #ifndef STBI_NO_PNG
689 if (stbi__png_test(s)) return stbi__png_load(s,x,y,comp,req_comp, ri);
690 #endif
691 #ifndef STBI_NO_BMP
692 if (stbi__bmp_test(s)) return stbi__bmp_load(s,x,y,comp,req_comp, ri);
693 #endif
694 #ifndef STBI_NO_GIF
695 if (stbi__gif_test(s)) return stbi__gif_load(s,x,y,comp,req_comp, ri);
696 #endif
697 #ifndef STBI_NO_PSD
698 if (stbi__psd_test(s)) return stbi__psd_load(s,x,y,comp,req_comp, ri, bpc);
699 #else
700 STBI_NOTUSED(bpc);
701 #endif
702 #ifndef STBI_NO_PIC
703 if (stbi__pic_test(s)) return stbi__pic_load(s,x,y,comp,req_comp, ri);
704 #endif
705
706 // then the formats that can end up attempting to load with just 1 or 2
707 // bytes matching expectations; these are prone to false positives, so
708 // try them later
709 #ifndef STBI_NO_JPEG
710 if (stbi__jpeg_test(s)) return stbi__jpeg_load(s,x,y,comp,req_comp, ri);
711 #endif
712 #ifndef STBI_NO_PNM
713 if (stbi__pnm_test(s)) return stbi__pnm_load(s,x,y,comp,req_comp, ri);
714 #endif
715
716 #ifndef STBI_NO_HDR
717 if (stbi__hdr_test(s)) {
718 float *hdr = stbi__hdr_load(s, x,y,comp,req_comp, ri);
719 return stbi__hdr_to_ldr(hdr, *x, *y, req_comp ? req_comp : *comp);
720 }
721 #endif
722
723 #ifndef STBI_NO_TGA
724 // test tga last because it's a crappy test!
725 if (stbi__tga_test(s))
726 return stbi__tga_load(s,x,y,comp,req_comp, ri);
727 #endif
728
729 return stbi__errpuc("unknown image type", "Image not of any known type, or corrupt");
730}
731
732static stbi_uc *stbi__convert_16_to_8(stbi__uint16 *orig, int w, int h, int channels)
733{
734 int i;
735 int img_len = w * h * channels;
736 stbi_uc *reduced;
737
738 reduced = (stbi_uc *) stbi__malloc(img_len);
739 if (reduced == NULL) return stbi__errpuc("outofmem", "Out of memory");
740
741 for (i = 0; i < img_len; ++i)
742 reduced[i] = (stbi_uc)((orig[i] >> 8) & 0xFF); // top half of each byte is sufficient approx of 16->8 bit scaling
743
744 STBI_FREE(orig);
745 return reduced;
746}
747
748static stbi__uint16 *stbi__convert_8_to_16(stbi_uc *orig, int w, int h, int channels)
749{
750 int i;
751 int img_len = w * h * channels;
752 stbi__uint16 *enlarged;
753
754 enlarged = (stbi__uint16 *) stbi__malloc(img_len*2);
755 if (enlarged == NULL) return (stbi__uint16 *) stbi__errpuc("outofmem", "Out of memory");
756
757 for (i = 0; i < img_len; ++i)
758 enlarged[i] = (stbi__uint16)((orig[i] << 8) + orig[i]); // replicate to high and low byte, maps 0->0, 255->0xffff
759
760 STBI_FREE(orig);
761 return enlarged;
762}
763
764static void stbi__vertical_flip(void *image, int w, int h, int bytes_per_pixel)
765{
766 int row;
767 size_t bytes_per_row = (size_t)w * bytes_per_pixel;
768 stbi_uc temp[2048];
769 stbi_uc *bytes = (stbi_uc *)image;
770
771 for (row = 0; row < (h>>1); row++) {
772 stbi_uc *row0 = bytes + row*bytes_per_row;
773 stbi_uc *row1 = bytes + (h - row - 1)*bytes_per_row;
774 // swap row0 with row1
775 size_t bytes_left = bytes_per_row;
776 while (bytes_left) {
777 size_t bytes_copy = (bytes_left < sizeof(temp)) ? bytes_left : sizeof(temp);
778 memcpy(temp, row0, bytes_copy);
779 memcpy(row0, row1, bytes_copy);
780 memcpy(row1, temp, bytes_copy);
781 row0 += bytes_copy;
782 row1 += bytes_copy;
783 bytes_left -= bytes_copy;
784 }
785 }
786}
787
788#ifndef STBI_NO_GIF
789static void stbi__vertical_flip_slices(void *image, int w, int h, int z, int bytes_per_pixel)
790{
791 int slice;
792 int slice_size = w * h * bytes_per_pixel;
793
794 stbi_uc *bytes = (stbi_uc *)image;
795 for (slice = 0; slice < z; ++slice) {
796 stbi__vertical_flip(bytes, w, h, bytes_per_pixel);
797 bytes += slice_size;
798 }
799}
800#endif
801
802static unsigned char *stbi__load_and_postprocess_8bit(stbi__context *s, int *x, int *y, int *comp, int req_comp)
803{
804 stbi__result_info ri;
805 void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 8);
806
807 if (result == NULL)
808 return NULL;
809
810 // it is the responsibility of the loaders to make sure we get either 8 or 16 bit.
811 STBI_ASSERT(ri.bits_per_channel == 8 || ri.bits_per_channel == 16);
812
813 if (ri.bits_per_channel != 8) {
814 result = stbi__convert_16_to_8((stbi__uint16 *) result, *x, *y, req_comp == 0 ? *comp : req_comp);
815 ri.bits_per_channel = 8;
816 }
817
818 // @TODO: move stbi__convert_format to here
819
820 if (stbi__vertically_flip_on_load) {
821 int channels = req_comp ? req_comp : *comp;
822 stbi__vertical_flip(result, *x, *y, channels * sizeof(stbi_uc));
823 }
824
825 return (unsigned char *) result;
826}
827
828static stbi__uint16 *stbi__load_and_postprocess_16bit(stbi__context *s, int *x, int *y, int *comp, int req_comp)
829{
830 stbi__result_info ri;
831 void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 16);
832
833 if (result == NULL)
834 return NULL;
835
836 // it is the responsibility of the loaders to make sure we get either 8 or 16 bit.
837 STBI_ASSERT(ri.bits_per_channel == 8 || ri.bits_per_channel == 16);
838
839 if (ri.bits_per_channel != 16) {
840 result = stbi__convert_8_to_16((stbi_uc *) result, *x, *y, req_comp == 0 ? *comp : req_comp);
841 ri.bits_per_channel = 16;
842 }
843
844 // @TODO: move stbi__convert_format16 to here
845 // @TODO: special case RGB-to-Y (and RGBA-to-YA) for 8-bit-to-16-bit case to keep more precision
846
847 if (stbi__vertically_flip_on_load) {
848 int channels = req_comp ? req_comp : *comp;
849 stbi__vertical_flip(result, *x, *y, channels * sizeof(stbi__uint16));
850 }
851
852 return (stbi__uint16 *) result;
853}
854
855#if !defined(STBI_NO_HDR) && !defined(STBI_NO_LINEAR)
856static void stbi__float_postprocess(float *result, int *x, int *y, int *comp, int req_comp)
857{
858 if (stbi__vertically_flip_on_load && result != NULL) {
859 int channels = req_comp ? req_comp : *comp;
860 stbi__vertical_flip(result, *x, *y, channels * sizeof(float));
861 }
862}
863#endif
864
865#ifndef STBI_NO_STDIO
866
867#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
868STBI_EXTERN __declspec(dllimport) int __stdcall MultiByteToWideChar(unsigned int cp, unsigned long flags, const char *str, int cbmb, wchar_t *widestr, int cchwide);
869STBI_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned int cp, unsigned long flags, const wchar_t *widestr, int cchwide, char *str, int cbmb, const char *defchar, int *used_default);
870#endif
871
872#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
873STBIDEF int stbi_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
874{
875 return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
876}
877#endif
878
879static FILE *stbi__fopen(char const *filename, char const *mode)
880{
881 FILE *f;
882#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
883 wchar_t wMode[64];
884 wchar_t wFilename[1024];
885 if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)/sizeof(*wFilename)))
886 return 0;
887
888 if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)/sizeof(*wMode)))
889 return 0;
890
891#if defined(_MSC_VER) && _MSC_VER >= 1400
892 if (0 != _wfopen_s(&f, wFilename, wMode))
893 f = 0;
894#else
895 f = _wfopen(wFilename, wMode);
896#endif
897
898#elif defined(_MSC_VER) && _MSC_VER >= 1400
899 if (0 != fopen_s(&f, filename, mode))
900 f=0;
901#else
902 f = fopen(filename, mode);
903#endif
904 return f;
905}
906
907
908STBIDEF stbi_uc *stbi_load(char const *filename, int *x, int *y, int *comp, int req_comp)
909{
910 FILE *f = stbi__fopen(filename, "rb");
911 unsigned char *result;
912 if (!f) return stbi__errpuc("can't fopen", "Unable to open file");
913 result = stbi_load_from_file(f,x,y,comp,req_comp);
914 fclose(f);
915 return result;
916}
917
918STBIDEF stbi_uc *stbi_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
919{
920 unsigned char *result;
921 stbi__context s;
922 stbi__start_file(&s,f);
923 result = stbi__load_and_postprocess_8bit(&s,x,y,comp,req_comp);
924 if (result) {
925 // need to 'unget' all the characters in the IO buffer
926 fseek(f, - (int) (s.img_buffer_end - s.img_buffer), SEEK_CUR);
927 }
928 return result;
929}
930
931STBIDEF stbi__uint16 *stbi_load_from_file_16(FILE *f, int *x, int *y, int *comp, int req_comp)
932{
933 stbi__uint16 *result;
934 stbi__context s;
935 stbi__start_file(&s,f);
936 result = stbi__load_and_postprocess_16bit(&s,x,y,comp,req_comp);
937 if (result) {
938 // need to 'unget' all the characters in the IO buffer
939 fseek(f, - (int) (s.img_buffer_end - s.img_buffer), SEEK_CUR);
940 }
941 return result;
942}
943
944STBIDEF stbi_us *stbi_load_16(char const *filename, int *x, int *y, int *comp, int req_comp)
945{
946 FILE *f = stbi__fopen(filename, "rb");
947 stbi__uint16 *result;
948 if (!f) return (stbi_us *) stbi__errpuc("can't fopen", "Unable to open file");
949 result = stbi_load_from_file_16(f,x,y,comp,req_comp);
950 fclose(f);
951 return result;
952}
953
954
955#endif //!STBI_NO_STDIO
956
957STBIDEF stbi_us *stbi_load_16_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels)
958{
959 stbi__context s;
960 stbi__start_mem(&s,buffer,len);
961 return stbi__load_and_postprocess_16bit(&s,x,y,channels_in_file,desired_channels);
962}
963
964STBIDEF stbi_us *stbi_load_16_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *channels_in_file, int desired_channels)
965{
966 stbi__context s;
967 stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
968 return stbi__load_and_postprocess_16bit(&s,x,y,channels_in_file,desired_channels);
969}
970
971STBIDEF stbi_uc *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
972{
973 stbi__context s;
974 stbi__start_mem(&s,buffer,len);
975 return stbi__load_and_postprocess_8bit(&s,x,y,comp,req_comp);
976}
977
978STBIDEF stbi_uc *stbi_load_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
979{
980 stbi__context s;
981 stbi__start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
982 return stbi__load_and_postprocess_8bit(&s,x,y,comp,req_comp);
983}
984
985#ifndef STBI_NO_GIF
986STBIDEF stbi_uc *stbi_load_gif_from_memory(stbi_uc const *buffer, int len, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
987{
988 unsigned char *result;
989 stbi__context s;
990 stbi__start_mem(&s,buffer,len);
991
992 result = (unsigned char*) stbi__load_gif_main(&s, delays, x, y, z, comp, req_comp);
993 if (stbi__vertically_flip_on_load) {
994 stbi__vertical_flip_slices( result, *x, *y, *z, *comp );
995 }
996
997 return result;
998}
999#endif
1000
1001#ifndef STBI_NO_LINEAR
1002static float *stbi__loadf_main(stbi__context *s, int *x, int *y, int *comp, int req_comp)
1003{
1004 unsigned char *data;
1005 #ifndef STBI_NO_HDR
1006 if (stbi__hdr_test(s)) {
1007 stbi__result_info ri;
1008 float *hdr_data = stbi__hdr_load(s,x,y,comp,req_comp, &ri);
1009 if (hdr_data)
1010 stbi__float_postprocess(hdr_data,x,y,comp,req_comp);
1011 return hdr_data;
1012 }
1013 #endif
1014 data = stbi__load_and_postprocess_8bit(s, x, y, comp, req_comp);
1015 if (data)
1016 return stbi__ldr_to_hdr(data, *x, *y, req_comp ? req_comp : *comp);
1017 return stbi__errpf("unknown image type", "Image not of any known type, or corrupt");
1018}
1019
1020STBIDEF float *stbi_loadf_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
1021{
1022 stbi__context s;
1023 stbi__start_mem(&s,buffer,len);
1024 return stbi__loadf_main(&s,x,y,comp,req_comp);
1025}
1026
1027STBIDEF float *stbi_loadf_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
1028{
1029 stbi__context s;
1030 stbi__start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
1031 return stbi__loadf_main(&s,x,y,comp,req_comp);
1032}
1033
1034#ifndef STBI_NO_STDIO
1035STBIDEF float *stbi_loadf(char const *filename, int *x, int *y, int *comp, int req_comp)
1036{
1037 float *result;
1038 FILE *f = stbi__fopen(filename, "rb");
1039 if (!f) return stbi__errpf("can't fopen", "Unable to open file");
1040 result = stbi_loadf_from_file(f,x,y,comp,req_comp);
1041 fclose(f);
1042 return result;
1043}
1044
1045STBIDEF float *stbi_loadf_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
1046{
1047 stbi__context s;
1048 stbi__start_file(&s,f);
1049 return stbi__loadf_main(&s,x,y,comp,req_comp);
1050}
1051#endif // !STBI_NO_STDIO
1052
1053#endif // !STBI_NO_LINEAR
1054
1055// these is-hdr-or-not is defined independent of whether STBI_NO_LINEAR is
1056// defined, for API simplicity; if STBI_NO_LINEAR is defined, it always
1057// reports false!
1058
1059STBIDEF int stbi_is_hdr_from_memory(stbi_uc const *buffer, int len)
1060{
1061 #ifndef STBI_NO_HDR
1062 stbi__context s;
1063 stbi__start_mem(&s,buffer,len);
1064 return stbi__hdr_test(&s);
1065 #else
1066 STBI_NOTUSED(buffer);
1067 STBI_NOTUSED(len);
1068 return 0;
1069 #endif
1070}
1071
1072#ifndef STBI_NO_STDIO
1073STBIDEF int stbi_is_hdr (char const *filename)
1074{
1075 FILE *f = stbi__fopen(filename, "rb");
1076 int result=0;
1077 if (f) {
1078 result = stbi_is_hdr_from_file(f);
1079 fclose(f);
1080 }
1081 return result;
1082}
1083
1084STBIDEF int stbi_is_hdr_from_file(FILE *f)
1085{
1086 #ifndef STBI_NO_HDR
1087 long pos = ftell(f);
1088 int res;
1089 stbi__context s;
1090 stbi__start_file(&s,f);
1091 res = stbi__hdr_test(&s);
1092 fseek(f, pos, SEEK_SET);
1093 return res;
1094 #else
1095 STBI_NOTUSED(f);
1096 return 0;
1097 #endif
1098}
1099#endif // !STBI_NO_STDIO
1100
1101STBIDEF int stbi_is_hdr_from_callbacks(stbi_io_callbacks const *clbk, void *user)
1102{
1103 #ifndef STBI_NO_HDR
1104 stbi__context s;
1105 stbi__start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
1106 return stbi__hdr_test(&s);
1107 #else
1108 STBI_NOTUSED(clbk);
1109 STBI_NOTUSED(user);
1110 return 0;
1111 #endif
1112}
1113
1114#ifndef STBI_NO_LINEAR
1115static float stbi__l2h_gamma=2.2f, stbi__l2h_scale=1.0f;
1116
1117STBIDEF void stbi_ldr_to_hdr_gamma(float gamma) { stbi__l2h_gamma = gamma; }
1118STBIDEF void stbi_ldr_to_hdr_scale(float scale) { stbi__l2h_scale = scale; }
1119#endif
1120
1121static float stbi__h2l_gamma_i=1.0f/2.2f, stbi__h2l_scale_i=1.0f;
1122
1123STBIDEF void stbi_hdr_to_ldr_gamma(float gamma) { stbi__h2l_gamma_i = 1/gamma; }
1124STBIDEF void stbi_hdr_to_ldr_scale(float scale) { stbi__h2l_scale_i = 1/scale; }
1125
1126
1127//////////////////////////////////////////////////////////////////////////////
1128//
1129// Common code used by all image loaders
1130//
1131
1132enum
1133{
1134 STBI__SCAN_load=0,
1135 STBI__SCAN_type,
1136 STBI__SCAN_header
1137};
1138
1139static void stbi__refill_buffer(stbi__context *s)
1140{
1141 int n = (s->io.read)(s->io_user_data,(char*)s->buffer_start,s->buflen);
1142 s->callback_already_read += (int) (s->img_buffer - s->img_buffer_original);
1143 if (n == 0) {
1144 // at end of file, treat same as if from memory, but need to handle case
1145 // where s->img_buffer isn't pointing to safe memory, e.g. 0-byte file
1146 s->read_from_callbacks = 0;
1147 s->img_buffer = s->buffer_start;
1148 s->img_buffer_end = s->buffer_start+1;
1149 *s->img_buffer = 0;
1150 } else {
1151 s->img_buffer = s->buffer_start;
1152 s->img_buffer_end = s->buffer_start + n;
1153 }
1154}
1155
1156stbi_inline static stbi_uc stbi__get8(stbi__context *s)
1157{
1158 if (s->img_buffer < s->img_buffer_end)
1159 return *s->img_buffer++;
1160 if (s->read_from_callbacks) {
1161 stbi__refill_buffer(s);
1162 return *s->img_buffer++;
1163 }
1164 return 0;
1165}
1166
1167#if defined(STBI_NO_JPEG) && defined(STBI_NO_HDR) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
1168// nothing
1169#else
1170stbi_inline static int stbi__at_eof(stbi__context *s)
1171{
1172 if (s->io.read) {
1173 if (!(s->io.eof)(s->io_user_data)) return 0;
1174 // if feof() is true, check if buffer = end
1175 // special case: we've only got the special 0 character at the end
1176 if (s->read_from_callbacks == 0) return 1;
1177 }
1178
1179 return s->img_buffer >= s->img_buffer_end;
1180}
1181#endif
1182
1183#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC)
1184// nothing
1185#else
1186static void stbi__skip(stbi__context *s, int n)
1187{
1188 if (n == 0) return; // already there!
1189 if (n < 0) {
1190 s->img_buffer = s->img_buffer_end;
1191 return;
1192 }
1193 if (s->io.read) {
1194 int blen = (int) (s->img_buffer_end - s->img_buffer);
1195 if (blen < n) {
1196 s->img_buffer = s->img_buffer_end;
1197 (s->io.skip)(s->io_user_data, n - blen);
1198 return;
1199 }
1200 }
1201 s->img_buffer += n;
1202}
1203#endif
1204
1205#if defined(STBI_NO_PNG) && defined(STBI_NO_TGA) && defined(STBI_NO_HDR) && defined(STBI_NO_PNM)
1206// nothing
1207#else
1208static int stbi__getn(stbi__context *s, stbi_uc *buffer, int n)
1209{
1210 if (s->io.read) {
1211 int blen = (int) (s->img_buffer_end - s->img_buffer);
1212 if (blen < n) {
1213 int res, count;
1214
1215 memcpy(buffer, s->img_buffer, blen);
1216
1217 count = (s->io.read)(s->io_user_data, (char*) buffer + blen, n - blen);
1218 res = (count == (n-blen));
1219 s->img_buffer = s->img_buffer_end;
1220 return res;
1221 }
1222 }
1223
1224 if (s->img_buffer+n <= s->img_buffer_end) {
1225 memcpy(buffer, s->img_buffer, n);
1226 s->img_buffer += n;
1227 return 1;
1228 } else
1229 return 0;
1230}
1231#endif
1232
1233#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
1234// nothing
1235#else
1236static int stbi__get16be(stbi__context *s)
1237{
1238 int z = stbi__get8(s);
1239 return (z << 8) + stbi__get8(s);
1240}
1241#endif
1242
1243#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
1244// nothing
1245#else
1246static stbi__uint32 stbi__get32be(stbi__context *s)
1247{
1248 stbi__uint32 z = stbi__get16be(s);
1249 return (z << 16) + stbi__get16be(s);
1250}
1251#endif
1252
1253#if defined(STBI_NO_BMP) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF)
1254// nothing
1255#else
1256static int stbi__get16le(stbi__context *s)
1257{
1258 int z = stbi__get8(s);
1259 return z + (stbi__get8(s) << 8);
1260}
1261#endif
1262
1263#ifndef STBI_NO_BMP
1264static stbi__uint32 stbi__get32le(stbi__context *s)
1265{
1266 stbi__uint32 z = stbi__get16le(s);
1267 z += (stbi__uint32)stbi__get16le(s) << 16;
1268 return z;
1269}
1270#endif
1271
1272#define STBI__BYTECAST(x) ((stbi_uc) ((x) & 255)) // truncate int to byte without warnings
1273
1274#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
1275// nothing
1276#else
1277//////////////////////////////////////////////////////////////////////////////
1278//
1279// generic converter from built-in img_n to req_comp
1280// individual types do this automatically as much as possible (e.g. jpeg
1281// does all cases internally since it needs to colorspace convert anyway,
1282// and it never has alpha, so very few cases ). png can automatically
1283// interleave an alpha=255 channel, but falls back to this for other cases
1284//
1285// assume data buffer is malloced, so malloc a new one and free that one
1286// only failure mode is malloc failing
1287
1288static stbi_uc stbi__compute_y(int r, int g, int b)
1289{
1290 return (stbi_uc) (((r*77) + (g*150) + (29*b)) >> 8);
1291}
1292#endif
1293
1294#if defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
1295// nothing
1296#else
1297static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y)
1298{
1299 int i,j;
1300 unsigned char *good;
1301
1302 if (req_comp == img_n) return data;
1303 STBI_ASSERT(req_comp >= 1 && req_comp <= 4);
1304
1305 good = (unsigned char *) stbi__malloc_mad3(req_comp, x, y, 0);
1306 if (good == NULL) {
1307 STBI_FREE(data);
1308 return stbi__errpuc("outofmem", "Out of memory");
1309 }
1310
1311 for (j=0; j < (int) y; ++j) {
1312 unsigned char *src = data + j * x * img_n ;
1313 unsigned char *dest = good + j * x * req_comp;
1314
1315 #define STBI__COMBO(a,b) ((a)*8+(b))
1316 #define STBI__CASE(a,b) case STBI__COMBO(a,b): for(i=x-1; i >= 0; --i, src += a, dest += b)
1317 // convert source image with img_n components to one with req_comp components;
1318 // avoid switch per pixel, so use switch per scanline and massive macros
1319 switch (STBI__COMBO(img_n, req_comp)) {
1320 STBI__CASE(1,2) { dest[0]=src[0]; dest[1]=255; } break;
1321 STBI__CASE(1,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1322 STBI__CASE(1,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=255; } break;
1323 STBI__CASE(2,1) { dest[0]=src[0]; } break;
1324 STBI__CASE(2,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1325 STBI__CASE(2,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=src[1]; } break;
1326 STBI__CASE(3,4) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2];dest[3]=255; } break;
1327 STBI__CASE(3,1) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); } break;
1328 STBI__CASE(3,2) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); dest[1] = 255; } break;
1329 STBI__CASE(4,1) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); } break;
1330 STBI__CASE(4,2) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); dest[1] = src[3]; } break;
1331 STBI__CASE(4,3) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2]; } break;
1332 default: STBI_ASSERT(0); STBI_FREE(data); STBI_FREE(good); return stbi__errpuc("unsupported", "Unsupported format conversion");
1333 }
1334 #undef STBI__CASE
1335 }
1336
1337 STBI_FREE(data);
1338 return good;
1339}
1340#endif
1341
1342#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
1343// nothing
1344#else
1345static stbi__uint16 stbi__compute_y_16(int r, int g, int b)
1346{
1347 return (stbi__uint16) (((r*77) + (g*150) + (29*b)) >> 8);
1348}
1349#endif
1350
1351#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
1352// nothing
1353#else
1354static stbi__uint16 *stbi__convert_format16(stbi__uint16 *data, int img_n, int req_comp, unsigned int x, unsigned int y)
1355{
1356 int i,j;
1357 stbi__uint16 *good;
1358
1359 if (req_comp == img_n) return data;
1360 STBI_ASSERT(req_comp >= 1 && req_comp <= 4);
1361
1362 good = (stbi__uint16 *) stbi__malloc(req_comp * x * y * 2);
1363 if (good == NULL) {
1364 STBI_FREE(data);
1365 return (stbi__uint16 *) stbi__errpuc("outofmem", "Out of memory");
1366 }
1367
1368 for (j=0; j < (int) y; ++j) {
1369 stbi__uint16 *src = data + j * x * img_n ;
1370 stbi__uint16 *dest = good + j * x * req_comp;
1371
1372 #define STBI__COMBO(a,b) ((a)*8+(b))
1373 #define STBI__CASE(a,b) case STBI__COMBO(a,b): for(i=x-1; i >= 0; --i, src += a, dest += b)
1374 // convert source image with img_n components to one with req_comp components;
1375 // avoid switch per pixel, so use switch per scanline and massive macros
1376 switch (STBI__COMBO(img_n, req_comp)) {
1377 STBI__CASE(1,2) { dest[0]=src[0]; dest[1]=0xffff; } break;
1378 STBI__CASE(1,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1379 STBI__CASE(1,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=0xffff; } break;
1380 STBI__CASE(2,1) { dest[0]=src[0]; } break;
1381 STBI__CASE(2,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1382 STBI__CASE(2,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=src[1]; } break;
1383 STBI__CASE(3,4) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2];dest[3]=0xffff; } break;
1384 STBI__CASE(3,1) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); } break;
1385 STBI__CASE(3,2) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); dest[1] = 0xffff; } break;
1386 STBI__CASE(4,1) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); } break;
1387 STBI__CASE(4,2) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); dest[1] = src[3]; } break;
1388 STBI__CASE(4,3) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2]; } break;
1389 default: STBI_ASSERT(0); STBI_FREE(data); STBI_FREE(good); return (stbi__uint16*) stbi__errpuc("unsupported", "Unsupported format conversion");
1390 }
1391 #undef STBI__CASE
1392 }
1393
1394 STBI_FREE(data);
1395 return good;
1396}
1397#endif
1398
1399#ifndef STBI_NO_LINEAR
1400static float *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp)
1401{
1402 int i,k,n;
1403 float *output;
1404 if (!data) return NULL;
1405 output = (float *) stbi__malloc_mad4(x, y, comp, sizeof(float), 0);
1406 if (output == NULL) { STBI_FREE(data); return stbi__errpf("outofmem", "Out of memory"); }
1407 // compute number of non-alpha components
1408 if (comp & 1) n = comp; else n = comp-1;
1409 for (i=0; i < x*y; ++i) {
1410 for (k=0; k < n; ++k) {
1411 output[i*comp + k] = (float) (pow(data[i*comp+k]/255.0f, stbi__l2h_gamma) * stbi__l2h_scale);
1412 }
1413 }
1414 if (n < comp) {
1415 for (i=0; i < x*y; ++i) {
1416 output[i*comp + n] = data[i*comp + n]/255.0f;
1417 }
1418 }
1419 STBI_FREE(data);
1420 return output;
1421}
1422#endif
1423
1424#ifndef STBI_NO_HDR
1425#define stbi__float2int(x) ((int) (x))
1426static stbi_uc *stbi__hdr_to_ldr(float *data, int x, int y, int comp)
1427{
1428 int i,k,n;
1429 stbi_uc *output;
1430 if (!data) return NULL;
1431 output = (stbi_uc *) stbi__malloc_mad3(x, y, comp, 0);
1432 if (output == NULL) { STBI_FREE(data); return stbi__errpuc("outofmem", "Out of memory"); }
1433 // compute number of non-alpha components
1434 if (comp & 1) n = comp; else n = comp-1;
1435 for (i=0; i < x*y; ++i) {
1436 for (k=0; k < n; ++k) {
1437 float z = (float) pow(data[i*comp+k]*stbi__h2l_scale_i, stbi__h2l_gamma_i) * 255 + 0.5f;
1438 if (z < 0) z = 0;
1439 if (z > 255) z = 255;
1440 output[i*comp + k] = (stbi_uc) stbi__float2int(z);
1441 }
1442 if (k < comp) {
1443 float z = data[i*comp+k] * 255 + 0.5f;
1444 if (z < 0) z = 0;
1445 if (z > 255) z = 255;
1446 output[i*comp + k] = (stbi_uc) stbi__float2int(z);
1447 }
1448 }
1449 STBI_FREE(data);
1450 return output;
1451}
1452#endif
1453
1454//////////////////////////////////////////////////////////////////////////////
1455//
1456// "baseline" JPEG/JFIF decoder
1457//
1458// simple implementation
1459// - doesn't support delayed output of y-dimension
1460// - simple interface (only one output format: 8-bit interleaved RGB)
1461// - doesn't try to recover corrupt jpegs
1462// - doesn't allow partial loading, loading multiple at once
1463// - still fast on x86 (copying globals into locals doesn't help x86)
1464// - allocates lots of intermediate memory (full size of all components)
1465// - non-interleaved case requires this anyway
1466// - allows good upsampling (see next)
1467// high-quality
1468// - upsampled channels are bilinearly interpolated, even across blocks
1469// - quality integer IDCT derived from IJG's 'slow'
1470// performance
1471// - fast huffman; reasonable integer IDCT
1472// - some SIMD kernels for common paths on targets with SSE2/NEON
1473// - uses a lot of intermediate memory, could cache poorly
1474
1475#ifndef STBI_NO_JPEG
1476
1477// huffman decoding acceleration
1478#define FAST_BITS 9 // larger handles more cases; smaller stomps less cache
1479
1480typedef struct
1481{
1482 stbi_uc fast[1 << FAST_BITS];
1483 // weirdly, repacking this into AoS is a 10% speed loss, instead of a win
1484 stbi__uint16 code[256];
1485 stbi_uc values[256];
1486 stbi_uc size[257];
1487 unsigned int maxcode[18];
1488 int delta[17]; // old 'firstsymbol' - old 'firstcode'
1489} stbi__huffman;
1490
1491typedef struct
1492{
1493 stbi__context *s;
1494 stbi__huffman huff_dc[4];
1495 stbi__huffman huff_ac[4];
1496 stbi__uint16 dequant[4][64];
1497 stbi__int16 fast_ac[4][1 << FAST_BITS];
1498
1499// sizes for components, interleaved MCUs
1500 int img_h_max, img_v_max;
1501 int img_mcu_x, img_mcu_y;
1502 int img_mcu_w, img_mcu_h;
1503
1504// definition of jpeg image component
1505 struct
1506 {
1507 int id;
1508 int h,v;
1509 int tq;
1510 int hd,ha;
1511 int dc_pred;
1512
1513 int x,y,w2,h2;
1514 stbi_uc *data;
1515 void *raw_data, *raw_coeff;
1516 stbi_uc *linebuf;
1517 short *coeff; // progressive only
1518 int coeff_w, coeff_h; // number of 8x8 coefficient blocks
1519 } img_comp[4];
1520
1521 stbi__uint32 code_buffer; // jpeg entropy-coded buffer
1522 int code_bits; // number of valid bits
1523 unsigned char marker; // marker seen while filling entropy buffer
1524 int nomore; // flag if we saw a marker so must stop
1525
1526 int progressive;
1527 int spec_start;
1528 int spec_end;
1529 int succ_high;
1530 int succ_low;
1531 int eob_run;
1532 int jfif;
1533 int app14_color_transform; // Adobe APP14 tag
1534 int rgb;
1535
1536 int scan_n, order[4];
1537 int restart_interval, todo;
1538
1539// kernels
1540 void (*idct_block_kernel)(stbi_uc *out, int out_stride, short data[64]);
1541 void (*YCbCr_to_RGB_kernel)(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step);
1542 stbi_uc *(*resample_row_hv_2_kernel)(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs);
1543} stbi__jpeg;
1544
1545static int stbi__build_huffman(stbi__huffman *h, int *count)
1546{
1547 int i,j,k=0;
1548 unsigned int code;
1549 // build size list for each symbol (from JPEG spec)
1550 for (i=0; i < 16; ++i) {
1551 for (j=0; j < count[i]; ++j) {
1552 h->size[k++] = (stbi_uc) (i+1);
1553 if(k >= 257) return stbi__err("bad size list","Corrupt JPEG");
1554 }
1555 }
1556 h->size[k] = 0;
1557
1558 // compute actual symbols (from jpeg spec)
1559 code = 0;
1560 k = 0;
1561 for(j=1; j <= 16; ++j) {
1562 // compute delta to add to code to compute symbol id
1563 h->delta[j] = k - code;
1564 if (h->size[k] == j) {
1565 while (h->size[k] == j)
1566 h->code[k++] = (stbi__uint16) (code++);
1567 if (code-1 >= (1u << j)) return stbi__err("bad code lengths","Corrupt JPEG");
1568 }
1569 // compute largest code + 1 for this size, preshifted as needed later
1570 h->maxcode[j] = code << (16-j);
1571 code <<= 1;
1572 }
1573 h->maxcode[j] = 0xffffffff;
1574
1575 // build non-spec acceleration table; 255 is flag for not-accelerated
1576 memset(h->fast, 255, 1 << FAST_BITS);
1577 for (i=0; i < k; ++i) {
1578 int s = h->size[i];
1579 if (s <= FAST_BITS) {
1580 int c = h->code[i] << (FAST_BITS-s);
1581 int m = 1 << (FAST_BITS-s);
1582 for (j=0; j < m; ++j) {
1583 h->fast[c+j] = (stbi_uc) i;
1584 }
1585 }
1586 }
1587 return 1;
1588}
1589
1590// build a table that decodes both magnitude and value of small ACs in
1591// one go.
1592static void stbi__build_fast_ac(stbi__int16 *fast_ac, stbi__huffman *h)
1593{
1594 int i;
1595 for (i=0; i < (1 << FAST_BITS); ++i) {
1596 stbi_uc fast = h->fast[i];
1597 fast_ac[i] = 0;
1598 if (fast < 255) {
1599 int rs = h->values[fast];
1600 int run = (rs >> 4) & 15;
1601 int magbits = rs & 15;
1602 int len = h->size[fast];
1603
1604 if (magbits && len + magbits <= FAST_BITS) {
1605 // magnitude code followed by receive_extend code
1606 int k = ((i << len) & ((1 << FAST_BITS) - 1)) >> (FAST_BITS - magbits);
1607 int m = 1 << (magbits - 1);
1608 if (k < m) k += (~0U << magbits) + 1;
1609 // if the result is small enough, we can fit it in fast_ac table
1610 if (k >= -128 && k <= 127)
1611 fast_ac[i] = (stbi__int16) ((k * 256) + (run * 16) + (len + magbits));
1612 }
1613 }
1614 }
1615}
1616
1617static void stbi__grow_buffer_unsafe(stbi__jpeg *j)
1618{
1619 do {
1620 unsigned int b = j->nomore ? 0 : stbi__get8(j->s);
1621 if (b == 0xff) {
1622 int c = stbi__get8(j->s);
1623 while (c == 0xff) c = stbi__get8(j->s); // consume fill bytes
1624 if (c != 0) {
1625 j->marker = (unsigned char) c;
1626 j->nomore = 1;
1627 return;
1628 }
1629 }
1630 j->code_buffer |= b << (24 - j->code_bits);
1631 j->code_bits += 8;
1632 } while (j->code_bits <= 24);
1633}
1634
1635// (1 << n) - 1
1636static const stbi__uint32 stbi__bmask[17]={0,1,3,7,15,31,63,127,255,511,1023,2047,4095,8191,16383,32767,65535};
1637
1638// decode a jpeg huffman value from the bitstream
1639stbi_inline static int stbi__jpeg_huff_decode(stbi__jpeg *j, stbi__huffman *h)
1640{
1641 unsigned int temp;
1642 int c,k;
1643
1644 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
1645
1646 // look at the top FAST_BITS and determine what symbol ID it is,
1647 // if the code is <= FAST_BITS
1648 c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
1649 k = h->fast[c];
1650 if (k < 255) {
1651 int s = h->size[k];
1652 if (s > j->code_bits)
1653 return -1;
1654 j->code_buffer <<= s;
1655 j->code_bits -= s;
1656 return h->values[k];
1657 }
1658
1659 // naive test is to shift the code_buffer down so k bits are
1660 // valid, then test against maxcode. To speed this up, we've
1661 // preshifted maxcode left so that it has (16-k) 0s at the
1662 // end; in other words, regardless of the number of bits, it
1663 // wants to be compared against something shifted to have 16;
1664 // that way we don't need to shift inside the loop.
1665 temp = j->code_buffer >> 16;
1666 for (k=FAST_BITS+1 ; ; ++k)
1667 if (temp < h->maxcode[k])
1668 break;
1669 if (k == 17) {
1670 // error! code not found
1671 j->code_bits -= 16;
1672 return -1;
1673 }
1674
1675 if (k > j->code_bits)
1676 return -1;
1677
1678 // convert the huffman code to the symbol id
1679 c = ((j->code_buffer >> (32 - k)) & stbi__bmask[k]) + h->delta[k];
1680 if(c < 0 || c >= 256) // symbol id out of bounds!
1681 return -1;
1682 STBI_ASSERT((((j->code_buffer) >> (32 - h->size[c])) & stbi__bmask[h->size[c]]) == h->code[c]);
1683
1684 // convert the id to a symbol
1685 j->code_bits -= k;
1686 j->code_buffer <<= k;
1687 return h->values[c];
1688}
1689
1690// bias[n] = (-1<<n) + 1
1691static const int stbi__jbias[16] = {0,-1,-3,-7,-15,-31,-63,-127,-255,-511,-1023,-2047,-4095,-8191,-16383,-32767};
1692
1693// combined JPEG 'receive' and JPEG 'extend', since baseline
1694// always extends everything it receives.
1695stbi_inline static int stbi__extend_receive(stbi__jpeg *j, int n)
1696{
1697 unsigned int k;
1698 int sgn;
1699 if (j->code_bits < n) stbi__grow_buffer_unsafe(j);
1700 if (j->code_bits < n) return 0; // ran out of bits from stream, return 0s intead of continuing
1701
1702 sgn = j->code_buffer >> 31; // sign bit always in MSB; 0 if MSB clear (positive), 1 if MSB set (negative)
1703 k = stbi_lrot(j->code_buffer, n);
1704 j->code_buffer = k & ~stbi__bmask[n];
1705 k &= stbi__bmask[n];
1706 j->code_bits -= n;
1707 return k + (stbi__jbias[n] & (sgn - 1));
1708}
1709
1710// get some unsigned bits
1711stbi_inline static int stbi__jpeg_get_bits(stbi__jpeg *j, int n)
1712{
1713 unsigned int k;
1714 if (j->code_bits < n) stbi__grow_buffer_unsafe(j);
1715 if (j->code_bits < n) return 0; // ran out of bits from stream, return 0s intead of continuing
1716 k = stbi_lrot(j->code_buffer, n);
1717 j->code_buffer = k & ~stbi__bmask[n];
1718 k &= stbi__bmask[n];
1719 j->code_bits -= n;
1720 return k;
1721}
1722
1723stbi_inline static int stbi__jpeg_get_bit(stbi__jpeg *j)
1724{
1725 unsigned int k;
1726 if (j->code_bits < 1) stbi__grow_buffer_unsafe(j);
1727 if (j->code_bits < 1) return 0; // ran out of bits from stream, return 0s intead of continuing
1728 k = j->code_buffer;
1729 j->code_buffer <<= 1;
1730 --j->code_bits;
1731 return k & 0x80000000;
1732}
1733
1734// given a value that's at position X in the zigzag stream,
1735// where does it appear in the 8x8 matrix coded as row-major?
1736static const stbi_uc stbi__jpeg_dezigzag[64+15] =
1737{
1738 0, 1, 8, 16, 9, 2, 3, 10,
1739 17, 24, 32, 25, 18, 11, 4, 5,
1740 12, 19, 26, 33, 40, 48, 41, 34,
1741 27, 20, 13, 6, 7, 14, 21, 28,
1742 35, 42, 49, 56, 57, 50, 43, 36,
1743 29, 22, 15, 23, 30, 37, 44, 51,
1744 58, 59, 52, 45, 38, 31, 39, 46,
1745 53, 60, 61, 54, 47, 55, 62, 63,
1746 // let corrupt input sample past end
1747 63, 63, 63, 63, 63, 63, 63, 63,
1748 63, 63, 63, 63, 63, 63, 63
1749};
1750
1751// decode one 64-entry block--
1752static int stbi__jpeg_decode_block(stbi__jpeg *j, short data[64], stbi__huffman *hdc, stbi__huffman *hac, stbi__int16 *fac, int b, stbi__uint16 *dequant)
1753{
1754 int diff,dc,k;
1755 int t;
1756
1757 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
1758 t = stbi__jpeg_huff_decode(j, hdc);
1759 if (t < 0 || t > 15) return stbi__err("bad huffman code","Corrupt JPEG");
1760
1761 // 0 all the ac values now so we can do it 32-bits at a time
1762 memset(data,0,64*sizeof(data[0]));
1763
1764 diff = t ? stbi__extend_receive(j, t) : 0;
1765 if (!stbi__addints_valid(j->img_comp[b].dc_pred, diff)) return stbi__err("bad delta","Corrupt JPEG");
1766 dc = j->img_comp[b].dc_pred + diff;
1767 j->img_comp[b].dc_pred = dc;
1768 if (!stbi__mul2shorts_valid(dc, dequant[0])) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
1769 data[0] = (short) (dc * dequant[0]);
1770
1771 // decode AC components, see JPEG spec
1772 k = 1;
1773 do {
1774 unsigned int zig;
1775 int c,r,s;
1776 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
1777 c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
1778 r = fac[c];
1779 if (r) { // fast-AC path
1780 k += (r >> 4) & 15; // run
1781 s = r & 15; // combined length
1782 if (s > j->code_bits) return stbi__err("bad huffman code", "Combined length longer than code bits available");
1783 j->code_buffer <<= s;
1784 j->code_bits -= s;
1785 // decode into unzigzag'd location
1786 zig = stbi__jpeg_dezigzag[k++];
1787 data[zig] = (short) ((r >> 8) * dequant[zig]);
1788 } else {
1789 int rs = stbi__jpeg_huff_decode(j, hac);
1790 if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
1791 s = rs & 15;
1792 r = rs >> 4;
1793 if (s == 0) {
1794 if (rs != 0xf0) break; // end block
1795 k += 16;
1796 } else {
1797 k += r;
1798 // decode into unzigzag'd location
1799 zig = stbi__jpeg_dezigzag[k++];
1800 data[zig] = (short) (stbi__extend_receive(j,s) * dequant[zig]);
1801 }
1802 }
1803 } while (k < 64);
1804 return 1;
1805}
1806
1807static int stbi__jpeg_decode_block_prog_dc(stbi__jpeg *j, short data[64], stbi__huffman *hdc, int b)
1808{
1809 int diff,dc;
1810 int t;
1811 if (j->spec_end != 0) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
1812
1813 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
1814
1815 if (j->succ_high == 0) {
1816 // first scan for DC coefficient, must be first
1817 memset(data,0,64*sizeof(data[0])); // 0 all the ac values now
1818 t = stbi__jpeg_huff_decode(j, hdc);
1819 if (t < 0 || t > 15) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
1820 diff = t ? stbi__extend_receive(j, t) : 0;
1821
1822 if (!stbi__addints_valid(j->img_comp[b].dc_pred, diff)) return stbi__err("bad delta", "Corrupt JPEG");
1823 dc = j->img_comp[b].dc_pred + diff;
1824 j->img_comp[b].dc_pred = dc;
1825 if (!stbi__mul2shorts_valid(dc, 1 << j->succ_low)) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
1826 data[0] = (short) (dc * (1 << j->succ_low));
1827 } else {
1828 // refinement scan for DC coefficient
1829 if (stbi__jpeg_get_bit(j))
1830 data[0] += (short) (1 << j->succ_low);
1831 }
1832 return 1;
1833}
1834
1835// @OPTIMIZE: store non-zigzagged during the decode passes,
1836// and only de-zigzag when dequantizing
1837static int stbi__jpeg_decode_block_prog_ac(stbi__jpeg *j, short data[64], stbi__huffman *hac, stbi__int16 *fac)
1838{
1839 int k;
1840 if (j->spec_start == 0) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
1841
1842 if (j->succ_high == 0) {
1843 int shift = j->succ_low;
1844
1845 if (j->eob_run) {
1846 --j->eob_run;
1847 return 1;
1848 }
1849
1850 k = j->spec_start;
1851 do {
1852 unsigned int zig;
1853 int c,r,s;
1854 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
1855 c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
1856 r = fac[c];
1857 if (r) { // fast-AC path
1858 k += (r >> 4) & 15; // run
1859 s = r & 15; // combined length
1860 if (s > j->code_bits) return stbi__err("bad huffman code", "Combined length longer than code bits available");
1861 j->code_buffer <<= s;
1862 j->code_bits -= s;
1863 zig = stbi__jpeg_dezigzag[k++];
1864 data[zig] = (short) ((r >> 8) * (1 << shift));
1865 } else {
1866 int rs = stbi__jpeg_huff_decode(j, hac);
1867 if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
1868 s = rs & 15;
1869 r = rs >> 4;
1870 if (s == 0) {
1871 if (r < 15) {
1872 j->eob_run = (1 << r);
1873 if (r)
1874 j->eob_run += stbi__jpeg_get_bits(j, r);
1875 --j->eob_run;
1876 break;
1877 }
1878 k += 16;
1879 } else {
1880 k += r;
1881 zig = stbi__jpeg_dezigzag[k++];
1882 data[zig] = (short) (stbi__extend_receive(j,s) * (1 << shift));
1883 }
1884 }
1885 } while (k <= j->spec_end);
1886 } else {
1887 // refinement scan for these AC coefficients
1888
1889 short bit = (short) (1 << j->succ_low);
1890
1891 if (j->eob_run) {
1892 --j->eob_run;
1893 for (k = j->spec_start; k <= j->spec_end; ++k) {
1894 short *p = &data[stbi__jpeg_dezigzag[k]];
1895 if (*p != 0)
1896 if (stbi__jpeg_get_bit(j))
1897 if ((*p & bit)==0) {
1898 if (*p > 0)
1899 *p += bit;
1900 else
1901 *p -= bit;
1902 }
1903 }
1904 } else {
1905 k = j->spec_start;
1906 do {
1907 int r,s;
1908 int rs = stbi__jpeg_huff_decode(j, hac); // @OPTIMIZE see if we can use the fast path here, advance-by-r is so slow, eh
1909 if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
1910 s = rs & 15;
1911 r = rs >> 4;
1912 if (s == 0) {
1913 if (r < 15) {
1914 j->eob_run = (1 << r) - 1;
1915 if (r)
1916 j->eob_run += stbi__jpeg_get_bits(j, r);
1917 r = 64; // force end of block
1918 } else {
1919 // r=15 s=0 should write 16 0s, so we just do
1920 // a run of 15 0s and then write s (which is 0),
1921 // so we don't have to do anything special here
1922 }
1923 } else {
1924 if (s != 1) return stbi__err("bad huffman code", "Corrupt JPEG");
1925 // sign bit
1926 if (stbi__jpeg_get_bit(j))
1927 s = bit;
1928 else
1929 s = -bit;
1930 }
1931
1932 // advance by r
1933 while (k <= j->spec_end) {
1934 short *p = &data[stbi__jpeg_dezigzag[k++]];
1935 if (*p != 0) {
1936 if (stbi__jpeg_get_bit(j))
1937 if ((*p & bit)==0) {
1938 if (*p > 0)
1939 *p += bit;
1940 else
1941 *p -= bit;
1942 }
1943 } else {
1944 if (r == 0) {
1945 *p = (short) s;
1946 break;
1947 }
1948 --r;
1949 }
1950 }
1951 } while (k <= j->spec_end);
1952 }
1953 }
1954 return 1;
1955}
1956
1957// take a -128..127 value and stbi__clamp it and convert to 0..255
1958stbi_inline static stbi_uc stbi__clamp(int x)
1959{
1960 // trick to use a single test to catch both cases
1961 if ((unsigned int) x > 255) {
1962 if (x < 0) return 0;
1963 if (x > 255) return 255;
1964 }
1965 return (stbi_uc) x;
1966}
1967
1968#define stbi__f2f(x) ((int) (((x) * 4096 + 0.5)))
1969#define stbi__fsh(x) ((x) * 4096)
1970
1971// derived from jidctint -- DCT_ISLOW
1972#define STBI__IDCT_1D(s0,s1,s2,s3,s4,s5,s6,s7) \
1973 int t0,t1,t2,t3,p1,p2,p3,p4,p5,x0,x1,x2,x3; \
1974 p2 = s2; \
1975 p3 = s6; \
1976 p1 = (p2+p3) * stbi__f2f(0.5411961f); \
1977 t2 = p1 + p3*stbi__f2f(-1.847759065f); \
1978 t3 = p1 + p2*stbi__f2f( 0.765366865f); \
1979 p2 = s0; \
1980 p3 = s4; \
1981 t0 = stbi__fsh(p2+p3); \
1982 t1 = stbi__fsh(p2-p3); \
1983 x0 = t0+t3; \
1984 x3 = t0-t3; \
1985 x1 = t1+t2; \
1986 x2 = t1-t2; \
1987 t0 = s7; \
1988 t1 = s5; \
1989 t2 = s3; \
1990 t3 = s1; \
1991 p3 = t0+t2; \
1992 p4 = t1+t3; \
1993 p1 = t0+t3; \
1994 p2 = t1+t2; \
1995 p5 = (p3+p4)*stbi__f2f( 1.175875602f); \
1996 t0 = t0*stbi__f2f( 0.298631336f); \
1997 t1 = t1*stbi__f2f( 2.053119869f); \
1998 t2 = t2*stbi__f2f( 3.072711026f); \
1999 t3 = t3*stbi__f2f( 1.501321110f); \
2000 p1 = p5 + p1*stbi__f2f(-0.899976223f); \
2001 p2 = p5 + p2*stbi__f2f(-2.562915447f); \
2002 p3 = p3*stbi__f2f(-1.961570560f); \
2003 p4 = p4*stbi__f2f(-0.390180644f); \
2004 t3 += p1+p4; \
2005 t2 += p2+p3; \
2006 t1 += p2+p4; \
2007 t0 += p1+p3;
2008
2009static void stbi__idct_block(stbi_uc *out, int out_stride, short data[64])
2010{
2011 int i,val[64],*v=val;
2012 stbi_uc *o;
2013 short *d = data;
2014
2015 // columns
2016 for (i=0; i < 8; ++i,++d, ++v) {
2017 // if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing
2018 if (d[ 8]==0 && d[16]==0 && d[24]==0 && d[32]==0
2019 && d[40]==0 && d[48]==0 && d[56]==0) {
2020 // no shortcut 0 seconds
2021 // (1|2|3|4|5|6|7)==0 0 seconds
2022 // all separate -0.047 seconds
2023 // 1 && 2|3 && 4|5 && 6|7: -0.047 seconds
2024 int dcterm = d[0]*4;
2025 v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm;
2026 } else {
2027 STBI__IDCT_1D(d[ 0],d[ 8],d[16],d[24],d[32],d[40],d[48],d[56])
2028 // constants scaled things up by 1<<12; let's bring them back
2029 // down, but keep 2 extra bits of precision
2030 x0 += 512; x1 += 512; x2 += 512; x3 += 512;
2031 v[ 0] = (x0+t3) >> 10;
2032 v[56] = (x0-t3) >> 10;
2033 v[ 8] = (x1+t2) >> 10;
2034 v[48] = (x1-t2) >> 10;
2035 v[16] = (x2+t1) >> 10;
2036 v[40] = (x2-t1) >> 10;
2037 v[24] = (x3+t0) >> 10;
2038 v[32] = (x3-t0) >> 10;
2039 }
2040 }
2041
2042 for (i=0, v=val, o=out; i < 8; ++i,v+=8,o+=out_stride) {
2043 // no fast case since the first 1D IDCT spread components out
2044 STBI__IDCT_1D(v[0],v[1],v[2],v[3],v[4],v[5],v[6],v[7])
2045 // constants scaled things up by 1<<12, plus we had 1<<2 from first
2046 // loop, plus horizontal and vertical each scale by sqrt(8) so together
2047 // we've got an extra 1<<3, so 1<<17 total we need to remove.
2048 // so we want to round that, which means adding 0.5 * 1<<17,
2049 // aka 65536. Also, we'll end up with -128 to 127 that we want
2050 // to encode as 0..255 by adding 128, so we'll add that before the shift
2051 x0 += 65536 + (128<<17);
2052 x1 += 65536 + (128<<17);
2053 x2 += 65536 + (128<<17);
2054 x3 += 65536 + (128<<17);
2055 // tried computing the shifts into temps, or'ing the temps to see
2056 // if any were out of range, but that was slower
2057 o[0] = stbi__clamp((x0+t3) >> 17);
2058 o[7] = stbi__clamp((x0-t3) >> 17);
2059 o[1] = stbi__clamp((x1+t2) >> 17);
2060 o[6] = stbi__clamp((x1-t2) >> 17);
2061 o[2] = stbi__clamp((x2+t1) >> 17);
2062 o[5] = stbi__clamp((x2-t1) >> 17);
2063 o[3] = stbi__clamp((x3+t0) >> 17);
2064 o[4] = stbi__clamp((x3-t0) >> 17);
2065 }
2066}
2067
2068#ifdef STBI_SSE2
2069// sse2 integer IDCT. not the fastest possible implementation but it
2070// produces bit-identical results to the generic C version so it's
2071// fully "transparent".
2072static void stbi__idct_simd(stbi_uc *out, int out_stride, short data[64])
2073{
2074 // This is constructed to match our regular (generic) integer IDCT exactly.
2075 __m128i row0, row1, row2, row3, row4, row5, row6, row7;
2076 __m128i tmp;
2077
2078 // dot product constant: even elems=x, odd elems=y
2079 #define dct_const(x,y) _mm_setr_epi16((x),(y),(x),(y),(x),(y),(x),(y))
2080
2081 // out(0) = c0[even]*x + c0[odd]*y (c0, x, y 16-bit, out 32-bit)
2082 // out(1) = c1[even]*x + c1[odd]*y
2083 #define dct_rot(out0,out1, x,y,c0,c1) \
2084 __m128i c0##lo = _mm_unpacklo_epi16((x),(y)); \
2085 __m128i c0##hi = _mm_unpackhi_epi16((x),(y)); \
2086 __m128i out0##_l = _mm_madd_epi16(c0##lo, c0); \
2087 __m128i out0##_h = _mm_madd_epi16(c0##hi, c0); \
2088 __m128i out1##_l = _mm_madd_epi16(c0##lo, c1); \
2089 __m128i out1##_h = _mm_madd_epi16(c0##hi, c1)
2090
2091 // out = in << 12 (in 16-bit, out 32-bit)
2092 #define dct_widen(out, in) \
2093 __m128i out##_l = _mm_srai_epi32(_mm_unpacklo_epi16(_mm_setzero_si128(), (in)), 4); \
2094 __m128i out##_h = _mm_srai_epi32(_mm_unpackhi_epi16(_mm_setzero_si128(), (in)), 4)
2095
2096 // wide add
2097 #define dct_wadd(out, a, b) \
2098 __m128i out##_l = _mm_add_epi32(a##_l, b##_l); \
2099 __m128i out##_h = _mm_add_epi32(a##_h, b##_h)
2100
2101 // wide sub
2102 #define dct_wsub(out, a, b) \
2103 __m128i out##_l = _mm_sub_epi32(a##_l, b##_l); \
2104 __m128i out##_h = _mm_sub_epi32(a##_h, b##_h)
2105
2106 // butterfly a/b, add bias, then shift by "s" and pack
2107 #define dct_bfly32o(out0, out1, a,b,bias,s) \
2108 { \
2109 __m128i abiased_l = _mm_add_epi32(a##_l, bias); \
2110 __m128i abiased_h = _mm_add_epi32(a##_h, bias); \
2111 dct_wadd(sum, abiased, b); \
2112 dct_wsub(dif, abiased, b); \
2113 out0 = _mm_packs_epi32(_mm_srai_epi32(sum_l, s), _mm_srai_epi32(sum_h, s)); \
2114 out1 = _mm_packs_epi32(_mm_srai_epi32(dif_l, s), _mm_srai_epi32(dif_h, s)); \
2115 }
2116
2117 // 8-bit interleave step (for transposes)
2118 #define dct_interleave8(a, b) \
2119 tmp = a; \
2120 a = _mm_unpacklo_epi8(a, b); \
2121 b = _mm_unpackhi_epi8(tmp, b)
2122
2123 // 16-bit interleave step (for transposes)
2124 #define dct_interleave16(a, b) \
2125 tmp = a; \
2126 a = _mm_unpacklo_epi16(a, b); \
2127 b = _mm_unpackhi_epi16(tmp, b)
2128
2129 #define dct_pass(bias,shift) \
2130 { \
2131 /* even part */ \
2132 dct_rot(t2e,t3e, row2,row6, rot0_0,rot0_1); \
2133 __m128i sum04 = _mm_add_epi16(row0, row4); \
2134 __m128i dif04 = _mm_sub_epi16(row0, row4); \
2135 dct_widen(t0e, sum04); \
2136 dct_widen(t1e, dif04); \
2137 dct_wadd(x0, t0e, t3e); \
2138 dct_wsub(x3, t0e, t3e); \
2139 dct_wadd(x1, t1e, t2e); \
2140 dct_wsub(x2, t1e, t2e); \
2141 /* odd part */ \
2142 dct_rot(y0o,y2o, row7,row3, rot2_0,rot2_1); \
2143 dct_rot(y1o,y3o, row5,row1, rot3_0,rot3_1); \
2144 __m128i sum17 = _mm_add_epi16(row1, row7); \
2145 __m128i sum35 = _mm_add_epi16(row3, row5); \
2146 dct_rot(y4o,y5o, sum17,sum35, rot1_0,rot1_1); \
2147 dct_wadd(x4, y0o, y4o); \
2148 dct_wadd(x5, y1o, y5o); \
2149 dct_wadd(x6, y2o, y5o); \
2150 dct_wadd(x7, y3o, y4o); \
2151 dct_bfly32o(row0,row7, x0,x7,bias,shift); \
2152 dct_bfly32o(row1,row6, x1,x6,bias,shift); \
2153 dct_bfly32o(row2,row5, x2,x5,bias,shift); \
2154 dct_bfly32o(row3,row4, x3,x4,bias,shift); \
2155 }
2156
2157 __m128i rot0_0 = dct_const(stbi__f2f(0.5411961f), stbi__f2f(0.5411961f) + stbi__f2f(-1.847759065f));
2158 __m128i rot0_1 = dct_const(stbi__f2f(0.5411961f) + stbi__f2f( 0.765366865f), stbi__f2f(0.5411961f));
2159 __m128i rot1_0 = dct_const(stbi__f2f(1.175875602f) + stbi__f2f(-0.899976223f), stbi__f2f(1.175875602f));
2160 __m128i rot1_1 = dct_const(stbi__f2f(1.175875602f), stbi__f2f(1.175875602f) + stbi__f2f(-2.562915447f));
2161 __m128i rot2_0 = dct_const(stbi__f2f(-1.961570560f) + stbi__f2f( 0.298631336f), stbi__f2f(-1.961570560f));
2162 __m128i rot2_1 = dct_const(stbi__f2f(-1.961570560f), stbi__f2f(-1.961570560f) + stbi__f2f( 3.072711026f));
2163 __m128i rot3_0 = dct_const(stbi__f2f(-0.390180644f) + stbi__f2f( 2.053119869f), stbi__f2f(-0.390180644f));
2164 __m128i rot3_1 = dct_const(stbi__f2f(-0.390180644f), stbi__f2f(-0.390180644f) + stbi__f2f( 1.501321110f));
2165
2166 // rounding biases in column/row passes, see stbi__idct_block for explanation.
2167 __m128i bias_0 = _mm_set1_epi32(512);
2168 __m128i bias_1 = _mm_set1_epi32(65536 + (128<<17));
2169
2170 // load
2171 row0 = _mm_load_si128((const __m128i *) (data + 0*8));
2172 row1 = _mm_load_si128((const __m128i *) (data + 1*8));
2173 row2 = _mm_load_si128((const __m128i *) (data + 2*8));
2174 row3 = _mm_load_si128((const __m128i *) (data + 3*8));
2175 row4 = _mm_load_si128((const __m128i *) (data + 4*8));
2176 row5 = _mm_load_si128((const __m128i *) (data + 5*8));
2177 row6 = _mm_load_si128((const __m128i *) (data + 6*8));
2178 row7 = _mm_load_si128((const __m128i *) (data + 7*8));
2179
2180 // column pass
2181 dct_pass(bias_0, 10);
2182
2183 {
2184 // 16bit 8x8 transpose pass 1
2185 dct_interleave16(row0, row4);
2186 dct_interleave16(row1, row5);
2187 dct_interleave16(row2, row6);
2188 dct_interleave16(row3, row7);
2189
2190 // transpose pass 2
2191 dct_interleave16(row0, row2);
2192 dct_interleave16(row1, row3);
2193 dct_interleave16(row4, row6);
2194 dct_interleave16(row5, row7);
2195
2196 // transpose pass 3
2197 dct_interleave16(row0, row1);
2198 dct_interleave16(row2, row3);
2199 dct_interleave16(row4, row5);
2200 dct_interleave16(row6, row7);
2201 }
2202
2203 // row pass
2204 dct_pass(bias_1, 17);
2205
2206 {
2207 // pack
2208 __m128i p0 = _mm_packus_epi16(row0, row1); // a0a1a2a3...a7b0b1b2b3...b7
2209 __m128i p1 = _mm_packus_epi16(row2, row3);
2210 __m128i p2 = _mm_packus_epi16(row4, row5);
2211 __m128i p3 = _mm_packus_epi16(row6, row7);
2212
2213 // 8bit 8x8 transpose pass 1
2214 dct_interleave8(p0, p2); // a0e0a1e1...
2215 dct_interleave8(p1, p3); // c0g0c1g1...
2216
2217 // transpose pass 2
2218 dct_interleave8(p0, p1); // a0c0e0g0...
2219 dct_interleave8(p2, p3); // b0d0f0h0...
2220
2221 // transpose pass 3
2222 dct_interleave8(p0, p2); // a0b0c0d0...
2223 dct_interleave8(p1, p3); // a4b4c4d4...
2224
2225 // store
2226 _mm_storel_epi64((__m128i *) out, p0); out += out_stride;
2227 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p0, 0x4e)); out += out_stride;
2228 _mm_storel_epi64((__m128i *) out, p2); out += out_stride;
2229 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p2, 0x4e)); out += out_stride;
2230 _mm_storel_epi64((__m128i *) out, p1); out += out_stride;
2231 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p1, 0x4e)); out += out_stride;
2232 _mm_storel_epi64((__m128i *) out, p3); out += out_stride;
2233 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p3, 0x4e));
2234 }
2235
2236#undef dct_const
2237#undef dct_rot
2238#undef dct_widen
2239#undef dct_wadd
2240#undef dct_wsub
2241#undef dct_bfly32o
2242#undef dct_interleave8
2243#undef dct_interleave16
2244#undef dct_pass
2245}
2246
2247#endif // STBI_SSE2
2248
2249#ifdef STBI_NEON
2250
2251// NEON integer IDCT. should produce bit-identical
2252// results to the generic C version.
2253static void stbi__idct_simd(stbi_uc *out, int out_stride, short data[64])
2254{
2255 int16x8_t row0, row1, row2, row3, row4, row5, row6, row7;
2256
2257 int16x4_t rot0_0 = vdup_n_s16(stbi__f2f(0.5411961f));
2258 int16x4_t rot0_1 = vdup_n_s16(stbi__f2f(-1.847759065f));
2259 int16x4_t rot0_2 = vdup_n_s16(stbi__f2f( 0.765366865f));
2260 int16x4_t rot1_0 = vdup_n_s16(stbi__f2f( 1.175875602f));
2261 int16x4_t rot1_1 = vdup_n_s16(stbi__f2f(-0.899976223f));
2262 int16x4_t rot1_2 = vdup_n_s16(stbi__f2f(-2.562915447f));
2263 int16x4_t rot2_0 = vdup_n_s16(stbi__f2f(-1.961570560f));
2264 int16x4_t rot2_1 = vdup_n_s16(stbi__f2f(-0.390180644f));
2265 int16x4_t rot3_0 = vdup_n_s16(stbi__f2f( 0.298631336f));
2266 int16x4_t rot3_1 = vdup_n_s16(stbi__f2f( 2.053119869f));
2267 int16x4_t rot3_2 = vdup_n_s16(stbi__f2f( 3.072711026f));
2268 int16x4_t rot3_3 = vdup_n_s16(stbi__f2f( 1.501321110f));
2269
2270#define dct_long_mul(out, inq, coeff) \
2271 int32x4_t out##_l = vmull_s16(vget_low_s16(inq), coeff); \
2272 int32x4_t out##_h = vmull_s16(vget_high_s16(inq), coeff)
2273
2274#define dct_long_mac(out, acc, inq, coeff) \
2275 int32x4_t out##_l = vmlal_s16(acc##_l, vget_low_s16(inq), coeff); \
2276 int32x4_t out##_h = vmlal_s16(acc##_h, vget_high_s16(inq), coeff)
2277
2278#define dct_widen(out, inq) \
2279 int32x4_t out##_l = vshll_n_s16(vget_low_s16(inq), 12); \
2280 int32x4_t out##_h = vshll_n_s16(vget_high_s16(inq), 12)
2281
2282// wide add
2283#define dct_wadd(out, a, b) \
2284 int32x4_t out##_l = vaddq_s32(a##_l, b##_l); \
2285 int32x4_t out##_h = vaddq_s32(a##_h, b##_h)
2286
2287// wide sub
2288#define dct_wsub(out, a, b) \
2289 int32x4_t out##_l = vsubq_s32(a##_l, b##_l); \
2290 int32x4_t out##_h = vsubq_s32(a##_h, b##_h)
2291
2292// butterfly a/b, then shift using "shiftop" by "s" and pack
2293#define dct_bfly32o(out0,out1, a,b,shiftop,s) \
2294 { \
2295 dct_wadd(sum, a, b); \
2296 dct_wsub(dif, a, b); \
2297 out0 = vcombine_s16(shiftop(sum_l, s), shiftop(sum_h, s)); \
2298 out1 = vcombine_s16(shiftop(dif_l, s), shiftop(dif_h, s)); \
2299 }
2300
2301#define dct_pass(shiftop, shift) \
2302 { \
2303 /* even part */ \
2304 int16x8_t sum26 = vaddq_s16(row2, row6); \
2305 dct_long_mul(p1e, sum26, rot0_0); \
2306 dct_long_mac(t2e, p1e, row6, rot0_1); \
2307 dct_long_mac(t3e, p1e, row2, rot0_2); \
2308 int16x8_t sum04 = vaddq_s16(row0, row4); \
2309 int16x8_t dif04 = vsubq_s16(row0, row4); \
2310 dct_widen(t0e, sum04); \
2311 dct_widen(t1e, dif04); \
2312 dct_wadd(x0, t0e, t3e); \
2313 dct_wsub(x3, t0e, t3e); \
2314 dct_wadd(x1, t1e, t2e); \
2315 dct_wsub(x2, t1e, t2e); \
2316 /* odd part */ \
2317 int16x8_t sum15 = vaddq_s16(row1, row5); \
2318 int16x8_t sum17 = vaddq_s16(row1, row7); \
2319 int16x8_t sum35 = vaddq_s16(row3, row5); \
2320 int16x8_t sum37 = vaddq_s16(row3, row7); \
2321 int16x8_t sumodd = vaddq_s16(sum17, sum35); \
2322 dct_long_mul(p5o, sumodd, rot1_0); \
2323 dct_long_mac(p1o, p5o, sum17, rot1_1); \
2324 dct_long_mac(p2o, p5o, sum35, rot1_2); \
2325 dct_long_mul(p3o, sum37, rot2_0); \
2326 dct_long_mul(p4o, sum15, rot2_1); \
2327 dct_wadd(sump13o, p1o, p3o); \
2328 dct_wadd(sump24o, p2o, p4o); \
2329 dct_wadd(sump23o, p2o, p3o); \
2330 dct_wadd(sump14o, p1o, p4o); \
2331 dct_long_mac(x4, sump13o, row7, rot3_0); \
2332 dct_long_mac(x5, sump24o, row5, rot3_1); \
2333 dct_long_mac(x6, sump23o, row3, rot3_2); \
2334 dct_long_mac(x7, sump14o, row1, rot3_3); \
2335 dct_bfly32o(row0,row7, x0,x7,shiftop,shift); \
2336 dct_bfly32o(row1,row6, x1,x6,shiftop,shift); \
2337 dct_bfly32o(row2,row5, x2,x5,shiftop,shift); \
2338 dct_bfly32o(row3,row4, x3,x4,shiftop,shift); \
2339 }
2340
2341 // load
2342 row0 = vld1q_s16(data + 0*8);
2343 row1 = vld1q_s16(data + 1*8);
2344 row2 = vld1q_s16(data + 2*8);
2345 row3 = vld1q_s16(data + 3*8);
2346 row4 = vld1q_s16(data + 4*8);
2347 row5 = vld1q_s16(data + 5*8);
2348 row6 = vld1q_s16(data + 6*8);
2349 row7 = vld1q_s16(data + 7*8);
2350
2351 // add DC bias
2352 row0 = vaddq_s16(row0, vsetq_lane_s16(1024, vdupq_n_s16(0), 0));
2353
2354 // column pass
2355 dct_pass(vrshrn_n_s32, 10);
2356
2357 // 16bit 8x8 transpose
2358 {
2359// these three map to a single VTRN.16, VTRN.32, and VSWP, respectively.
2360// whether compilers actually get this is another story, sadly.
2361#define dct_trn16(x, y) { int16x8x2_t t = vtrnq_s16(x, y); x = t.val[0]; y = t.val[1]; }
2362#define dct_trn32(x, y) { int32x4x2_t t = vtrnq_s32(vreinterpretq_s32_s16(x), vreinterpretq_s32_s16(y)); x = vreinterpretq_s16_s32(t.val[0]); y = vreinterpretq_s16_s32(t.val[1]); }
2363#define dct_trn64(x, y) { int16x8_t x0 = x; int16x8_t y0 = y; x = vcombine_s16(vget_low_s16(x0), vget_low_s16(y0)); y = vcombine_s16(vget_high_s16(x0), vget_high_s16(y0)); }
2364
2365 // pass 1
2366 dct_trn16(row0, row1); // a0b0a2b2a4b4a6b6
2367 dct_trn16(row2, row3);
2368 dct_trn16(row4, row5);
2369 dct_trn16(row6, row7);
2370
2371 // pass 2
2372 dct_trn32(row0, row2); // a0b0c0d0a4b4c4d4
2373 dct_trn32(row1, row3);
2374 dct_trn32(row4, row6);
2375 dct_trn32(row5, row7);
2376
2377 // pass 3
2378 dct_trn64(row0, row4); // a0b0c0d0e0f0g0h0
2379 dct_trn64(row1, row5);
2380 dct_trn64(row2, row6);
2381 dct_trn64(row3, row7);
2382
2383#undef dct_trn16
2384#undef dct_trn32
2385#undef dct_trn64
2386 }
2387
2388 // row pass
2389 // vrshrn_n_s32 only supports shifts up to 16, we need
2390 // 17. so do a non-rounding shift of 16 first then follow
2391 // up with a rounding shift by 1.
2392 dct_pass(vshrn_n_s32, 16);
2393
2394 {
2395 // pack and round
2396 uint8x8_t p0 = vqrshrun_n_s16(row0, 1);
2397 uint8x8_t p1 = vqrshrun_n_s16(row1, 1);
2398 uint8x8_t p2 = vqrshrun_n_s16(row2, 1);
2399 uint8x8_t p3 = vqrshrun_n_s16(row3, 1);
2400 uint8x8_t p4 = vqrshrun_n_s16(row4, 1);
2401 uint8x8_t p5 = vqrshrun_n_s16(row5, 1);
2402 uint8x8_t p6 = vqrshrun_n_s16(row6, 1);
2403 uint8x8_t p7 = vqrshrun_n_s16(row7, 1);
2404
2405 // again, these can translate into one instruction, but often don't.
2406#define dct_trn8_8(x, y) { uint8x8x2_t t = vtrn_u8(x, y); x = t.val[0]; y = t.val[1]; }
2407#define dct_trn8_16(x, y) { uint16x4x2_t t = vtrn_u16(vreinterpret_u16_u8(x), vreinterpret_u16_u8(y)); x = vreinterpret_u8_u16(t.val[0]); y = vreinterpret_u8_u16(t.val[1]); }
2408#define dct_trn8_32(x, y) { uint32x2x2_t t = vtrn_u32(vreinterpret_u32_u8(x), vreinterpret_u32_u8(y)); x = vreinterpret_u8_u32(t.val[0]); y = vreinterpret_u8_u32(t.val[1]); }
2409
2410 // sadly can't use interleaved stores here since we only write
2411 // 8 bytes to each scan line!
2412
2413 // 8x8 8-bit transpose pass 1
2414 dct_trn8_8(p0, p1);
2415 dct_trn8_8(p2, p3);
2416 dct_trn8_8(p4, p5);
2417 dct_trn8_8(p6, p7);
2418
2419 // pass 2
2420 dct_trn8_16(p0, p2);
2421 dct_trn8_16(p1, p3);
2422 dct_trn8_16(p4, p6);
2423 dct_trn8_16(p5, p7);
2424
2425 // pass 3
2426 dct_trn8_32(p0, p4);
2427 dct_trn8_32(p1, p5);
2428 dct_trn8_32(p2, p6);
2429 dct_trn8_32(p3, p7);
2430
2431 // store
2432 vst1_u8(out, p0); out += out_stride;
2433 vst1_u8(out, p1); out += out_stride;
2434 vst1_u8(out, p2); out += out_stride;
2435 vst1_u8(out, p3); out += out_stride;
2436 vst1_u8(out, p4); out += out_stride;
2437 vst1_u8(out, p5); out += out_stride;
2438 vst1_u8(out, p6); out += out_stride;
2439 vst1_u8(out, p7);
2440
2441#undef dct_trn8_8
2442#undef dct_trn8_16
2443#undef dct_trn8_32
2444 }
2445
2446#undef dct_long_mul
2447#undef dct_long_mac
2448#undef dct_widen
2449#undef dct_wadd
2450#undef dct_wsub
2451#undef dct_bfly32o
2452#undef dct_pass
2453}
2454
2455#endif // STBI_NEON
2456
2457#define STBI__MARKER_none 0xff
2458// if there's a pending marker from the entropy stream, return that
2459// otherwise, fetch from the stream and get a marker. if there's no
2460// marker, return 0xff, which is never a valid marker value
2461static stbi_uc stbi__get_marker(stbi__jpeg *j)
2462{
2463 stbi_uc x;
2464 if (j->marker != STBI__MARKER_none) { x = j->marker; j->marker = STBI__MARKER_none; return x; }
2465 x = stbi__get8(j->s);
2466 if (x != 0xff) return STBI__MARKER_none;
2467 while (x == 0xff)
2468 x = stbi__get8(j->s); // consume repeated 0xff fill bytes
2469 return x;
2470}
2471
2472// in each scan, we'll have scan_n components, and the order
2473// of the components is specified by order[]
2474#define STBI__RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7)
2475
2476// after a restart interval, stbi__jpeg_reset the entropy decoder and
2477// the dc prediction
2478static void stbi__jpeg_reset(stbi__jpeg *j)
2479{
2480 j->code_bits = 0;
2481 j->code_buffer = 0;
2482 j->nomore = 0;
2483 j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = j->img_comp[3].dc_pred = 0;
2484 j->marker = STBI__MARKER_none;
2485 j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff;
2486 j->eob_run = 0;
2487 // no more than 1<<31 MCUs if no restart_interal? that's plenty safe,
2488 // since we don't even allow 1<<30 pixels
2489}
2490
2491static int stbi__parse_entropy_coded_data(stbi__jpeg *z)
2492{
2493 stbi__jpeg_reset(z);
2494 if (!z->progressive) {
2495 if (z->scan_n == 1) {
2496 int i,j;
2497 STBI_SIMD_ALIGN(short, data[64]);
2498 int n = z->order[0];
2499 // non-interleaved data, we just need to process one block at a time,
2500 // in trivial scanline order
2501 // number of blocks to do just depends on how many actual "pixels" this
2502 // component has, independent of interleaved MCU blocking and such
2503 int w = (z->img_comp[n].x+7) >> 3;
2504 int h = (z->img_comp[n].y+7) >> 3;
2505 for (j=0; j < h; ++j) {
2506 for (i=0; i < w; ++i) {
2507 int ha = z->img_comp[n].ha;
2508 if (!stbi__jpeg_decode_block(z, data, z->huff_dc+z->img_comp[n].hd, z->huff_ac+ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq])) return 0;
2509 z->idct_block_kernel(z->img_comp[n].data+z->img_comp[n].w2*j*8+i*8, z->img_comp[n].w2, data);
2510 // every data block is an MCU, so countdown the restart interval
2511 if (--z->todo <= 0) {
2512 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
2513 // if it's NOT a restart, then just bail, so we get corrupt data
2514 // rather than no data
2515 if (!STBI__RESTART(z->marker)) return 1;
2516 stbi__jpeg_reset(z);
2517 }
2518 }
2519 }
2520 return 1;
2521 } else { // interleaved
2522 int i,j,k,x,y;
2523 STBI_SIMD_ALIGN(short, data[64]);
2524 for (j=0; j < z->img_mcu_y; ++j) {
2525 for (i=0; i < z->img_mcu_x; ++i) {
2526 // scan an interleaved mcu... process scan_n components in order
2527 for (k=0; k < z->scan_n; ++k) {
2528 int n = z->order[k];
2529 // scan out an mcu's worth of this component; that's just determined
2530 // by the basic H and V specified for the component
2531 for (y=0; y < z->img_comp[n].v; ++y) {
2532 for (x=0; x < z->img_comp[n].h; ++x) {
2533 int x2 = (i*z->img_comp[n].h + x)*8;
2534 int y2 = (j*z->img_comp[n].v + y)*8;
2535 int ha = z->img_comp[n].ha;
2536 if (!stbi__jpeg_decode_block(z, data, z->huff_dc+z->img_comp[n].hd, z->huff_ac+ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq])) return 0;
2537 z->idct_block_kernel(z->img_comp[n].data+z->img_comp[n].w2*y2+x2, z->img_comp[n].w2, data);
2538 }
2539 }
2540 }
2541 // after all interleaved components, that's an interleaved MCU,
2542 // so now count down the restart interval
2543 if (--z->todo <= 0) {
2544 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
2545 if (!STBI__RESTART(z->marker)) return 1;
2546 stbi__jpeg_reset(z);
2547 }
2548 }
2549 }
2550 return 1;
2551 }
2552 } else {
2553 if (z->scan_n == 1) {
2554 int i,j;
2555 int n = z->order[0];
2556 // non-interleaved data, we just need to process one block at a time,
2557 // in trivial scanline order
2558 // number of blocks to do just depends on how many actual "pixels" this
2559 // component has, independent of interleaved MCU blocking and such
2560 int w = (z->img_comp[n].x+7) >> 3;
2561 int h = (z->img_comp[n].y+7) >> 3;
2562 for (j=0; j < h; ++j) {
2563 for (i=0; i < w; ++i) {
2564 short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w);
2565 if (z->spec_start == 0) {
2566 if (!stbi__jpeg_decode_block_prog_dc(z, data, &z->huff_dc[z->img_comp[n].hd], n))
2567 return 0;
2568 } else {
2569 int ha = z->img_comp[n].ha;
2570 if (!stbi__jpeg_decode_block_prog_ac(z, data, &z->huff_ac[ha], z->fast_ac[ha]))
2571 return 0;
2572 }
2573 // every data block is an MCU, so countdown the restart interval
2574 if (--z->todo <= 0) {
2575 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
2576 if (!STBI__RESTART(z->marker)) return 1;
2577 stbi__jpeg_reset(z);
2578 }
2579 }
2580 }
2581 return 1;
2582 } else { // interleaved
2583 int i,j,k,x,y;
2584 for (j=0; j < z->img_mcu_y; ++j) {
2585 for (i=0; i < z->img_mcu_x; ++i) {
2586 // scan an interleaved mcu... process scan_n components in order
2587 for (k=0; k < z->scan_n; ++k) {
2588 int n = z->order[k];
2589 // scan out an mcu's worth of this component; that's just determined
2590 // by the basic H and V specified for the component
2591 for (y=0; y < z->img_comp[n].v; ++y) {
2592 for (x=0; x < z->img_comp[n].h; ++x) {
2593 int x2 = (i*z->img_comp[n].h + x);
2594 int y2 = (j*z->img_comp[n].v + y);
2595 short *data = z->img_comp[n].coeff + 64 * (x2 + y2 * z->img_comp[n].coeff_w);
2596 if (!stbi__jpeg_decode_block_prog_dc(z, data, &z->huff_dc[z->img_comp[n].hd], n))
2597 return 0;
2598 }
2599 }
2600 }
2601 // after all interleaved components, that's an interleaved MCU,
2602 // so now count down the restart interval
2603 if (--z->todo <= 0) {
2604 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
2605 if (!STBI__RESTART(z->marker)) return 1;
2606 stbi__jpeg_reset(z);
2607 }
2608 }
2609 }
2610 return 1;
2611 }
2612 }
2613}
2614
2615static void stbi__jpeg_dequantize(short *data, stbi__uint16 *dequant)
2616{
2617 int i;
2618 for (i=0; i < 64; ++i)
2619 data[i] *= dequant[i];
2620}
2621
2622static void stbi__jpeg_finish(stbi__jpeg *z)
2623{
2624 if (z->progressive) {
2625 // dequantize and idct the data
2626 int i,j,n;
2627 for (n=0; n < z->s->img_n; ++n) {
2628 int w = (z->img_comp[n].x+7) >> 3;
2629 int h = (z->img_comp[n].y+7) >> 3;
2630 for (j=0; j < h; ++j) {
2631 for (i=0; i < w; ++i) {
2632 short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w);
2633 stbi__jpeg_dequantize(data, z->dequant[z->img_comp[n].tq]);
2634 z->idct_block_kernel(z->img_comp[n].data+z->img_comp[n].w2*j*8+i*8, z->img_comp[n].w2, data);
2635 }
2636 }
2637 }
2638 }
2639}
2640
2641static int stbi__process_marker(stbi__jpeg *z, int m)
2642{
2643 int L;
2644 switch (m) {
2645 case STBI__MARKER_none: // no marker found
2646 return stbi__err("expected marker","Corrupt JPEG");
2647
2648 case 0xDD: // DRI - specify restart interval
2649 if (stbi__get16be(z->s) != 4) return stbi__err("bad DRI len","Corrupt JPEG");
2650 z->restart_interval = stbi__get16be(z->s);
2651 return 1;
2652
2653 case 0xDB: // DQT - define quantization table
2654 L = stbi__get16be(z->s)-2;
2655 while (L > 0) {
2656 int q = stbi__get8(z->s);
2657 int p = q >> 4, sixteen = (p != 0);
2658 int t = q & 15,i;
2659 if (p != 0 && p != 1) return stbi__err("bad DQT type","Corrupt JPEG");
2660 if (t > 3) return stbi__err("bad DQT table","Corrupt JPEG");
2661
2662 for (i=0; i < 64; ++i)
2663 z->dequant[t][stbi__jpeg_dezigzag[i]] = (stbi__uint16)(sixteen ? stbi__get16be(z->s) : stbi__get8(z->s));
2664 L -= (sixteen ? 129 : 65);
2665 }
2666 return L==0;
2667
2668 case 0xC4: // DHT - define huffman table
2669 L = stbi__get16be(z->s)-2;
2670 while (L > 0) {
2671 stbi_uc *v;
2672 int sizes[16],i,n=0;
2673 int q = stbi__get8(z->s);
2674 int tc = q >> 4;
2675 int th = q & 15;
2676 if (tc > 1 || th > 3) return stbi__err("bad DHT header","Corrupt JPEG");
2677 for (i=0; i < 16; ++i) {
2678 sizes[i] = stbi__get8(z->s);
2679 n += sizes[i];
2680 }
2681 if(n > 256) return stbi__err("bad DHT header","Corrupt JPEG"); // Loop over i < n would write past end of values!
2682 L -= 17;
2683 if (tc == 0) {
2684 if (!stbi__build_huffman(z->huff_dc+th, sizes)) return 0;
2685 v = z->huff_dc[th].values;
2686 } else {
2687 if (!stbi__build_huffman(z->huff_ac+th, sizes)) return 0;
2688 v = z->huff_ac[th].values;
2689 }
2690 for (i=0; i < n; ++i)
2691 v[i] = stbi__get8(z->s);
2692 if (tc != 0)
2693 stbi__build_fast_ac(z->fast_ac[th], z->huff_ac + th);
2694 L -= n;
2695 }
2696 return L==0;
2697 }
2698
2699 // check for comment block or APP blocks
2700 if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE) {
2701 L = stbi__get16be(z->s);
2702 if (L < 2) {
2703 if (m == 0xFE)
2704 return stbi__err("bad COM len","Corrupt JPEG");
2705 else
2706 return stbi__err("bad APP len","Corrupt JPEG");
2707 }
2708 L -= 2;
2709
2710 if (m == 0xE0 && L >= 5) { // JFIF APP0 segment
2711 static const unsigned char tag[5] = {'J','F','I','F','\0'};
2712 int ok = 1;
2713 int i;
2714 for (i=0; i < 5; ++i)
2715 if (stbi__get8(z->s) != tag[i])
2716 ok = 0;
2717 L -= 5;
2718 if (ok)
2719 z->jfif = 1;
2720 } else if (m == 0xEE && L >= 12) { // Adobe APP14 segment
2721 static const unsigned char tag[6] = {'A','d','o','b','e','\0'};
2722 int ok = 1;
2723 int i;
2724 for (i=0; i < 6; ++i)
2725 if (stbi__get8(z->s) != tag[i])
2726 ok = 0;
2727 L -= 6;
2728 if (ok) {
2729 stbi__get8(z->s); // version
2730 stbi__get16be(z->s); // flags0
2731 stbi__get16be(z->s); // flags1
2732 z->app14_color_transform = stbi__get8(z->s); // color transform
2733 L -= 6;
2734 }
2735 }
2736
2737 stbi__skip(z->s, L);
2738 return 1;
2739 }
2740
2741 return stbi__err("unknown marker","Corrupt JPEG");
2742}
2743
2744// after we see SOS
2745static int stbi__process_scan_header(stbi__jpeg *z)
2746{
2747 int i;
2748 int Ls = stbi__get16be(z->s);
2749 z->scan_n = stbi__get8(z->s);
2750 if (z->scan_n < 1 || z->scan_n > 4 || z->scan_n > (int) z->s->img_n) return stbi__err("bad SOS component count","Corrupt JPEG");
2751 if (Ls != 6+2*z->scan_n) return stbi__err("bad SOS len","Corrupt JPEG");
2752 for (i=0; i < z->scan_n; ++i) {
2753 int id = stbi__get8(z->s), which;
2754 int q = stbi__get8(z->s);
2755 for (which = 0; which < z->s->img_n; ++which)
2756 if (z->img_comp[which].id == id)
2757 break;
2758 if (which == z->s->img_n) return 0; // no match
2759 z->img_comp[which].hd = q >> 4; if (z->img_comp[which].hd > 3) return stbi__err("bad DC huff","Corrupt JPEG");
2760 z->img_comp[which].ha = q & 15; if (z->img_comp[which].ha > 3) return stbi__err("bad AC huff","Corrupt JPEG");
2761 z->order[i] = which;
2762 }
2763
2764 {
2765 int aa;
2766 z->spec_start = stbi__get8(z->s);
2767 z->spec_end = stbi__get8(z->s); // should be 63, but might be 0
2768 aa = stbi__get8(z->s);
2769 z->succ_high = (aa >> 4);
2770 z->succ_low = (aa & 15);
2771 if (z->progressive) {
2772 if (z->spec_start > 63 || z->spec_end > 63 || z->spec_start > z->spec_end || z->succ_high > 13 || z->succ_low > 13)
2773 return stbi__err("bad SOS", "Corrupt JPEG");
2774 } else {
2775 if (z->spec_start != 0) return stbi__err("bad SOS","Corrupt JPEG");
2776 if (z->succ_high != 0 || z->succ_low != 0) return stbi__err("bad SOS","Corrupt JPEG");
2777 z->spec_end = 63;
2778 }
2779 }
2780
2781 return 1;
2782}
2783
2784static int stbi__free_jpeg_components(stbi__jpeg *z, int ncomp, int why)
2785{
2786 int i;
2787 for (i=0; i < ncomp; ++i) {
2788 if (z->img_comp[i].raw_data) {
2789 STBI_FREE(z->img_comp[i].raw_data);
2790 z->img_comp[i].raw_data = NULL;
2791 z->img_comp[i].data = NULL;
2792 }
2793 if (z->img_comp[i].raw_coeff) {
2794 STBI_FREE(z->img_comp[i].raw_coeff);
2795 z->img_comp[i].raw_coeff = 0;
2796 z->img_comp[i].coeff = 0;
2797 }
2798 if (z->img_comp[i].linebuf) {
2799 STBI_FREE(z->img_comp[i].linebuf);
2800 z->img_comp[i].linebuf = NULL;
2801 }
2802 }
2803 return why;
2804}
2805
2806static int stbi__process_frame_header(stbi__jpeg *z, int scan)
2807{
2808 stbi__context *s = z->s;
2809 int Lf,p,i,q, h_max=1,v_max=1,c;
2810 Lf = stbi__get16be(s); if (Lf < 11) return stbi__err("bad SOF len","Corrupt JPEG"); // JPEG
2811 p = stbi__get8(s); if (p != 8) return stbi__err("only 8-bit","JPEG format not supported: 8-bit only"); // JPEG baseline
2812 s->img_y = stbi__get16be(s); if (s->img_y == 0) return stbi__err("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
2813 s->img_x = stbi__get16be(s); if (s->img_x == 0) return stbi__err("0 width","Corrupt JPEG"); // JPEG requires
2814 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
2815 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
2816 c = stbi__get8(s);
2817 if (c != 3 && c != 1 && c != 4) return stbi__err("bad component count","Corrupt JPEG");
2818 s->img_n = c;
2819 for (i=0; i < c; ++i) {
2820 z->img_comp[i].data = NULL;
2821 z->img_comp[i].linebuf = NULL;
2822 }
2823
2824 if (Lf != 8+3*s->img_n) return stbi__err("bad SOF len","Corrupt JPEG");
2825
2826 z->rgb = 0;
2827 for (i=0; i < s->img_n; ++i) {
2828 static const unsigned char rgb[3] = { 'R', 'G', 'B' };
2829 z->img_comp[i].id = stbi__get8(s);
2830 if (s->img_n == 3 && z->img_comp[i].id == rgb[i])
2831 ++z->rgb;
2832 q = stbi__get8(s);
2833 z->img_comp[i].h = (q >> 4); if (!z->img_comp[i].h || z->img_comp[i].h > 4) return stbi__err("bad H","Corrupt JPEG");
2834 z->img_comp[i].v = q & 15; if (!z->img_comp[i].v || z->img_comp[i].v > 4) return stbi__err("bad V","Corrupt JPEG");
2835 z->img_comp[i].tq = stbi__get8(s); if (z->img_comp[i].tq > 3) return stbi__err("bad TQ","Corrupt JPEG");
2836 }
2837
2838 if (scan != STBI__SCAN_load) return 1;
2839
2840 if (!stbi__mad3sizes_valid(s->img_x, s->img_y, s->img_n, 0)) return stbi__err("too large", "Image too large to decode");
2841
2842 for (i=0; i < s->img_n; ++i) {
2843 if (z->img_comp[i].h > h_max) h_max = z->img_comp[i].h;
2844 if (z->img_comp[i].v > v_max) v_max = z->img_comp[i].v;
2845 }
2846
2847 // check that plane subsampling factors are integer ratios; our resamplers can't deal with fractional ratios
2848 // and I've never seen a non-corrupted JPEG file actually use them
2849 for (i=0; i < s->img_n; ++i) {
2850 if (h_max % z->img_comp[i].h != 0) return stbi__err("bad H","Corrupt JPEG");
2851 if (v_max % z->img_comp[i].v != 0) return stbi__err("bad V","Corrupt JPEG");
2852 }
2853
2854 // compute interleaved mcu info
2855 z->img_h_max = h_max;
2856 z->img_v_max = v_max;
2857 z->img_mcu_w = h_max * 8;
2858 z->img_mcu_h = v_max * 8;
2859 // these sizes can't be more than 17 bits
2860 z->img_mcu_x = (s->img_x + z->img_mcu_w-1) / z->img_mcu_w;
2861 z->img_mcu_y = (s->img_y + z->img_mcu_h-1) / z->img_mcu_h;
2862
2863 for (i=0; i < s->img_n; ++i) {
2864 // number of effective pixels (e.g. for non-interleaved MCU)
2865 z->img_comp[i].x = (s->img_x * z->img_comp[i].h + h_max-1) / h_max;
2866 z->img_comp[i].y = (s->img_y * z->img_comp[i].v + v_max-1) / v_max;
2867 // to simplify generation, we'll allocate enough memory to decode
2868 // the bogus oversized data from using interleaved MCUs and their
2869 // big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't
2870 // discard the extra data until colorspace conversion
2871 //
2872 // img_mcu_x, img_mcu_y: <=17 bits; comp[i].h and .v are <=4 (checked earlier)
2873 // so these muls can't overflow with 32-bit ints (which we require)
2874 z->img_comp[i].w2 = z->img_mcu_x * z->img_comp[i].h * 8;
2875 z->img_comp[i].h2 = z->img_mcu_y * z->img_comp[i].v * 8;
2876 z->img_comp[i].coeff = 0;
2877 z->img_comp[i].raw_coeff = 0;
2878 z->img_comp[i].linebuf = NULL;
2879 z->img_comp[i].raw_data = stbi__malloc_mad2(z->img_comp[i].w2, z->img_comp[i].h2, 15);
2880 if (z->img_comp[i].raw_data == NULL)
2881 return stbi__free_jpeg_components(z, i+1, stbi__err("outofmem", "Out of memory"));
2882 // align blocks for idct using mmx/sse
2883 z->img_comp[i].data = (stbi_uc*) (((size_t) z->img_comp[i].raw_data + 15) & ~15);
2884 if (z->progressive) {
2885 // w2, h2 are multiples of 8 (see above)
2886 z->img_comp[i].coeff_w = z->img_comp[i].w2 / 8;
2887 z->img_comp[i].coeff_h = z->img_comp[i].h2 / 8;
2888 z->img_comp[i].raw_coeff = stbi__malloc_mad3(z->img_comp[i].w2, z->img_comp[i].h2, sizeof(short), 15);
2889 if (z->img_comp[i].raw_coeff == NULL)
2890 return stbi__free_jpeg_components(z, i+1, stbi__err("outofmem", "Out of memory"));
2891 z->img_comp[i].coeff = (short*) (((size_t) z->img_comp[i].raw_coeff + 15) & ~15);
2892 }
2893 }
2894
2895 return 1;
2896}
2897
2898// use comparisons since in some cases we handle more than one case (e.g. SOF)
2899#define stbi__DNL(x) ((x) == 0xdc)
2900#define stbi__SOI(x) ((x) == 0xd8)
2901#define stbi__EOI(x) ((x) == 0xd9)
2902#define stbi__SOF(x) ((x) == 0xc0 || (x) == 0xc1 || (x) == 0xc2)
2903#define stbi__SOS(x) ((x) == 0xda)
2904
2905#define stbi__SOF_progressive(x) ((x) == 0xc2)
2906
2907static int stbi__decode_jpeg_header(stbi__jpeg *z, int scan)
2908{
2909 int m;
2910 z->jfif = 0;
2911 z->app14_color_transform = -1; // valid values are 0,1,2
2912 z->marker = STBI__MARKER_none; // initialize cached marker to empty
2913 m = stbi__get_marker(z);
2914 if (!stbi__SOI(m)) return stbi__err("no SOI","Corrupt JPEG");
2915 if (scan == STBI__SCAN_type) return 1;
2916 m = stbi__get_marker(z);
2917 while (!stbi__SOF(m)) {
2918 if (!stbi__process_marker(z,m)) return 0;
2919 m = stbi__get_marker(z);
2920 while (m == STBI__MARKER_none) {
2921 // some files have extra padding after their blocks, so ok, we'll scan
2922 if (stbi__at_eof(z->s)) return stbi__err("no SOF", "Corrupt JPEG");
2923 m = stbi__get_marker(z);
2924 }
2925 }
2926 z->progressive = stbi__SOF_progressive(m);
2927 if (!stbi__process_frame_header(z, scan)) return 0;
2928 return 1;
2929}
2930
2931static int stbi__skip_jpeg_junk_at_end(stbi__jpeg *j)
2932{
2933 // some JPEGs have junk at end, skip over it but if we find what looks
2934 // like a valid marker, resume there
2935 while (!stbi__at_eof(j->s)) {
2936 int x = stbi__get8(j->s);
2937 while (x == 255) { // might be a marker
2938 if (stbi__at_eof(j->s)) return STBI__MARKER_none;
2939 x = stbi__get8(j->s);
2940 if (x != 0x00 && x != 0xff) {
2941 // not a stuffed zero or lead-in to another marker, looks
2942 // like an actual marker, return it
2943 return x;
2944 }
2945 // stuffed zero has x=0 now which ends the loop, meaning we go
2946 // back to regular scan loop.
2947 // repeated 0xff keeps trying to read the next byte of the marker.
2948 }
2949 }
2950 return STBI__MARKER_none;
2951}
2952
2953// decode image to YCbCr format
2954static int stbi__decode_jpeg_image(stbi__jpeg *j)
2955{
2956 int m;
2957 for (m = 0; m < 4; m++) {
2958 j->img_comp[m].raw_data = NULL;
2959 j->img_comp[m].raw_coeff = NULL;
2960 }
2961 j->restart_interval = 0;
2962 if (!stbi__decode_jpeg_header(j, STBI__SCAN_load)) return 0;
2963 m = stbi__get_marker(j);
2964 while (!stbi__EOI(m)) {
2965 if (stbi__SOS(m)) {
2966 if (!stbi__process_scan_header(j)) return 0;
2967 if (!stbi__parse_entropy_coded_data(j)) return 0;
2968 if (j->marker == STBI__MARKER_none ) {
2969 j->marker = stbi__skip_jpeg_junk_at_end(j);
2970 // if we reach eof without hitting a marker, stbi__get_marker() below will fail and we'll eventually return 0
2971 }
2972 m = stbi__get_marker(j);
2973 if (STBI__RESTART(m))
2974 m = stbi__get_marker(j);
2975 } else if (stbi__DNL(m)) {
2976 int Ld = stbi__get16be(j->s);
2977 stbi__uint32 NL = stbi__get16be(j->s);
2978 if (Ld != 4) return stbi__err("bad DNL len", "Corrupt JPEG");
2979 if (NL != j->s->img_y) return stbi__err("bad DNL height", "Corrupt JPEG");
2980 m = stbi__get_marker(j);
2981 } else {
2982 if (!stbi__process_marker(j, m)) return 1;
2983 m = stbi__get_marker(j);
2984 }
2985 }
2986 if (j->progressive)
2987 stbi__jpeg_finish(j);
2988 return 1;
2989}
2990
2991// static jfif-centered resampling (across block boundaries)
2992
2993typedef stbi_uc *(*resample_row_func)(stbi_uc *out, stbi_uc *in0, stbi_uc *in1,
2994 int w, int hs);
2995
2996#define stbi__div4(x) ((stbi_uc) ((x) >> 2))
2997
2998static stbi_uc *resample_row_1(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
2999{
3000 STBI_NOTUSED(out);
3001 STBI_NOTUSED(in_far);
3002 STBI_NOTUSED(w);
3003 STBI_NOTUSED(hs);
3004 return in_near;
3005}
3006
3007static stbi_uc* stbi__resample_row_v_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3008{
3009 // need to generate two samples vertically for every one in input
3010 int i;
3011 STBI_NOTUSED(hs);
3012 for (i=0; i < w; ++i)
3013 out[i] = stbi__div4(3*in_near[i] + in_far[i] + 2);
3014 return out;
3015}
3016
3017static stbi_uc* stbi__resample_row_h_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3018{
3019 // need to generate two samples horizontally for every one in input
3020 int i;
3021 stbi_uc *input = in_near;
3022
3023 if (w == 1) {
3024 // if only one sample, can't do any interpolation
3025 out[0] = out[1] = input[0];
3026 return out;
3027 }
3028
3029 out[0] = input[0];
3030 out[1] = stbi__div4(input[0]*3 + input[1] + 2);
3031 for (i=1; i < w-1; ++i) {
3032 int n = 3*input[i]+2;
3033 out[i*2+0] = stbi__div4(n+input[i-1]);
3034 out[i*2+1] = stbi__div4(n+input[i+1]);
3035 }
3036 out[i*2+0] = stbi__div4(input[w-2]*3 + input[w-1] + 2);
3037 out[i*2+1] = input[w-1];
3038
3039 STBI_NOTUSED(in_far);
3040 STBI_NOTUSED(hs);
3041
3042 return out;
3043}
3044
3045#define stbi__div16(x) ((stbi_uc) ((x) >> 4))
3046
3047static stbi_uc *stbi__resample_row_hv_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3048{
3049 // need to generate 2x2 samples for every one in input
3050 int i,t0,t1;
3051 if (w == 1) {
3052 out[0] = out[1] = stbi__div4(3*in_near[0] + in_far[0] + 2);
3053 return out;
3054 }
3055
3056 t1 = 3*in_near[0] + in_far[0];
3057 out[0] = stbi__div4(t1+2);
3058 for (i=1; i < w; ++i) {
3059 t0 = t1;
3060 t1 = 3*in_near[i]+in_far[i];
3061 out[i*2-1] = stbi__div16(3*t0 + t1 + 8);
3062 out[i*2 ] = stbi__div16(3*t1 + t0 + 8);
3063 }
3064 out[w*2-1] = stbi__div4(t1+2);
3065
3066 STBI_NOTUSED(hs);
3067
3068 return out;
3069}
3070
3071#if defined(STBI_SSE2) || defined(STBI_NEON)
3072static stbi_uc *stbi__resample_row_hv_2_simd(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3073{
3074 // need to generate 2x2 samples for every one in input
3075 int i=0,t0,t1;
3076
3077 if (w == 1) {
3078 out[0] = out[1] = stbi__div4(3*in_near[0] + in_far[0] + 2);
3079 return out;
3080 }
3081
3082 t1 = 3*in_near[0] + in_far[0];
3083 // process groups of 8 pixels for as long as we can.
3084 // note we can't handle the last pixel in a row in this loop
3085 // because we need to handle the filter boundary conditions.
3086 for (; i < ((w-1) & ~7); i += 8) {
3087#if defined(STBI_SSE2)
3088 // load and perform the vertical filtering pass
3089 // this uses 3*x + y = 4*x + (y - x)
3090 __m128i zero = _mm_setzero_si128();
3091 __m128i farb = _mm_loadl_epi64((__m128i *) (in_far + i));
3092 __m128i nearb = _mm_loadl_epi64((__m128i *) (in_near + i));
3093 __m128i farw = _mm_unpacklo_epi8(farb, zero);
3094 __m128i nearw = _mm_unpacklo_epi8(nearb, zero);
3095 __m128i diff = _mm_sub_epi16(farw, nearw);
3096 __m128i nears = _mm_slli_epi16(nearw, 2);
3097 __m128i curr = _mm_add_epi16(nears, diff); // current row
3098
3099 // horizontal filter works the same based on shifted vers of current
3100 // row. "prev" is current row shifted right by 1 pixel; we need to
3101 // insert the previous pixel value (from t1).
3102 // "next" is current row shifted left by 1 pixel, with first pixel
3103 // of next block of 8 pixels added in.
3104 __m128i prv0 = _mm_slli_si128(curr, 2);
3105 __m128i nxt0 = _mm_srli_si128(curr, 2);
3106 __m128i prev = _mm_insert_epi16(prv0, t1, 0);
3107 __m128i next = _mm_insert_epi16(nxt0, 3*in_near[i+8] + in_far[i+8], 7);
3108
3109 // horizontal filter, polyphase implementation since it's convenient:
3110 // even pixels = 3*cur + prev = cur*4 + (prev - cur)
3111 // odd pixels = 3*cur + next = cur*4 + (next - cur)
3112 // note the shared term.
3113 __m128i bias = _mm_set1_epi16(8);
3114 __m128i curs = _mm_slli_epi16(curr, 2);
3115 __m128i prvd = _mm_sub_epi16(prev, curr);
3116 __m128i nxtd = _mm_sub_epi16(next, curr);
3117 __m128i curb = _mm_add_epi16(curs, bias);
3118 __m128i even = _mm_add_epi16(prvd, curb);
3119 __m128i odd = _mm_add_epi16(nxtd, curb);
3120
3121 // interleave even and odd pixels, then undo scaling.
3122 __m128i int0 = _mm_unpacklo_epi16(even, odd);
3123 __m128i int1 = _mm_unpackhi_epi16(even, odd);
3124 __m128i de0 = _mm_srli_epi16(int0, 4);
3125 __m128i de1 = _mm_srli_epi16(int1, 4);
3126
3127 // pack and write output
3128 __m128i outv = _mm_packus_epi16(de0, de1);
3129 _mm_storeu_si128((__m128i *) (out + i*2), outv);
3130#elif defined(STBI_NEON)
3131 // load and perform the vertical filtering pass
3132 // this uses 3*x + y = 4*x + (y - x)
3133 uint8x8_t farb = vld1_u8(in_far + i);
3134 uint8x8_t nearb = vld1_u8(in_near + i);
3135 int16x8_t diff = vreinterpretq_s16_u16(vsubl_u8(farb, nearb));
3136 int16x8_t nears = vreinterpretq_s16_u16(vshll_n_u8(nearb, 2));
3137 int16x8_t curr = vaddq_s16(nears, diff); // current row
3138
3139 // horizontal filter works the same based on shifted vers of current
3140 // row. "prev" is current row shifted right by 1 pixel; we need to
3141 // insert the previous pixel value (from t1).
3142 // "next" is current row shifted left by 1 pixel, with first pixel
3143 // of next block of 8 pixels added in.
3144 int16x8_t prv0 = vextq_s16(curr, curr, 7);
3145 int16x8_t nxt0 = vextq_s16(curr, curr, 1);
3146 int16x8_t prev = vsetq_lane_s16(t1, prv0, 0);
3147 int16x8_t next = vsetq_lane_s16(3*in_near[i+8] + in_far[i+8], nxt0, 7);
3148
3149 // horizontal filter, polyphase implementation since it's convenient:
3150 // even pixels = 3*cur + prev = cur*4 + (prev - cur)
3151 // odd pixels = 3*cur + next = cur*4 + (next - cur)
3152 // note the shared term.
3153 int16x8_t curs = vshlq_n_s16(curr, 2);
3154 int16x8_t prvd = vsubq_s16(prev, curr);
3155 int16x8_t nxtd = vsubq_s16(next, curr);
3156 int16x8_t even = vaddq_s16(curs, prvd);
3157 int16x8_t odd = vaddq_s16(curs, nxtd);
3158
3159 // undo scaling and round, then store with even/odd phases interleaved
3160 uint8x8x2_t o;
3161 o.val[0] = vqrshrun_n_s16(even, 4);
3162 o.val[1] = vqrshrun_n_s16(odd, 4);
3163 vst2_u8(out + i*2, o);
3164#endif
3165
3166 // "previous" value for next iter
3167 t1 = 3*in_near[i+7] + in_far[i+7];
3168 }
3169
3170 t0 = t1;
3171 t1 = 3*in_near[i] + in_far[i];
3172 out[i*2] = stbi__div16(3*t1 + t0 + 8);
3173
3174 for (++i; i < w; ++i) {
3175 t0 = t1;
3176 t1 = 3*in_near[i]+in_far[i];
3177 out[i*2-1] = stbi__div16(3*t0 + t1 + 8);
3178 out[i*2 ] = stbi__div16(3*t1 + t0 + 8);
3179 }
3180 out[w*2-1] = stbi__div4(t1+2);
3181
3182 STBI_NOTUSED(hs);
3183
3184 return out;
3185}
3186#endif
3187
3188static stbi_uc *stbi__resample_row_generic(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3189{
3190 // resample with nearest-neighbor
3191 int i,j;
3192 STBI_NOTUSED(in_far);
3193 for (i=0; i < w; ++i)
3194 for (j=0; j < hs; ++j)
3195 out[i*hs+j] = in_near[i];
3196 return out;
3197}
3198
3199// this is a reduced-precision calculation of YCbCr-to-RGB introduced
3200// to make sure the code produces the same results in both SIMD and scalar
3201#define stbi__float2fixed(x) (((int) ((x) * 4096.0f + 0.5f)) << 8)
3202static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step)
3203{
3204 int i;
3205 for (i=0; i < count; ++i) {
3206 int y_fixed = (y[i] << 20) + (1<<19); // rounding
3207 int r,g,b;
3208 int cr = pcr[i] - 128;
3209 int cb = pcb[i] - 128;
3210 r = y_fixed + cr* stbi__float2fixed(1.40200f);
3211 g = y_fixed + (cr*-stbi__float2fixed(0.71414f)) + ((cb*-stbi__float2fixed(0.34414f)) & 0xffff0000);
3212 b = y_fixed + cb* stbi__float2fixed(1.77200f);
3213 r >>= 20;
3214 g >>= 20;
3215 b >>= 20;
3216 if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; }
3217 if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; }
3218 if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; }
3219 out[0] = (stbi_uc)r;
3220 out[1] = (stbi_uc)g;
3221 out[2] = (stbi_uc)b;
3222 out[3] = 255;
3223 out += step;
3224 }
3225}
3226
3227#if defined(STBI_SSE2) || defined(STBI_NEON)
3228static void stbi__YCbCr_to_RGB_simd(stbi_uc *out, stbi_uc const *y, stbi_uc const *pcb, stbi_uc const *pcr, int count, int step)
3229{
3230 int i = 0;
3231
3232#ifdef STBI_SSE2
3233 // step == 3 is pretty ugly on the final interleave, and i'm not convinced
3234 // it's useful in practice (you wouldn't use it for textures, for example).
3235 // so just accelerate step == 4 case.
3236 if (step == 4) {
3237 // this is a fairly straightforward implementation and not super-optimized.
3238 __m128i signflip = _mm_set1_epi8(-0x80);
3239 __m128i cr_const0 = _mm_set1_epi16( (short) ( 1.40200f*4096.0f+0.5f));
3240 __m128i cr_const1 = _mm_set1_epi16( - (short) ( 0.71414f*4096.0f+0.5f));
3241 __m128i cb_const0 = _mm_set1_epi16( - (short) ( 0.34414f*4096.0f+0.5f));
3242 __m128i cb_const1 = _mm_set1_epi16( (short) ( 1.77200f*4096.0f+0.5f));
3243 __m128i y_bias = _mm_set1_epi8((char) (unsigned char) 128);
3244 __m128i xw = _mm_set1_epi16(255); // alpha channel
3245
3246 for (; i+7 < count; i += 8) {
3247 // load
3248 __m128i y_bytes = _mm_loadl_epi64((__m128i *) (y+i));
3249 __m128i cr_bytes = _mm_loadl_epi64((__m128i *) (pcr+i));
3250 __m128i cb_bytes = _mm_loadl_epi64((__m128i *) (pcb+i));
3251 __m128i cr_biased = _mm_xor_si128(cr_bytes, signflip); // -128
3252 __m128i cb_biased = _mm_xor_si128(cb_bytes, signflip); // -128
3253
3254 // unpack to short (and left-shift cr, cb by 8)
3255 __m128i yw = _mm_unpacklo_epi8(y_bias, y_bytes);
3256 __m128i crw = _mm_unpacklo_epi8(_mm_setzero_si128(), cr_biased);
3257 __m128i cbw = _mm_unpacklo_epi8(_mm_setzero_si128(), cb_biased);
3258
3259 // color transform
3260 __m128i yws = _mm_srli_epi16(yw, 4);
3261 __m128i cr0 = _mm_mulhi_epi16(cr_const0, crw);
3262 __m128i cb0 = _mm_mulhi_epi16(cb_const0, cbw);
3263 __m128i cb1 = _mm_mulhi_epi16(cbw, cb_const1);
3264 __m128i cr1 = _mm_mulhi_epi16(crw, cr_const1);
3265 __m128i rws = _mm_add_epi16(cr0, yws);
3266 __m128i gwt = _mm_add_epi16(cb0, yws);
3267 __m128i bws = _mm_add_epi16(yws, cb1);
3268 __m128i gws = _mm_add_epi16(gwt, cr1);
3269
3270 // descale
3271 __m128i rw = _mm_srai_epi16(rws, 4);
3272 __m128i bw = _mm_srai_epi16(bws, 4);
3273 __m128i gw = _mm_srai_epi16(gws, 4);
3274
3275 // back to byte, set up for transpose
3276 __m128i brb = _mm_packus_epi16(rw, bw);
3277 __m128i gxb = _mm_packus_epi16(gw, xw);
3278
3279 // transpose to interleave channels
3280 __m128i t0 = _mm_unpacklo_epi8(brb, gxb);
3281 __m128i t1 = _mm_unpackhi_epi8(brb, gxb);
3282 __m128i o0 = _mm_unpacklo_epi16(t0, t1);
3283 __m128i o1 = _mm_unpackhi_epi16(t0, t1);
3284
3285 // store
3286 _mm_storeu_si128((__m128i *) (out + 0), o0);
3287 _mm_storeu_si128((__m128i *) (out + 16), o1);
3288 out += 32;
3289 }
3290 }
3291#endif
3292
3293#ifdef STBI_NEON
3294 // in this version, step=3 support would be easy to add. but is there demand?
3295 if (step == 4) {
3296 // this is a fairly straightforward implementation and not super-optimized.
3297 uint8x8_t signflip = vdup_n_u8(0x80);
3298 int16x8_t cr_const0 = vdupq_n_s16( (short) ( 1.40200f*4096.0f+0.5f));
3299 int16x8_t cr_const1 = vdupq_n_s16( - (short) ( 0.71414f*4096.0f+0.5f));
3300 int16x8_t cb_const0 = vdupq_n_s16( - (short) ( 0.34414f*4096.0f+0.5f));
3301 int16x8_t cb_const1 = vdupq_n_s16( (short) ( 1.77200f*4096.0f+0.5f));
3302
3303 for (; i+7 < count; i += 8) {
3304 // load
3305 uint8x8_t y_bytes = vld1_u8(y + i);
3306 uint8x8_t cr_bytes = vld1_u8(pcr + i);
3307 uint8x8_t cb_bytes = vld1_u8(pcb + i);
3308 int8x8_t cr_biased = vreinterpret_s8_u8(vsub_u8(cr_bytes, signflip));
3309 int8x8_t cb_biased = vreinterpret_s8_u8(vsub_u8(cb_bytes, signflip));
3310
3311 // expand to s16
3312 int16x8_t yws = vreinterpretq_s16_u16(vshll_n_u8(y_bytes, 4));
3313 int16x8_t crw = vshll_n_s8(cr_biased, 7);
3314 int16x8_t cbw = vshll_n_s8(cb_biased, 7);
3315
3316 // color transform
3317 int16x8_t cr0 = vqdmulhq_s16(crw, cr_const0);
3318 int16x8_t cb0 = vqdmulhq_s16(cbw, cb_const0);
3319 int16x8_t cr1 = vqdmulhq_s16(crw, cr_const1);
3320 int16x8_t cb1 = vqdmulhq_s16(cbw, cb_const1);
3321 int16x8_t rws = vaddq_s16(yws, cr0);
3322 int16x8_t gws = vaddq_s16(vaddq_s16(yws, cb0), cr1);
3323 int16x8_t bws = vaddq_s16(yws, cb1);
3324
3325 // undo scaling, round, convert to byte
3326 uint8x8x4_t o;
3327 o.val[0] = vqrshrun_n_s16(rws, 4);
3328 o.val[1] = vqrshrun_n_s16(gws, 4);
3329 o.val[2] = vqrshrun_n_s16(bws, 4);
3330 o.val[3] = vdup_n_u8(255);
3331
3332 // store, interleaving r/g/b/a
3333 vst4_u8(out, o);
3334 out += 8*4;
3335 }
3336 }
3337#endif
3338
3339 for (; i < count; ++i) {
3340 int y_fixed = (y[i] << 20) + (1<<19); // rounding
3341 int r,g,b;
3342 int cr = pcr[i] - 128;
3343 int cb = pcb[i] - 128;
3344 r = y_fixed + cr* stbi__float2fixed(1.40200f);
3345 g = y_fixed + cr*-stbi__float2fixed(0.71414f) + ((cb*-stbi__float2fixed(0.34414f)) & 0xffff0000);
3346 b = y_fixed + cb* stbi__float2fixed(1.77200f);
3347 r >>= 20;
3348 g >>= 20;
3349 b >>= 20;
3350 if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; }
3351 if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; }
3352 if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; }
3353 out[0] = (stbi_uc)r;
3354 out[1] = (stbi_uc)g;
3355 out[2] = (stbi_uc)b;
3356 out[3] = 255;
3357 out += step;
3358 }
3359}
3360#endif
3361
3362// set up the kernels
3363static void stbi__setup_jpeg(stbi__jpeg *j)
3364{
3365 j->idct_block_kernel = stbi__idct_block;
3366 j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_row;
3367 j->resample_row_hv_2_kernel = stbi__resample_row_hv_2;
3368
3369#ifdef STBI_SSE2
3370 if (stbi__sse2_available()) {
3371 j->idct_block_kernel = stbi__idct_simd;
3372 j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
3373 j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
3374 }
3375#endif
3376
3377#ifdef STBI_NEON
3378 j->idct_block_kernel = stbi__idct_simd;
3379 j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
3380 j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
3381#endif
3382}
3383
3384// clean up the temporary component buffers
3385static void stbi__cleanup_jpeg(stbi__jpeg *j)
3386{
3387 stbi__free_jpeg_components(j, j->s->img_n, 0);
3388}
3389
3390typedef struct
3391{
3392 resample_row_func resample;
3393 stbi_uc *line0,*line1;
3394 int hs,vs; // expansion factor in each axis
3395 int w_lores; // horizontal pixels pre-expansion
3396 int ystep; // how far through vertical expansion we are
3397 int ypos; // which pre-expansion row we're on
3398} stbi__resample;
3399
3400// fast 0..255 * 0..255 => 0..255 rounded multiplication
3401static stbi_uc stbi__blinn_8x8(stbi_uc x, stbi_uc y)
3402{
3403 unsigned int t = x*y + 128;
3404 return (stbi_uc) ((t + (t >>8)) >> 8);
3405}
3406
3407static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp, int req_comp)
3408{
3409 int n, decode_n, is_rgb;
3410 z->s->img_n = 0; // make stbi__cleanup_jpeg safe
3411
3412 // validate req_comp
3413 if (req_comp < 0 || req_comp > 4) return stbi__errpuc("bad req_comp", "Internal error");
3414
3415 // load a jpeg image from whichever source, but leave in YCbCr format
3416 if (!stbi__decode_jpeg_image(z)) { stbi__cleanup_jpeg(z); return NULL; }
3417
3418 // determine actual number of components to generate
3419 n = req_comp ? req_comp : z->s->img_n >= 3 ? 3 : 1;
3420
3421 is_rgb = z->s->img_n == 3 && (z->rgb == 3 || (z->app14_color_transform == 0 && !z->jfif));
3422
3423 if (z->s->img_n == 3 && n < 3 && !is_rgb)
3424 decode_n = 1;
3425 else
3426 decode_n = z->s->img_n;
3427
3428 // nothing to do if no components requested; check this now to avoid
3429 // accessing uninitialized coutput[0] later
3430 if (decode_n <= 0) { stbi__cleanup_jpeg(z); return NULL; }
3431
3432 // resample and color-convert
3433 {
3434 int k;
3435 unsigned int i,j;
3436 stbi_uc *output;
3437 stbi_uc *coutput[4] = { NULL, NULL, NULL, NULL };
3438
3439 stbi__resample res_comp[4];
3440
3441 for (k=0; k < decode_n; ++k) {
3442 stbi__resample *r = &res_comp[k];
3443
3444 // allocate line buffer big enough for upsampling off the edges
3445 // with upsample factor of 4
3446 z->img_comp[k].linebuf = (stbi_uc *) stbi__malloc(z->s->img_x + 3);
3447 if (!z->img_comp[k].linebuf) { stbi__cleanup_jpeg(z); return stbi__errpuc("outofmem", "Out of memory"); }
3448
3449 r->hs = z->img_h_max / z->img_comp[k].h;
3450 r->vs = z->img_v_max / z->img_comp[k].v;
3451 r->ystep = r->vs >> 1;
3452 r->w_lores = (z->s->img_x + r->hs-1) / r->hs;
3453 r->ypos = 0;
3454 r->line0 = r->line1 = z->img_comp[k].data;
3455
3456 if (r->hs == 1 && r->vs == 1) r->resample = resample_row_1;
3457 else if (r->hs == 1 && r->vs == 2) r->resample = stbi__resample_row_v_2;
3458 else if (r->hs == 2 && r->vs == 1) r->resample = stbi__resample_row_h_2;
3459 else if (r->hs == 2 && r->vs == 2) r->resample = z->resample_row_hv_2_kernel;
3460 else r->resample = stbi__resample_row_generic;
3461 }
3462
3463 // can't error after this so, this is safe
3464 output = (stbi_uc *) stbi__malloc_mad3(n, z->s->img_x, z->s->img_y, 1);
3465 if (!output) { stbi__cleanup_jpeg(z); return stbi__errpuc("outofmem", "Out of memory"); }
3466
3467 // now go ahead and resample
3468 for (j=0; j < z->s->img_y; ++j) {
3469 stbi_uc *out = output + n * z->s->img_x * j;
3470 for (k=0; k < decode_n; ++k) {
3471 stbi__resample *r = &res_comp[k];
3472 int y_bot = r->ystep >= (r->vs >> 1);
3473 coutput[k] = r->resample(z->img_comp[k].linebuf,
3474 y_bot ? r->line1 : r->line0,
3475 y_bot ? r->line0 : r->line1,
3476 r->w_lores, r->hs);
3477 if (++r->ystep >= r->vs) {
3478 r->ystep = 0;
3479 r->line0 = r->line1;
3480 if (++r->ypos < z->img_comp[k].y)
3481 r->line1 += z->img_comp[k].w2;
3482 }
3483 }
3484 if (n >= 3) {
3485 stbi_uc *y = coutput[0];
3486 if (z->s->img_n == 3) {
3487 if (is_rgb) {
3488 for (i=0; i < z->s->img_x; ++i) {
3489 out[0] = y[i];
3490 out[1] = coutput[1][i];
3491 out[2] = coutput[2][i];
3492 out[3] = 255;
3493 out += n;
3494 }
3495 } else {
3496 z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
3497 }
3498 } else if (z->s->img_n == 4) {
3499 if (z->app14_color_transform == 0) { // CMYK
3500 for (i=0; i < z->s->img_x; ++i) {
3501 stbi_uc m = coutput[3][i];
3502 out[0] = stbi__blinn_8x8(coutput[0][i], m);
3503 out[1] = stbi__blinn_8x8(coutput[1][i], m);
3504 out[2] = stbi__blinn_8x8(coutput[2][i], m);
3505 out[3] = 255;
3506 out += n;
3507 }
3508 } else if (z->app14_color_transform == 2) { // YCCK
3509 z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
3510 for (i=0; i < z->s->img_x; ++i) {
3511 stbi_uc m = coutput[3][i];
3512 out[0] = stbi__blinn_8x8(255 - out[0], m);
3513 out[1] = stbi__blinn_8x8(255 - out[1], m);
3514 out[2] = stbi__blinn_8x8(255 - out[2], m);
3515 out += n;
3516 }
3517 } else { // YCbCr + alpha? Ignore the fourth channel for now
3518 z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
3519 }
3520 } else
3521 for (i=0; i < z->s->img_x; ++i) {
3522 out[0] = out[1] = out[2] = y[i];
3523 out[3] = 255; // not used if n==3
3524 out += n;
3525 }
3526 } else {
3527 if (is_rgb) {
3528 if (n == 1)
3529 for (i=0; i < z->s->img_x; ++i)
3530 *out++ = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]);
3531 else {
3532 for (i=0; i < z->s->img_x; ++i, out += 2) {
3533 out[0] = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]);
3534 out[1] = 255;
3535 }
3536 }
3537 } else if (z->s->img_n == 4 && z->app14_color_transform == 0) {
3538 for (i=0; i < z->s->img_x; ++i) {
3539 stbi_uc m = coutput[3][i];
3540 stbi_uc r = stbi__blinn_8x8(coutput[0][i], m);
3541 stbi_uc g = stbi__blinn_8x8(coutput[1][i], m);
3542 stbi_uc b = stbi__blinn_8x8(coutput[2][i], m);
3543 out[0] = stbi__compute_y(r, g, b);
3544 out[1] = 255;
3545 out += n;
3546 }
3547 } else if (z->s->img_n == 4 && z->app14_color_transform == 2) {
3548 for (i=0; i < z->s->img_x; ++i) {
3549 out[0] = stbi__blinn_8x8(255 - coutput[0][i], coutput[3][i]);
3550 out[1] = 255;
3551 out += n;
3552 }
3553 } else {
3554 stbi_uc *y = coutput[0];
3555 if (n == 1)
3556 for (i=0; i < z->s->img_x; ++i) out[i] = y[i];
3557 else
3558 for (i=0; i < z->s->img_x; ++i) { *out++ = y[i]; *out++ = 255; }
3559 }
3560 }
3561 }
3562 stbi__cleanup_jpeg(z);
3563 *out_x = z->s->img_x;
3564 *out_y = z->s->img_y;
3565 if (comp) *comp = z->s->img_n >= 3 ? 3 : 1; // report original components, not output
3566 return output;
3567 }
3568}
3569
3570static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
3571{
3572 unsigned char* result;
3573 stbi__jpeg* j = (stbi__jpeg*) stbi__malloc(sizeof(stbi__jpeg));
3574 if (!j) return stbi__errpuc("outofmem", "Out of memory");
3575 memset(j, 0, sizeof(stbi__jpeg));
3576 STBI_NOTUSED(ri);
3577 j->s = s;
3578 stbi__setup_jpeg(j);
3579 result = load_jpeg_image(j, x,y,comp,req_comp);
3580 STBI_FREE(j);
3581 return result;
3582}
3583
3584static int stbi__jpeg_test(stbi__context *s)
3585{
3586 int r;
3587 stbi__jpeg* j = (stbi__jpeg*)stbi__malloc(sizeof(stbi__jpeg));
3588 if (!j) return stbi__err("outofmem", "Out of memory");
3589 memset(j, 0, sizeof(stbi__jpeg));
3590 j->s = s;
3591 stbi__setup_jpeg(j);
3592 r = stbi__decode_jpeg_header(j, STBI__SCAN_type);
3593 stbi__rewind(s);
3594 STBI_FREE(j);
3595 return r;
3596}
3597
3598static int stbi__jpeg_info_raw(stbi__jpeg *j, int *x, int *y, int *comp)
3599{
3600 if (!stbi__decode_jpeg_header(j, STBI__SCAN_header)) {
3601 stbi__rewind( j->s );
3602 return 0;
3603 }
3604 if (x) *x = j->s->img_x;
3605 if (y) *y = j->s->img_y;
3606 if (comp) *comp = j->s->img_n >= 3 ? 3 : 1;
3607 return 1;
3608}
3609
3610static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp)
3611{
3612 int result;
3613 stbi__jpeg* j = (stbi__jpeg*) (stbi__malloc(sizeof(stbi__jpeg)));
3614 if (!j) return stbi__err("outofmem", "Out of memory");
3615 memset(j, 0, sizeof(stbi__jpeg));
3616 j->s = s;
3617 result = stbi__jpeg_info_raw(j, x, y, comp);
3618 STBI_FREE(j);
3619 return result;
3620}
3621#endif
3622
3623// public domain zlib decode v0.2 Sean Barrett 2006-11-18
3624// simple implementation
3625// - all input must be provided in an upfront buffer
3626// - all output is written to a single output buffer (can malloc/realloc)
3627// performance
3628// - fast huffman
3629
3630#ifndef STBI_NO_ZLIB
3631
3632// fast-way is faster to check than jpeg huffman, but slow way is slower
3633#define STBI__ZFAST_BITS 9 // accelerate all cases in default tables
3634#define STBI__ZFAST_MASK ((1 << STBI__ZFAST_BITS) - 1)
3635#define STBI__ZNSYMS 288 // number of symbols in literal/length alphabet
3636
3637// zlib-style huffman encoding
3638// (jpegs packs from left, zlib from right, so can't share code)
3639typedef struct
3640{
3641 stbi__uint16 fast[1 << STBI__ZFAST_BITS];
3642 stbi__uint16 firstcode[16];
3643 int maxcode[17];
3644 stbi__uint16 firstsymbol[16];
3645 stbi_uc size[STBI__ZNSYMS];
3646 stbi__uint16 value[STBI__ZNSYMS];
3647} stbi__zhuffman;
3648
3649stbi_inline static int stbi__bitreverse16(int n)
3650{
3651 n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1);
3652 n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2);
3653 n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4);
3654 n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8);
3655 return n;
3656}
3657
3658stbi_inline static int stbi__bit_reverse(int v, int bits)
3659{
3660 STBI_ASSERT(bits <= 16);
3661 // to bit reverse n bits, reverse 16 and shift
3662 // e.g. 11 bits, bit reverse and shift away 5
3663 return stbi__bitreverse16(v) >> (16-bits);
3664}
3665
3666static int stbi__zbuild_huffman(stbi__zhuffman *z, const stbi_uc *sizelist, int num)
3667{
3668 int i,k=0;
3669 int code, next_code[16], sizes[17];
3670
3671 // DEFLATE spec for generating codes
3672 memset(sizes, 0, sizeof(sizes));
3673 memset(z->fast, 0, sizeof(z->fast));
3674 for (i=0; i < num; ++i)
3675 ++sizes[sizelist[i]];
3676 sizes[0] = 0;
3677 for (i=1; i < 16; ++i)
3678 if (sizes[i] > (1 << i))
3679 return stbi__err("bad sizes", "Corrupt PNG");
3680 code = 0;
3681 for (i=1; i < 16; ++i) {
3682 next_code[i] = code;
3683 z->firstcode[i] = (stbi__uint16) code;
3684 z->firstsymbol[i] = (stbi__uint16) k;
3685 code = (code + sizes[i]);
3686 if (sizes[i])
3687 if (code-1 >= (1 << i)) return stbi__err("bad codelengths","Corrupt PNG");
3688 z->maxcode[i] = code << (16-i); // preshift for inner loop
3689 code <<= 1;
3690 k += sizes[i];
3691 }
3692 z->maxcode[16] = 0x10000; // sentinel
3693 for (i=0; i < num; ++i) {
3694 int s = sizelist[i];
3695 if (s) {
3696 int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s];
3697 stbi__uint16 fastv = (stbi__uint16) ((s << 9) | i);
3698 z->size [c] = (stbi_uc ) s;
3699 z->value[c] = (stbi__uint16) i;
3700 if (s <= STBI__ZFAST_BITS) {
3701 int j = stbi__bit_reverse(next_code[s],s);
3702 while (j < (1 << STBI__ZFAST_BITS)) {
3703 z->fast[j] = fastv;
3704 j += (1 << s);
3705 }
3706 }
3707 ++next_code[s];
3708 }
3709 }
3710 return 1;
3711}
3712
3713// zlib-from-memory implementation for PNG reading
3714// because PNG allows splitting the zlib stream arbitrarily,
3715// and it's annoying structurally to have PNG call ZLIB call PNG,
3716// we require PNG read all the IDATs and combine them into a single
3717// memory buffer
3718
3719typedef struct
3720{
3721 stbi_uc *zbuffer, *zbuffer_end;
3722 int num_bits;
3723 stbi__uint32 code_buffer;
3724
3725 char *zout;
3726 char *zout_start;
3727 char *zout_end;
3728 int z_expandable;
3729
3730 stbi__zhuffman z_length, z_distance;
3731} stbi__zbuf;
3732
3733stbi_inline static int stbi__zeof(stbi__zbuf *z)
3734{
3735 return (z->zbuffer >= z->zbuffer_end);
3736}
3737
3738stbi_inline static stbi_uc stbi__zget8(stbi__zbuf *z)
3739{
3740 return stbi__zeof(z) ? 0 : *z->zbuffer++;
3741}
3742
3743static void stbi__fill_bits(stbi__zbuf *z)
3744{
3745 do {
3746 if (z->code_buffer >= (1U << z->num_bits)) {
3747 z->zbuffer = z->zbuffer_end; /* treat this as EOF so we fail. */
3748 return;
3749 }
3750 z->code_buffer |= (unsigned int) stbi__zget8(z) << z->num_bits;
3751 z->num_bits += 8;
3752 } while (z->num_bits <= 24);
3753}
3754
3755stbi_inline static unsigned int stbi__zreceive(stbi__zbuf *z, int n)
3756{
3757 unsigned int k;
3758 if (z->num_bits < n) stbi__fill_bits(z);
3759 k = z->code_buffer & ((1 << n) - 1);
3760 z->code_buffer >>= n;
3761 z->num_bits -= n;
3762 return k;
3763}
3764
3765static int stbi__zhuffman_decode_slowpath(stbi__zbuf *a, stbi__zhuffman *z)
3766{
3767 int b,s,k;
3768 // not resolved by fast table, so compute it the slow way
3769 // use jpeg approach, which requires MSbits at top
3770 k = stbi__bit_reverse(a->code_buffer, 16);
3771 for (s=STBI__ZFAST_BITS+1; ; ++s)
3772 if (k < z->maxcode[s])
3773 break;
3774 if (s >= 16) return -1; // invalid code!
3775 // code size is s, so:
3776 b = (k >> (16-s)) - z->firstcode[s] + z->firstsymbol[s];
3777 if (b >= STBI__ZNSYMS) return -1; // some data was corrupt somewhere!
3778 if (z->size[b] != s) return -1; // was originally an assert, but report failure instead.
3779 a->code_buffer >>= s;
3780 a->num_bits -= s;
3781 return z->value[b];
3782}
3783
3784stbi_inline static int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z)
3785{
3786 int b,s;
3787 if (a->num_bits < 16) {
3788 if (stbi__zeof(a)) {
3789 return -1; /* report error for unexpected end of data. */
3790 }
3791 stbi__fill_bits(a);
3792 }
3793 b = z->fast[a->code_buffer & STBI__ZFAST_MASK];
3794 if (b) {
3795 s = b >> 9;
3796 a->code_buffer >>= s;
3797 a->num_bits -= s;
3798 return b & 511;
3799 }
3800 return stbi__zhuffman_decode_slowpath(a, z);
3801}
3802
3803static int stbi__zexpand(stbi__zbuf *z, char *zout, int n) // need to make room for n bytes
3804{
3805 char *q;
3806 unsigned int cur, limit, old_limit;
3807 z->zout = zout;
3808 if (!z->z_expandable) return stbi__err("output buffer limit","Corrupt PNG");
3809 cur = (unsigned int) (z->zout - z->zout_start);
3810 limit = old_limit = (unsigned) (z->zout_end - z->zout_start);
3811 if (UINT_MAX - cur < (unsigned) n) return stbi__err("outofmem", "Out of memory");
3812 while (cur + n > limit) {
3813 if(limit > UINT_MAX / 2) return stbi__err("outofmem", "Out of memory");
3814 limit *= 2;
3815 }
3816 q = (char *) STBI_REALLOC_SIZED(z->zout_start, old_limit, limit);
3817 STBI_NOTUSED(old_limit);
3818 if (q == NULL) return stbi__err("outofmem", "Out of memory");
3819 z->zout_start = q;
3820 z->zout = q + cur;
3821 z->zout_end = q + limit;
3822 return 1;
3823}
3824
3825static const int stbi__zlength_base[31] = {
3826 3,4,5,6,7,8,9,10,11,13,
3827 15,17,19,23,27,31,35,43,51,59,
3828 67,83,99,115,131,163,195,227,258,0,0 };
3829
3830static const int stbi__zlength_extra[31]=
3831{ 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0,0,0 };
3832
3833static const int stbi__zdist_base[32] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,
3834257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577,0,0};
3835
3836static const int stbi__zdist_extra[32] =
3837{ 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
3838
3839static int stbi__parse_huffman_block(stbi__zbuf *a)
3840{
3841 char *zout = a->zout;
3842 for(;;) {
3843 int z = stbi__zhuffman_decode(a, &a->z_length);
3844 if (z < 256) {
3845 if (z < 0) return stbi__err("bad huffman code","Corrupt PNG"); // error in huffman codes
3846 if (zout >= a->zout_end) {
3847 if (!stbi__zexpand(a, zout, 1)) return 0;
3848 zout = a->zout;
3849 }
3850 *zout++ = (char) z;
3851 } else {
3852 stbi_uc *p;
3853 int len,dist;
3854 if (z == 256) {
3855 a->zout = zout;
3856 return 1;
3857 }
3858 if (z >= 286) return stbi__err("bad huffman code","Corrupt PNG"); // per DEFLATE, length codes 286 and 287 must not appear in compressed data
3859 z -= 257;
3860 len = stbi__zlength_base[z];
3861 if (stbi__zlength_extra[z]) len += stbi__zreceive(a, stbi__zlength_extra[z]);
3862 z = stbi__zhuffman_decode(a, &a->z_distance);
3863 if (z < 0 || z >= 30) return stbi__err("bad huffman code","Corrupt PNG"); // per DEFLATE, distance codes 30 and 31 must not appear in compressed data
3864 dist = stbi__zdist_base[z];
3865 if (stbi__zdist_extra[z]) dist += stbi__zreceive(a, stbi__zdist_extra[z]);
3866 if (zout - a->zout_start < dist) return stbi__err("bad dist","Corrupt PNG");
3867 if (zout + len > a->zout_end) {
3868 if (!stbi__zexpand(a, zout, len)) return 0;
3869 zout = a->zout;
3870 }
3871 p = (stbi_uc *) (zout - dist);
3872 if (dist == 1) { // run of one byte; common in images.
3873 stbi_uc v = *p;
3874 if (len) { do *zout++ = v; while (--len); }
3875 } else {
3876 if (len) { do *zout++ = *p++; while (--len); }
3877 }
3878 }
3879 }
3880}
3881
3882static int stbi__compute_huffman_codes(stbi__zbuf *a)
3883{
3884 static const stbi_uc length_dezigzag[19] = { 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 };
3885 stbi__zhuffman z_codelength;
3886 stbi_uc lencodes[286+32+137];//padding for maximum single op
3887 stbi_uc codelength_sizes[19];
3888 int i,n;
3889
3890 int hlit = stbi__zreceive(a,5) + 257;
3891 int hdist = stbi__zreceive(a,5) + 1;
3892 int hclen = stbi__zreceive(a,4) + 4;
3893 int ntot = hlit + hdist;
3894
3895 memset(codelength_sizes, 0, sizeof(codelength_sizes));
3896 for (i=0; i < hclen; ++i) {
3897 int s = stbi__zreceive(a,3);
3898 codelength_sizes[length_dezigzag[i]] = (stbi_uc) s;
3899 }
3900 if (!stbi__zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0;
3901
3902 n = 0;
3903 while (n < ntot) {
3904 int c = stbi__zhuffman_decode(a, &z_codelength);
3905 if (c < 0 || c >= 19) return stbi__err("bad codelengths", "Corrupt PNG");
3906 if (c < 16)
3907 lencodes[n++] = (stbi_uc) c;
3908 else {
3909 stbi_uc fill = 0;
3910 if (c == 16) {
3911 c = stbi__zreceive(a,2)+3;
3912 if (n == 0) return stbi__err("bad codelengths", "Corrupt PNG");
3913 fill = lencodes[n-1];
3914 } else if (c == 17) {
3915 c = stbi__zreceive(a,3)+3;
3916 } else if (c == 18) {
3917 c = stbi__zreceive(a,7)+11;
3918 } else {
3919 return stbi__err("bad codelengths", "Corrupt PNG");
3920 }
3921 if (ntot - n < c) return stbi__err("bad codelengths", "Corrupt PNG");
3922 memset(lencodes+n, fill, c);
3923 n += c;
3924 }
3925 }
3926 if (n != ntot) return stbi__err("bad codelengths","Corrupt PNG");
3927 if (!stbi__zbuild_huffman(&a->z_length, lencodes, hlit)) return 0;
3928 if (!stbi__zbuild_huffman(&a->z_distance, lencodes+hlit, hdist)) return 0;
3929 return 1;
3930}
3931
3932static int stbi__parse_uncompressed_block(stbi__zbuf *a)
3933{
3934 stbi_uc header[4];
3935 int len,nlen,k;
3936 if (a->num_bits & 7)
3937 stbi__zreceive(a, a->num_bits & 7); // discard
3938 // drain the bit-packed data into header
3939 k = 0;
3940 while (a->num_bits > 0) {
3941 header[k++] = (stbi_uc) (a->code_buffer & 255); // suppress MSVC run-time check
3942 a->code_buffer >>= 8;
3943 a->num_bits -= 8;
3944 }
3945 if (a->num_bits < 0) return stbi__err("zlib corrupt","Corrupt PNG");
3946 // now fill header the normal way
3947 while (k < 4)
3948 header[k++] = stbi__zget8(a);
3949 len = header[1] * 256 + header[0];
3950 nlen = header[3] * 256 + header[2];
3951 if (nlen != (len ^ 0xffff)) return stbi__err("zlib corrupt","Corrupt PNG");
3952 if (a->zbuffer + len > a->zbuffer_end) return stbi__err("read past buffer","Corrupt PNG");
3953 if (a->zout + len > a->zout_end)
3954 if (!stbi__zexpand(a, a->zout, len)) return 0;
3955 memcpy(a->zout, a->zbuffer, len);
3956 a->zbuffer += len;
3957 a->zout += len;
3958 return 1;
3959}
3960
3961static int stbi__parse_zlib_header(stbi__zbuf *a)
3962{
3963 int cmf = stbi__zget8(a);
3964 int cm = cmf & 15;
3965 /* int cinfo = cmf >> 4; */
3966 int flg = stbi__zget8(a);
3967 if (stbi__zeof(a)) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec
3968 if ((cmf*256+flg) % 31 != 0) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec
3969 if (flg & 32) return stbi__err("no preset dict","Corrupt PNG"); // preset dictionary not allowed in png
3970 if (cm != 8) return stbi__err("bad compression","Corrupt PNG"); // DEFLATE required for png
3971 // window = 1 << (8 + cinfo)... but who cares, we fully buffer output
3972 return 1;
3973}
3974
3975static const stbi_uc stbi__zdefault_length[STBI__ZNSYMS] =
3976{
3977 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
3978 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
3979 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
3980 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
3981 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
3982 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
3983 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
3984 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
3985 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,8,8,8,8,8,8,8,8
3986};
3987static const stbi_uc stbi__zdefault_distance[32] =
3988{
3989 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5
3990};
3991/*
3992Init algorithm:
3993{
3994 int i; // use <= to match clearly with spec
3995 for (i=0; i <= 143; ++i) stbi__zdefault_length[i] = 8;
3996 for ( ; i <= 255; ++i) stbi__zdefault_length[i] = 9;
3997 for ( ; i <= 279; ++i) stbi__zdefault_length[i] = 7;
3998 for ( ; i <= 287; ++i) stbi__zdefault_length[i] = 8;
3999
4000 for (i=0; i <= 31; ++i) stbi__zdefault_distance[i] = 5;
4001}
4002*/
4003
4004static int stbi__parse_zlib(stbi__zbuf *a, int parse_header)
4005{
4006 int final, type;
4007 if (parse_header)
4008 if (!stbi__parse_zlib_header(a)) return 0;
4009 a->num_bits = 0;
4010 a->code_buffer = 0;
4011 do {
4012 final = stbi__zreceive(a,1);
4013 type = stbi__zreceive(a,2);
4014 if (type == 0) {
4015 if (!stbi__parse_uncompressed_block(a)) return 0;
4016 } else if (type == 3) {
4017 return 0;
4018 } else {
4019 if (type == 1) {
4020 // use fixed code lengths
4021 if (!stbi__zbuild_huffman(&a->z_length , stbi__zdefault_length , STBI__ZNSYMS)) return 0;
4022 if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance, 32)) return 0;
4023 } else {
4024 if (!stbi__compute_huffman_codes(a)) return 0;
4025 }
4026 if (!stbi__parse_huffman_block(a)) return 0;
4027 }
4028 } while (!final);
4029 return 1;
4030}
4031
4032static int stbi__do_zlib(stbi__zbuf *a, char *obuf, int olen, int exp, int parse_header)
4033{
4034 a->zout_start = obuf;
4035 a->zout = obuf;
4036 a->zout_end = obuf + olen;
4037 a->z_expandable = exp;
4038
4039 return stbi__parse_zlib(a, parse_header);
4040}
4041
4042STBIDEF char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen)
4043{
4044 stbi__zbuf a;
4045 char *p = (char *) stbi__malloc(initial_size);
4046 if (p == NULL) return NULL;
4047 a.zbuffer = (stbi_uc *) buffer;
4048 a.zbuffer_end = (stbi_uc *) buffer + len;
4049 if (stbi__do_zlib(&a, p, initial_size, 1, 1)) {
4050 if (outlen) *outlen = (int) (a.zout - a.zout_start);
4051 return a.zout_start;
4052 } else {
4053 STBI_FREE(a.zout_start);
4054 return NULL;
4055 }
4056}
4057
4058STBIDEF char *stbi_zlib_decode_malloc(char const *buffer, int len, int *outlen)
4059{
4060 return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen);
4061}
4062
4063STBIDEF char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header)
4064{
4065 stbi__zbuf a;
4066 char *p = (char *) stbi__malloc(initial_size);
4067 if (p == NULL) return NULL;
4068 a.zbuffer = (stbi_uc *) buffer;
4069 a.zbuffer_end = (stbi_uc *) buffer + len;
4070 if (stbi__do_zlib(&a, p, initial_size, 1, parse_header)) {
4071 if (outlen) *outlen = (int) (a.zout - a.zout_start);
4072 return a.zout_start;
4073 } else {
4074 STBI_FREE(a.zout_start);
4075 return NULL;
4076 }
4077}
4078
4079STBIDEF int stbi_zlib_decode_buffer(char *obuffer, int olen, char const *ibuffer, int ilen)
4080{
4081 stbi__zbuf a;
4082 a.zbuffer = (stbi_uc *) ibuffer;
4083 a.zbuffer_end = (stbi_uc *) ibuffer + ilen;
4084 if (stbi__do_zlib(&a, obuffer, olen, 0, 1))
4085 return (int) (a.zout - a.zout_start);
4086 else
4087 return -1;
4088}
4089
4090STBIDEF char *stbi_zlib_decode_noheader_malloc(char const *buffer, int len, int *outlen)
4091{
4092 stbi__zbuf a;
4093 char *p = (char *) stbi__malloc(16384);
4094 if (p == NULL) return NULL;
4095 a.zbuffer = (stbi_uc *) buffer;
4096 a.zbuffer_end = (stbi_uc *) buffer+len;
4097 if (stbi__do_zlib(&a, p, 16384, 1, 0)) {
4098 if (outlen) *outlen = (int) (a.zout - a.zout_start);
4099 return a.zout_start;
4100 } else {
4101 STBI_FREE(a.zout_start);
4102 return NULL;
4103 }
4104}
4105
4106STBIDEF int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen)
4107{
4108 stbi__zbuf a;
4109 a.zbuffer = (stbi_uc *) ibuffer;
4110 a.zbuffer_end = (stbi_uc *) ibuffer + ilen;
4111 if (stbi__do_zlib(&a, obuffer, olen, 0, 0))
4112 return (int) (a.zout - a.zout_start);
4113 else
4114 return -1;
4115}
4116#endif
4117
4118// public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18
4119// simple implementation
4120// - only 8-bit samples
4121// - no CRC checking
4122// - allocates lots of intermediate memory
4123// - avoids problem of streaming data between subsystems
4124// - avoids explicit window management
4125// performance
4126// - uses stb_zlib, a PD zlib implementation with fast huffman decoding
4127
4128#ifndef STBI_NO_PNG
4129typedef struct
4130{
4131 stbi__uint32 length;
4132 stbi__uint32 type;
4133} stbi__pngchunk;
4134
4135static stbi__pngchunk stbi__get_chunk_header(stbi__context *s)
4136{
4137 stbi__pngchunk c;
4138 c.length = stbi__get32be(s);
4139 c.type = stbi__get32be(s);
4140 return c;
4141}
4142
4143static int stbi__check_png_header(stbi__context *s)
4144{
4145 static const stbi_uc png_sig[8] = { 137,80,78,71,13,10,26,10 };
4146 int i;
4147 for (i=0; i < 8; ++i)
4148 if (stbi__get8(s) != png_sig[i]) return stbi__err("bad png sig","Not a PNG");
4149 return 1;
4150}
4151
4152typedef struct
4153{
4154 stbi__context *s;
4155 stbi_uc *idata, *expanded, *out;
4156 int depth;
4157} stbi__png;
4158
4159
4160enum {
4161 STBI__F_none=0,
4162 STBI__F_sub=1,
4163 STBI__F_up=2,
4164 STBI__F_avg=3,
4165 STBI__F_paeth=4,
4166 // synthetic filters used for first scanline to avoid needing a dummy row of 0s
4167 STBI__F_avg_first,
4168 STBI__F_paeth_first
4169};
4170
4171static stbi_uc first_row_filter[5] =
4172{
4173 STBI__F_none,
4174 STBI__F_sub,
4175 STBI__F_none,
4176 STBI__F_avg_first,
4177 STBI__F_paeth_first
4178};
4179
4180static int stbi__paeth(int a, int b, int c)
4181{
4182 int p = a + b - c;
4183 int pa = abs(p-a);
4184 int pb = abs(p-b);
4185 int pc = abs(p-c);
4186 if (pa <= pb && pa <= pc) return a;
4187 if (pb <= pc) return b;
4188 return c;
4189}
4190
4191static const stbi_uc stbi__depth_scale_table[9] = { 0, 0xff, 0x55, 0, 0x11, 0,0,0, 0x01 };
4192
4193// create the png data from post-deflated data
4194static int stbi__create_png_image_raw(stbi__png *a, stbi_uc *raw, stbi__uint32 raw_len, int out_n, stbi__uint32 x, stbi__uint32 y, int depth, int color)
4195{
4196 int bytes = (depth == 16? 2 : 1);
4197 stbi__context *s = a->s;
4198 stbi__uint32 i,j,stride = x*out_n*bytes;
4199 stbi__uint32 img_len, img_width_bytes;
4200 int k;
4201 int img_n = s->img_n; // copy it into a local for later
4202
4203 int output_bytes = out_n*bytes;
4204 int filter_bytes = img_n*bytes;
4205 int width = x;
4206
4207 STBI_ASSERT(out_n == s->img_n || out_n == s->img_n+1);
4208 a->out = (stbi_uc *) stbi__malloc_mad3(x, y, output_bytes, 0); // extra bytes to write off the end into
4209 if (!a->out) return stbi__err("outofmem", "Out of memory");
4210
4211 if (!stbi__mad3sizes_valid(img_n, x, depth, 7)) return stbi__err("too large", "Corrupt PNG");
4212 img_width_bytes = (((img_n * x * depth) + 7) >> 3);
4213 img_len = (img_width_bytes + 1) * y;
4214
4215 // we used to check for exact match between raw_len and img_len on non-interlaced PNGs,
4216 // but issue #276 reported a PNG in the wild that had extra data at the end (all zeros),
4217 // so just check for raw_len < img_len always.
4218 if (raw_len < img_len) return stbi__err("not enough pixels","Corrupt PNG");
4219
4220 for (j=0; j < y; ++j) {
4221 stbi_uc *cur = a->out + stride*j;
4222 stbi_uc *prior;
4223 int filter = *raw++;
4224
4225 if (filter > 4)
4226 return stbi__err("invalid filter","Corrupt PNG");
4227
4228 if (depth < 8) {
4229 if (img_width_bytes > x) return stbi__err("invalid width","Corrupt PNG");
4230 cur += x*out_n - img_width_bytes; // store output to the rightmost img_len bytes, so we can decode in place
4231 filter_bytes = 1;
4232 width = img_width_bytes;
4233 }
4234 prior = cur - stride; // bugfix: need to compute this after 'cur +=' computation above
4235
4236 // if first row, use special filter that doesn't sample previous row
4237 if (j == 0) filter = first_row_filter[filter];
4238
4239 // handle first byte explicitly
4240 for (k=0; k < filter_bytes; ++k) {
4241 switch (filter) {
4242 case STBI__F_none : cur[k] = raw[k]; break;
4243 case STBI__F_sub : cur[k] = raw[k]; break;
4244 case STBI__F_up : cur[k] = STBI__BYTECAST(raw[k] + prior[k]); break;
4245 case STBI__F_avg : cur[k] = STBI__BYTECAST(raw[k] + (prior[k]>>1)); break;
4246 case STBI__F_paeth : cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(0,prior[k],0)); break;
4247 case STBI__F_avg_first : cur[k] = raw[k]; break;
4248 case STBI__F_paeth_first: cur[k] = raw[k]; break;
4249 }
4250 }
4251
4252 if (depth == 8) {
4253 if (img_n != out_n)
4254 cur[img_n] = 255; // first pixel
4255 raw += img_n;
4256 cur += out_n;
4257 prior += out_n;
4258 } else if (depth == 16) {
4259 if (img_n != out_n) {
4260 cur[filter_bytes] = 255; // first pixel top byte
4261 cur[filter_bytes+1] = 255; // first pixel bottom byte
4262 }
4263 raw += filter_bytes;
4264 cur += output_bytes;
4265 prior += output_bytes;
4266 } else {
4267 raw += 1;
4268 cur += 1;
4269 prior += 1;
4270 }
4271
4272 // this is a little gross, so that we don't switch per-pixel or per-component
4273 if (depth < 8 || img_n == out_n) {
4274 int nk = (width - 1)*filter_bytes;
4275 #define STBI__CASE(f) \
4276 case f: \
4277 for (k=0; k < nk; ++k)
4278 switch (filter) {
4279 // "none" filter turns into a memcpy here; make that explicit.
4280 case STBI__F_none: memcpy(cur, raw, nk); break;
4281 STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k-filter_bytes]); } break;
4282 STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); } break;
4283 STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k-filter_bytes])>>1)); } break;
4284 STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k-filter_bytes],prior[k],prior[k-filter_bytes])); } break;
4285 STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k-filter_bytes] >> 1)); } break;
4286 STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k-filter_bytes],0,0)); } break;
4287 }
4288 #undef STBI__CASE
4289 raw += nk;
4290 } else {
4291 STBI_ASSERT(img_n+1 == out_n);
4292 #define STBI__CASE(f) \
4293 case f: \
4294 for (i=x-1; i >= 1; --i, cur[filter_bytes]=255,raw+=filter_bytes,cur+=output_bytes,prior+=output_bytes) \
4295 for (k=0; k < filter_bytes; ++k)
4296 switch (filter) {
4297 STBI__CASE(STBI__F_none) { cur[k] = raw[k]; } break;
4298 STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k- output_bytes]); } break;
4299 STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); } break;
4300 STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k- output_bytes])>>1)); } break;
4301 STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k- output_bytes],prior[k],prior[k- output_bytes])); } break;
4302 STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k- output_bytes] >> 1)); } break;
4303 STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k- output_bytes],0,0)); } break;
4304 }
4305 #undef STBI__CASE
4306
4307 // the loop above sets the high byte of the pixels' alpha, but for
4308 // 16 bit png files we also need the low byte set. we'll do that here.
4309 if (depth == 16) {
4310 cur = a->out + stride*j; // start at the beginning of the row again
4311 for (i=0; i < x; ++i,cur+=output_bytes) {
4312 cur[filter_bytes+1] = 255;
4313 }
4314 }
4315 }
4316 }
4317
4318 // we make a separate pass to expand bits to pixels; for performance,
4319 // this could run two scanlines behind the above code, so it won't
4320 // intefere with filtering but will still be in the cache.
4321 if (depth < 8) {
4322 for (j=0; j < y; ++j) {
4323 stbi_uc *cur = a->out + stride*j;
4324 stbi_uc *in = a->out + stride*j + x*out_n - img_width_bytes;
4325 // unpack 1/2/4-bit into a 8-bit buffer. allows us to keep the common 8-bit path optimal at minimal cost for 1/2/4-bit
4326 // png guarante byte alignment, if width is not multiple of 8/4/2 we'll decode dummy trailing data that will be skipped in the later loop
4327 stbi_uc scale = (color == 0) ? stbi__depth_scale_table[depth] : 1; // scale grayscale values to 0..255 range
4328
4329 // note that the final byte might overshoot and write more data than desired.
4330 // we can allocate enough data that this never writes out of memory, but it
4331 // could also overwrite the next scanline. can it overwrite non-empty data
4332 // on the next scanline? yes, consider 1-pixel-wide scanlines with 1-bit-per-pixel.
4333 // so we need to explicitly clamp the final ones
4334
4335 if (depth == 4) {
4336 for (k=x*img_n; k >= 2; k-=2, ++in) {
4337 *cur++ = scale * ((*in >> 4) );
4338 *cur++ = scale * ((*in ) & 0x0f);
4339 }
4340 if (k > 0) *cur++ = scale * ((*in >> 4) );
4341 } else if (depth == 2) {
4342 for (k=x*img_n; k >= 4; k-=4, ++in) {
4343 *cur++ = scale * ((*in >> 6) );
4344 *cur++ = scale * ((*in >> 4) & 0x03);
4345 *cur++ = scale * ((*in >> 2) & 0x03);
4346 *cur++ = scale * ((*in ) & 0x03);
4347 }
4348 if (k > 0) *cur++ = scale * ((*in >> 6) );
4349 if (k > 1) *cur++ = scale * ((*in >> 4) & 0x03);
4350 if (k > 2) *cur++ = scale * ((*in >> 2) & 0x03);
4351 } else if (depth == 1) {
4352 for (k=x*img_n; k >= 8; k-=8, ++in) {
4353 *cur++ = scale * ((*in >> 7) );
4354 *cur++ = scale * ((*in >> 6) & 0x01);
4355 *cur++ = scale * ((*in >> 5) & 0x01);
4356 *cur++ = scale * ((*in >> 4) & 0x01);
4357 *cur++ = scale * ((*in >> 3) & 0x01);
4358 *cur++ = scale * ((*in >> 2) & 0x01);
4359 *cur++ = scale * ((*in >> 1) & 0x01);
4360 *cur++ = scale * ((*in ) & 0x01);
4361 }
4362 if (k > 0) *cur++ = scale * ((*in >> 7) );
4363 if (k > 1) *cur++ = scale * ((*in >> 6) & 0x01);
4364 if (k > 2) *cur++ = scale * ((*in >> 5) & 0x01);
4365 if (k > 3) *cur++ = scale * ((*in >> 4) & 0x01);
4366 if (k > 4) *cur++ = scale * ((*in >> 3) & 0x01);
4367 if (k > 5) *cur++ = scale * ((*in >> 2) & 0x01);
4368 if (k > 6) *cur++ = scale * ((*in >> 1) & 0x01);
4369 }
4370 if (img_n != out_n) {
4371 int q;
4372 // insert alpha = 255
4373 cur = a->out + stride*j;
4374 if (img_n == 1) {
4375 for (q=x-1; q >= 0; --q) {
4376 cur[q*2+1] = 255;
4377 cur[q*2+0] = cur[q];
4378 }
4379 } else {
4380 STBI_ASSERT(img_n == 3);
4381 for (q=x-1; q >= 0; --q) {
4382 cur[q*4+3] = 255;
4383 cur[q*4+2] = cur[q*3+2];
4384 cur[q*4+1] = cur[q*3+1];
4385 cur[q*4+0] = cur[q*3+0];
4386 }
4387 }
4388 }
4389 }
4390 } else if (depth == 16) {
4391 // force the image data from big-endian to platform-native.
4392 // this is done in a separate pass due to the decoding relying
4393 // on the data being untouched, but could probably be done
4394 // per-line during decode if care is taken.
4395 stbi_uc *cur = a->out;
4396 stbi__uint16 *cur16 = (stbi__uint16*)cur;
4397
4398 for(i=0; i < x*y*out_n; ++i,cur16++,cur+=2) {
4399 *cur16 = (cur[0] << 8) | cur[1];
4400 }
4401 }
4402
4403 return 1;
4404}
4405
4406static int stbi__create_png_image(stbi__png *a, stbi_uc *image_data, stbi__uint32 image_data_len, int out_n, int depth, int color, int interlaced)
4407{
4408 int bytes = (depth == 16 ? 2 : 1);
4409 int out_bytes = out_n * bytes;
4410 stbi_uc *final;
4411 int p;
4412 if (!interlaced)
4413 return stbi__create_png_image_raw(a, image_data, image_data_len, out_n, a->s->img_x, a->s->img_y, depth, color);
4414
4415 // de-interlacing
4416 final = (stbi_uc *) stbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0);
4417 if (!final) return stbi__err("outofmem", "Out of memory");
4418 for (p=0; p < 7; ++p) {
4419 int xorig[] = { 0,4,0,2,0,1,0 };
4420 int yorig[] = { 0,0,4,0,2,0,1 };
4421 int xspc[] = { 8,8,4,4,2,2,1 };
4422 int yspc[] = { 8,8,8,4,4,2,2 };
4423 int i,j,x,y;
4424 // pass1_x[4] = 0, pass1_x[5] = 1, pass1_x[12] = 1
4425 x = (a->s->img_x - xorig[p] + xspc[p]-1) / xspc[p];
4426 y = (a->s->img_y - yorig[p] + yspc[p]-1) / yspc[p];
4427 if (x && y) {
4428 stbi__uint32 img_len = ((((a->s->img_n * x * depth) + 7) >> 3) + 1) * y;
4429 if (!stbi__create_png_image_raw(a, image_data, image_data_len, out_n, x, y, depth, color)) {
4430 STBI_FREE(final);
4431 return 0;
4432 }
4433 for (j=0; j < y; ++j) {
4434 for (i=0; i < x; ++i) {
4435 int out_y = j*yspc[p]+yorig[p];
4436 int out_x = i*xspc[p]+xorig[p];
4437 memcpy(final + out_y*a->s->img_x*out_bytes + out_x*out_bytes,
4438 a->out + (j*x+i)*out_bytes, out_bytes);
4439 }
4440 }
4441 STBI_FREE(a->out);
4442 image_data += img_len;
4443 image_data_len -= img_len;
4444 }
4445 }
4446 a->out = final;
4447
4448 return 1;
4449}
4450
4451static int stbi__compute_transparency(stbi__png *z, stbi_uc tc[3], int out_n)
4452{
4453 stbi__context *s = z->s;
4454 stbi__uint32 i, pixel_count = s->img_x * s->img_y;
4455 stbi_uc *p = z->out;
4456
4457 // compute color-based transparency, assuming we've
4458 // already got 255 as the alpha value in the output
4459 STBI_ASSERT(out_n == 2 || out_n == 4);
4460
4461 if (out_n == 2) {
4462 for (i=0; i < pixel_count; ++i) {
4463 p[1] = (p[0] == tc[0] ? 0 : 255);
4464 p += 2;
4465 }
4466 } else {
4467 for (i=0; i < pixel_count; ++i) {
4468 if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
4469 p[3] = 0;
4470 p += 4;
4471 }
4472 }
4473 return 1;
4474}
4475
4476static int stbi__compute_transparency16(stbi__png *z, stbi__uint16 tc[3], int out_n)
4477{
4478 stbi__context *s = z->s;
4479 stbi__uint32 i, pixel_count = s->img_x * s->img_y;
4480 stbi__uint16 *p = (stbi__uint16*) z->out;
4481
4482 // compute color-based transparency, assuming we've
4483 // already got 65535 as the alpha value in the output
4484 STBI_ASSERT(out_n == 2 || out_n == 4);
4485
4486 if (out_n == 2) {
4487 for (i = 0; i < pixel_count; ++i) {
4488 p[1] = (p[0] == tc[0] ? 0 : 65535);
4489 p += 2;
4490 }
4491 } else {
4492 for (i = 0; i < pixel_count; ++i) {
4493 if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
4494 p[3] = 0;
4495 p += 4;
4496 }
4497 }
4498 return 1;
4499}
4500
4501static int stbi__expand_png_palette(stbi__png *a, stbi_uc *palette, int len, int pal_img_n)
4502{
4503 stbi__uint32 i, pixel_count = a->s->img_x * a->s->img_y;
4504 stbi_uc *p, *temp_out, *orig = a->out;
4505
4506 p = (stbi_uc *) stbi__malloc_mad2(pixel_count, pal_img_n, 0);
4507 if (p == NULL) return stbi__err("outofmem", "Out of memory");
4508
4509 // between here and free(out) below, exitting would leak
4510 temp_out = p;
4511
4512 if (pal_img_n == 3) {
4513 for (i=0; i < pixel_count; ++i) {
4514 int n = orig[i]*4;
4515 p[0] = palette[n ];
4516 p[1] = palette[n+1];
4517 p[2] = palette[n+2];
4518 p += 3;
4519 }
4520 } else {
4521 for (i=0; i < pixel_count; ++i) {
4522 int n = orig[i]*4;
4523 p[0] = palette[n ];
4524 p[1] = palette[n+1];
4525 p[2] = palette[n+2];
4526 p[3] = palette[n+3];
4527 p += 4;
4528 }
4529 }
4530 STBI_FREE(a->out);
4531 a->out = temp_out;
4532
4533 STBI_NOTUSED(len);
4534
4535 return 1;
4536}
4537
4538static int stbi__unpremultiply_on_load_global = 0;
4539static int stbi__de_iphone_flag_global = 0;
4540
4541STBIDEF void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply)
4542{
4543 stbi__unpremultiply_on_load_global = flag_true_if_should_unpremultiply;
4544}
4545
4546STBIDEF void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert)
4547{
4548 stbi__de_iphone_flag_global = flag_true_if_should_convert;
4549}
4550
4551#ifndef STBI_THREAD_LOCAL
4552#define stbi__unpremultiply_on_load stbi__unpremultiply_on_load_global
4553#define stbi__de_iphone_flag stbi__de_iphone_flag_global
4554#else
4555static STBI_THREAD_LOCAL int stbi__unpremultiply_on_load_local, stbi__unpremultiply_on_load_set;
4556static STBI_THREAD_LOCAL int stbi__de_iphone_flag_local, stbi__de_iphone_flag_set;
4557
4558STBIDEF void stbi_set_unpremultiply_on_load_thread(int flag_true_if_should_unpremultiply)
4559{
4560 stbi__unpremultiply_on_load_local = flag_true_if_should_unpremultiply;
4561 stbi__unpremultiply_on_load_set = 1;
4562}
4563
4564STBIDEF void stbi_convert_iphone_png_to_rgb_thread(int flag_true_if_should_convert)
4565{
4566 stbi__de_iphone_flag_local = flag_true_if_should_convert;
4567 stbi__de_iphone_flag_set = 1;
4568}
4569
4570#define stbi__unpremultiply_on_load (stbi__unpremultiply_on_load_set \
4571 ? stbi__unpremultiply_on_load_local \
4572 : stbi__unpremultiply_on_load_global)
4573#define stbi__de_iphone_flag (stbi__de_iphone_flag_set \
4574 ? stbi__de_iphone_flag_local \
4575 : stbi__de_iphone_flag_global)
4576#endif // STBI_THREAD_LOCAL
4577
4578static void stbi__de_iphone(stbi__png *z)
4579{
4580 stbi__context *s = z->s;
4581 stbi__uint32 i, pixel_count = s->img_x * s->img_y;
4582 stbi_uc *p = z->out;
4583
4584 if (s->img_out_n == 3) { // convert bgr to rgb
4585 for (i=0; i < pixel_count; ++i) {
4586 stbi_uc t = p[0];
4587 p[0] = p[2];
4588 p[2] = t;
4589 p += 3;
4590 }
4591 } else {
4592 STBI_ASSERT(s->img_out_n == 4);
4593 if (stbi__unpremultiply_on_load) {
4594 // convert bgr to rgb and unpremultiply
4595 for (i=0; i < pixel_count; ++i) {
4596 stbi_uc a = p[3];
4597 stbi_uc t = p[0];
4598 if (a) {
4599 stbi_uc half = a / 2;
4600 p[0] = (p[2] * 255 + half) / a;
4601 p[1] = (p[1] * 255 + half) / a;
4602 p[2] = ( t * 255 + half) / a;
4603 } else {
4604 p[0] = p[2];
4605 p[2] = t;
4606 }
4607 p += 4;
4608 }
4609 } else {
4610 // convert bgr to rgb
4611 for (i=0; i < pixel_count; ++i) {
4612 stbi_uc t = p[0];
4613 p[0] = p[2];
4614 p[2] = t;
4615 p += 4;
4616 }
4617 }
4618 }
4619}
4620
4621#define STBI__PNG_TYPE(a,b,c,d) (((unsigned) (a) << 24) + ((unsigned) (b) << 16) + ((unsigned) (c) << 8) + (unsigned) (d))
4622
4623static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
4624{
4625 stbi_uc palette[1024], pal_img_n=0;
4626 stbi_uc has_trans=0, tc[3]={0};
4627 stbi__uint16 tc16[3];
4628 stbi__uint32 ioff=0, idata_limit=0, i, pal_len=0;
4629 int first=1,k,interlace=0, color=0, is_iphone=0;
4630 stbi__context *s = z->s;
4631
4632 z->expanded = NULL;
4633 z->idata = NULL;
4634 z->out = NULL;
4635
4636 if (!stbi__check_png_header(s)) return 0;
4637
4638 if (scan == STBI__SCAN_type) return 1;
4639
4640 for (;;) {
4641 stbi__pngchunk c = stbi__get_chunk_header(s);
4642 switch (c.type) {
4643 case STBI__PNG_TYPE('C','g','B','I'):
4644 is_iphone = 1;
4645 stbi__skip(s, c.length);
4646 break;
4647 case STBI__PNG_TYPE('I','H','D','R'): {
4648 int comp,filter;
4649 if (!first) return stbi__err("multiple IHDR","Corrupt PNG");
4650 first = 0;
4651 if (c.length != 13) return stbi__err("bad IHDR len","Corrupt PNG");
4652 s->img_x = stbi__get32be(s);
4653 s->img_y = stbi__get32be(s);
4654 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
4655 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
4656 z->depth = stbi__get8(s); if (z->depth != 1 && z->depth != 2 && z->depth != 4 && z->depth != 8 && z->depth != 16) return stbi__err("1/2/4/8/16-bit only","PNG not supported: 1/2/4/8/16-bit only");
4657 color = stbi__get8(s); if (color > 6) return stbi__err("bad ctype","Corrupt PNG");
4658 if (color == 3 && z->depth == 16) return stbi__err("bad ctype","Corrupt PNG");
4659 if (color == 3) pal_img_n = 3; else if (color & 1) return stbi__err("bad ctype","Corrupt PNG");
4660 comp = stbi__get8(s); if (comp) return stbi__err("bad comp method","Corrupt PNG");
4661 filter= stbi__get8(s); if (filter) return stbi__err("bad filter method","Corrupt PNG");
4662 interlace = stbi__get8(s); if (interlace>1) return stbi__err("bad interlace method","Corrupt PNG");
4663 if (!s->img_x || !s->img_y) return stbi__err("0-pixel image","Corrupt PNG");
4664 if (!pal_img_n) {
4665 s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
4666 if ((1 << 30) / s->img_x / s->img_n < s->img_y) return stbi__err("too large", "Image too large to decode");
4667 } else {
4668 // if paletted, then pal_n is our final components, and
4669 // img_n is # components to decompress/filter.
4670 s->img_n = 1;
4671 if ((1 << 30) / s->img_x / 4 < s->img_y) return stbi__err("too large","Corrupt PNG");
4672 }
4673 // even with SCAN_header, have to scan to see if we have a tRNS
4674 break;
4675 }
4676
4677 case STBI__PNG_TYPE('P','L','T','E'): {
4678 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
4679 if (c.length > 256*3) return stbi__err("invalid PLTE","Corrupt PNG");
4680 pal_len = c.length / 3;
4681 if (pal_len * 3 != c.length) return stbi__err("invalid PLTE","Corrupt PNG");
4682 for (i=0; i < pal_len; ++i) {
4683 palette[i*4+0] = stbi__get8(s);
4684 palette[i*4+1] = stbi__get8(s);
4685 palette[i*4+2] = stbi__get8(s);
4686 palette[i*4+3] = 255;
4687 }
4688 break;
4689 }
4690
4691 case STBI__PNG_TYPE('t','R','N','S'): {
4692 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
4693 if (z->idata) return stbi__err("tRNS after IDAT","Corrupt PNG");
4694 if (pal_img_n) {
4695 if (scan == STBI__SCAN_header) { s->img_n = 4; return 1; }
4696 if (pal_len == 0) return stbi__err("tRNS before PLTE","Corrupt PNG");
4697 if (c.length > pal_len) return stbi__err("bad tRNS len","Corrupt PNG");
4698 pal_img_n = 4;
4699 for (i=0; i < c.length; ++i)
4700 palette[i*4+3] = stbi__get8(s);
4701 } else {
4702 if (!(s->img_n & 1)) return stbi__err("tRNS with alpha","Corrupt PNG");
4703 if (c.length != (stbi__uint32) s->img_n*2) return stbi__err("bad tRNS len","Corrupt PNG");
4704 has_trans = 1;
4705 // non-paletted with tRNS = constant alpha. if header-scanning, we can stop now.
4706 if (scan == STBI__SCAN_header) { ++s->img_n; return 1; }
4707 if (z->depth == 16) {
4708 for (k = 0; k < s->img_n; ++k) tc16[k] = (stbi__uint16)stbi__get16be(s); // copy the values as-is
4709 } else {
4710 for (k = 0; k < s->img_n; ++k) tc[k] = (stbi_uc)(stbi__get16be(s) & 255) * stbi__depth_scale_table[z->depth]; // non 8-bit images will be larger
4711 }
4712 }
4713 break;
4714 }
4715
4716 case STBI__PNG_TYPE('I','D','A','T'): {
4717 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
4718 if (pal_img_n && !pal_len) return stbi__err("no PLTE","Corrupt PNG");
4719 if (scan == STBI__SCAN_header) {
4720 // header scan definitely stops at first IDAT
4721 if (pal_img_n)
4722 s->img_n = pal_img_n;
4723 return 1;
4724 }
4725 if (c.length > (1u << 30)) return stbi__err("IDAT size limit", "IDAT section larger than 2^30 bytes");
4726 if ((int)(ioff + c.length) < (int)ioff) return 0;
4727 if (ioff + c.length > idata_limit) {
4728 stbi__uint32 idata_limit_old = idata_limit;
4729 stbi_uc *p;
4730 if (idata_limit == 0) idata_limit = c.length > 4096 ? c.length : 4096;
4731 while (ioff + c.length > idata_limit)
4732 idata_limit *= 2;
4733 STBI_NOTUSED(idata_limit_old);
4734 p = (stbi_uc *) STBI_REALLOC_SIZED(z->idata, idata_limit_old, idata_limit); if (p == NULL) return stbi__err("outofmem", "Out of memory");
4735 z->idata = p;
4736 }
4737 if (!stbi__getn(s, z->idata+ioff,c.length)) return stbi__err("outofdata","Corrupt PNG");
4738 ioff += c.length;
4739 break;
4740 }
4741
4742 case STBI__PNG_TYPE('I','E','N','D'): {
4743 stbi__uint32 raw_len, bpl;
4744 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
4745 if (scan != STBI__SCAN_load) return 1;
4746 if (z->idata == NULL) return stbi__err("no IDAT","Corrupt PNG");
4747 // initial guess for decoded data size to avoid unnecessary reallocs
4748 bpl = (s->img_x * z->depth + 7) / 8; // bytes per line, per component
4749 raw_len = bpl * s->img_y * s->img_n /* pixels */ + s->img_y /* filter mode per row */;
4750 z->expanded = (stbi_uc *) stbi_zlib_decode_malloc_guesssize_headerflag((char *) z->idata, ioff, raw_len, (int *) &raw_len, !is_iphone);
4751 if (z->expanded == NULL) return 0; // zlib should set error
4752 STBI_FREE(z->idata); z->idata = NULL;
4753 if ((req_comp == s->img_n+1 && req_comp != 3 && !pal_img_n) || has_trans)
4754 s->img_out_n = s->img_n+1;
4755 else
4756 s->img_out_n = s->img_n;
4757 if (!stbi__create_png_image(z, z->expanded, raw_len, s->img_out_n, z->depth, color, interlace)) return 0;
4758 if (has_trans) {
4759 if (z->depth == 16) {
4760 if (!stbi__compute_transparency16(z, tc16, s->img_out_n)) return 0;
4761 } else {
4762 if (!stbi__compute_transparency(z, tc, s->img_out_n)) return 0;
4763 }
4764 }
4765 if (is_iphone && stbi__de_iphone_flag && s->img_out_n > 2)
4766 stbi__de_iphone(z);
4767 if (pal_img_n) {
4768 // pal_img_n == 3 or 4
4769 s->img_n = pal_img_n; // record the actual colors we had
4770 s->img_out_n = pal_img_n;
4771 if (req_comp >= 3) s->img_out_n = req_comp;
4772 if (!stbi__expand_png_palette(z, palette, pal_len, s->img_out_n))
4773 return 0;
4774 } else if (has_trans) {
4775 // non-paletted image with tRNS -> source image has (constant) alpha
4776 ++s->img_n;
4777 }
4778 STBI_FREE(z->expanded); z->expanded = NULL;
4779 // end of PNG chunk, read and skip CRC
4780 stbi__get32be(s);
4781 return 1;
4782 }
4783
4784 default:
4785 // if critical, fail
4786 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
4787 if ((c.type & (1 << 29)) == 0) {
4788 #ifndef STBI_NO_FAILURE_STRINGS
4789 // not threadsafe
4790 static char invalid_chunk[] = "XXXX PNG chunk not known";
4791 invalid_chunk[0] = STBI__BYTECAST(c.type >> 24);
4792 invalid_chunk[1] = STBI__BYTECAST(c.type >> 16);
4793 invalid_chunk[2] = STBI__BYTECAST(c.type >> 8);
4794 invalid_chunk[3] = STBI__BYTECAST(c.type >> 0);
4795 #endif
4796 return stbi__err(invalid_chunk, "PNG not supported: unknown PNG chunk type");
4797 }
4798 stbi__skip(s, c.length);
4799 break;
4800 }
4801 // end of PNG chunk, read and skip CRC
4802 stbi__get32be(s);
4803 }
4804}
4805
4806static void *stbi__do_png(stbi__png *p, int *x, int *y, int *n, int req_comp, stbi__result_info *ri)
4807{
4808 void *result=NULL;
4809 if (req_comp < 0 || req_comp > 4) return stbi__errpuc("bad req_comp", "Internal error");
4810 if (stbi__parse_png_file(p, STBI__SCAN_load, req_comp)) {
4811 if (p->depth <= 8)
4812 ri->bits_per_channel = 8;
4813 else if (p->depth == 16)
4814 ri->bits_per_channel = 16;
4815 else
4816 return stbi__errpuc("bad bits_per_channel", "PNG not supported: unsupported color depth");
4817 result = p->out;
4818 p->out = NULL;
4819 if (req_comp && req_comp != p->s->img_out_n) {
4820 if (ri->bits_per_channel == 8)
4821 result = stbi__convert_format((unsigned char *) result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
4822 else
4823 result = stbi__convert_format16((stbi__uint16 *) result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
4824 p->s->img_out_n = req_comp;
4825 if (result == NULL) return result;
4826 }
4827 *x = p->s->img_x;
4828 *y = p->s->img_y;
4829 if (n) *n = p->s->img_n;
4830 }
4831 STBI_FREE(p->out); p->out = NULL;
4832 STBI_FREE(p->expanded); p->expanded = NULL;
4833 STBI_FREE(p->idata); p->idata = NULL;
4834
4835 return result;
4836}
4837
4838static void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
4839{
4840 stbi__png p;
4841 p.s = s;
4842 return stbi__do_png(&p, x,y,comp,req_comp, ri);
4843}
4844
4845static int stbi__png_test(stbi__context *s)
4846{
4847 int r;
4848 r = stbi__check_png_header(s);
4849 stbi__rewind(s);
4850 return r;
4851}
4852
4853static int stbi__png_info_raw(stbi__png *p, int *x, int *y, int *comp)
4854{
4855 if (!stbi__parse_png_file(p, STBI__SCAN_header, 0)) {
4856 stbi__rewind( p->s );
4857 return 0;
4858 }
4859 if (x) *x = p->s->img_x;
4860 if (y) *y = p->s->img_y;
4861 if (comp) *comp = p->s->img_n;
4862 return 1;
4863}
4864
4865static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp)
4866{
4867 stbi__png p;
4868 p.s = s;
4869 return stbi__png_info_raw(&p, x, y, comp);
4870}
4871
4872static int stbi__png_is16(stbi__context *s)
4873{
4874 stbi__png p;
4875 p.s = s;
4876 if (!stbi__png_info_raw(&p, NULL, NULL, NULL))
4877 return 0;
4878 if (p.depth != 16) {
4879 stbi__rewind(p.s);
4880 return 0;
4881 }
4882 return 1;
4883}
4884#endif
4885
4886// Microsoft/Windows BMP image
4887
4888#ifndef STBI_NO_BMP
4889static int stbi__bmp_test_raw(stbi__context *s)
4890{
4891 int r;
4892 int sz;
4893 if (stbi__get8(s) != 'B') return 0;
4894 if (stbi__get8(s) != 'M') return 0;
4895 stbi__get32le(s); // discard filesize
4896 stbi__get16le(s); // discard reserved
4897 stbi__get16le(s); // discard reserved
4898 stbi__get32le(s); // discard data offset
4899 sz = stbi__get32le(s);
4900 r = (sz == 12 || sz == 40 || sz == 56 || sz == 108 || sz == 124);
4901 return r;
4902}
4903
4904static int stbi__bmp_test(stbi__context *s)
4905{
4906 int r = stbi__bmp_test_raw(s);
4907 stbi__rewind(s);
4908 return r;
4909}
4910
4911
4912// returns 0..31 for the highest set bit
4913static int stbi__high_bit(unsigned int z)
4914{
4915 int n=0;
4916 if (z == 0) return -1;
4917 if (z >= 0x10000) { n += 16; z >>= 16; }
4918 if (z >= 0x00100) { n += 8; z >>= 8; }
4919 if (z >= 0x00010) { n += 4; z >>= 4; }
4920 if (z >= 0x00004) { n += 2; z >>= 2; }
4921 if (z >= 0x00002) { n += 1;/* >>= 1;*/ }
4922 return n;
4923}
4924
4925static int stbi__bitcount(unsigned int a)
4926{
4927 a = (a & 0x55555555) + ((a >> 1) & 0x55555555); // max 2
4928 a = (a & 0x33333333) + ((a >> 2) & 0x33333333); // max 4
4929 a = (a + (a >> 4)) & 0x0f0f0f0f; // max 8 per 4, now 8 bits
4930 a = (a + (a >> 8)); // max 16 per 8 bits
4931 a = (a + (a >> 16)); // max 32 per 8 bits
4932 return a & 0xff;
4933}
4934
4935// extract an arbitrarily-aligned N-bit value (N=bits)
4936// from v, and then make it 8-bits long and fractionally
4937// extend it to full full range.
4938static int stbi__shiftsigned(unsigned int v, int shift, int bits)
4939{
4940 static unsigned int mul_table[9] = {
4941 0,
4942 0xff/*0b11111111*/, 0x55/*0b01010101*/, 0x49/*0b01001001*/, 0x11/*0b00010001*/,
4943 0x21/*0b00100001*/, 0x41/*0b01000001*/, 0x81/*0b10000001*/, 0x01/*0b00000001*/,
4944 };
4945 static unsigned int shift_table[9] = {
4946 0, 0,0,1,0,2,4,6,0,
4947 };
4948 if (shift < 0)
4949 v <<= -shift;
4950 else
4951 v >>= shift;
4952 STBI_ASSERT(v < 256);
4953 v >>= (8-bits);
4954 STBI_ASSERT(bits >= 0 && bits <= 8);
4955 return (int) ((unsigned) v * mul_table[bits]) >> shift_table[bits];
4956}
4957
4958typedef struct
4959{
4960 int bpp, offset, hsz;
4961 unsigned int mr,mg,mb,ma, all_a;
4962 int extra_read;
4963} stbi__bmp_data;
4964
4965static int stbi__bmp_set_mask_defaults(stbi__bmp_data *info, int compress)
4966{
4967 // BI_BITFIELDS specifies masks explicitly, don't override
4968 if (compress == 3)
4969 return 1;
4970
4971 if (compress == 0) {
4972 if (info->bpp == 16) {
4973 info->mr = 31u << 10;
4974 info->mg = 31u << 5;
4975 info->mb = 31u << 0;
4976 } else if (info->bpp == 32) {
4977 info->mr = 0xffu << 16;
4978 info->mg = 0xffu << 8;
4979 info->mb = 0xffu << 0;
4980 info->ma = 0xffu << 24;
4981 info->all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
4982 } else {
4983 // otherwise, use defaults, which is all-0
4984 info->mr = info->mg = info->mb = info->ma = 0;
4985 }
4986 return 1;
4987 }
4988 return 0; // error
4989}
4990
4991static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
4992{
4993 int hsz;
4994 if (stbi__get8(s) != 'B' || stbi__get8(s) != 'M') return stbi__errpuc("not BMP", "Corrupt BMP");
4995 stbi__get32le(s); // discard filesize
4996 stbi__get16le(s); // discard reserved
4997 stbi__get16le(s); // discard reserved
4998 info->offset = stbi__get32le(s);
4999 info->hsz = hsz = stbi__get32le(s);
5000 info->mr = info->mg = info->mb = info->ma = 0;
5001 info->extra_read = 14;
5002
5003 if (info->offset < 0) return stbi__errpuc("bad BMP", "bad BMP");
5004
5005 if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108 && hsz != 124) return stbi__errpuc("unknown BMP", "BMP type not supported: unknown");
5006 if (hsz == 12) {
5007 s->img_x = stbi__get16le(s);
5008 s->img_y = stbi__get16le(s);
5009 } else {
5010 s->img_x = stbi__get32le(s);
5011 s->img_y = stbi__get32le(s);
5012 }
5013 if (stbi__get16le(s) != 1) return stbi__errpuc("bad BMP", "bad BMP");
5014 info->bpp = stbi__get16le(s);
5015 if (hsz != 12) {
5016 int compress = stbi__get32le(s);
5017 if (compress == 1 || compress == 2) return stbi__errpuc("BMP RLE", "BMP type not supported: RLE");
5018 if (compress >= 4) return stbi__errpuc("BMP JPEG/PNG", "BMP type not supported: unsupported compression"); // this includes PNG/JPEG modes
5019 if (compress == 3 && info->bpp != 16 && info->bpp != 32) return stbi__errpuc("bad BMP", "bad BMP"); // bitfields requires 16 or 32 bits/pixel
5020 stbi__get32le(s); // discard sizeof
5021 stbi__get32le(s); // discard hres
5022 stbi__get32le(s); // discard vres
5023 stbi__get32le(s); // discard colorsused
5024 stbi__get32le(s); // discard max important
5025 if (hsz == 40 || hsz == 56) {
5026 if (hsz == 56) {
5027 stbi__get32le(s);
5028 stbi__get32le(s);
5029 stbi__get32le(s);
5030 stbi__get32le(s);
5031 }
5032 if (info->bpp == 16 || info->bpp == 32) {
5033 if (compress == 0) {
5034 stbi__bmp_set_mask_defaults(info, compress);
5035 } else if (compress == 3) {
5036 info->mr = stbi__get32le(s);
5037 info->mg = stbi__get32le(s);
5038 info->mb = stbi__get32le(s);
5039 info->extra_read += 12;
5040 // not documented, but generated by photoshop and handled by mspaint
5041 if (info->mr == info->mg && info->mg == info->mb) {
5042 // ?!?!?
5043 return stbi__errpuc("bad BMP", "bad BMP");
5044 }
5045 } else
5046 return stbi__errpuc("bad BMP", "bad BMP");
5047 }
5048 } else {
5049 // V4/V5 header
5050 int i;
5051 if (hsz != 108 && hsz != 124)
5052 return stbi__errpuc("bad BMP", "bad BMP");
5053 info->mr = stbi__get32le(s);
5054 info->mg = stbi__get32le(s);
5055 info->mb = stbi__get32le(s);
5056 info->ma = stbi__get32le(s);
5057 if (compress != 3) // override mr/mg/mb unless in BI_BITFIELDS mode, as per docs
5058 stbi__bmp_set_mask_defaults(info, compress);
5059 stbi__get32le(s); // discard color space
5060 for (i=0; i < 12; ++i)
5061 stbi__get32le(s); // discard color space parameters
5062 if (hsz == 124) {
5063 stbi__get32le(s); // discard rendering intent
5064 stbi__get32le(s); // discard offset of profile data
5065 stbi__get32le(s); // discard size of profile data
5066 stbi__get32le(s); // discard reserved
5067 }
5068 }
5069 }
5070 return (void *) 1;
5071}
5072
5073
5074static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
5075{
5076 stbi_uc *out;
5077 unsigned int mr=0,mg=0,mb=0,ma=0, all_a;
5078 stbi_uc pal[256][4];
5079 int psize=0,i,j,width;
5080 int flip_vertically, pad, target;
5081 stbi__bmp_data info;
5082 STBI_NOTUSED(ri);
5083
5084 info.all_a = 255;
5085 if (stbi__bmp_parse_header(s, &info) == NULL)
5086 return NULL; // error code already set
5087
5088 flip_vertically = ((int) s->img_y) > 0;
5089 s->img_y = abs((int) s->img_y);
5090
5091 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5092 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5093
5094 mr = info.mr;
5095 mg = info.mg;
5096 mb = info.mb;
5097 ma = info.ma;
5098 all_a = info.all_a;
5099
5100 if (info.hsz == 12) {
5101 if (info.bpp < 24)
5102 psize = (info.offset - info.extra_read - 24) / 3;
5103 } else {
5104 if (info.bpp < 16)
5105 psize = (info.offset - info.extra_read - info.hsz) >> 2;
5106 }
5107 if (psize == 0) {
5108 // accept some number of extra bytes after the header, but if the offset points either to before
5109 // the header ends or implies a large amount of extra data, reject the file as malformed
5110 int bytes_read_so_far = s->callback_already_read + (int)(s->img_buffer - s->img_buffer_original);
5111 int header_limit = 1024; // max we actually read is below 256 bytes currently.
5112 int extra_data_limit = 256*4; // what ordinarily goes here is a palette; 256 entries*4 bytes is its max size.
5113 if (bytes_read_so_far <= 0 || bytes_read_so_far > header_limit) {
5114 return stbi__errpuc("bad header", "Corrupt BMP");
5115 }
5116 // we established that bytes_read_so_far is positive and sensible.
5117 // the first half of this test rejects offsets that are either too small positives, or
5118 // negative, and guarantees that info.offset >= bytes_read_so_far > 0. this in turn
5119 // ensures the number computed in the second half of the test can't overflow.
5120 if (info.offset < bytes_read_so_far || info.offset - bytes_read_so_far > extra_data_limit) {
5121 return stbi__errpuc("bad offset", "Corrupt BMP");
5122 } else {
5123 stbi__skip(s, info.offset - bytes_read_so_far);
5124 }
5125 }
5126
5127 if (info.bpp == 24 && ma == 0xff000000)
5128 s->img_n = 3;
5129 else
5130 s->img_n = ma ? 4 : 3;
5131 if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
5132 target = req_comp;
5133 else
5134 target = s->img_n; // if they want monochrome, we'll post-convert
5135
5136 // sanity-check size
5137 if (!stbi__mad3sizes_valid(target, s->img_x, s->img_y, 0))
5138 return stbi__errpuc("too large", "Corrupt BMP");
5139
5140 out = (stbi_uc *) stbi__malloc_mad3(target, s->img_x, s->img_y, 0);
5141 if (!out) return stbi__errpuc("outofmem", "Out of memory");
5142 if (info.bpp < 16) {
5143 int z=0;
5144 if (psize == 0 || psize > 256) { STBI_FREE(out); return stbi__errpuc("invalid", "Corrupt BMP"); }
5145 for (i=0; i < psize; ++i) {
5146 pal[i][2] = stbi__get8(s);
5147 pal[i][1] = stbi__get8(s);
5148 pal[i][0] = stbi__get8(s);
5149 if (info.hsz != 12) stbi__get8(s);
5150 pal[i][3] = 255;
5151 }
5152 stbi__skip(s, info.offset - info.extra_read - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
5153 if (info.bpp == 1) width = (s->img_x + 7) >> 3;
5154 else if (info.bpp == 4) width = (s->img_x + 1) >> 1;
5155 else if (info.bpp == 8) width = s->img_x;
5156 else { STBI_FREE(out); return stbi__errpuc("bad bpp", "Corrupt BMP"); }
5157 pad = (-width)&3;
5158 if (info.bpp == 1) {
5159 for (j=0; j < (int) s->img_y; ++j) {
5160 int bit_offset = 7, v = stbi__get8(s);
5161 for (i=0; i < (int) s->img_x; ++i) {
5162 int color = (v>>bit_offset)&0x1;
5163 out[z++] = pal[color][0];
5164 out[z++] = pal[color][1];
5165 out[z++] = pal[color][2];
5166 if (target == 4) out[z++] = 255;
5167 if (i+1 == (int) s->img_x) break;
5168 if((--bit_offset) < 0) {
5169 bit_offset = 7;
5170 v = stbi__get8(s);
5171 }
5172 }
5173 stbi__skip(s, pad);
5174 }
5175 } else {
5176 for (j=0; j < (int) s->img_y; ++j) {
5177 for (i=0; i < (int) s->img_x; i += 2) {
5178 int v=stbi__get8(s),v2=0;
5179 if (info.bpp == 4) {
5180 v2 = v & 15;
5181 v >>= 4;
5182 }
5183 out[z++] = pal[v][0];
5184 out[z++] = pal[v][1];
5185 out[z++] = pal[v][2];
5186 if (target == 4) out[z++] = 255;
5187 if (i+1 == (int) s->img_x) break;
5188 v = (info.bpp == 8) ? stbi__get8(s) : v2;
5189 out[z++] = pal[v][0];
5190 out[z++] = pal[v][1];
5191 out[z++] = pal[v][2];
5192 if (target == 4) out[z++] = 255;
5193 }
5194 stbi__skip(s, pad);
5195 }
5196 }
5197 } else {
5198 int rshift=0,gshift=0,bshift=0,ashift=0,rcount=0,gcount=0,bcount=0,acount=0;
5199 int z = 0;
5200 int easy=0;
5201 stbi__skip(s, info.offset - info.extra_read - info.hsz);
5202 if (info.bpp == 24) width = 3 * s->img_x;
5203 else if (info.bpp == 16) width = 2*s->img_x;
5204 else /* bpp = 32 and pad = 0 */ width=0;
5205 pad = (-width) & 3;
5206 if (info.bpp == 24) {
5207 easy = 1;
5208 } else if (info.bpp == 32) {
5209 if (mb == 0xff && mg == 0xff00 && mr == 0x00ff0000 && ma == 0xff000000)
5210 easy = 2;
5211 }
5212 if (!easy) {
5213 if (!mr || !mg || !mb) { STBI_FREE(out); return stbi__errpuc("bad masks", "Corrupt BMP"); }
5214 // right shift amt to put high bit in position #7
5215 rshift = stbi__high_bit(mr)-7; rcount = stbi__bitcount(mr);
5216 gshift = stbi__high_bit(mg)-7; gcount = stbi__bitcount(mg);
5217 bshift = stbi__high_bit(mb)-7; bcount = stbi__bitcount(mb);
5218 ashift = stbi__high_bit(ma)-7; acount = stbi__bitcount(ma);
5219 if (rcount > 8 || gcount > 8 || bcount > 8 || acount > 8) { STBI_FREE(out); return stbi__errpuc("bad masks", "Corrupt BMP"); }
5220 }
5221 for (j=0; j < (int) s->img_y; ++j) {
5222 if (easy) {
5223 for (i=0; i < (int) s->img_x; ++i) {
5224 unsigned char a;
5225 out[z+2] = stbi__get8(s);
5226 out[z+1] = stbi__get8(s);
5227 out[z+0] = stbi__get8(s);
5228 z += 3;
5229 a = (easy == 2 ? stbi__get8(s) : 255);
5230 all_a |= a;
5231 if (target == 4) out[z++] = a;
5232 }
5233 } else {
5234 int bpp = info.bpp;
5235 for (i=0; i < (int) s->img_x; ++i) {
5236 stbi__uint32 v = (bpp == 16 ? (stbi__uint32) stbi__get16le(s) : stbi__get32le(s));
5237 unsigned int a;
5238 out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mr, rshift, rcount));
5239 out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mg, gshift, gcount));
5240 out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mb, bshift, bcount));
5241 a = (ma ? stbi__shiftsigned(v & ma, ashift, acount) : 255);
5242 all_a |= a;
5243 if (target == 4) out[z++] = STBI__BYTECAST(a);
5244 }
5245 }
5246 stbi__skip(s, pad);
5247 }
5248 }
5249
5250 // if alpha channel is all 0s, replace with all 255s
5251 if (target == 4 && all_a == 0)
5252 for (i=4*s->img_x*s->img_y-1; i >= 0; i -= 4)
5253 out[i] = 255;
5254
5255 if (flip_vertically) {
5256 stbi_uc t;
5257 for (j=0; j < (int) s->img_y>>1; ++j) {
5258 stbi_uc *p1 = out + j *s->img_x*target;
5259 stbi_uc *p2 = out + (s->img_y-1-j)*s->img_x*target;
5260 for (i=0; i < (int) s->img_x*target; ++i) {
5261 t = p1[i]; p1[i] = p2[i]; p2[i] = t;
5262 }
5263 }
5264 }
5265
5266 if (req_comp && req_comp != target) {
5267 out = stbi__convert_format(out, target, req_comp, s->img_x, s->img_y);
5268 if (out == NULL) return out; // stbi__convert_format frees input on failure
5269 }
5270
5271 *x = s->img_x;
5272 *y = s->img_y;
5273 if (comp) *comp = s->img_n;
5274 return out;
5275}
5276#endif
5277
5278// Targa Truevision - TGA
5279// by Jonathan Dummer
5280#ifndef STBI_NO_TGA
5281// returns STBI_rgb or whatever, 0 on error
5282static int stbi__tga_get_comp(int bits_per_pixel, int is_grey, int* is_rgb16)
5283{
5284 // only RGB or RGBA (incl. 16bit) or grey allowed
5285 if (is_rgb16) *is_rgb16 = 0;
5286 switch(bits_per_pixel) {
5287 case 8: return STBI_grey;
5288 case 16: if(is_grey) return STBI_grey_alpha;
5289 // fallthrough
5290 case 15: if(is_rgb16) *is_rgb16 = 1;
5291 return STBI_rgb;
5292 case 24: // fallthrough
5293 case 32: return bits_per_pixel/8;
5294 default: return 0;
5295 }
5296}
5297
5298static int stbi__tga_info(stbi__context *s, int *x, int *y, int *comp)
5299{
5300 int tga_w, tga_h, tga_comp, tga_image_type, tga_bits_per_pixel, tga_colormap_bpp;
5301 int sz, tga_colormap_type;
5302 stbi__get8(s); // discard Offset
5303 tga_colormap_type = stbi__get8(s); // colormap type
5304 if( tga_colormap_type > 1 ) {
5305 stbi__rewind(s);
5306 return 0; // only RGB or indexed allowed
5307 }
5308 tga_image_type = stbi__get8(s); // image type
5309 if ( tga_colormap_type == 1 ) { // colormapped (paletted) image
5310 if (tga_image_type != 1 && tga_image_type != 9) {
5311 stbi__rewind(s);
5312 return 0;
5313 }
5314 stbi__skip(s,4); // skip index of first colormap entry and number of entries
5315 sz = stbi__get8(s); // check bits per palette color entry
5316 if ( (sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32) ) {
5317 stbi__rewind(s);
5318 return 0;
5319 }
5320 stbi__skip(s,4); // skip image x and y origin
5321 tga_colormap_bpp = sz;
5322 } else { // "normal" image w/o colormap - only RGB or grey allowed, +/- RLE
5323 if ( (tga_image_type != 2) && (tga_image_type != 3) && (tga_image_type != 10) && (tga_image_type != 11) ) {
5324 stbi__rewind(s);
5325 return 0; // only RGB or grey allowed, +/- RLE
5326 }
5327 stbi__skip(s,9); // skip colormap specification and image x/y origin
5328 tga_colormap_bpp = 0;
5329 }
5330 tga_w = stbi__get16le(s);
5331 if( tga_w < 1 ) {
5332 stbi__rewind(s);
5333 return 0; // test width
5334 }
5335 tga_h = stbi__get16le(s);
5336 if( tga_h < 1 ) {
5337 stbi__rewind(s);
5338 return 0; // test height
5339 }
5340 tga_bits_per_pixel = stbi__get8(s); // bits per pixel
5341 stbi__get8(s); // ignore alpha bits
5342 if (tga_colormap_bpp != 0) {
5343 if((tga_bits_per_pixel != 8) && (tga_bits_per_pixel != 16)) {
5344 // when using a colormap, tga_bits_per_pixel is the size of the indexes
5345 // I don't think anything but 8 or 16bit indexes makes sense
5346 stbi__rewind(s);
5347 return 0;
5348 }
5349 tga_comp = stbi__tga_get_comp(tga_colormap_bpp, 0, NULL);
5350 } else {
5351 tga_comp = stbi__tga_get_comp(tga_bits_per_pixel, (tga_image_type == 3) || (tga_image_type == 11), NULL);
5352 }
5353 if(!tga_comp) {
5354 stbi__rewind(s);
5355 return 0;
5356 }
5357 if (x) *x = tga_w;
5358 if (y) *y = tga_h;
5359 if (comp) *comp = tga_comp;
5360 return 1; // seems to have passed everything
5361}
5362
5363static int stbi__tga_test(stbi__context *s)
5364{
5365 int res = 0;
5366 int sz, tga_color_type;
5367 stbi__get8(s); // discard Offset
5368 tga_color_type = stbi__get8(s); // color type
5369 if ( tga_color_type > 1 ) goto errorEnd; // only RGB or indexed allowed
5370 sz = stbi__get8(s); // image type
5371 if ( tga_color_type == 1 ) { // colormapped (paletted) image
5372 if (sz != 1 && sz != 9) goto errorEnd; // colortype 1 demands image type 1 or 9
5373 stbi__skip(s,4); // skip index of first colormap entry and number of entries
5374 sz = stbi__get8(s); // check bits per palette color entry
5375 if ( (sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32) ) goto errorEnd;
5376 stbi__skip(s,4); // skip image x and y origin
5377 } else { // "normal" image w/o colormap
5378 if ( (sz != 2) && (sz != 3) && (sz != 10) && (sz != 11) ) goto errorEnd; // only RGB or grey allowed, +/- RLE
5379 stbi__skip(s,9); // skip colormap specification and image x/y origin
5380 }
5381 if ( stbi__get16le(s) < 1 ) goto errorEnd; // test width
5382 if ( stbi__get16le(s) < 1 ) goto errorEnd; // test height
5383 sz = stbi__get8(s); // bits per pixel
5384 if ( (tga_color_type == 1) && (sz != 8) && (sz != 16) ) goto errorEnd; // for colormapped images, bpp is size of an index
5385 if ( (sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32) ) goto errorEnd;
5386
5387 res = 1; // if we got this far, everything's good and we can return 1 instead of 0
5388
5389errorEnd:
5390 stbi__rewind(s);
5391 return res;
5392}
5393
5394// read 16bit value and convert to 24bit RGB
5395static void stbi__tga_read_rgb16(stbi__context *s, stbi_uc* out)
5396{
5397 stbi__uint16 px = (stbi__uint16)stbi__get16le(s);
5398 stbi__uint16 fiveBitMask = 31;
5399 // we have 3 channels with 5bits each
5400 int r = (px >> 10) & fiveBitMask;
5401 int g = (px >> 5) & fiveBitMask;
5402 int b = px & fiveBitMask;
5403 // Note that this saves the data in RGB(A) order, so it doesn't need to be swapped later
5404 out[0] = (stbi_uc)((r * 255)/31);
5405 out[1] = (stbi_uc)((g * 255)/31);
5406 out[2] = (stbi_uc)((b * 255)/31);
5407
5408 // some people claim that the most significant bit might be used for alpha
5409 // (possibly if an alpha-bit is set in the "image descriptor byte")
5410 // but that only made 16bit test images completely translucent..
5411 // so let's treat all 15 and 16bit TGAs as RGB with no alpha.
5412}
5413
5414static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
5415{
5416 // read in the TGA header stuff
5417 int tga_offset = stbi__get8(s);
5418 int tga_indexed = stbi__get8(s);
5419 int tga_image_type = stbi__get8(s);
5420 int tga_is_RLE = 0;
5421 int tga_palette_start = stbi__get16le(s);
5422 int tga_palette_len = stbi__get16le(s);
5423 int tga_palette_bits = stbi__get8(s);
5424 int tga_x_origin = stbi__get16le(s);
5425 int tga_y_origin = stbi__get16le(s);
5426 int tga_width = stbi__get16le(s);
5427 int tga_height = stbi__get16le(s);
5428 int tga_bits_per_pixel = stbi__get8(s);
5429 int tga_comp, tga_rgb16=0;
5430 int tga_inverted = stbi__get8(s);
5431 // int tga_alpha_bits = tga_inverted & 15; // the 4 lowest bits - unused (useless?)
5432 // image data
5433 unsigned char *tga_data;
5434 unsigned char *tga_palette = NULL;
5435 int i, j;
5436 unsigned char raw_data[4] = {0};
5437 int RLE_count = 0;
5438 int RLE_repeating = 0;
5439 int read_next_pixel = 1;
5440 STBI_NOTUSED(ri);
5441 STBI_NOTUSED(tga_x_origin); // @TODO
5442 STBI_NOTUSED(tga_y_origin); // @TODO
5443
5444 if (tga_height > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5445 if (tga_width > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5446
5447 // do a tiny bit of precessing
5448 if ( tga_image_type >= 8 )
5449 {
5450 tga_image_type -= 8;
5451 tga_is_RLE = 1;
5452 }
5453 tga_inverted = 1 - ((tga_inverted >> 5) & 1);
5454
5455 // If I'm paletted, then I'll use the number of bits from the palette
5456 if ( tga_indexed ) tga_comp = stbi__tga_get_comp(tga_palette_bits, 0, &tga_rgb16);
5457 else tga_comp = stbi__tga_get_comp(tga_bits_per_pixel, (tga_image_type == 3), &tga_rgb16);
5458
5459 if(!tga_comp) // shouldn't really happen, stbi__tga_test() should have ensured basic consistency
5460 return stbi__errpuc("bad format", "Can't find out TGA pixelformat");
5461
5462 // tga info
5463 *x = tga_width;
5464 *y = tga_height;
5465 if (comp) *comp = tga_comp;
5466
5467 if (!stbi__mad3sizes_valid(tga_width, tga_height, tga_comp, 0))
5468 return stbi__errpuc("too large", "Corrupt TGA");
5469
5470 tga_data = (unsigned char*)stbi__malloc_mad3(tga_width, tga_height, tga_comp, 0);
5471 if (!tga_data) return stbi__errpuc("outofmem", "Out of memory");
5472
5473 // skip to the data's starting position (offset usually = 0)
5474 stbi__skip(s, tga_offset );
5475
5476 if ( !tga_indexed && !tga_is_RLE && !tga_rgb16 ) {
5477 for (i=0; i < tga_height; ++i) {
5478 int row = tga_inverted ? tga_height -i - 1 : i;
5479 stbi_uc *tga_row = tga_data + row*tga_width*tga_comp;
5480 stbi__getn(s, tga_row, tga_width * tga_comp);
5481 }
5482 } else {
5483 // do I need to load a palette?
5484 if ( tga_indexed)
5485 {
5486 if (tga_palette_len == 0) { /* you have to have at least one entry! */
5487 STBI_FREE(tga_data);
5488 return stbi__errpuc("bad palette", "Corrupt TGA");
5489 }
5490
5491 // any data to skip? (offset usually = 0)
5492 stbi__skip(s, tga_palette_start );
5493 // load the palette
5494 tga_palette = (unsigned char*)stbi__malloc_mad2(tga_palette_len, tga_comp, 0);
5495 if (!tga_palette) {
5496 STBI_FREE(tga_data);
5497 return stbi__errpuc("outofmem", "Out of memory");
5498 }
5499 if (tga_rgb16) {
5500 stbi_uc *pal_entry = tga_palette;
5501 STBI_ASSERT(tga_comp == STBI_rgb);
5502 for (i=0; i < tga_palette_len; ++i) {
5503 stbi__tga_read_rgb16(s, pal_entry);
5504 pal_entry += tga_comp;
5505 }
5506 } else if (!stbi__getn(s, tga_palette, tga_palette_len * tga_comp)) {
5507 STBI_FREE(tga_data);
5508 STBI_FREE(tga_palette);
5509 return stbi__errpuc("bad palette", "Corrupt TGA");
5510 }
5511 }
5512 // load the data
5513 for (i=0; i < tga_width * tga_height; ++i)
5514 {
5515 // if I'm in RLE mode, do I need to get a RLE stbi__pngchunk?
5516 if ( tga_is_RLE )
5517 {
5518 if ( RLE_count == 0 )
5519 {
5520 // yep, get the next byte as a RLE command
5521 int RLE_cmd = stbi__get8(s);
5522 RLE_count = 1 + (RLE_cmd & 127);
5523 RLE_repeating = RLE_cmd >> 7;
5524 read_next_pixel = 1;
5525 } else if ( !RLE_repeating )
5526 {
5527 read_next_pixel = 1;
5528 }
5529 } else
5530 {
5531 read_next_pixel = 1;
5532 }
5533 // OK, if I need to read a pixel, do it now
5534 if ( read_next_pixel )
5535 {
5536 // load however much data we did have
5537 if ( tga_indexed )
5538 {
5539 // read in index, then perform the lookup
5540 int pal_idx = (tga_bits_per_pixel == 8) ? stbi__get8(s) : stbi__get16le(s);
5541 if ( pal_idx >= tga_palette_len ) {
5542 // invalid index
5543 pal_idx = 0;
5544 }
5545 pal_idx *= tga_comp;
5546 for (j = 0; j < tga_comp; ++j) {
5547 raw_data[j] = tga_palette[pal_idx+j];
5548 }
5549 } else if(tga_rgb16) {
5550 STBI_ASSERT(tga_comp == STBI_rgb);
5551 stbi__tga_read_rgb16(s, raw_data);
5552 } else {
5553 // read in the data raw
5554 for (j = 0; j < tga_comp; ++j) {
5555 raw_data[j] = stbi__get8(s);
5556 }
5557 }
5558 // clear the reading flag for the next pixel
5559 read_next_pixel = 0;
5560 } // end of reading a pixel
5561
5562 // copy data
5563 for (j = 0; j < tga_comp; ++j)
5564 tga_data[i*tga_comp+j] = raw_data[j];
5565
5566 // in case we're in RLE mode, keep counting down
5567 --RLE_count;
5568 }
5569 // do I need to invert the image?
5570 if ( tga_inverted )
5571 {
5572 for (j = 0; j*2 < tga_height; ++j)
5573 {
5574 int index1 = j * tga_width * tga_comp;
5575 int index2 = (tga_height - 1 - j) * tga_width * tga_comp;
5576 for (i = tga_width * tga_comp; i > 0; --i)
5577 {
5578 unsigned char temp = tga_data[index1];
5579 tga_data[index1] = tga_data[index2];
5580 tga_data[index2] = temp;
5581 ++index1;
5582 ++index2;
5583 }
5584 }
5585 }
5586 // clear my palette, if I had one
5587 if ( tga_palette != NULL )
5588 {
5589 STBI_FREE( tga_palette );
5590 }
5591 }
5592
5593 // swap RGB - if the source data was RGB16, it already is in the right order
5594 if (tga_comp >= 3 && !tga_rgb16)
5595 {
5596 unsigned char* tga_pixel = tga_data;
5597 for (i=0; i < tga_width * tga_height; ++i)
5598 {
5599 unsigned char temp = tga_pixel[0];
5600 tga_pixel[0] = tga_pixel[2];
5601 tga_pixel[2] = temp;
5602 tga_pixel += tga_comp;
5603 }
5604 }
5605
5606 // convert to target component count
5607 if (req_comp && req_comp != tga_comp)
5608 tga_data = stbi__convert_format(tga_data, tga_comp, req_comp, tga_width, tga_height);
5609
5610 // the things I do to get rid of an error message, and yet keep
5611 // Microsoft's C compilers happy... [8^(
5612 tga_palette_start = tga_palette_len = tga_palette_bits =
5613 tga_x_origin = tga_y_origin = 0;
5614 STBI_NOTUSED(tga_palette_start);
5615 // OK, done
5616 return tga_data;
5617}
5618#endif
5619
5620// *************************************************************************************************
5621// Photoshop PSD loader -- PD by Thatcher Ulrich, integration by Nicolas Schulz, tweaked by STB
5622
5623#ifndef STBI_NO_PSD
5624static int stbi__psd_test(stbi__context *s)
5625{
5626 int r = (stbi__get32be(s) == 0x38425053);
5627 stbi__rewind(s);
5628 return r;
5629}
5630
5631static int stbi__psd_decode_rle(stbi__context *s, stbi_uc *p, int pixelCount)
5632{
5633 int count, nleft, len;
5634
5635 count = 0;
5636 while ((nleft = pixelCount - count) > 0) {
5637 len = stbi__get8(s);
5638 if (len == 128) {
5639 // No-op.
5640 } else if (len < 128) {
5641 // Copy next len+1 bytes literally.
5642 len++;
5643 if (len > nleft) return 0; // corrupt data
5644 count += len;
5645 while (len) {
5646 *p = stbi__get8(s);
5647 p += 4;
5648 len--;
5649 }
5650 } else if (len > 128) {
5651 stbi_uc val;
5652 // Next -len+1 bytes in the dest are replicated from next source byte.
5653 // (Interpret len as a negative 8-bit int.)
5654 len = 257 - len;
5655 if (len > nleft) return 0; // corrupt data
5656 val = stbi__get8(s);
5657 count += len;
5658 while (len) {
5659 *p = val;
5660 p += 4;
5661 len--;
5662 }
5663 }
5664 }
5665
5666 return 1;
5667}
5668
5669static void *stbi__psd_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
5670{
5671 int pixelCount;
5672 int channelCount, compression;
5673 int channel, i;
5674 int bitdepth;
5675 int w,h;
5676 stbi_uc *out;
5677 STBI_NOTUSED(ri);
5678
5679 // Check identifier
5680 if (stbi__get32be(s) != 0x38425053) // "8BPS"
5681 return stbi__errpuc("not PSD", "Corrupt PSD image");
5682
5683 // Check file type version.
5684 if (stbi__get16be(s) != 1)
5685 return stbi__errpuc("wrong version", "Unsupported version of PSD image");
5686
5687 // Skip 6 reserved bytes.
5688 stbi__skip(s, 6 );
5689
5690 // Read the number of channels (R, G, B, A, etc).
5691 channelCount = stbi__get16be(s);
5692 if (channelCount < 0 || channelCount > 16)
5693 return stbi__errpuc("wrong channel count", "Unsupported number of channels in PSD image");
5694
5695 // Read the rows and columns of the image.
5696 h = stbi__get32be(s);
5697 w = stbi__get32be(s);
5698
5699 if (h > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5700 if (w > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5701
5702 // Make sure the depth is 8 bits.
5703 bitdepth = stbi__get16be(s);
5704 if (bitdepth != 8 && bitdepth != 16)
5705 return stbi__errpuc("unsupported bit depth", "PSD bit depth is not 8 or 16 bit");
5706
5707 // Make sure the color mode is RGB.
5708 // Valid options are:
5709 // 0: Bitmap
5710 // 1: Grayscale
5711 // 2: Indexed color
5712 // 3: RGB color
5713 // 4: CMYK color
5714 // 7: Multichannel
5715 // 8: Duotone
5716 // 9: Lab color
5717 if (stbi__get16be(s) != 3)
5718 return stbi__errpuc("wrong color format", "PSD is not in RGB color format");
5719
5720 // Skip the Mode Data. (It's the palette for indexed color; other info for other modes.)
5721 stbi__skip(s,stbi__get32be(s) );
5722
5723 // Skip the image resources. (resolution, pen tool paths, etc)
5724 stbi__skip(s, stbi__get32be(s) );
5725
5726 // Skip the reserved data.
5727 stbi__skip(s, stbi__get32be(s) );
5728
5729 // Find out if the data is compressed.
5730 // Known values:
5731 // 0: no compression
5732 // 1: RLE compressed
5733 compression = stbi__get16be(s);
5734 if (compression > 1)
5735 return stbi__errpuc("bad compression", "PSD has an unknown compression format");
5736
5737 // Check size
5738 if (!stbi__mad3sizes_valid(4, w, h, 0))
5739 return stbi__errpuc("too large", "Corrupt PSD");
5740
5741 // Create the destination image.
5742
5743 if (!compression && bitdepth == 16 && bpc == 16) {
5744 out = (stbi_uc *) stbi__malloc_mad3(8, w, h, 0);
5745 ri->bits_per_channel = 16;
5746 } else
5747 out = (stbi_uc *) stbi__malloc(4 * w*h);
5748
5749 if (!out) return stbi__errpuc("outofmem", "Out of memory");
5750 pixelCount = w*h;
5751
5752 // Initialize the data to zero.
5753 //memset( out, 0, pixelCount * 4 );
5754
5755 // Finally, the image data.
5756 if (compression) {
5757 // RLE as used by .PSD and .TIFF
5758 // Loop until you get the number of unpacked bytes you are expecting:
5759 // Read the next source byte into n.
5760 // If n is between 0 and 127 inclusive, copy the next n+1 bytes literally.
5761 // Else if n is between -127 and -1 inclusive, copy the next byte -n+1 times.
5762 // Else if n is 128, noop.
5763 // Endloop
5764
5765 // The RLE-compressed data is preceded by a 2-byte data count for each row in the data,
5766 // which we're going to just skip.
5767 stbi__skip(s, h * channelCount * 2 );
5768
5769 // Read the RLE data by channel.
5770 for (channel = 0; channel < 4; channel++) {
5771 stbi_uc *p;
5772
5773 p = out+channel;
5774 if (channel >= channelCount) {
5775 // Fill this channel with default data.
5776 for (i = 0; i < pixelCount; i++, p += 4)
5777 *p = (channel == 3 ? 255 : 0);
5778 } else {
5779 // Read the RLE data.
5780 if (!stbi__psd_decode_rle(s, p, pixelCount)) {
5781 STBI_FREE(out);
5782 return stbi__errpuc("corrupt", "bad RLE data");
5783 }
5784 }
5785 }
5786
5787 } else {
5788 // We're at the raw image data. It's each channel in order (Red, Green, Blue, Alpha, ...)
5789 // where each channel consists of an 8-bit (or 16-bit) value for each pixel in the image.
5790
5791 // Read the data by channel.
5792 for (channel = 0; channel < 4; channel++) {
5793 if (channel >= channelCount) {
5794 // Fill this channel with default data.
5795 if (bitdepth == 16 && bpc == 16) {
5796 stbi__uint16 *q = ((stbi__uint16 *) out) + channel;
5797 stbi__uint16 val = channel == 3 ? 65535 : 0;
5798 for (i = 0; i < pixelCount; i++, q += 4)
5799 *q = val;
5800 } else {
5801 stbi_uc *p = out+channel;
5802 stbi_uc val = channel == 3 ? 255 : 0;
5803 for (i = 0; i < pixelCount; i++, p += 4)
5804 *p = val;
5805 }
5806 } else {
5807 if (ri->bits_per_channel == 16) { // output bpc
5808 stbi__uint16 *q = ((stbi__uint16 *) out) + channel;
5809 for (i = 0; i < pixelCount; i++, q += 4)
5810 *q = (stbi__uint16) stbi__get16be(s);
5811 } else {
5812 stbi_uc *p = out+channel;
5813 if (bitdepth == 16) { // input bpc
5814 for (i = 0; i < pixelCount; i++, p += 4)
5815 *p = (stbi_uc) (stbi__get16be(s) >> 8);
5816 } else {
5817 for (i = 0; i < pixelCount; i++, p += 4)
5818 *p = stbi__get8(s);
5819 }
5820 }
5821 }
5822 }
5823 }
5824
5825 // remove weird white matte from PSD
5826 if (channelCount >= 4) {
5827 if (ri->bits_per_channel == 16) {
5828 for (i=0; i < w*h; ++i) {
5829 stbi__uint16 *pixel = (stbi__uint16 *) out + 4*i;
5830 if (pixel[3] != 0 && pixel[3] != 65535) {
5831 float a = pixel[3] / 65535.0f;
5832 float ra = 1.0f / a;
5833 float inv_a = 65535.0f * (1 - ra);
5834 pixel[0] = (stbi__uint16) (pixel[0]*ra + inv_a);
5835 pixel[1] = (stbi__uint16) (pixel[1]*ra + inv_a);
5836 pixel[2] = (stbi__uint16) (pixel[2]*ra + inv_a);
5837 }
5838 }
5839 } else {
5840 for (i=0; i < w*h; ++i) {
5841 unsigned char *pixel = out + 4*i;
5842 if (pixel[3] != 0 && pixel[3] != 255) {
5843 float a = pixel[3] / 255.0f;
5844 float ra = 1.0f / a;
5845 float inv_a = 255.0f * (1 - ra);
5846 pixel[0] = (unsigned char) (pixel[0]*ra + inv_a);
5847 pixel[1] = (unsigned char) (pixel[1]*ra + inv_a);
5848 pixel[2] = (unsigned char) (pixel[2]*ra + inv_a);
5849 }
5850 }
5851 }
5852 }
5853
5854 // convert to desired output format
5855 if (req_comp && req_comp != 4) {
5856 if (ri->bits_per_channel == 16)
5857 out = (stbi_uc *) stbi__convert_format16((stbi__uint16 *) out, 4, req_comp, w, h);
5858 else
5859 out = stbi__convert_format(out, 4, req_comp, w, h);
5860 if (out == NULL) return out; // stbi__convert_format frees input on failure
5861 }
5862
5863 if (comp) *comp = 4;
5864 *y = h;
5865 *x = w;
5866
5867 return out;
5868}
5869#endif
5870
5871// *************************************************************************************************
5872// Softimage PIC loader
5873// by Tom Seddon
5874//
5875// See http://softimage.wiki.softimage.com/index.php/INFO:_PIC_file_format
5876// See http://ozviz.wasp.uwa.edu.au/~pbourke/dataformats/softimagepic/
5877
5878#ifndef STBI_NO_PIC
5879static int stbi__pic_is4(stbi__context *s,const char *str)
5880{
5881 int i;
5882 for (i=0; i<4; ++i)
5883 if (stbi__get8(s) != (stbi_uc)str[i])
5884 return 0;
5885
5886 return 1;
5887}
5888
5889static int stbi__pic_test_core(stbi__context *s)
5890{
5891 int i;
5892
5893 if (!stbi__pic_is4(s,"\x53\x80\xF6\x34"))
5894 return 0;
5895
5896 for(i=0;i<84;++i)
5897 stbi__get8(s);
5898
5899 if (!stbi__pic_is4(s,"PICT"))
5900 return 0;
5901
5902 return 1;
5903}
5904
5905typedef struct
5906{
5907 stbi_uc size,type,channel;
5908} stbi__pic_packet;
5909
5910static stbi_uc *stbi__readval(stbi__context *s, int channel, stbi_uc *dest)
5911{
5912 int mask=0x80, i;
5913
5914 for (i=0; i<4; ++i, mask>>=1) {
5915 if (channel & mask) {
5916 if (stbi__at_eof(s)) return stbi__errpuc("bad file","PIC file too short");
5917 dest[i]=stbi__get8(s);
5918 }
5919 }
5920
5921 return dest;
5922}
5923
5924static void stbi__copyval(int channel,stbi_uc *dest,const stbi_uc *src)
5925{
5926 int mask=0x80,i;
5927
5928 for (i=0;i<4; ++i, mask>>=1)
5929 if (channel&mask)
5930 dest[i]=src[i];
5931}
5932
5933static stbi_uc *stbi__pic_load_core(stbi__context *s,int width,int height,int *comp, stbi_uc *result)
5934{
5935 int act_comp=0,num_packets=0,y,chained;
5936 stbi__pic_packet packets[10];
5937
5938 // this will (should...) cater for even some bizarre stuff like having data
5939 // for the same channel in multiple packets.
5940 do {
5941 stbi__pic_packet *packet;
5942
5943 if (num_packets==sizeof(packets)/sizeof(packets[0]))
5944 return stbi__errpuc("bad format","too many packets");
5945
5946 packet = &packets[num_packets++];
5947
5948 chained = stbi__get8(s);
5949 packet->size = stbi__get8(s);
5950 packet->type = stbi__get8(s);
5951 packet->channel = stbi__get8(s);
5952
5953 act_comp |= packet->channel;
5954
5955 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (reading packets)");
5956 if (packet->size != 8) return stbi__errpuc("bad format","packet isn't 8bpp");
5957 } while (chained);
5958
5959 *comp = (act_comp & 0x10 ? 4 : 3); // has alpha channel?
5960
5961 for(y=0; y<height; ++y) {
5962 int packet_idx;
5963
5964 for(packet_idx=0; packet_idx < num_packets; ++packet_idx) {
5965 stbi__pic_packet *packet = &packets[packet_idx];
5966 stbi_uc *dest = result+y*width*4;
5967
5968 switch (packet->type) {
5969 default:
5970 return stbi__errpuc("bad format","packet has bad compression type");
5971
5972 case 0: {//uncompressed
5973 int x;
5974
5975 for(x=0;x<width;++x, dest+=4)
5976 if (!stbi__readval(s,packet->channel,dest))
5977 return 0;
5978 break;
5979 }
5980
5981 case 1://Pure RLE
5982 {
5983 int left=width, i;
5984
5985 while (left>0) {
5986 stbi_uc count,value[4];
5987
5988 count=stbi__get8(s);
5989 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (pure read count)");
5990
5991 if (count > left)
5992 count = (stbi_uc) left;
5993
5994 if (!stbi__readval(s,packet->channel,value)) return 0;
5995
5996 for(i=0; i<count; ++i,dest+=4)
5997 stbi__copyval(packet->channel,dest,value);
5998 left -= count;
5999 }
6000 }
6001 break;
6002
6003 case 2: {//Mixed RLE
6004 int left=width;
6005 while (left>0) {
6006 int count = stbi__get8(s), i;
6007 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (mixed read count)");
6008
6009 if (count >= 128) { // Repeated
6010 stbi_uc value[4];
6011
6012 if (count==128)
6013 count = stbi__get16be(s);
6014 else
6015 count -= 127;
6016 if (count > left)
6017 return stbi__errpuc("bad file","scanline overrun");
6018
6019 if (!stbi__readval(s,packet->channel,value))
6020 return 0;
6021
6022 for(i=0;i<count;++i, dest += 4)
6023 stbi__copyval(packet->channel,dest,value);
6024 } else { // Raw
6025 ++count;
6026 if (count>left) return stbi__errpuc("bad file","scanline overrun");
6027
6028 for(i=0;i<count;++i, dest+=4)
6029 if (!stbi__readval(s,packet->channel,dest))
6030 return 0;
6031 }
6032 left-=count;
6033 }
6034 break;
6035 }
6036 }
6037 }
6038 }
6039
6040 return result;
6041}
6042
6043static void *stbi__pic_load(stbi__context *s,int *px,int *py,int *comp,int req_comp, stbi__result_info *ri)
6044{
6045 stbi_uc *result;
6046 int i, x,y, internal_comp;
6047 STBI_NOTUSED(ri);
6048
6049 if (!comp) comp = &internal_comp;
6050
6051 for (i=0; i<92; ++i)
6052 stbi__get8(s);
6053
6054 x = stbi__get16be(s);
6055 y = stbi__get16be(s);
6056
6057 if (y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
6058 if (x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
6059
6060 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (pic header)");
6061 if (!stbi__mad3sizes_valid(x, y, 4, 0)) return stbi__errpuc("too large", "PIC image too large to decode");
6062
6063 stbi__get32be(s); //skip `ratio'
6064 stbi__get16be(s); //skip `fields'
6065 stbi__get16be(s); //skip `pad'
6066
6067 // intermediate buffer is RGBA
6068 result = (stbi_uc *) stbi__malloc_mad3(x, y, 4, 0);
6069 if (!result) return stbi__errpuc("outofmem", "Out of memory");
6070 memset(result, 0xff, x*y*4);
6071
6072 if (!stbi__pic_load_core(s,x,y,comp, result)) {
6073 STBI_FREE(result);
6074 result=0;
6075 }
6076 *px = x;
6077 *py = y;
6078 if (req_comp == 0) req_comp = *comp;
6079 result=stbi__convert_format(result,4,req_comp,x,y);
6080
6081 return result;
6082}
6083
6084static int stbi__pic_test(stbi__context *s)
6085{
6086 int r = stbi__pic_test_core(s);
6087 stbi__rewind(s);
6088 return r;
6089}
6090#endif
6091
6092// *************************************************************************************************
6093// GIF loader -- public domain by Jean-Marc Lienher -- simplified/shrunk by stb
6094
6095#ifndef STBI_NO_GIF
6096typedef struct
6097{
6098 stbi__int16 prefix;
6099 stbi_uc first;
6100 stbi_uc suffix;
6101} stbi__gif_lzw;
6102
6103typedef struct
6104{
6105 int w,h;
6106 stbi_uc *out; // output buffer (always 4 components)
6107 stbi_uc *background; // The current "background" as far as a gif is concerned
6108 stbi_uc *history;
6109 int flags, bgindex, ratio, transparent, eflags;
6110 stbi_uc pal[256][4];
6111 stbi_uc lpal[256][4];
6112 stbi__gif_lzw codes[8192];
6113 stbi_uc *color_table;
6114 int parse, step;
6115 int lflags;
6116 int start_x, start_y;
6117 int max_x, max_y;
6118 int cur_x, cur_y;
6119 int line_size;
6120 int delay;
6121} stbi__gif;
6122
6123static int stbi__gif_test_raw(stbi__context *s)
6124{
6125 int sz;
6126 if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8') return 0;
6127 sz = stbi__get8(s);
6128 if (sz != '9' && sz != '7') return 0;
6129 if (stbi__get8(s) != 'a') return 0;
6130 return 1;
6131}
6132
6133static int stbi__gif_test(stbi__context *s)
6134{
6135 int r = stbi__gif_test_raw(s);
6136 stbi__rewind(s);
6137 return r;
6138}
6139
6140static void stbi__gif_parse_colortable(stbi__context *s, stbi_uc pal[256][4], int num_entries, int transp)
6141{
6142 int i;
6143 for (i=0; i < num_entries; ++i) {
6144 pal[i][2] = stbi__get8(s);
6145 pal[i][1] = stbi__get8(s);
6146 pal[i][0] = stbi__get8(s);
6147 pal[i][3] = transp == i ? 0 : 255;
6148 }
6149}
6150
6151static int stbi__gif_header(stbi__context *s, stbi__gif *g, int *comp, int is_info)
6152{
6153 stbi_uc version;
6154 if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8')
6155 return stbi__err("not GIF", "Corrupt GIF");
6156
6157 version = stbi__get8(s);
6158 if (version != '7' && version != '9') return stbi__err("not GIF", "Corrupt GIF");
6159 if (stbi__get8(s) != 'a') return stbi__err("not GIF", "Corrupt GIF");
6160
6161 stbi__g_failure_reason = "";
6162 g->w = stbi__get16le(s);
6163 g->h = stbi__get16le(s);
6164 g->flags = stbi__get8(s);
6165 g->bgindex = stbi__get8(s);
6166 g->ratio = stbi__get8(s);
6167 g->transparent = -1;
6168
6169 if (g->w > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
6170 if (g->h > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
6171
6172 if (comp != 0) *comp = 4; // can't actually tell whether it's 3 or 4 until we parse the comments
6173
6174 if (is_info) return 1;
6175
6176 if (g->flags & 0x80)
6177 stbi__gif_parse_colortable(s,g->pal, 2 << (g->flags & 7), -1);
6178
6179 return 1;
6180}
6181
6182static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp)
6183{
6184 stbi__gif* g = (stbi__gif*) stbi__malloc(sizeof(stbi__gif));
6185 if (!g) return stbi__err("outofmem", "Out of memory");
6186 if (!stbi__gif_header(s, g, comp, 1)) {
6187 STBI_FREE(g);
6188 stbi__rewind( s );
6189 return 0;
6190 }
6191 if (x) *x = g->w;
6192 if (y) *y = g->h;
6193 STBI_FREE(g);
6194 return 1;
6195}
6196
6197static void stbi__out_gif_code(stbi__gif *g, stbi__uint16 code)
6198{
6199 stbi_uc *p, *c;
6200 int idx;
6201
6202 // recurse to decode the prefixes, since the linked-list is backwards,
6203 // and working backwards through an interleaved image would be nasty
6204 if (g->codes[code].prefix >= 0)
6205 stbi__out_gif_code(g, g->codes[code].prefix);
6206
6207 if (g->cur_y >= g->max_y) return;
6208
6209 idx = g->cur_x + g->cur_y;
6210 p = &g->out[idx];
6211 g->history[idx / 4] = 1;
6212
6213 c = &g->color_table[g->codes[code].suffix * 4];
6214 if (c[3] > 128) { // don't render transparent pixels;
6215 p[0] = c[2];
6216 p[1] = c[1];
6217 p[2] = c[0];
6218 p[3] = c[3];
6219 }
6220 g->cur_x += 4;
6221
6222 if (g->cur_x >= g->max_x) {
6223 g->cur_x = g->start_x;
6224 g->cur_y += g->step;
6225
6226 while (g->cur_y >= g->max_y && g->parse > 0) {
6227 g->step = (1 << g->parse) * g->line_size;
6228 g->cur_y = g->start_y + (g->step >> 1);
6229 --g->parse;
6230 }
6231 }
6232}
6233
6234static stbi_uc *stbi__process_gif_raster(stbi__context *s, stbi__gif *g)
6235{
6236 stbi_uc lzw_cs;
6237 stbi__int32 len, init_code;
6238 stbi__uint32 first;
6239 stbi__int32 codesize, codemask, avail, oldcode, bits, valid_bits, clear;
6240 stbi__gif_lzw *p;
6241
6242 lzw_cs = stbi__get8(s);
6243 if (lzw_cs > 12) return NULL;
6244 clear = 1 << lzw_cs;
6245 first = 1;
6246 codesize = lzw_cs + 1;
6247 codemask = (1 << codesize) - 1;
6248 bits = 0;
6249 valid_bits = 0;
6250 for (init_code = 0; init_code < clear; init_code++) {
6251 g->codes[init_code].prefix = -1;
6252 g->codes[init_code].first = (stbi_uc) init_code;
6253 g->codes[init_code].suffix = (stbi_uc) init_code;
6254 }
6255
6256 // support no starting clear code
6257 avail = clear+2;
6258 oldcode = -1;
6259
6260 len = 0;
6261 for(;;) {
6262 if (valid_bits < codesize) {
6263 if (len == 0) {
6264 len = stbi__get8(s); // start new block
6265 if (len == 0)
6266 return g->out;
6267 }
6268 --len;
6269 bits |= (stbi__int32) stbi__get8(s) << valid_bits;
6270 valid_bits += 8;
6271 } else {
6272 stbi__int32 code = bits & codemask;
6273 bits >>= codesize;
6274 valid_bits -= codesize;
6275 // @OPTIMIZE: is there some way we can accelerate the non-clear path?
6276 if (code == clear) { // clear code
6277 codesize = lzw_cs + 1;
6278 codemask = (1 << codesize) - 1;
6279 avail = clear + 2;
6280 oldcode = -1;
6281 first = 0;
6282 } else if (code == clear + 1) { // end of stream code
6283 stbi__skip(s, len);
6284 while ((len = stbi__get8(s)) > 0)
6285 stbi__skip(s,len);
6286 return g->out;
6287 } else if (code <= avail) {
6288 if (first) {
6289 return stbi__errpuc("no clear code", "Corrupt GIF");
6290 }
6291
6292 if (oldcode >= 0) {
6293 p = &g->codes[avail++];
6294 if (avail > 8192) {
6295 return stbi__errpuc("too many codes", "Corrupt GIF");
6296 }
6297
6298 p->prefix = (stbi__int16) oldcode;
6299 p->first = g->codes[oldcode].first;
6300 p->suffix = (code == avail) ? p->first : g->codes[code].first;
6301 } else if (code == avail)
6302 return stbi__errpuc("illegal code in raster", "Corrupt GIF");
6303
6304 stbi__out_gif_code(g, (stbi__uint16) code);
6305
6306 if ((avail & codemask) == 0 && avail <= 0x0FFF) {
6307 codesize++;
6308 codemask = (1 << codesize) - 1;
6309 }
6310
6311 oldcode = code;
6312 } else {
6313 return stbi__errpuc("illegal code in raster", "Corrupt GIF");
6314 }
6315 }
6316 }
6317}
6318
6319// this function is designed to support animated gifs, although stb_image doesn't support it
6320// two back is the image from two frames ago, used for a very specific disposal format
6321static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp, stbi_uc *two_back)
6322{
6323 int dispose;
6324 int first_frame;
6325 int pi;
6326 int pcount;
6327 STBI_NOTUSED(req_comp);
6328
6329 // on first frame, any non-written pixels get the background colour (non-transparent)
6330 first_frame = 0;
6331 if (g->out == 0) {
6332 if (!stbi__gif_header(s, g, comp,0)) return 0; // stbi__g_failure_reason set by stbi__gif_header
6333 if (!stbi__mad3sizes_valid(4, g->w, g->h, 0))
6334 return stbi__errpuc("too large", "GIF image is too large");
6335 pcount = g->w * g->h;
6336 g->out = (stbi_uc *) stbi__malloc(4 * pcount);
6337 g->background = (stbi_uc *) stbi__malloc(4 * pcount);
6338 g->history = (stbi_uc *) stbi__malloc(pcount);
6339 if (!g->out || !g->background || !g->history)
6340 return stbi__errpuc("outofmem", "Out of memory");
6341
6342 // image is treated as "transparent" at the start - ie, nothing overwrites the current background;
6343 // background colour is only used for pixels that are not rendered first frame, after that "background"
6344 // color refers to the color that was there the previous frame.
6345 memset(g->out, 0x00, 4 * pcount);
6346 memset(g->background, 0x00, 4 * pcount); // state of the background (starts transparent)
6347 memset(g->history, 0x00, pcount); // pixels that were affected previous frame
6348 first_frame = 1;
6349 } else {
6350 // second frame - how do we dispose of the previous one?
6351 dispose = (g->eflags & 0x1C) >> 2;
6352 pcount = g->w * g->h;
6353
6354 if ((dispose == 3) && (two_back == 0)) {
6355 dispose = 2; // if I don't have an image to revert back to, default to the old background
6356 }
6357
6358 if (dispose == 3) { // use previous graphic
6359 for (pi = 0; pi < pcount; ++pi) {
6360 if (g->history[pi]) {
6361 memcpy( &g->out[pi * 4], &two_back[pi * 4], 4 );
6362 }
6363 }
6364 } else if (dispose == 2) {
6365 // restore what was changed last frame to background before that frame;
6366 for (pi = 0; pi < pcount; ++pi) {
6367 if (g->history[pi]) {
6368 memcpy( &g->out[pi * 4], &g->background[pi * 4], 4 );
6369 }
6370 }
6371 } else {
6372 // This is a non-disposal case eithe way, so just
6373 // leave the pixels as is, and they will become the new background
6374 // 1: do not dispose
6375 // 0: not specified.
6376 }
6377
6378 // background is what out is after the undoing of the previou frame;
6379 memcpy( g->background, g->out, 4 * g->w * g->h );
6380 }
6381
6382 // clear my history;
6383 memset( g->history, 0x00, g->w * g->h ); // pixels that were affected previous frame
6384
6385 for (;;) {
6386 int tag = stbi__get8(s);
6387 switch (tag) {
6388 case 0x2C: /* Image Descriptor */
6389 {
6390 stbi__int32 x, y, w, h;
6391 stbi_uc *o;
6392
6393 x = stbi__get16le(s);
6394 y = stbi__get16le(s);
6395 w = stbi__get16le(s);
6396 h = stbi__get16le(s);
6397 if (((x + w) > (g->w)) || ((y + h) > (g->h)))
6398 return stbi__errpuc("bad Image Descriptor", "Corrupt GIF");
6399
6400 g->line_size = g->w * 4;
6401 g->start_x = x * 4;
6402 g->start_y = y * g->line_size;
6403 g->max_x = g->start_x + w * 4;
6404 g->max_y = g->start_y + h * g->line_size;
6405 g->cur_x = g->start_x;
6406 g->cur_y = g->start_y;
6407
6408 // if the width of the specified rectangle is 0, that means
6409 // we may not see *any* pixels or the image is malformed;
6410 // to make sure this is caught, move the current y down to
6411 // max_y (which is what out_gif_code checks).
6412 if (w == 0)
6413 g->cur_y = g->max_y;
6414
6415 g->lflags = stbi__get8(s);
6416
6417 if (g->lflags & 0x40) {
6418 g->step = 8 * g->line_size; // first interlaced spacing
6419 g->parse = 3;
6420 } else {
6421 g->step = g->line_size;
6422 g->parse = 0;
6423 }
6424
6425 if (g->lflags & 0x80) {
6426 stbi__gif_parse_colortable(s,g->lpal, 2 << (g->lflags & 7), g->eflags & 0x01 ? g->transparent : -1);
6427 g->color_table = (stbi_uc *) g->lpal;
6428 } else if (g->flags & 0x80) {
6429 g->color_table = (stbi_uc *) g->pal;
6430 } else
6431 return stbi__errpuc("missing color table", "Corrupt GIF");
6432
6433 o = stbi__process_gif_raster(s, g);
6434 if (!o) return NULL;
6435
6436 // if this was the first frame,
6437 pcount = g->w * g->h;
6438 if (first_frame && (g->bgindex > 0)) {
6439 // if first frame, any pixel not drawn to gets the background color
6440 for (pi = 0; pi < pcount; ++pi) {
6441 if (g->history[pi] == 0) {
6442 g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be;
6443 memcpy( &g->out[pi * 4], &g->pal[g->bgindex], 4 );
6444 }
6445 }
6446 }
6447
6448 return o;
6449 }
6450
6451 case 0x21: // Comment Extension.
6452 {
6453 int len;
6454 int ext = stbi__get8(s);
6455 if (ext == 0xF9) { // Graphic Control Extension.
6456 len = stbi__get8(s);
6457 if (len == 4) {
6458 g->eflags = stbi__get8(s);
6459 g->delay = 10 * stbi__get16le(s); // delay - 1/100th of a second, saving as 1/1000ths.
6460
6461 // unset old transparent
6462 if (g->transparent >= 0) {
6463 g->pal[g->transparent][3] = 255;
6464 }
6465 if (g->eflags & 0x01) {
6466 g->transparent = stbi__get8(s);
6467 if (g->transparent >= 0) {
6468 g->pal[g->transparent][3] = 0;
6469 }
6470 } else {
6471 // don't need transparent
6472 stbi__skip(s, 1);
6473 g->transparent = -1;
6474 }
6475 } else {
6476 stbi__skip(s, len);
6477 break;
6478 }
6479 }
6480 while ((len = stbi__get8(s)) != 0) {
6481 stbi__skip(s, len);
6482 }
6483 break;
6484 }
6485
6486 case 0x3B: // gif stream termination code
6487 return (stbi_uc *) s; // using '1' causes warning on some compilers
6488
6489 default:
6490 return stbi__errpuc("unknown code", "Corrupt GIF");
6491 }
6492 }
6493}
6494
6495static void *stbi__load_gif_main_outofmem(stbi__gif *g, stbi_uc *out, int **delays)
6496{
6497 STBI_FREE(g->out);
6498 STBI_FREE(g->history);
6499 STBI_FREE(g->background);
6500
6501 if (out) STBI_FREE(out);
6502 if (delays && *delays) STBI_FREE(*delays);
6503 return stbi__errpuc("outofmem", "Out of memory");
6504}
6505
6506static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
6507{
6508 if (stbi__gif_test(s)) {
6509 int layers = 0;
6510 stbi_uc *u = 0;
6511 stbi_uc *out = 0;
6512 stbi_uc *two_back = 0;
6513 stbi__gif g;
6514 int stride;
6515 int out_size = 0;
6516 int delays_size = 0;
6517
6518 STBI_NOTUSED(out_size);
6519 STBI_NOTUSED(delays_size);
6520
6521 memset(&g, 0, sizeof(g));
6522 if (delays) {
6523 *delays = 0;
6524 }
6525
6526 do {
6527 u = stbi__gif_load_next(s, &g, comp, req_comp, two_back);
6528 if (u == (stbi_uc *) s) u = 0; // end of animated gif marker
6529
6530 if (u) {
6531 *x = g.w;
6532 *y = g.h;
6533 ++layers;
6534 stride = g.w * g.h * 4;
6535
6536 if (out) {
6537 void *tmp = (stbi_uc*) STBI_REALLOC_SIZED( out, out_size, layers * stride );
6538 if (!tmp)
6539 return stbi__load_gif_main_outofmem(&g, out, delays);
6540 else {
6541 out = (stbi_uc*) tmp;
6542 out_size = layers * stride;
6543 }
6544
6545 if (delays) {
6546 int *new_delays = (int*) STBI_REALLOC_SIZED( *delays, delays_size, sizeof(int) * layers );
6547 if (!new_delays)
6548 return stbi__load_gif_main_outofmem(&g, out, delays);
6549 *delays = new_delays;
6550 delays_size = layers * sizeof(int);
6551 }
6552 } else {
6553 out = (stbi_uc*)stbi__malloc( layers * stride );
6554 if (!out)
6555 return stbi__load_gif_main_outofmem(&g, out, delays);
6556 out_size = layers * stride;
6557 if (delays) {
6558 *delays = (int*) stbi__malloc( layers * sizeof(int) );
6559 if (!*delays)
6560 return stbi__load_gif_main_outofmem(&g, out, delays);
6561 delays_size = layers * sizeof(int);
6562 }
6563 }
6564 memcpy( out + ((layers - 1) * stride), u, stride );
6565 if (layers >= 2) {
6566 two_back = out - 2 * stride;
6567 }
6568
6569 if (delays) {
6570 (*delays)[layers - 1U] = g.delay;
6571 }
6572 }
6573 } while (u != 0);
6574
6575 // free temp buffer;
6576 STBI_FREE(g.out);
6577 STBI_FREE(g.history);
6578 STBI_FREE(g.background);
6579
6580 // do the final conversion after loading everything;
6581 if (req_comp && req_comp != 4)
6582 out = stbi__convert_format(out, 4, req_comp, layers * g.w, g.h);
6583
6584 *z = layers;
6585 return out;
6586 } else {
6587 return stbi__errpuc("not GIF", "Image was not as a gif type.");
6588 }
6589}
6590
6591static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
6592{
6593 stbi_uc *u = 0;
6594 stbi__gif g;
6595 memset(&g, 0, sizeof(g));
6596 STBI_NOTUSED(ri);
6597
6598 u = stbi__gif_load_next(s, &g, comp, req_comp, 0);
6599 if (u == (stbi_uc *) s) u = 0; // end of animated gif marker
6600 if (u) {
6601 *x = g.w;
6602 *y = g.h;
6603
6604 // moved conversion to after successful load so that the same
6605 // can be done for multiple frames.
6606 if (req_comp && req_comp != 4)
6607 u = stbi__convert_format(u, 4, req_comp, g.w, g.h);
6608 } else if (g.out) {
6609 // if there was an error and we allocated an image buffer, free it!
6610 STBI_FREE(g.out);
6611 }
6612
6613 // free buffers needed for multiple frame loading;
6614 STBI_FREE(g.history);
6615 STBI_FREE(g.background);
6616
6617 return u;
6618}
6619
6620static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp)
6621{
6622 return stbi__gif_info_raw(s,x,y,comp);
6623}
6624#endif
6625
6626// *************************************************************************************************
6627// Radiance RGBE HDR loader
6628// originally by Nicolas Schulz
6629#ifndef STBI_NO_HDR
6630static int stbi__hdr_test_core(stbi__context *s, const char *signature)
6631{
6632 int i;
6633 for (i=0; signature[i]; ++i)
6634 if (stbi__get8(s) != signature[i])
6635 return 0;
6636 stbi__rewind(s);
6637 return 1;
6638}
6639
6640static int stbi__hdr_test(stbi__context* s)
6641{
6642 int r = stbi__hdr_test_core(s, "#?RADIANCE\n");
6643 stbi__rewind(s);
6644 if(!r) {
6645 r = stbi__hdr_test_core(s, "#?RGBE\n");
6646 stbi__rewind(s);
6647 }
6648 return r;
6649}
6650
6651#define STBI__HDR_BUFLEN 1024
6652static char *stbi__hdr_gettoken(stbi__context *z, char *buffer)
6653{
6654 int len=0;
6655 char c = '\0';
6656
6657 c = (char) stbi__get8(z);
6658
6659 while (!stbi__at_eof(z) && c != '\n') {
6660 buffer[len++] = c;
6661 if (len == STBI__HDR_BUFLEN-1) {
6662 // flush to end of line
6663 while (!stbi__at_eof(z) && stbi__get8(z) != '\n')
6664 ;
6665 break;
6666 }
6667 c = (char) stbi__get8(z);
6668 }
6669
6670 buffer[len] = 0;
6671 return buffer;
6672}
6673
6674static void stbi__hdr_convert(float *output, stbi_uc *input, int req_comp)
6675{
6676 if ( input[3] != 0 ) {
6677 float f1;
6678 // Exponent
6679 f1 = (float) ldexp(1.0f, input[3] - (int)(128 + 8));
6680 if (req_comp <= 2)
6681 output[0] = (input[0] + input[1] + input[2]) * f1 / 3;
6682 else {
6683 output[0] = input[0] * f1;
6684 output[1] = input[1] * f1;
6685 output[2] = input[2] * f1;
6686 }
6687 if (req_comp == 2) output[1] = 1;
6688 if (req_comp == 4) output[3] = 1;
6689 } else {
6690 switch (req_comp) {
6691 case 4: output[3] = 1; /* fallthrough */
6692 case 3: output[0] = output[1] = output[2] = 0;
6693 break;
6694 case 2: output[1] = 1; /* fallthrough */
6695 case 1: output[0] = 0;
6696 break;
6697 }
6698 }
6699}
6700
6701static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
6702{
6703 char buffer[STBI__HDR_BUFLEN];
6704 char *token;
6705 int valid = 0;
6706 int width, height;
6707 stbi_uc *scanline;
6708 float *hdr_data;
6709 int len;
6710 unsigned char count, value;
6711 int i, j, k, c1,c2, z;
6712 const char *headerToken;
6713 STBI_NOTUSED(ri);
6714
6715 // Check identifier
6716 headerToken = stbi__hdr_gettoken(s,buffer);
6717 if (strcmp(headerToken, "#?RADIANCE") != 0 && strcmp(headerToken, "#?RGBE") != 0)
6718 return stbi__errpf("not HDR", "Corrupt HDR image");
6719
6720 // Parse header
6721 for(;;) {
6722 token = stbi__hdr_gettoken(s,buffer);
6723 if (token[0] == 0) break;
6724 if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0) valid = 1;
6725 }
6726
6727 if (!valid) return stbi__errpf("unsupported format", "Unsupported HDR format");
6728
6729 // Parse width and height
6730 // can't use sscanf() if we're not using stdio!
6731 token = stbi__hdr_gettoken(s,buffer);
6732 if (strncmp(token, "-Y ", 3)) return stbi__errpf("unsupported data layout", "Unsupported HDR format");
6733 token += 3;
6734 height = (int) strtol(token, &token, 10);
6735 while (*token == ' ') ++token;
6736 if (strncmp(token, "+X ", 3)) return stbi__errpf("unsupported data layout", "Unsupported HDR format");
6737 token += 3;
6738 width = (int) strtol(token, NULL, 10);
6739
6740 if (height > STBI_MAX_DIMENSIONS) return stbi__errpf("too large","Very large image (corrupt?)");
6741 if (width > STBI_MAX_DIMENSIONS) return stbi__errpf("too large","Very large image (corrupt?)");
6742
6743 *x = width;
6744 *y = height;
6745
6746 if (comp) *comp = 3;
6747 if (req_comp == 0) req_comp = 3;
6748
6749 if (!stbi__mad4sizes_valid(width, height, req_comp, sizeof(float), 0))
6750 return stbi__errpf("too large", "HDR image is too large");
6751
6752 // Read data
6753 hdr_data = (float *) stbi__malloc_mad4(width, height, req_comp, sizeof(float), 0);
6754 if (!hdr_data)
6755 return stbi__errpf("outofmem", "Out of memory");
6756
6757 // Load image data
6758 // image data is stored as some number of sca
6759 if ( width < 8 || width >= 32768) {
6760 // Read flat data
6761 for (j=0; j < height; ++j) {
6762 for (i=0; i < width; ++i) {
6763 stbi_uc rgbe[4];
6764 main_decode_loop:
6765 stbi__getn(s, rgbe, 4);
6766 stbi__hdr_convert(hdr_data + j * width * req_comp + i * req_comp, rgbe, req_comp);
6767 }
6768 }
6769 } else {
6770 // Read RLE-encoded data
6771 scanline = NULL;
6772
6773 for (j = 0; j < height; ++j) {
6774 c1 = stbi__get8(s);
6775 c2 = stbi__get8(s);
6776 len = stbi__get8(s);
6777 if (c1 != 2 || c2 != 2 || (len & 0x80)) {
6778 // not run-length encoded, so we have to actually use THIS data as a decoded
6779 // pixel (note this can't be a valid pixel--one of RGB must be >= 128)
6780 stbi_uc rgbe[4];
6781 rgbe[0] = (stbi_uc) c1;
6782 rgbe[1] = (stbi_uc) c2;
6783 rgbe[2] = (stbi_uc) len;
6784 rgbe[3] = (stbi_uc) stbi__get8(s);
6785 stbi__hdr_convert(hdr_data, rgbe, req_comp);
6786 i = 1;
6787 j = 0;
6788 STBI_FREE(scanline);
6789 goto main_decode_loop; // yes, this makes no sense
6790 }
6791 len <<= 8;
6792 len |= stbi__get8(s);
6793 if (len != width) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("invalid decoded scanline length", "corrupt HDR"); }
6794 if (scanline == NULL) {
6795 scanline = (stbi_uc *) stbi__malloc_mad2(width, 4, 0);
6796 if (!scanline) {
6797 STBI_FREE(hdr_data);
6798 return stbi__errpf("outofmem", "Out of memory");
6799 }
6800 }
6801
6802 for (k = 0; k < 4; ++k) {
6803 int nleft;
6804 i = 0;
6805 while ((nleft = width - i) > 0) {
6806 count = stbi__get8(s);
6807 if (count > 128) {
6808 // Run
6809 value = stbi__get8(s);
6810 count -= 128;
6811 if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
6812 for (z = 0; z < count; ++z)
6813 scanline[i++ * 4 + k] = value;
6814 } else {
6815 // Dump
6816 if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
6817 for (z = 0; z < count; ++z)
6818 scanline[i++ * 4 + k] = stbi__get8(s);
6819 }
6820 }
6821 }
6822 for (i=0; i < width; ++i)
6823 stbi__hdr_convert(hdr_data+(j*width + i)*req_comp, scanline + i*4, req_comp);
6824 }
6825 if (scanline)
6826 STBI_FREE(scanline);
6827 }
6828
6829 return hdr_data;
6830}
6831
6832static int stbi__hdr_info(stbi__context *s, int *x, int *y, int *comp)
6833{
6834 char buffer[STBI__HDR_BUFLEN];
6835 char *token;
6836 int valid = 0;
6837 int dummy;
6838
6839 if (!x) x = &dummy;
6840 if (!y) y = &dummy;
6841 if (!comp) comp = &dummy;
6842
6843 if (stbi__hdr_test(s) == 0) {
6844 stbi__rewind( s );
6845 return 0;
6846 }
6847
6848 for(;;) {
6849 token = stbi__hdr_gettoken(s,buffer);
6850 if (token[0] == 0) break;
6851 if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0) valid = 1;
6852 }
6853
6854 if (!valid) {
6855 stbi__rewind( s );
6856 return 0;
6857 }
6858 token = stbi__hdr_gettoken(s,buffer);
6859 if (strncmp(token, "-Y ", 3)) {
6860 stbi__rewind( s );
6861 return 0;
6862 }
6863 token += 3;
6864 *y = (int) strtol(token, &token, 10);
6865 while (*token == ' ') ++token;
6866 if (strncmp(token, "+X ", 3)) {
6867 stbi__rewind( s );
6868 return 0;
6869 }
6870 token += 3;
6871 *x = (int) strtol(token, NULL, 10);
6872 *comp = 3;
6873 return 1;
6874}
6875#endif // STBI_NO_HDR
6876
6877#ifndef STBI_NO_BMP
6878static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp)
6879{
6880 void *p;
6881 stbi__bmp_data info;
6882
6883 info.all_a = 255;
6884 p = stbi__bmp_parse_header(s, &info);
6885 if (p == NULL) {
6886 stbi__rewind( s );
6887 return 0;
6888 }
6889 if (x) *x = s->img_x;
6890 if (y) *y = s->img_y;
6891 if (comp) {
6892 if (info.bpp == 24 && info.ma == 0xff000000)
6893 *comp = 3;
6894 else
6895 *comp = info.ma ? 4 : 3;
6896 }
6897 return 1;
6898}
6899#endif
6900
6901#ifndef STBI_NO_PSD
6902static int stbi__psd_info(stbi__context *s, int *x, int *y, int *comp)
6903{
6904 int channelCount, dummy, depth;
6905 if (!x) x = &dummy;
6906 if (!y) y = &dummy;
6907 if (!comp) comp = &dummy;
6908 if (stbi__get32be(s) != 0x38425053) {
6909 stbi__rewind( s );
6910 return 0;
6911 }
6912 if (stbi__get16be(s) != 1) {
6913 stbi__rewind( s );
6914 return 0;
6915 }
6916 stbi__skip(s, 6);
6917 channelCount = stbi__get16be(s);
6918 if (channelCount < 0 || channelCount > 16) {
6919 stbi__rewind( s );
6920 return 0;
6921 }
6922 *y = stbi__get32be(s);
6923 *x = stbi__get32be(s);
6924 depth = stbi__get16be(s);
6925 if (depth != 8 && depth != 16) {
6926 stbi__rewind( s );
6927 return 0;
6928 }
6929 if (stbi__get16be(s) != 3) {
6930 stbi__rewind( s );
6931 return 0;
6932 }
6933 *comp = 4;
6934 return 1;
6935}
6936
6937static int stbi__psd_is16(stbi__context *s)
6938{
6939 int channelCount, depth;
6940 if (stbi__get32be(s) != 0x38425053) {
6941 stbi__rewind( s );
6942 return 0;
6943 }
6944 if (stbi__get16be(s) != 1) {
6945 stbi__rewind( s );
6946 return 0;
6947 }
6948 stbi__skip(s, 6);
6949 channelCount = stbi__get16be(s);
6950 if (channelCount < 0 || channelCount > 16) {
6951 stbi__rewind( s );
6952 return 0;
6953 }
6954 STBI_NOTUSED(stbi__get32be(s));
6955 STBI_NOTUSED(stbi__get32be(s));
6956 depth = stbi__get16be(s);
6957 if (depth != 16) {
6958 stbi__rewind( s );
6959 return 0;
6960 }
6961 return 1;
6962}
6963#endif
6964
6965#ifndef STBI_NO_PIC
6966static int stbi__pic_info(stbi__context *s, int *x, int *y, int *comp)
6967{
6968 int act_comp=0,num_packets=0,chained,dummy;
6969 stbi__pic_packet packets[10];
6970
6971 if (!x) x = &dummy;
6972 if (!y) y = &dummy;
6973 if (!comp) comp = &dummy;
6974
6975 if (!stbi__pic_is4(s,"\x53\x80\xF6\x34")) {
6976 stbi__rewind(s);
6977 return 0;
6978 }
6979
6980 stbi__skip(s, 88);
6981
6982 *x = stbi__get16be(s);
6983 *y = stbi__get16be(s);
6984 if (stbi__at_eof(s)) {
6985 stbi__rewind( s);
6986 return 0;
6987 }
6988 if ( (*x) != 0 && (1 << 28) / (*x) < (*y)) {
6989 stbi__rewind( s );
6990 return 0;
6991 }
6992
6993 stbi__skip(s, 8);
6994
6995 do {
6996 stbi__pic_packet *packet;
6997
6998 if (num_packets==sizeof(packets)/sizeof(packets[0]))
6999 return 0;
7000
7001 packet = &packets[num_packets++];
7002 chained = stbi__get8(s);
7003 packet->size = stbi__get8(s);
7004 packet->type = stbi__get8(s);
7005 packet->channel = stbi__get8(s);
7006 act_comp |= packet->channel;
7007
7008 if (stbi__at_eof(s)) {
7009 stbi__rewind( s );
7010 return 0;
7011 }
7012 if (packet->size != 8) {
7013 stbi__rewind( s );
7014 return 0;
7015 }
7016 } while (chained);
7017
7018 *comp = (act_comp & 0x10 ? 4 : 3);
7019
7020 return 1;
7021}
7022#endif
7023
7024// *************************************************************************************************
7025// Portable Gray Map and Portable Pixel Map loader
7026// by Ken Miller
7027//
7028// PGM: http://netpbm.sourceforge.net/doc/pgm.html
7029// PPM: http://netpbm.sourceforge.net/doc/ppm.html
7030//
7031// Known limitations:
7032// Does not support comments in the header section
7033// Does not support ASCII image data (formats P2 and P3)
7034
7035#ifndef STBI_NO_PNM
7036
7037static int stbi__pnm_test(stbi__context *s)
7038{
7039 char p, t;
7040 p = (char) stbi__get8(s);
7041 t = (char) stbi__get8(s);
7042 if (p != 'P' || (t != '5' && t != '6')) {
7043 stbi__rewind( s );
7044 return 0;
7045 }
7046 return 1;
7047}
7048
7049static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
7050{
7051 stbi_uc *out;
7052 STBI_NOTUSED(ri);
7053
7054 ri->bits_per_channel = stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n);
7055 if (ri->bits_per_channel == 0)
7056 return 0;
7057
7058 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
7059 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
7060
7061 *x = s->img_x;
7062 *y = s->img_y;
7063 if (comp) *comp = s->img_n;
7064
7065 if (!stbi__mad4sizes_valid(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0))
7066 return stbi__errpuc("too large", "PNM too large");
7067
7068 out = (stbi_uc *) stbi__malloc_mad4(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0);
7069 if (!out) return stbi__errpuc("outofmem", "Out of memory");
7070 if (!stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8))) {
7071 STBI_FREE(out);
7072 return stbi__errpuc("bad PNM", "PNM file truncated");
7073 }
7074
7075 if (req_comp && req_comp != s->img_n) {
7076 if (ri->bits_per_channel == 16) {
7077 out = (stbi_uc *) stbi__convert_format16((stbi__uint16 *) out, s->img_n, req_comp, s->img_x, s->img_y);
7078 } else {
7079 out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
7080 }
7081 if (out == NULL) return out; // stbi__convert_format frees input on failure
7082 }
7083 return out;
7084}
7085
7086static int stbi__pnm_isspace(char c)
7087{
7088 return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r';
7089}
7090
7091static void stbi__pnm_skip_whitespace(stbi__context *s, char *c)
7092{
7093 for (;;) {
7094 while (!stbi__at_eof(s) && stbi__pnm_isspace(*c))
7095 *c = (char) stbi__get8(s);
7096
7097 if (stbi__at_eof(s) || *c != '#')
7098 break;
7099
7100 while (!stbi__at_eof(s) && *c != '\n' && *c != '\r' )
7101 *c = (char) stbi__get8(s);
7102 }
7103}
7104
7105static int stbi__pnm_isdigit(char c)
7106{
7107 return c >= '0' && c <= '9';
7108}
7109
7110static int stbi__pnm_getinteger(stbi__context *s, char *c)
7111{
7112 int value = 0;
7113
7114 while (!stbi__at_eof(s) && stbi__pnm_isdigit(*c)) {
7115 value = value*10 + (*c - '0');
7116 *c = (char) stbi__get8(s);
7117 if((value > 214748364) || (value == 214748364 && *c > '7'))
7118 return stbi__err("integer parse overflow", "Parsing an integer in the PPM header overflowed a 32-bit int");
7119 }
7120
7121 return value;
7122}
7123
7124static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp)
7125{
7126 int maxv, dummy;
7127 char c, p, t;
7128
7129 if (!x) x = &dummy;
7130 if (!y) y = &dummy;
7131 if (!comp) comp = &dummy;
7132
7133 stbi__rewind(s);
7134
7135 // Get identifier
7136 p = (char) stbi__get8(s);
7137 t = (char) stbi__get8(s);
7138 if (p != 'P' || (t != '5' && t != '6')) {
7139 stbi__rewind(s);
7140 return 0;
7141 }
7142
7143 *comp = (t == '6') ? 3 : 1; // '5' is 1-component .pgm; '6' is 3-component .ppm
7144
7145 c = (char) stbi__get8(s);
7146 stbi__pnm_skip_whitespace(s, &c);
7147
7148 *x = stbi__pnm_getinteger(s, &c); // read width
7149 if(*x == 0)
7150 return stbi__err("invalid width", "PPM image header had zero or overflowing width");
7151 stbi__pnm_skip_whitespace(s, &c);
7152
7153 *y = stbi__pnm_getinteger(s, &c); // read height
7154 if (*y == 0)
7155 return stbi__err("invalid width", "PPM image header had zero or overflowing width");
7156 stbi__pnm_skip_whitespace(s, &c);
7157
7158 maxv = stbi__pnm_getinteger(s, &c); // read max value
7159 if (maxv > 65535)
7160 return stbi__err("max value > 65535", "PPM image supports only 8-bit and 16-bit images");
7161 else if (maxv > 255)
7162 return 16;
7163 else
7164 return 8;
7165}
7166
7167static int stbi__pnm_is16(stbi__context *s)
7168{
7169 if (stbi__pnm_info(s, NULL, NULL, NULL) == 16)
7170 return 1;
7171 return 0;
7172}
7173#endif
7174
7175static int stbi__info_main(stbi__context *s, int *x, int *y, int *comp)
7176{
7177 #ifndef STBI_NO_JPEG
7178 if (stbi__jpeg_info(s, x, y, comp)) return 1;
7179 #endif
7180
7181 #ifndef STBI_NO_PNG
7182 if (stbi__png_info(s, x, y, comp)) return 1;
7183 #endif
7184
7185 #ifndef STBI_NO_GIF
7186 if (stbi__gif_info(s, x, y, comp)) return 1;
7187 #endif
7188
7189 #ifndef STBI_NO_BMP
7190 if (stbi__bmp_info(s, x, y, comp)) return 1;
7191 #endif
7192
7193 #ifndef STBI_NO_PSD
7194 if (stbi__psd_info(s, x, y, comp)) return 1;
7195 #endif
7196
7197 #ifndef STBI_NO_PIC
7198 if (stbi__pic_info(s, x, y, comp)) return 1;
7199 #endif
7200
7201 #ifndef STBI_NO_PNM
7202 if (stbi__pnm_info(s, x, y, comp)) return 1;
7203 #endif
7204
7205 #ifndef STBI_NO_HDR
7206 if (stbi__hdr_info(s, x, y, comp)) return 1;
7207 #endif
7208
7209 // test tga last because it's a crappy test!
7210 #ifndef STBI_NO_TGA
7211 if (stbi__tga_info(s, x, y, comp))
7212 return 1;
7213 #endif
7214 return stbi__err("unknown image type", "Image not of any known type, or corrupt");
7215}
7216
7217static int stbi__is_16_main(stbi__context *s)
7218{
7219 #ifndef STBI_NO_PNG
7220 if (stbi__png_is16(s)) return 1;
7221 #endif
7222
7223 #ifndef STBI_NO_PSD
7224 if (stbi__psd_is16(s)) return 1;
7225 #endif
7226
7227 #ifndef STBI_NO_PNM
7228 if (stbi__pnm_is16(s)) return 1;
7229 #endif
7230 return 0;
7231}
7232
7233#ifndef STBI_NO_STDIO
7234STBIDEF int stbi_info(char const *filename, int *x, int *y, int *comp)
7235{
7236 FILE *f = stbi__fopen(filename, "rb");
7237 int result;
7238 if (!f) return stbi__err("can't fopen", "Unable to open file");
7239 result = stbi_info_from_file(f, x, y, comp);
7240 fclose(f);
7241 return result;
7242}
7243
7244STBIDEF int stbi_info_from_file(FILE *f, int *x, int *y, int *comp)
7245{
7246 int r;
7247 stbi__context s;
7248 long pos = ftell(f);
7249 stbi__start_file(&s, f);
7250 r = stbi__info_main(&s,x,y,comp);
7251 fseek(f,pos,SEEK_SET);
7252 return r;
7253}
7254
7255STBIDEF int stbi_is_16_bit(char const *filename)
7256{
7257 FILE *f = stbi__fopen(filename, "rb");
7258 int result;
7259 if (!f) return stbi__err("can't fopen", "Unable to open file");
7260 result = stbi_is_16_bit_from_file(f);
7261 fclose(f);
7262 return result;
7263}
7264
7265STBIDEF int stbi_is_16_bit_from_file(FILE *f)
7266{
7267 int r;
7268 stbi__context s;
7269 long pos = ftell(f);
7270 stbi__start_file(&s, f);
7271 r = stbi__is_16_main(&s);
7272 fseek(f,pos,SEEK_SET);
7273 return r;
7274}
7275#endif // !STBI_NO_STDIO
7276
7277STBIDEF int stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp)
7278{
7279 stbi__context s;
7280 stbi__start_mem(&s,buffer,len);
7281 return stbi__info_main(&s,x,y,comp);
7282}
7283
7284STBIDEF int stbi_info_from_callbacks(stbi_io_callbacks const *c, void *user, int *x, int *y, int *comp)
7285{
7286 stbi__context s;
7287 stbi__start_callbacks(&s, (stbi_io_callbacks *) c, user);
7288 return stbi__info_main(&s,x,y,comp);
7289}
7290
7291STBIDEF int stbi_is_16_bit_from_memory(stbi_uc const *buffer, int len)
7292{
7293 stbi__context s;
7294 stbi__start_mem(&s,buffer,len);
7295 return stbi__is_16_main(&s);
7296}
7297
7298STBIDEF int stbi_is_16_bit_from_callbacks(stbi_io_callbacks const *c, void *user)
7299{
7300 stbi__context s;
7301 stbi__start_callbacks(&s, (stbi_io_callbacks *) c, user);
7302 return stbi__is_16_main(&s);
7303}
7304
7305/*
7306 revision history:
7307 2.20 (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
7308 2.19 (2018-02-11) fix warning
7309 2.18 (2018-01-30) fix warnings
7310 2.17 (2018-01-29) change sbti__shiftsigned to avoid clang -O2 bug
7311 1-bit BMP
7312 *_is_16_bit api
7313 avoid warnings
7314 2.16 (2017-07-23) all functions have 16-bit variants;
7315 STBI_NO_STDIO works again;
7316 compilation fixes;
7317 fix rounding in unpremultiply;
7318 optimize vertical flip;
7319 disable raw_len validation;
7320 documentation fixes
7321 2.15 (2017-03-18) fix png-1,2,4 bug; now all Imagenet JPGs decode;
7322 warning fixes; disable run-time SSE detection on gcc;
7323 uniform handling of optional "return" values;
7324 thread-safe initialization of zlib tables
7325 2.14 (2017-03-03) remove deprecated STBI_JPEG_OLD; fixes for Imagenet JPGs
7326 2.13 (2016-11-29) add 16-bit API, only supported for PNG right now
7327 2.12 (2016-04-02) fix typo in 2.11 PSD fix that caused crashes
7328 2.11 (2016-04-02) allocate large structures on the stack
7329 remove white matting for transparent PSD
7330 fix reported channel count for PNG & BMP
7331 re-enable SSE2 in non-gcc 64-bit
7332 support RGB-formatted JPEG
7333 read 16-bit PNGs (only as 8-bit)
7334 2.10 (2016-01-22) avoid warning introduced in 2.09 by STBI_REALLOC_SIZED
7335 2.09 (2016-01-16) allow comments in PNM files
7336 16-bit-per-pixel TGA (not bit-per-component)
7337 info() for TGA could break due to .hdr handling
7338 info() for BMP to shares code instead of sloppy parse
7339 can use STBI_REALLOC_SIZED if allocator doesn't support realloc
7340 code cleanup
7341 2.08 (2015-09-13) fix to 2.07 cleanup, reading RGB PSD as RGBA
7342 2.07 (2015-09-13) fix compiler warnings
7343 partial animated GIF support
7344 limited 16-bpc PSD support
7345 #ifdef unused functions
7346 bug with < 92 byte PIC,PNM,HDR,TGA
7347 2.06 (2015-04-19) fix bug where PSD returns wrong '*comp' value
7348 2.05 (2015-04-19) fix bug in progressive JPEG handling, fix warning
7349 2.04 (2015-04-15) try to re-enable SIMD on MinGW 64-bit
7350 2.03 (2015-04-12) extra corruption checking (mmozeiko)
7351 stbi_set_flip_vertically_on_load (nguillemot)
7352 fix NEON support; fix mingw support
7353 2.02 (2015-01-19) fix incorrect assert, fix warning
7354 2.01 (2015-01-17) fix various warnings; suppress SIMD on gcc 32-bit without -msse2
7355 2.00b (2014-12-25) fix STBI_MALLOC in progressive JPEG
7356 2.00 (2014-12-25) optimize JPG, including x86 SSE2 & NEON SIMD (ryg)
7357 progressive JPEG (stb)
7358 PGM/PPM support (Ken Miller)
7359 STBI_MALLOC,STBI_REALLOC,STBI_FREE
7360 GIF bugfix -- seemingly never worked
7361 STBI_NO_*, STBI_ONLY_*
7362 1.48 (2014-12-14) fix incorrectly-named assert()
7363 1.47 (2014-12-14) 1/2/4-bit PNG support, both direct and paletted (Omar Cornut & stb)
7364 optimize PNG (ryg)
7365 fix bug in interlaced PNG with user-specified channel count (stb)
7366 1.46 (2014-08-26)
7367 fix broken tRNS chunk (colorkey-style transparency) in non-paletted PNG
7368 1.45 (2014-08-16)
7369 fix MSVC-ARM internal compiler error by wrapping malloc
7370 1.44 (2014-08-07)
7371 various warning fixes from Ronny Chevalier
7372 1.43 (2014-07-15)
7373 fix MSVC-only compiler problem in code changed in 1.42
7374 1.42 (2014-07-09)
7375 don't define _CRT_SECURE_NO_WARNINGS (affects user code)
7376 fixes to stbi__cleanup_jpeg path
7377 added STBI_ASSERT to avoid requiring assert.h
7378 1.41 (2014-06-25)
7379 fix search&replace from 1.36 that messed up comments/error messages
7380 1.40 (2014-06-22)
7381 fix gcc struct-initialization warning
7382 1.39 (2014-06-15)
7383 fix to TGA optimization when req_comp != number of components in TGA;
7384 fix to GIF loading because BMP wasn't rewinding (whoops, no GIFs in my test suite)
7385 add support for BMP version 5 (more ignored fields)
7386 1.38 (2014-06-06)
7387 suppress MSVC warnings on integer casts truncating values
7388 fix accidental rename of 'skip' field of I/O
7389 1.37 (2014-06-04)
7390 remove duplicate typedef
7391 1.36 (2014-06-03)
7392 convert to header file single-file library
7393 if de-iphone isn't set, load iphone images color-swapped instead of returning NULL
7394 1.35 (2014-05-27)
7395 various warnings
7396 fix broken STBI_SIMD path
7397 fix bug where stbi_load_from_file no longer left file pointer in correct place
7398 fix broken non-easy path for 32-bit BMP (possibly never used)
7399 TGA optimization by Arseny Kapoulkine
7400 1.34 (unknown)
7401 use STBI_NOTUSED in stbi__resample_row_generic(), fix one more leak in tga failure case
7402 1.33 (2011-07-14)
7403 make stbi_is_hdr work in STBI_NO_HDR (as specified), minor compiler-friendly improvements
7404 1.32 (2011-07-13)
7405 support for "info" function for all supported filetypes (SpartanJ)
7406 1.31 (2011-06-20)
7407 a few more leak fixes, bug in PNG handling (SpartanJ)
7408 1.30 (2011-06-11)
7409 added ability to load files via callbacks to accomidate custom input streams (Ben Wenger)
7410 removed deprecated format-specific test/load functions
7411 removed support for installable file formats (stbi_loader) -- would have been broken for IO callbacks anyway
7412 error cases in bmp and tga give messages and don't leak (Raymond Barbiero, grisha)
7413 fix inefficiency in decoding 32-bit BMP (David Woo)
7414 1.29 (2010-08-16)
7415 various warning fixes from Aurelien Pocheville
7416 1.28 (2010-08-01)
7417 fix bug in GIF palette transparency (SpartanJ)
7418 1.27 (2010-08-01)
7419 cast-to-stbi_uc to fix warnings
7420 1.26 (2010-07-24)
7421 fix bug in file buffering for PNG reported by SpartanJ
7422 1.25 (2010-07-17)
7423 refix trans_data warning (Won Chun)
7424 1.24 (2010-07-12)
7425 perf improvements reading from files on platforms with lock-heavy fgetc()
7426 minor perf improvements for jpeg
7427 deprecated type-specific functions so we'll get feedback if they're needed
7428 attempt to fix trans_data warning (Won Chun)
7429 1.23 fixed bug in iPhone support
7430 1.22 (2010-07-10)
7431 removed image *writing* support
7432 stbi_info support from Jetro Lauha
7433 GIF support from Jean-Marc Lienher
7434 iPhone PNG-extensions from James Brown
7435 warning-fixes from Nicolas Schulz and Janez Zemva (i.stbi__err. Janez (U+017D)emva)
7436 1.21 fix use of 'stbi_uc' in header (reported by jon blow)
7437 1.20 added support for Softimage PIC, by Tom Seddon
7438 1.19 bug in interlaced PNG corruption check (found by ryg)
7439 1.18 (2008-08-02)
7440 fix a threading bug (local mutable static)
7441 1.17 support interlaced PNG
7442 1.16 major bugfix - stbi__convert_format converted one too many pixels
7443 1.15 initialize some fields for thread safety
7444 1.14 fix threadsafe conversion bug
7445 header-file-only version (#define STBI_HEADER_FILE_ONLY before including)
7446 1.13 threadsafe
7447 1.12 const qualifiers in the API
7448 1.11 Support installable IDCT, colorspace conversion routines
7449 1.10 Fixes for 64-bit (don't use "unsigned long")
7450 optimized upsampling by Fabian "ryg" Giesen
7451 1.09 Fix format-conversion for PSD code (bad global variables!)
7452 1.08 Thatcher Ulrich's PSD code integrated by Nicolas Schulz
7453 1.07 attempt to fix C++ warning/errors again
7454 1.06 attempt to fix C++ warning/errors again
7455 1.05 fix TGA loading to return correct *comp and use good luminance calc
7456 1.04 default float alpha is 1, not 255; use 'void *' for stbi_image_free
7457 1.03 bugfixes to STBI_NO_STDIO, STBI_NO_HDR
7458 1.02 support for (subset of) HDR files, float interface for preferred access to them
7459 1.01 fix bug: possible bug in handling right-side up bmps... not sure
7460 fix bug: the stbi__bmp_load() and stbi__tga_load() functions didn't work at all
7461 1.00 interface to zlib that skips zlib header
7462 0.99 correct handling of alpha in palette
7463 0.98 TGA loader by lonesock; dynamically add loaders (untested)
7464 0.97 jpeg errors on too large a file; also catch another malloc failure
7465 0.96 fix detection of invalid v value - particleman@mollyrocket forum
7466 0.95 during header scan, seek to markers in case of padding
7467 0.94 STBI_NO_STDIO to disable stdio usage; rename all #defines the same
7468 0.93 handle jpegtran output; verbose errors
7469 0.92 read 4,8,16,24,32-bit BMP files of several formats
7470 0.91 output 24-bit Windows 3.0 BMP files
7471 0.90 fix a few more warnings; bump version number to approach 1.0
7472 0.61 bugfixes due to Marc LeBlanc, Christopher Lloyd
7473 0.60 fix compiling as c++
7474 0.59 fix warnings: merge Dave Moore's -Wall fixes
7475 0.58 fix bug: zlib uncompressed mode len/nlen was wrong endian
7476 0.57 fix bug: jpg last huffman symbol before marker was >9 bits but less than 16 available
7477 0.56 fix bug: zlib uncompressed mode len vs. nlen
7478 0.55 fix bug: restart_interval not initialized to 0
7479 0.54 allow NULL for 'int *comp'
7480 0.53 fix bug in png 3->4; speedup png decoding
7481 0.52 png handles req_comp=3,4 directly; minor cleanup; jpeg comments
7482 0.51 obey req_comp requests, 1-component jpegs return as 1-component,
7483 on 'test' only check type, not whether we support this variant
7484 0.50 (2006-11-19)
7485 first released version
7486*/
7487
7488
7489/*
7490------------------------------------------------------------------------------
7491This software is available under 2 licenses -- choose whichever you prefer.
7492------------------------------------------------------------------------------
7493ALTERNATIVE A - MIT License
7494Copyright (c) 2017 Sean Barrett
7495Permission is hereby granted, free of charge, to any person obtaining a copy of
7496this software and associated documentation files (the "Software"), to deal in
7497the Software without restriction, including without limitation the rights to
7498use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
7499of the Software, and to permit persons to whom the Software is furnished to do
7500so, subject to the following conditions:
7501The above copyright notice and this permission notice shall be included in all
7502copies or substantial portions of the Software.
7503THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
7504IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
7505FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
7506AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
7507LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
7508OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
7509SOFTWARE.
7510------------------------------------------------------------------------------
7511ALTERNATIVE B - Public Domain (www.unlicense.org)
7512This is free and unencumbered software released into the public domain.
7513Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
7514software, either in source code form or as a compiled binary, for any purpose,
7515commercial or non-commercial, and by any means.
7516In jurisdictions that recognize copyright laws, the author or authors of this
7517software dedicate any and all copyright interest in the software to the public
7518domain. We make this dedication for the benefit of the public at large and to
7519the detriment of our heirs and successors. We intend this dedication to be an
7520overt act of relinquishment in perpetuity of all present and future rights to
7521this software under copyright law.
7522THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
7523IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
7524FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
7525AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
7526ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
7527WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
7528------------------------------------------------------------------------------
7529*/
diff --git a/externals/stb/stb_image.h b/externals/stb/stb_image.h
index 7e8d1c124..f0dfad1c6 100644
--- a/externals/stb/stb_image.h
+++ b/externals/stb/stb_image.h
@@ -545,7224 +545,6 @@ STBIDEF int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const ch
545//// end header file ///////////////////////////////////////////////////// 545//// end header file /////////////////////////////////////////////////////
546#endif // STBI_INCLUDE_STB_IMAGE_H 546#endif // STBI_INCLUDE_STB_IMAGE_H
547 547
548#ifdef STB_IMAGE_IMPLEMENTATION
549
550#if defined(STBI_ONLY_JPEG) || defined(STBI_ONLY_PNG) || defined(STBI_ONLY_BMP) \
551 || defined(STBI_ONLY_TGA) || defined(STBI_ONLY_GIF) || defined(STBI_ONLY_PSD) \
552 || defined(STBI_ONLY_HDR) || defined(STBI_ONLY_PIC) || defined(STBI_ONLY_PNM) \
553 || defined(STBI_ONLY_ZLIB)
554 #ifndef STBI_ONLY_JPEG
555 #define STBI_NO_JPEG
556 #endif
557 #ifndef STBI_ONLY_PNG
558 #define STBI_NO_PNG
559 #endif
560 #ifndef STBI_ONLY_BMP
561 #define STBI_NO_BMP
562 #endif
563 #ifndef STBI_ONLY_PSD
564 #define STBI_NO_PSD
565 #endif
566 #ifndef STBI_ONLY_TGA
567 #define STBI_NO_TGA
568 #endif
569 #ifndef STBI_ONLY_GIF
570 #define STBI_NO_GIF
571 #endif
572 #ifndef STBI_ONLY_HDR
573 #define STBI_NO_HDR
574 #endif
575 #ifndef STBI_ONLY_PIC
576 #define STBI_NO_PIC
577 #endif
578 #ifndef STBI_ONLY_PNM
579 #define STBI_NO_PNM
580 #endif
581#endif
582
583#if defined(STBI_NO_PNG) && !defined(STBI_SUPPORT_ZLIB) && !defined(STBI_NO_ZLIB)
584#define STBI_NO_ZLIB
585#endif
586
587
588#include <stdarg.h>
589#include <stddef.h> // ptrdiff_t on osx
590#include <stdlib.h>
591#include <string.h>
592#include <limits.h>
593
594#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
595#include <math.h> // ldexp, pow
596#endif
597
598#ifndef STBI_NO_STDIO
599#include <stdio.h>
600#endif
601
602#ifndef STBI_ASSERT
603#include <assert.h>
604#define STBI_ASSERT(x) assert(x)
605#endif
606
607#ifdef __cplusplus
608#define STBI_EXTERN extern "C"
609#else
610#define STBI_EXTERN extern
611#endif
612
613
614#ifndef _MSC_VER
615 #ifdef __cplusplus
616 #define stbi_inline inline
617 #else
618 #define stbi_inline
619 #endif
620#else
621 #define stbi_inline __forceinline
622#endif
623
624#ifndef STBI_NO_THREAD_LOCALS
625 #if defined(__cplusplus) && __cplusplus >= 201103L
626 #define STBI_THREAD_LOCAL thread_local
627 #elif defined(__GNUC__) && __GNUC__ < 5
628 #define STBI_THREAD_LOCAL __thread
629 #elif defined(_MSC_VER)
630 #define STBI_THREAD_LOCAL __declspec(thread)
631 #elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_THREADS__)
632 #define STBI_THREAD_LOCAL _Thread_local
633 #endif
634
635 #ifndef STBI_THREAD_LOCAL
636 #if defined(__GNUC__)
637 #define STBI_THREAD_LOCAL __thread
638 #endif
639 #endif
640#endif
641
642#if defined(_MSC_VER) || defined(__SYMBIAN32__)
643typedef unsigned short stbi__uint16;
644typedef signed short stbi__int16;
645typedef unsigned int stbi__uint32;
646typedef signed int stbi__int32;
647#else
648#include <stdint.h>
649typedef uint16_t stbi__uint16;
650typedef int16_t stbi__int16;
651typedef uint32_t stbi__uint32;
652typedef int32_t stbi__int32;
653#endif
654
655// should produce compiler error if size is wrong
656typedef unsigned char validate_uint32[sizeof(stbi__uint32)==4 ? 1 : -1];
657
658#ifdef _MSC_VER
659#define STBI_NOTUSED(v) (void)(v)
660#else
661#define STBI_NOTUSED(v) (void)sizeof(v)
662#endif
663
664#ifdef _MSC_VER
665#define STBI_HAS_LROTL
666#endif
667
668#ifdef STBI_HAS_LROTL
669 #define stbi_lrot(x,y) _lrotl(x,y)
670#else
671 #define stbi_lrot(x,y) (((x) << (y)) | ((x) >> (-(y) & 31)))
672#endif
673
674#if defined(STBI_MALLOC) && defined(STBI_FREE) && (defined(STBI_REALLOC) || defined(STBI_REALLOC_SIZED))
675// ok
676#elif !defined(STBI_MALLOC) && !defined(STBI_FREE) && !defined(STBI_REALLOC) && !defined(STBI_REALLOC_SIZED)
677// ok
678#else
679#error "Must define all or none of STBI_MALLOC, STBI_FREE, and STBI_REALLOC (or STBI_REALLOC_SIZED)."
680#endif
681
682#ifndef STBI_MALLOC
683#define STBI_MALLOC(sz) malloc(sz)
684#define STBI_REALLOC(p,newsz) realloc(p,newsz)
685#define STBI_FREE(p) free(p)
686#endif
687
688#ifndef STBI_REALLOC_SIZED
689#define STBI_REALLOC_SIZED(p,oldsz,newsz) STBI_REALLOC(p,newsz)
690#endif
691
692// x86/x64 detection
693#if defined(__x86_64__) || defined(_M_X64)
694#define STBI__X64_TARGET
695#elif defined(__i386) || defined(_M_IX86)
696#define STBI__X86_TARGET
697#endif
698
699#if defined(__GNUC__) && defined(STBI__X86_TARGET) && !defined(__SSE2__) && !defined(STBI_NO_SIMD)
700// gcc doesn't support sse2 intrinsics unless you compile with -msse2,
701// which in turn means it gets to use SSE2 everywhere. This is unfortunate,
702// but previous attempts to provide the SSE2 functions with runtime
703// detection caused numerous issues. The way architecture extensions are
704// exposed in GCC/Clang is, sadly, not really suited for one-file libs.
705// New behavior: if compiled with -msse2, we use SSE2 without any
706// detection; if not, we don't use it at all.
707#define STBI_NO_SIMD
708#endif
709
710#if defined(__MINGW32__) && defined(STBI__X86_TARGET) && !defined(STBI_MINGW_ENABLE_SSE2) && !defined(STBI_NO_SIMD)
711// Note that __MINGW32__ doesn't actually mean 32-bit, so we have to avoid STBI__X64_TARGET
712//
713// 32-bit MinGW wants ESP to be 16-byte aligned, but this is not in the
714// Windows ABI and VC++ as well as Windows DLLs don't maintain that invariant.
715// As a result, enabling SSE2 on 32-bit MinGW is dangerous when not
716// simultaneously enabling "-mstackrealign".
717//
718// See https://github.com/nothings/stb/issues/81 for more information.
719//
720// So default to no SSE2 on 32-bit MinGW. If you've read this far and added
721// -mstackrealign to your build settings, feel free to #define STBI_MINGW_ENABLE_SSE2.
722#define STBI_NO_SIMD
723#endif
724
725#if !defined(STBI_NO_SIMD) && (defined(STBI__X86_TARGET) || defined(STBI__X64_TARGET))
726#define STBI_SSE2
727#include <emmintrin.h>
728
729#ifdef _MSC_VER
730
731#if _MSC_VER >= 1400 // not VC6
732#include <intrin.h> // __cpuid
733static int stbi__cpuid3(void)
734{
735 int info[4];
736 __cpuid(info,1);
737 return info[3];
738}
739#else
740static int stbi__cpuid3(void)
741{
742 int res;
743 __asm {
744 mov eax,1
745 cpuid
746 mov res,edx
747 }
748 return res;
749}
750#endif
751
752#define STBI_SIMD_ALIGN(type, name) __declspec(align(16)) type name
753
754#if !defined(STBI_NO_JPEG) && defined(STBI_SSE2)
755static int stbi__sse2_available(void)
756{
757 int info3 = stbi__cpuid3();
758 return ((info3 >> 26) & 1) != 0;
759}
760#endif
761
762#else // assume GCC-style if not VC++
763#define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))
764
765#if !defined(STBI_NO_JPEG) && defined(STBI_SSE2)
766static int stbi__sse2_available(void)
767{
768 // If we're even attempting to compile this on GCC/Clang, that means
769 // -msse2 is on, which means the compiler is allowed to use SSE2
770 // instructions at will, and so are we.
771 return 1;
772}
773#endif
774
775#endif
776#endif
777
778// ARM NEON
779#if defined(STBI_NO_SIMD) && defined(STBI_NEON)
780#undef STBI_NEON
781#endif
782
783#ifdef STBI_NEON
784#include <arm_neon.h>
785#ifdef _MSC_VER
786#define STBI_SIMD_ALIGN(type, name) __declspec(align(16)) type name
787#else
788#define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))
789#endif
790#endif
791
792#ifndef STBI_SIMD_ALIGN
793#define STBI_SIMD_ALIGN(type, name) type name
794#endif
795
796#ifndef STBI_MAX_DIMENSIONS
797#define STBI_MAX_DIMENSIONS (1 << 24)
798#endif
799
800///////////////////////////////////////////////
801//
802// stbi__context struct and start_xxx functions
803
804// stbi__context structure is our basic context used by all images, so it
805// contains all the IO context, plus some basic image information
806typedef struct
807{
808 stbi__uint32 img_x, img_y;
809 int img_n, img_out_n;
810
811 stbi_io_callbacks io;
812 void *io_user_data;
813
814 int read_from_callbacks;
815 int buflen;
816 stbi_uc buffer_start[128];
817 int callback_already_read;
818
819 stbi_uc *img_buffer, *img_buffer_end;
820 stbi_uc *img_buffer_original, *img_buffer_original_end;
821} stbi__context;
822
823
824static void stbi__refill_buffer(stbi__context *s);
825
826// initialize a memory-decode context
827static void stbi__start_mem(stbi__context *s, stbi_uc const *buffer, int len)
828{
829 s->io.read = NULL;
830 s->read_from_callbacks = 0;
831 s->callback_already_read = 0;
832 s->img_buffer = s->img_buffer_original = (stbi_uc *) buffer;
833 s->img_buffer_end = s->img_buffer_original_end = (stbi_uc *) buffer+len;
834}
835
836// initialize a callback-based context
837static void stbi__start_callbacks(stbi__context *s, stbi_io_callbacks *c, void *user)
838{
839 s->io = *c;
840 s->io_user_data = user;
841 s->buflen = sizeof(s->buffer_start);
842 s->read_from_callbacks = 1;
843 s->callback_already_read = 0;
844 s->img_buffer = s->img_buffer_original = s->buffer_start;
845 stbi__refill_buffer(s);
846 s->img_buffer_original_end = s->img_buffer_end;
847}
848
849#ifndef STBI_NO_STDIO
850
851static int stbi__stdio_read(void *user, char *data, int size)
852{
853 return (int) fread(data,1,size,(FILE*) user);
854}
855
856static void stbi__stdio_skip(void *user, int n)
857{
858 int ch;
859 fseek((FILE*) user, n, SEEK_CUR);
860 ch = fgetc((FILE*) user); /* have to read a byte to reset feof()'s flag */
861 if (ch != EOF) {
862 ungetc(ch, (FILE *) user); /* push byte back onto stream if valid. */
863 }
864}
865
866static int stbi__stdio_eof(void *user)
867{
868 return feof((FILE*) user) || ferror((FILE *) user);
869}
870
871static stbi_io_callbacks stbi__stdio_callbacks =
872{
873 stbi__stdio_read,
874 stbi__stdio_skip,
875 stbi__stdio_eof,
876};
877
878static void stbi__start_file(stbi__context *s, FILE *f)
879{
880 stbi__start_callbacks(s, &stbi__stdio_callbacks, (void *) f);
881}
882
883//static void stop_file(stbi__context *s) { }
884
885#endif // !STBI_NO_STDIO
886
887static void stbi__rewind(stbi__context *s)
888{
889 // conceptually rewind SHOULD rewind to the beginning of the stream,
890 // but we just rewind to the beginning of the initial buffer, because
891 // we only use it after doing 'test', which only ever looks at at most 92 bytes
892 s->img_buffer = s->img_buffer_original;
893 s->img_buffer_end = s->img_buffer_original_end;
894}
895
896enum
897{
898 STBI_ORDER_RGB,
899 STBI_ORDER_BGR
900};
901
902typedef struct
903{
904 int bits_per_channel;
905 int num_channels;
906 int channel_order;
907} stbi__result_info;
908
909#ifndef STBI_NO_JPEG
910static int stbi__jpeg_test(stbi__context *s);
911static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
912static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp);
913#endif
914
915#ifndef STBI_NO_PNG
916static int stbi__png_test(stbi__context *s);
917static void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
918static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp);
919static int stbi__png_is16(stbi__context *s);
920#endif
921
922#ifndef STBI_NO_BMP
923static int stbi__bmp_test(stbi__context *s);
924static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
925static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp);
926#endif
927
928#ifndef STBI_NO_TGA
929static int stbi__tga_test(stbi__context *s);
930static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
931static int stbi__tga_info(stbi__context *s, int *x, int *y, int *comp);
932#endif
933
934#ifndef STBI_NO_PSD
935static int stbi__psd_test(stbi__context *s);
936static void *stbi__psd_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc);
937static int stbi__psd_info(stbi__context *s, int *x, int *y, int *comp);
938static int stbi__psd_is16(stbi__context *s);
939#endif
940
941#ifndef STBI_NO_HDR
942static int stbi__hdr_test(stbi__context *s);
943static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
944static int stbi__hdr_info(stbi__context *s, int *x, int *y, int *comp);
945#endif
946
947#ifndef STBI_NO_PIC
948static int stbi__pic_test(stbi__context *s);
949static void *stbi__pic_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
950static int stbi__pic_info(stbi__context *s, int *x, int *y, int *comp);
951#endif
952
953#ifndef STBI_NO_GIF
954static int stbi__gif_test(stbi__context *s);
955static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
956static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp);
957static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp);
958#endif
959
960#ifndef STBI_NO_PNM
961static int stbi__pnm_test(stbi__context *s);
962static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
963static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp);
964static int stbi__pnm_is16(stbi__context *s);
965#endif
966
967static
968#ifdef STBI_THREAD_LOCAL
969STBI_THREAD_LOCAL
970#endif
971const char *stbi__g_failure_reason;
972
973STBIDEF const char *stbi_failure_reason(void)
974{
975 return stbi__g_failure_reason;
976}
977
978#ifndef STBI_NO_FAILURE_STRINGS
979static int stbi__err(const char *str)
980{
981 stbi__g_failure_reason = str;
982 return 0;
983}
984#endif
985
986static void *stbi__malloc(size_t size)
987{
988 return STBI_MALLOC(size);
989}
990
991// stb_image uses ints pervasively, including for offset calculations.
992// therefore the largest decoded image size we can support with the
993// current code, even on 64-bit targets, is INT_MAX. this is not a
994// significant limitation for the intended use case.
995//
996// we do, however, need to make sure our size calculations don't
997// overflow. hence a few helper functions for size calculations that
998// multiply integers together, making sure that they're non-negative
999// and no overflow occurs.
1000
1001// return 1 if the sum is valid, 0 on overflow.
1002// negative terms are considered invalid.
1003static int stbi__addsizes_valid(int a, int b)
1004{
1005 if (b < 0) return 0;
1006 // now 0 <= b <= INT_MAX, hence also
1007 // 0 <= INT_MAX - b <= INTMAX.
1008 // And "a + b <= INT_MAX" (which might overflow) is the
1009 // same as a <= INT_MAX - b (no overflow)
1010 return a <= INT_MAX - b;
1011}
1012
1013// returns 1 if the product is valid, 0 on overflow.
1014// negative factors are considered invalid.
1015static int stbi__mul2sizes_valid(int a, int b)
1016{
1017 if (a < 0 || b < 0) return 0;
1018 if (b == 0) return 1; // mul-by-0 is always safe
1019 // portable way to check for no overflows in a*b
1020 return a <= INT_MAX/b;
1021}
1022
1023#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
1024// returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow
1025static int stbi__mad2sizes_valid(int a, int b, int add)
1026{
1027 return stbi__mul2sizes_valid(a, b) && stbi__addsizes_valid(a*b, add);
1028}
1029#endif
1030
1031// returns 1 if "a*b*c + add" has no negative terms/factors and doesn't overflow
1032static int stbi__mad3sizes_valid(int a, int b, int c, int add)
1033{
1034 return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a*b, c) &&
1035 stbi__addsizes_valid(a*b*c, add);
1036}
1037
1038// returns 1 if "a*b*c*d + add" has no negative terms/factors and doesn't overflow
1039#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
1040static int stbi__mad4sizes_valid(int a, int b, int c, int d, int add)
1041{
1042 return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a*b, c) &&
1043 stbi__mul2sizes_valid(a*b*c, d) && stbi__addsizes_valid(a*b*c*d, add);
1044}
1045#endif
1046
1047#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
1048// mallocs with size overflow checking
1049static void *stbi__malloc_mad2(int a, int b, int add)
1050{
1051 if (!stbi__mad2sizes_valid(a, b, add)) return NULL;
1052 return stbi__malloc(a*b + add);
1053}
1054#endif
1055
1056static void *stbi__malloc_mad3(int a, int b, int c, int add)
1057{
1058 if (!stbi__mad3sizes_valid(a, b, c, add)) return NULL;
1059 return stbi__malloc(a*b*c + add);
1060}
1061
1062#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
1063static void *stbi__malloc_mad4(int a, int b, int c, int d, int add)
1064{
1065 if (!stbi__mad4sizes_valid(a, b, c, d, add)) return NULL;
1066 return stbi__malloc(a*b*c*d + add);
1067}
1068#endif
1069
1070// returns 1 if the sum of two signed ints is valid (between -2^31 and 2^31-1 inclusive), 0 on overflow.
1071static int stbi__addints_valid(int a, int b)
1072{
1073 if ((a >= 0) != (b >= 0)) return 1; // a and b have different signs, so no overflow
1074 if (a < 0 && b < 0) return a >= INT_MIN - b; // same as a + b >= INT_MIN; INT_MIN - b cannot overflow since b < 0.
1075 return a <= INT_MAX - b;
1076}
1077
1078// returns 1 if the product of two signed shorts is valid, 0 on overflow.
1079static int stbi__mul2shorts_valid(short a, short b)
1080{
1081 if (b == 0 || b == -1) return 1; // multiplication by 0 is always 0; check for -1 so SHRT_MIN/b doesn't overflow
1082 if ((a >= 0) == (b >= 0)) return a <= SHRT_MAX/b; // product is positive, so similar to mul2sizes_valid
1083 if (b < 0) return a <= SHRT_MIN / b; // same as a * b >= SHRT_MIN
1084 return a >= SHRT_MIN / b;
1085}
1086
1087// stbi__err - error
1088// stbi__errpf - error returning pointer to float
1089// stbi__errpuc - error returning pointer to unsigned char
1090
1091#ifdef STBI_NO_FAILURE_STRINGS
1092 #define stbi__err(x,y) 0
1093#elif defined(STBI_FAILURE_USERMSG)
1094 #define stbi__err(x,y) stbi__err(y)
1095#else
1096 #define stbi__err(x,y) stbi__err(x)
1097#endif
1098
1099#define stbi__errpf(x,y) ((float *)(size_t) (stbi__err(x,y)?NULL:NULL))
1100#define stbi__errpuc(x,y) ((unsigned char *)(size_t) (stbi__err(x,y)?NULL:NULL))
1101
1102STBIDEF void stbi_image_free(void *retval_from_stbi_load)
1103{
1104 STBI_FREE(retval_from_stbi_load);
1105}
1106
1107#ifndef STBI_NO_LINEAR
1108static float *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp);
1109#endif
1110
1111#ifndef STBI_NO_HDR
1112static stbi_uc *stbi__hdr_to_ldr(float *data, int x, int y, int comp);
1113#endif
1114
1115static int stbi__vertically_flip_on_load_global = 0;
1116
1117STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip)
1118{
1119 stbi__vertically_flip_on_load_global = flag_true_if_should_flip;
1120}
1121
1122#ifndef STBI_THREAD_LOCAL
1123#define stbi__vertically_flip_on_load stbi__vertically_flip_on_load_global
1124#else
1125static STBI_THREAD_LOCAL int stbi__vertically_flip_on_load_local, stbi__vertically_flip_on_load_set;
1126
1127STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip)
1128{
1129 stbi__vertically_flip_on_load_local = flag_true_if_should_flip;
1130 stbi__vertically_flip_on_load_set = 1;
1131}
1132
1133#define stbi__vertically_flip_on_load (stbi__vertically_flip_on_load_set \
1134 ? stbi__vertically_flip_on_load_local \
1135 : stbi__vertically_flip_on_load_global)
1136#endif // STBI_THREAD_LOCAL
1137
1138static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
1139{
1140 memset(ri, 0, sizeof(*ri)); // make sure it's initialized if we add new fields
1141 ri->bits_per_channel = 8; // default is 8 so most paths don't have to be changed
1142 ri->channel_order = STBI_ORDER_RGB; // all current input & output are this, but this is here so we can add BGR order
1143 ri->num_channels = 0;
1144
1145 // test the formats with a very explicit header first (at least a FOURCC
1146 // or distinctive magic number first)
1147 #ifndef STBI_NO_PNG
1148 if (stbi__png_test(s)) return stbi__png_load(s,x,y,comp,req_comp, ri);
1149 #endif
1150 #ifndef STBI_NO_BMP
1151 if (stbi__bmp_test(s)) return stbi__bmp_load(s,x,y,comp,req_comp, ri);
1152 #endif
1153 #ifndef STBI_NO_GIF
1154 if (stbi__gif_test(s)) return stbi__gif_load(s,x,y,comp,req_comp, ri);
1155 #endif
1156 #ifndef STBI_NO_PSD
1157 if (stbi__psd_test(s)) return stbi__psd_load(s,x,y,comp,req_comp, ri, bpc);
1158 #else
1159 STBI_NOTUSED(bpc);
1160 #endif
1161 #ifndef STBI_NO_PIC
1162 if (stbi__pic_test(s)) return stbi__pic_load(s,x,y,comp,req_comp, ri);
1163 #endif
1164
1165 // then the formats that can end up attempting to load with just 1 or 2
1166 // bytes matching expectations; these are prone to false positives, so
1167 // try them later
1168 #ifndef STBI_NO_JPEG
1169 if (stbi__jpeg_test(s)) return stbi__jpeg_load(s,x,y,comp,req_comp, ri);
1170 #endif
1171 #ifndef STBI_NO_PNM
1172 if (stbi__pnm_test(s)) return stbi__pnm_load(s,x,y,comp,req_comp, ri);
1173 #endif
1174
1175 #ifndef STBI_NO_HDR
1176 if (stbi__hdr_test(s)) {
1177 float *hdr = stbi__hdr_load(s, x,y,comp,req_comp, ri);
1178 return stbi__hdr_to_ldr(hdr, *x, *y, req_comp ? req_comp : *comp);
1179 }
1180 #endif
1181
1182 #ifndef STBI_NO_TGA
1183 // test tga last because it's a crappy test!
1184 if (stbi__tga_test(s))
1185 return stbi__tga_load(s,x,y,comp,req_comp, ri);
1186 #endif
1187
1188 return stbi__errpuc("unknown image type", "Image not of any known type, or corrupt");
1189}
1190
1191static stbi_uc *stbi__convert_16_to_8(stbi__uint16 *orig, int w, int h, int channels)
1192{
1193 int i;
1194 int img_len = w * h * channels;
1195 stbi_uc *reduced;
1196
1197 reduced = (stbi_uc *) stbi__malloc(img_len);
1198 if (reduced == NULL) return stbi__errpuc("outofmem", "Out of memory");
1199
1200 for (i = 0; i < img_len; ++i)
1201 reduced[i] = (stbi_uc)((orig[i] >> 8) & 0xFF); // top half of each byte is sufficient approx of 16->8 bit scaling
1202
1203 STBI_FREE(orig);
1204 return reduced;
1205}
1206
1207static stbi__uint16 *stbi__convert_8_to_16(stbi_uc *orig, int w, int h, int channels)
1208{
1209 int i;
1210 int img_len = w * h * channels;
1211 stbi__uint16 *enlarged;
1212
1213 enlarged = (stbi__uint16 *) stbi__malloc(img_len*2);
1214 if (enlarged == NULL) return (stbi__uint16 *) stbi__errpuc("outofmem", "Out of memory");
1215
1216 for (i = 0; i < img_len; ++i)
1217 enlarged[i] = (stbi__uint16)((orig[i] << 8) + orig[i]); // replicate to high and low byte, maps 0->0, 255->0xffff
1218
1219 STBI_FREE(orig);
1220 return enlarged;
1221}
1222
1223static void stbi__vertical_flip(void *image, int w, int h, int bytes_per_pixel)
1224{
1225 int row;
1226 size_t bytes_per_row = (size_t)w * bytes_per_pixel;
1227 stbi_uc temp[2048];
1228 stbi_uc *bytes = (stbi_uc *)image;
1229
1230 for (row = 0; row < (h>>1); row++) {
1231 stbi_uc *row0 = bytes + row*bytes_per_row;
1232 stbi_uc *row1 = bytes + (h - row - 1)*bytes_per_row;
1233 // swap row0 with row1
1234 size_t bytes_left = bytes_per_row;
1235 while (bytes_left) {
1236 size_t bytes_copy = (bytes_left < sizeof(temp)) ? bytes_left : sizeof(temp);
1237 memcpy(temp, row0, bytes_copy);
1238 memcpy(row0, row1, bytes_copy);
1239 memcpy(row1, temp, bytes_copy);
1240 row0 += bytes_copy;
1241 row1 += bytes_copy;
1242 bytes_left -= bytes_copy;
1243 }
1244 }
1245}
1246
1247#ifndef STBI_NO_GIF
1248static void stbi__vertical_flip_slices(void *image, int w, int h, int z, int bytes_per_pixel)
1249{
1250 int slice;
1251 int slice_size = w * h * bytes_per_pixel;
1252
1253 stbi_uc *bytes = (stbi_uc *)image;
1254 for (slice = 0; slice < z; ++slice) {
1255 stbi__vertical_flip(bytes, w, h, bytes_per_pixel);
1256 bytes += slice_size;
1257 }
1258}
1259#endif
1260
1261static unsigned char *stbi__load_and_postprocess_8bit(stbi__context *s, int *x, int *y, int *comp, int req_comp)
1262{
1263 stbi__result_info ri;
1264 void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 8);
1265
1266 if (result == NULL)
1267 return NULL;
1268
1269 // it is the responsibility of the loaders to make sure we get either 8 or 16 bit.
1270 STBI_ASSERT(ri.bits_per_channel == 8 || ri.bits_per_channel == 16);
1271
1272 if (ri.bits_per_channel != 8) {
1273 result = stbi__convert_16_to_8((stbi__uint16 *) result, *x, *y, req_comp == 0 ? *comp : req_comp);
1274 ri.bits_per_channel = 8;
1275 }
1276
1277 // @TODO: move stbi__convert_format to here
1278
1279 if (stbi__vertically_flip_on_load) {
1280 int channels = req_comp ? req_comp : *comp;
1281 stbi__vertical_flip(result, *x, *y, channels * sizeof(stbi_uc));
1282 }
1283
1284 return (unsigned char *) result;
1285}
1286
1287static stbi__uint16 *stbi__load_and_postprocess_16bit(stbi__context *s, int *x, int *y, int *comp, int req_comp)
1288{
1289 stbi__result_info ri;
1290 void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 16);
1291
1292 if (result == NULL)
1293 return NULL;
1294
1295 // it is the responsibility of the loaders to make sure we get either 8 or 16 bit.
1296 STBI_ASSERT(ri.bits_per_channel == 8 || ri.bits_per_channel == 16);
1297
1298 if (ri.bits_per_channel != 16) {
1299 result = stbi__convert_8_to_16((stbi_uc *) result, *x, *y, req_comp == 0 ? *comp : req_comp);
1300 ri.bits_per_channel = 16;
1301 }
1302
1303 // @TODO: move stbi__convert_format16 to here
1304 // @TODO: special case RGB-to-Y (and RGBA-to-YA) for 8-bit-to-16-bit case to keep more precision
1305
1306 if (stbi__vertically_flip_on_load) {
1307 int channels = req_comp ? req_comp : *comp;
1308 stbi__vertical_flip(result, *x, *y, channels * sizeof(stbi__uint16));
1309 }
1310
1311 return (stbi__uint16 *) result;
1312}
1313
1314#if !defined(STBI_NO_HDR) && !defined(STBI_NO_LINEAR)
1315static void stbi__float_postprocess(float *result, int *x, int *y, int *comp, int req_comp)
1316{
1317 if (stbi__vertically_flip_on_load && result != NULL) {
1318 int channels = req_comp ? req_comp : *comp;
1319 stbi__vertical_flip(result, *x, *y, channels * sizeof(float));
1320 }
1321}
1322#endif
1323
1324#ifndef STBI_NO_STDIO
1325
1326#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
1327STBI_EXTERN __declspec(dllimport) int __stdcall MultiByteToWideChar(unsigned int cp, unsigned long flags, const char *str, int cbmb, wchar_t *widestr, int cchwide);
1328STBI_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned int cp, unsigned long flags, const wchar_t *widestr, int cchwide, char *str, int cbmb, const char *defchar, int *used_default);
1329#endif
1330
1331#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
1332STBIDEF int stbi_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
1333{
1334 return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
1335}
1336#endif
1337
1338static FILE *stbi__fopen(char const *filename, char const *mode)
1339{
1340 FILE *f;
1341#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
1342 wchar_t wMode[64];
1343 wchar_t wFilename[1024];
1344 if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)/sizeof(*wFilename)))
1345 return 0;
1346
1347 if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)/sizeof(*wMode)))
1348 return 0;
1349
1350#if defined(_MSC_VER) && _MSC_VER >= 1400
1351 if (0 != _wfopen_s(&f, wFilename, wMode))
1352 f = 0;
1353#else
1354 f = _wfopen(wFilename, wMode);
1355#endif
1356
1357#elif defined(_MSC_VER) && _MSC_VER >= 1400
1358 if (0 != fopen_s(&f, filename, mode))
1359 f=0;
1360#else
1361 f = fopen(filename, mode);
1362#endif
1363 return f;
1364}
1365
1366
1367STBIDEF stbi_uc *stbi_load(char const *filename, int *x, int *y, int *comp, int req_comp)
1368{
1369 FILE *f = stbi__fopen(filename, "rb");
1370 unsigned char *result;
1371 if (!f) return stbi__errpuc("can't fopen", "Unable to open file");
1372 result = stbi_load_from_file(f,x,y,comp,req_comp);
1373 fclose(f);
1374 return result;
1375}
1376
1377STBIDEF stbi_uc *stbi_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
1378{
1379 unsigned char *result;
1380 stbi__context s;
1381 stbi__start_file(&s,f);
1382 result = stbi__load_and_postprocess_8bit(&s,x,y,comp,req_comp);
1383 if (result) {
1384 // need to 'unget' all the characters in the IO buffer
1385 fseek(f, - (int) (s.img_buffer_end - s.img_buffer), SEEK_CUR);
1386 }
1387 return result;
1388}
1389
1390STBIDEF stbi__uint16 *stbi_load_from_file_16(FILE *f, int *x, int *y, int *comp, int req_comp)
1391{
1392 stbi__uint16 *result;
1393 stbi__context s;
1394 stbi__start_file(&s,f);
1395 result = stbi__load_and_postprocess_16bit(&s,x,y,comp,req_comp);
1396 if (result) {
1397 // need to 'unget' all the characters in the IO buffer
1398 fseek(f, - (int) (s.img_buffer_end - s.img_buffer), SEEK_CUR);
1399 }
1400 return result;
1401}
1402
1403STBIDEF stbi_us *stbi_load_16(char const *filename, int *x, int *y, int *comp, int req_comp)
1404{
1405 FILE *f = stbi__fopen(filename, "rb");
1406 stbi__uint16 *result;
1407 if (!f) return (stbi_us *) stbi__errpuc("can't fopen", "Unable to open file");
1408 result = stbi_load_from_file_16(f,x,y,comp,req_comp);
1409 fclose(f);
1410 return result;
1411}
1412
1413
1414#endif //!STBI_NO_STDIO
1415
1416STBIDEF stbi_us *stbi_load_16_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels)
1417{
1418 stbi__context s;
1419 stbi__start_mem(&s,buffer,len);
1420 return stbi__load_and_postprocess_16bit(&s,x,y,channels_in_file,desired_channels);
1421}
1422
1423STBIDEF stbi_us *stbi_load_16_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *channels_in_file, int desired_channels)
1424{
1425 stbi__context s;
1426 stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
1427 return stbi__load_and_postprocess_16bit(&s,x,y,channels_in_file,desired_channels);
1428}
1429
1430STBIDEF stbi_uc *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
1431{
1432 stbi__context s;
1433 stbi__start_mem(&s,buffer,len);
1434 return stbi__load_and_postprocess_8bit(&s,x,y,comp,req_comp);
1435}
1436
1437STBIDEF stbi_uc *stbi_load_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
1438{
1439 stbi__context s;
1440 stbi__start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
1441 return stbi__load_and_postprocess_8bit(&s,x,y,comp,req_comp);
1442}
1443
1444#ifndef STBI_NO_GIF
1445STBIDEF stbi_uc *stbi_load_gif_from_memory(stbi_uc const *buffer, int len, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
1446{
1447 unsigned char *result;
1448 stbi__context s;
1449 stbi__start_mem(&s,buffer,len);
1450
1451 result = (unsigned char*) stbi__load_gif_main(&s, delays, x, y, z, comp, req_comp);
1452 if (stbi__vertically_flip_on_load) {
1453 stbi__vertical_flip_slices( result, *x, *y, *z, *comp );
1454 }
1455
1456 return result;
1457}
1458#endif
1459
1460#ifndef STBI_NO_LINEAR
1461static float *stbi__loadf_main(stbi__context *s, int *x, int *y, int *comp, int req_comp)
1462{
1463 unsigned char *data;
1464 #ifndef STBI_NO_HDR
1465 if (stbi__hdr_test(s)) {
1466 stbi__result_info ri;
1467 float *hdr_data = stbi__hdr_load(s,x,y,comp,req_comp, &ri);
1468 if (hdr_data)
1469 stbi__float_postprocess(hdr_data,x,y,comp,req_comp);
1470 return hdr_data;
1471 }
1472 #endif
1473 data = stbi__load_and_postprocess_8bit(s, x, y, comp, req_comp);
1474 if (data)
1475 return stbi__ldr_to_hdr(data, *x, *y, req_comp ? req_comp : *comp);
1476 return stbi__errpf("unknown image type", "Image not of any known type, or corrupt");
1477}
1478
1479STBIDEF float *stbi_loadf_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
1480{
1481 stbi__context s;
1482 stbi__start_mem(&s,buffer,len);
1483 return stbi__loadf_main(&s,x,y,comp,req_comp);
1484}
1485
1486STBIDEF float *stbi_loadf_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
1487{
1488 stbi__context s;
1489 stbi__start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
1490 return stbi__loadf_main(&s,x,y,comp,req_comp);
1491}
1492
1493#ifndef STBI_NO_STDIO
1494STBIDEF float *stbi_loadf(char const *filename, int *x, int *y, int *comp, int req_comp)
1495{
1496 float *result;
1497 FILE *f = stbi__fopen(filename, "rb");
1498 if (!f) return stbi__errpf("can't fopen", "Unable to open file");
1499 result = stbi_loadf_from_file(f,x,y,comp,req_comp);
1500 fclose(f);
1501 return result;
1502}
1503
1504STBIDEF float *stbi_loadf_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
1505{
1506 stbi__context s;
1507 stbi__start_file(&s,f);
1508 return stbi__loadf_main(&s,x,y,comp,req_comp);
1509}
1510#endif // !STBI_NO_STDIO
1511
1512#endif // !STBI_NO_LINEAR
1513
1514// these is-hdr-or-not is defined independent of whether STBI_NO_LINEAR is
1515// defined, for API simplicity; if STBI_NO_LINEAR is defined, it always
1516// reports false!
1517
1518STBIDEF int stbi_is_hdr_from_memory(stbi_uc const *buffer, int len)
1519{
1520 #ifndef STBI_NO_HDR
1521 stbi__context s;
1522 stbi__start_mem(&s,buffer,len);
1523 return stbi__hdr_test(&s);
1524 #else
1525 STBI_NOTUSED(buffer);
1526 STBI_NOTUSED(len);
1527 return 0;
1528 #endif
1529}
1530
1531#ifndef STBI_NO_STDIO
1532STBIDEF int stbi_is_hdr (char const *filename)
1533{
1534 FILE *f = stbi__fopen(filename, "rb");
1535 int result=0;
1536 if (f) {
1537 result = stbi_is_hdr_from_file(f);
1538 fclose(f);
1539 }
1540 return result;
1541}
1542
1543STBIDEF int stbi_is_hdr_from_file(FILE *f)
1544{
1545 #ifndef STBI_NO_HDR
1546 long pos = ftell(f);
1547 int res;
1548 stbi__context s;
1549 stbi__start_file(&s,f);
1550 res = stbi__hdr_test(&s);
1551 fseek(f, pos, SEEK_SET);
1552 return res;
1553 #else
1554 STBI_NOTUSED(f);
1555 return 0;
1556 #endif
1557}
1558#endif // !STBI_NO_STDIO
1559
1560STBIDEF int stbi_is_hdr_from_callbacks(stbi_io_callbacks const *clbk, void *user)
1561{
1562 #ifndef STBI_NO_HDR
1563 stbi__context s;
1564 stbi__start_callbacks(&s, (stbi_io_callbacks *) clbk, user);
1565 return stbi__hdr_test(&s);
1566 #else
1567 STBI_NOTUSED(clbk);
1568 STBI_NOTUSED(user);
1569 return 0;
1570 #endif
1571}
1572
1573#ifndef STBI_NO_LINEAR
1574static float stbi__l2h_gamma=2.2f, stbi__l2h_scale=1.0f;
1575
1576STBIDEF void stbi_ldr_to_hdr_gamma(float gamma) { stbi__l2h_gamma = gamma; }
1577STBIDEF void stbi_ldr_to_hdr_scale(float scale) { stbi__l2h_scale = scale; }
1578#endif
1579
1580static float stbi__h2l_gamma_i=1.0f/2.2f, stbi__h2l_scale_i=1.0f;
1581
1582STBIDEF void stbi_hdr_to_ldr_gamma(float gamma) { stbi__h2l_gamma_i = 1/gamma; }
1583STBIDEF void stbi_hdr_to_ldr_scale(float scale) { stbi__h2l_scale_i = 1/scale; }
1584
1585
1586//////////////////////////////////////////////////////////////////////////////
1587//
1588// Common code used by all image loaders
1589//
1590
1591enum
1592{
1593 STBI__SCAN_load=0,
1594 STBI__SCAN_type,
1595 STBI__SCAN_header
1596};
1597
1598static void stbi__refill_buffer(stbi__context *s)
1599{
1600 int n = (s->io.read)(s->io_user_data,(char*)s->buffer_start,s->buflen);
1601 s->callback_already_read += (int) (s->img_buffer - s->img_buffer_original);
1602 if (n == 0) {
1603 // at end of file, treat same as if from memory, but need to handle case
1604 // where s->img_buffer isn't pointing to safe memory, e.g. 0-byte file
1605 s->read_from_callbacks = 0;
1606 s->img_buffer = s->buffer_start;
1607 s->img_buffer_end = s->buffer_start+1;
1608 *s->img_buffer = 0;
1609 } else {
1610 s->img_buffer = s->buffer_start;
1611 s->img_buffer_end = s->buffer_start + n;
1612 }
1613}
1614
1615stbi_inline static stbi_uc stbi__get8(stbi__context *s)
1616{
1617 if (s->img_buffer < s->img_buffer_end)
1618 return *s->img_buffer++;
1619 if (s->read_from_callbacks) {
1620 stbi__refill_buffer(s);
1621 return *s->img_buffer++;
1622 }
1623 return 0;
1624}
1625
1626#if defined(STBI_NO_JPEG) && defined(STBI_NO_HDR) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
1627// nothing
1628#else
1629stbi_inline static int stbi__at_eof(stbi__context *s)
1630{
1631 if (s->io.read) {
1632 if (!(s->io.eof)(s->io_user_data)) return 0;
1633 // if feof() is true, check if buffer = end
1634 // special case: we've only got the special 0 character at the end
1635 if (s->read_from_callbacks == 0) return 1;
1636 }
1637
1638 return s->img_buffer >= s->img_buffer_end;
1639}
1640#endif
1641
1642#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC)
1643// nothing
1644#else
1645static void stbi__skip(stbi__context *s, int n)
1646{
1647 if (n == 0) return; // already there!
1648 if (n < 0) {
1649 s->img_buffer = s->img_buffer_end;
1650 return;
1651 }
1652 if (s->io.read) {
1653 int blen = (int) (s->img_buffer_end - s->img_buffer);
1654 if (blen < n) {
1655 s->img_buffer = s->img_buffer_end;
1656 (s->io.skip)(s->io_user_data, n - blen);
1657 return;
1658 }
1659 }
1660 s->img_buffer += n;
1661}
1662#endif
1663
1664#if defined(STBI_NO_PNG) && defined(STBI_NO_TGA) && defined(STBI_NO_HDR) && defined(STBI_NO_PNM)
1665// nothing
1666#else
1667static int stbi__getn(stbi__context *s, stbi_uc *buffer, int n)
1668{
1669 if (s->io.read) {
1670 int blen = (int) (s->img_buffer_end - s->img_buffer);
1671 if (blen < n) {
1672 int res, count;
1673
1674 memcpy(buffer, s->img_buffer, blen);
1675
1676 count = (s->io.read)(s->io_user_data, (char*) buffer + blen, n - blen);
1677 res = (count == (n-blen));
1678 s->img_buffer = s->img_buffer_end;
1679 return res;
1680 }
1681 }
1682
1683 if (s->img_buffer+n <= s->img_buffer_end) {
1684 memcpy(buffer, s->img_buffer, n);
1685 s->img_buffer += n;
1686 return 1;
1687 } else
1688 return 0;
1689}
1690#endif
1691
1692#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
1693// nothing
1694#else
1695static int stbi__get16be(stbi__context *s)
1696{
1697 int z = stbi__get8(s);
1698 return (z << 8) + stbi__get8(s);
1699}
1700#endif
1701
1702#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
1703// nothing
1704#else
1705static stbi__uint32 stbi__get32be(stbi__context *s)
1706{
1707 stbi__uint32 z = stbi__get16be(s);
1708 return (z << 16) + stbi__get16be(s);
1709}
1710#endif
1711
1712#if defined(STBI_NO_BMP) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF)
1713// nothing
1714#else
1715static int stbi__get16le(stbi__context *s)
1716{
1717 int z = stbi__get8(s);
1718 return z + (stbi__get8(s) << 8);
1719}
1720#endif
1721
1722#ifndef STBI_NO_BMP
1723static stbi__uint32 stbi__get32le(stbi__context *s)
1724{
1725 stbi__uint32 z = stbi__get16le(s);
1726 z += (stbi__uint32)stbi__get16le(s) << 16;
1727 return z;
1728}
1729#endif
1730
1731#define STBI__BYTECAST(x) ((stbi_uc) ((x) & 255)) // truncate int to byte without warnings
1732
1733#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
1734// nothing
1735#else
1736//////////////////////////////////////////////////////////////////////////////
1737//
1738// generic converter from built-in img_n to req_comp
1739// individual types do this automatically as much as possible (e.g. jpeg
1740// does all cases internally since it needs to colorspace convert anyway,
1741// and it never has alpha, so very few cases ). png can automatically
1742// interleave an alpha=255 channel, but falls back to this for other cases
1743//
1744// assume data buffer is malloced, so malloc a new one and free that one
1745// only failure mode is malloc failing
1746
1747static stbi_uc stbi__compute_y(int r, int g, int b)
1748{
1749 return (stbi_uc) (((r*77) + (g*150) + (29*b)) >> 8);
1750}
1751#endif
1752
1753#if defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
1754// nothing
1755#else
1756static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y)
1757{
1758 int i,j;
1759 unsigned char *good;
1760
1761 if (req_comp == img_n) return data;
1762 STBI_ASSERT(req_comp >= 1 && req_comp <= 4);
1763
1764 good = (unsigned char *) stbi__malloc_mad3(req_comp, x, y, 0);
1765 if (good == NULL) {
1766 STBI_FREE(data);
1767 return stbi__errpuc("outofmem", "Out of memory");
1768 }
1769
1770 for (j=0; j < (int) y; ++j) {
1771 unsigned char *src = data + j * x * img_n ;
1772 unsigned char *dest = good + j * x * req_comp;
1773
1774 #define STBI__COMBO(a,b) ((a)*8+(b))
1775 #define STBI__CASE(a,b) case STBI__COMBO(a,b): for(i=x-1; i >= 0; --i, src += a, dest += b)
1776 // convert source image with img_n components to one with req_comp components;
1777 // avoid switch per pixel, so use switch per scanline and massive macros
1778 switch (STBI__COMBO(img_n, req_comp)) {
1779 STBI__CASE(1,2) { dest[0]=src[0]; dest[1]=255; } break;
1780 STBI__CASE(1,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1781 STBI__CASE(1,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=255; } break;
1782 STBI__CASE(2,1) { dest[0]=src[0]; } break;
1783 STBI__CASE(2,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1784 STBI__CASE(2,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=src[1]; } break;
1785 STBI__CASE(3,4) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2];dest[3]=255; } break;
1786 STBI__CASE(3,1) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); } break;
1787 STBI__CASE(3,2) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); dest[1] = 255; } break;
1788 STBI__CASE(4,1) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); } break;
1789 STBI__CASE(4,2) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); dest[1] = src[3]; } break;
1790 STBI__CASE(4,3) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2]; } break;
1791 default: STBI_ASSERT(0); STBI_FREE(data); STBI_FREE(good); return stbi__errpuc("unsupported", "Unsupported format conversion");
1792 }
1793 #undef STBI__CASE
1794 }
1795
1796 STBI_FREE(data);
1797 return good;
1798}
1799#endif
1800
1801#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
1802// nothing
1803#else
1804static stbi__uint16 stbi__compute_y_16(int r, int g, int b)
1805{
1806 return (stbi__uint16) (((r*77) + (g*150) + (29*b)) >> 8);
1807}
1808#endif
1809
1810#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
1811// nothing
1812#else
1813static stbi__uint16 *stbi__convert_format16(stbi__uint16 *data, int img_n, int req_comp, unsigned int x, unsigned int y)
1814{
1815 int i,j;
1816 stbi__uint16 *good;
1817
1818 if (req_comp == img_n) return data;
1819 STBI_ASSERT(req_comp >= 1 && req_comp <= 4);
1820
1821 good = (stbi__uint16 *) stbi__malloc(req_comp * x * y * 2);
1822 if (good == NULL) {
1823 STBI_FREE(data);
1824 return (stbi__uint16 *) stbi__errpuc("outofmem", "Out of memory");
1825 }
1826
1827 for (j=0; j < (int) y; ++j) {
1828 stbi__uint16 *src = data + j * x * img_n ;
1829 stbi__uint16 *dest = good + j * x * req_comp;
1830
1831 #define STBI__COMBO(a,b) ((a)*8+(b))
1832 #define STBI__CASE(a,b) case STBI__COMBO(a,b): for(i=x-1; i >= 0; --i, src += a, dest += b)
1833 // convert source image with img_n components to one with req_comp components;
1834 // avoid switch per pixel, so use switch per scanline and massive macros
1835 switch (STBI__COMBO(img_n, req_comp)) {
1836 STBI__CASE(1,2) { dest[0]=src[0]; dest[1]=0xffff; } break;
1837 STBI__CASE(1,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1838 STBI__CASE(1,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=0xffff; } break;
1839 STBI__CASE(2,1) { dest[0]=src[0]; } break;
1840 STBI__CASE(2,3) { dest[0]=dest[1]=dest[2]=src[0]; } break;
1841 STBI__CASE(2,4) { dest[0]=dest[1]=dest[2]=src[0]; dest[3]=src[1]; } break;
1842 STBI__CASE(3,4) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2];dest[3]=0xffff; } break;
1843 STBI__CASE(3,1) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); } break;
1844 STBI__CASE(3,2) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); dest[1] = 0xffff; } break;
1845 STBI__CASE(4,1) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); } break;
1846 STBI__CASE(4,2) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); dest[1] = src[3]; } break;
1847 STBI__CASE(4,3) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2]; } break;
1848 default: STBI_ASSERT(0); STBI_FREE(data); STBI_FREE(good); return (stbi__uint16*) stbi__errpuc("unsupported", "Unsupported format conversion");
1849 }
1850 #undef STBI__CASE
1851 }
1852
1853 STBI_FREE(data);
1854 return good;
1855}
1856#endif
1857
1858#ifndef STBI_NO_LINEAR
1859static float *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp)
1860{
1861 int i,k,n;
1862 float *output;
1863 if (!data) return NULL;
1864 output = (float *) stbi__malloc_mad4(x, y, comp, sizeof(float), 0);
1865 if (output == NULL) { STBI_FREE(data); return stbi__errpf("outofmem", "Out of memory"); }
1866 // compute number of non-alpha components
1867 if (comp & 1) n = comp; else n = comp-1;
1868 for (i=0; i < x*y; ++i) {
1869 for (k=0; k < n; ++k) {
1870 output[i*comp + k] = (float) (pow(data[i*comp+k]/255.0f, stbi__l2h_gamma) * stbi__l2h_scale);
1871 }
1872 }
1873 if (n < comp) {
1874 for (i=0; i < x*y; ++i) {
1875 output[i*comp + n] = data[i*comp + n]/255.0f;
1876 }
1877 }
1878 STBI_FREE(data);
1879 return output;
1880}
1881#endif
1882
1883#ifndef STBI_NO_HDR
1884#define stbi__float2int(x) ((int) (x))
1885static stbi_uc *stbi__hdr_to_ldr(float *data, int x, int y, int comp)
1886{
1887 int i,k,n;
1888 stbi_uc *output;
1889 if (!data) return NULL;
1890 output = (stbi_uc *) stbi__malloc_mad3(x, y, comp, 0);
1891 if (output == NULL) { STBI_FREE(data); return stbi__errpuc("outofmem", "Out of memory"); }
1892 // compute number of non-alpha components
1893 if (comp & 1) n = comp; else n = comp-1;
1894 for (i=0; i < x*y; ++i) {
1895 for (k=0; k < n; ++k) {
1896 float z = (float) pow(data[i*comp+k]*stbi__h2l_scale_i, stbi__h2l_gamma_i) * 255 + 0.5f;
1897 if (z < 0) z = 0;
1898 if (z > 255) z = 255;
1899 output[i*comp + k] = (stbi_uc) stbi__float2int(z);
1900 }
1901 if (k < comp) {
1902 float z = data[i*comp+k] * 255 + 0.5f;
1903 if (z < 0) z = 0;
1904 if (z > 255) z = 255;
1905 output[i*comp + k] = (stbi_uc) stbi__float2int(z);
1906 }
1907 }
1908 STBI_FREE(data);
1909 return output;
1910}
1911#endif
1912
1913//////////////////////////////////////////////////////////////////////////////
1914//
1915// "baseline" JPEG/JFIF decoder
1916//
1917// simple implementation
1918// - doesn't support delayed output of y-dimension
1919// - simple interface (only one output format: 8-bit interleaved RGB)
1920// - doesn't try to recover corrupt jpegs
1921// - doesn't allow partial loading, loading multiple at once
1922// - still fast on x86 (copying globals into locals doesn't help x86)
1923// - allocates lots of intermediate memory (full size of all components)
1924// - non-interleaved case requires this anyway
1925// - allows good upsampling (see next)
1926// high-quality
1927// - upsampled channels are bilinearly interpolated, even across blocks
1928// - quality integer IDCT derived from IJG's 'slow'
1929// performance
1930// - fast huffman; reasonable integer IDCT
1931// - some SIMD kernels for common paths on targets with SSE2/NEON
1932// - uses a lot of intermediate memory, could cache poorly
1933
1934#ifndef STBI_NO_JPEG
1935
1936// huffman decoding acceleration
1937#define FAST_BITS 9 // larger handles more cases; smaller stomps less cache
1938
1939typedef struct
1940{
1941 stbi_uc fast[1 << FAST_BITS];
1942 // weirdly, repacking this into AoS is a 10% speed loss, instead of a win
1943 stbi__uint16 code[256];
1944 stbi_uc values[256];
1945 stbi_uc size[257];
1946 unsigned int maxcode[18];
1947 int delta[17]; // old 'firstsymbol' - old 'firstcode'
1948} stbi__huffman;
1949
1950typedef struct
1951{
1952 stbi__context *s;
1953 stbi__huffman huff_dc[4];
1954 stbi__huffman huff_ac[4];
1955 stbi__uint16 dequant[4][64];
1956 stbi__int16 fast_ac[4][1 << FAST_BITS];
1957
1958// sizes for components, interleaved MCUs
1959 int img_h_max, img_v_max;
1960 int img_mcu_x, img_mcu_y;
1961 int img_mcu_w, img_mcu_h;
1962
1963// definition of jpeg image component
1964 struct
1965 {
1966 int id;
1967 int h,v;
1968 int tq;
1969 int hd,ha;
1970 int dc_pred;
1971
1972 int x,y,w2,h2;
1973 stbi_uc *data;
1974 void *raw_data, *raw_coeff;
1975 stbi_uc *linebuf;
1976 short *coeff; // progressive only
1977 int coeff_w, coeff_h; // number of 8x8 coefficient blocks
1978 } img_comp[4];
1979
1980 stbi__uint32 code_buffer; // jpeg entropy-coded buffer
1981 int code_bits; // number of valid bits
1982 unsigned char marker; // marker seen while filling entropy buffer
1983 int nomore; // flag if we saw a marker so must stop
1984
1985 int progressive;
1986 int spec_start;
1987 int spec_end;
1988 int succ_high;
1989 int succ_low;
1990 int eob_run;
1991 int jfif;
1992 int app14_color_transform; // Adobe APP14 tag
1993 int rgb;
1994
1995 int scan_n, order[4];
1996 int restart_interval, todo;
1997
1998// kernels
1999 void (*idct_block_kernel)(stbi_uc *out, int out_stride, short data[64]);
2000 void (*YCbCr_to_RGB_kernel)(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step);
2001 stbi_uc *(*resample_row_hv_2_kernel)(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs);
2002} stbi__jpeg;
2003
2004static int stbi__build_huffman(stbi__huffman *h, int *count)
2005{
2006 int i,j,k=0;
2007 unsigned int code;
2008 // build size list for each symbol (from JPEG spec)
2009 for (i=0; i < 16; ++i) {
2010 for (j=0; j < count[i]; ++j) {
2011 h->size[k++] = (stbi_uc) (i+1);
2012 if(k >= 257) return stbi__err("bad size list","Corrupt JPEG");
2013 }
2014 }
2015 h->size[k] = 0;
2016
2017 // compute actual symbols (from jpeg spec)
2018 code = 0;
2019 k = 0;
2020 for(j=1; j <= 16; ++j) {
2021 // compute delta to add to code to compute symbol id
2022 h->delta[j] = k - code;
2023 if (h->size[k] == j) {
2024 while (h->size[k] == j)
2025 h->code[k++] = (stbi__uint16) (code++);
2026 if (code-1 >= (1u << j)) return stbi__err("bad code lengths","Corrupt JPEG");
2027 }
2028 // compute largest code + 1 for this size, preshifted as needed later
2029 h->maxcode[j] = code << (16-j);
2030 code <<= 1;
2031 }
2032 h->maxcode[j] = 0xffffffff;
2033
2034 // build non-spec acceleration table; 255 is flag for not-accelerated
2035 memset(h->fast, 255, 1 << FAST_BITS);
2036 for (i=0; i < k; ++i) {
2037 int s = h->size[i];
2038 if (s <= FAST_BITS) {
2039 int c = h->code[i] << (FAST_BITS-s);
2040 int m = 1 << (FAST_BITS-s);
2041 for (j=0; j < m; ++j) {
2042 h->fast[c+j] = (stbi_uc) i;
2043 }
2044 }
2045 }
2046 return 1;
2047}
2048
2049// build a table that decodes both magnitude and value of small ACs in
2050// one go.
2051static void stbi__build_fast_ac(stbi__int16 *fast_ac, stbi__huffman *h)
2052{
2053 int i;
2054 for (i=0; i < (1 << FAST_BITS); ++i) {
2055 stbi_uc fast = h->fast[i];
2056 fast_ac[i] = 0;
2057 if (fast < 255) {
2058 int rs = h->values[fast];
2059 int run = (rs >> 4) & 15;
2060 int magbits = rs & 15;
2061 int len = h->size[fast];
2062
2063 if (magbits && len + magbits <= FAST_BITS) {
2064 // magnitude code followed by receive_extend code
2065 int k = ((i << len) & ((1 << FAST_BITS) - 1)) >> (FAST_BITS - magbits);
2066 int m = 1 << (magbits - 1);
2067 if (k < m) k += (~0U << magbits) + 1;
2068 // if the result is small enough, we can fit it in fast_ac table
2069 if (k >= -128 && k <= 127)
2070 fast_ac[i] = (stbi__int16) ((k * 256) + (run * 16) + (len + magbits));
2071 }
2072 }
2073 }
2074}
2075
2076static void stbi__grow_buffer_unsafe(stbi__jpeg *j)
2077{
2078 do {
2079 unsigned int b = j->nomore ? 0 : stbi__get8(j->s);
2080 if (b == 0xff) {
2081 int c = stbi__get8(j->s);
2082 while (c == 0xff) c = stbi__get8(j->s); // consume fill bytes
2083 if (c != 0) {
2084 j->marker = (unsigned char) c;
2085 j->nomore = 1;
2086 return;
2087 }
2088 }
2089 j->code_buffer |= b << (24 - j->code_bits);
2090 j->code_bits += 8;
2091 } while (j->code_bits <= 24);
2092}
2093
2094// (1 << n) - 1
2095static const stbi__uint32 stbi__bmask[17]={0,1,3,7,15,31,63,127,255,511,1023,2047,4095,8191,16383,32767,65535};
2096
2097// decode a jpeg huffman value from the bitstream
2098stbi_inline static int stbi__jpeg_huff_decode(stbi__jpeg *j, stbi__huffman *h)
2099{
2100 unsigned int temp;
2101 int c,k;
2102
2103 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
2104
2105 // look at the top FAST_BITS and determine what symbol ID it is,
2106 // if the code is <= FAST_BITS
2107 c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
2108 k = h->fast[c];
2109 if (k < 255) {
2110 int s = h->size[k];
2111 if (s > j->code_bits)
2112 return -1;
2113 j->code_buffer <<= s;
2114 j->code_bits -= s;
2115 return h->values[k];
2116 }
2117
2118 // naive test is to shift the code_buffer down so k bits are
2119 // valid, then test against maxcode. To speed this up, we've
2120 // preshifted maxcode left so that it has (16-k) 0s at the
2121 // end; in other words, regardless of the number of bits, it
2122 // wants to be compared against something shifted to have 16;
2123 // that way we don't need to shift inside the loop.
2124 temp = j->code_buffer >> 16;
2125 for (k=FAST_BITS+1 ; ; ++k)
2126 if (temp < h->maxcode[k])
2127 break;
2128 if (k == 17) {
2129 // error! code not found
2130 j->code_bits -= 16;
2131 return -1;
2132 }
2133
2134 if (k > j->code_bits)
2135 return -1;
2136
2137 // convert the huffman code to the symbol id
2138 c = ((j->code_buffer >> (32 - k)) & stbi__bmask[k]) + h->delta[k];
2139 if(c < 0 || c >= 256) // symbol id out of bounds!
2140 return -1;
2141 STBI_ASSERT((((j->code_buffer) >> (32 - h->size[c])) & stbi__bmask[h->size[c]]) == h->code[c]);
2142
2143 // convert the id to a symbol
2144 j->code_bits -= k;
2145 j->code_buffer <<= k;
2146 return h->values[c];
2147}
2148
2149// bias[n] = (-1<<n) + 1
2150static const int stbi__jbias[16] = {0,-1,-3,-7,-15,-31,-63,-127,-255,-511,-1023,-2047,-4095,-8191,-16383,-32767};
2151
2152// combined JPEG 'receive' and JPEG 'extend', since baseline
2153// always extends everything it receives.
2154stbi_inline static int stbi__extend_receive(stbi__jpeg *j, int n)
2155{
2156 unsigned int k;
2157 int sgn;
2158 if (j->code_bits < n) stbi__grow_buffer_unsafe(j);
2159 if (j->code_bits < n) return 0; // ran out of bits from stream, return 0s intead of continuing
2160
2161 sgn = j->code_buffer >> 31; // sign bit always in MSB; 0 if MSB clear (positive), 1 if MSB set (negative)
2162 k = stbi_lrot(j->code_buffer, n);
2163 j->code_buffer = k & ~stbi__bmask[n];
2164 k &= stbi__bmask[n];
2165 j->code_bits -= n;
2166 return k + (stbi__jbias[n] & (sgn - 1));
2167}
2168
2169// get some unsigned bits
2170stbi_inline static int stbi__jpeg_get_bits(stbi__jpeg *j, int n)
2171{
2172 unsigned int k;
2173 if (j->code_bits < n) stbi__grow_buffer_unsafe(j);
2174 if (j->code_bits < n) return 0; // ran out of bits from stream, return 0s intead of continuing
2175 k = stbi_lrot(j->code_buffer, n);
2176 j->code_buffer = k & ~stbi__bmask[n];
2177 k &= stbi__bmask[n];
2178 j->code_bits -= n;
2179 return k;
2180}
2181
2182stbi_inline static int stbi__jpeg_get_bit(stbi__jpeg *j)
2183{
2184 unsigned int k;
2185 if (j->code_bits < 1) stbi__grow_buffer_unsafe(j);
2186 if (j->code_bits < 1) return 0; // ran out of bits from stream, return 0s intead of continuing
2187 k = j->code_buffer;
2188 j->code_buffer <<= 1;
2189 --j->code_bits;
2190 return k & 0x80000000;
2191}
2192
2193// given a value that's at position X in the zigzag stream,
2194// where does it appear in the 8x8 matrix coded as row-major?
2195static const stbi_uc stbi__jpeg_dezigzag[64+15] =
2196{
2197 0, 1, 8, 16, 9, 2, 3, 10,
2198 17, 24, 32, 25, 18, 11, 4, 5,
2199 12, 19, 26, 33, 40, 48, 41, 34,
2200 27, 20, 13, 6, 7, 14, 21, 28,
2201 35, 42, 49, 56, 57, 50, 43, 36,
2202 29, 22, 15, 23, 30, 37, 44, 51,
2203 58, 59, 52, 45, 38, 31, 39, 46,
2204 53, 60, 61, 54, 47, 55, 62, 63,
2205 // let corrupt input sample past end
2206 63, 63, 63, 63, 63, 63, 63, 63,
2207 63, 63, 63, 63, 63, 63, 63
2208};
2209
2210// decode one 64-entry block--
2211static int stbi__jpeg_decode_block(stbi__jpeg *j, short data[64], stbi__huffman *hdc, stbi__huffman *hac, stbi__int16 *fac, int b, stbi__uint16 *dequant)
2212{
2213 int diff,dc,k;
2214 int t;
2215
2216 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
2217 t = stbi__jpeg_huff_decode(j, hdc);
2218 if (t < 0 || t > 15) return stbi__err("bad huffman code","Corrupt JPEG");
2219
2220 // 0 all the ac values now so we can do it 32-bits at a time
2221 memset(data,0,64*sizeof(data[0]));
2222
2223 diff = t ? stbi__extend_receive(j, t) : 0;
2224 if (!stbi__addints_valid(j->img_comp[b].dc_pred, diff)) return stbi__err("bad delta","Corrupt JPEG");
2225 dc = j->img_comp[b].dc_pred + diff;
2226 j->img_comp[b].dc_pred = dc;
2227 if (!stbi__mul2shorts_valid(dc, dequant[0])) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
2228 data[0] = (short) (dc * dequant[0]);
2229
2230 // decode AC components, see JPEG spec
2231 k = 1;
2232 do {
2233 unsigned int zig;
2234 int c,r,s;
2235 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
2236 c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
2237 r = fac[c];
2238 if (r) { // fast-AC path
2239 k += (r >> 4) & 15; // run
2240 s = r & 15; // combined length
2241 if (s > j->code_bits) return stbi__err("bad huffman code", "Combined length longer than code bits available");
2242 j->code_buffer <<= s;
2243 j->code_bits -= s;
2244 // decode into unzigzag'd location
2245 zig = stbi__jpeg_dezigzag[k++];
2246 data[zig] = (short) ((r >> 8) * dequant[zig]);
2247 } else {
2248 int rs = stbi__jpeg_huff_decode(j, hac);
2249 if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
2250 s = rs & 15;
2251 r = rs >> 4;
2252 if (s == 0) {
2253 if (rs != 0xf0) break; // end block
2254 k += 16;
2255 } else {
2256 k += r;
2257 // decode into unzigzag'd location
2258 zig = stbi__jpeg_dezigzag[k++];
2259 data[zig] = (short) (stbi__extend_receive(j,s) * dequant[zig]);
2260 }
2261 }
2262 } while (k < 64);
2263 return 1;
2264}
2265
2266static int stbi__jpeg_decode_block_prog_dc(stbi__jpeg *j, short data[64], stbi__huffman *hdc, int b)
2267{
2268 int diff,dc;
2269 int t;
2270 if (j->spec_end != 0) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
2271
2272 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
2273
2274 if (j->succ_high == 0) {
2275 // first scan for DC coefficient, must be first
2276 memset(data,0,64*sizeof(data[0])); // 0 all the ac values now
2277 t = stbi__jpeg_huff_decode(j, hdc);
2278 if (t < 0 || t > 15) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
2279 diff = t ? stbi__extend_receive(j, t) : 0;
2280
2281 if (!stbi__addints_valid(j->img_comp[b].dc_pred, diff)) return stbi__err("bad delta", "Corrupt JPEG");
2282 dc = j->img_comp[b].dc_pred + diff;
2283 j->img_comp[b].dc_pred = dc;
2284 if (!stbi__mul2shorts_valid(dc, 1 << j->succ_low)) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
2285 data[0] = (short) (dc * (1 << j->succ_low));
2286 } else {
2287 // refinement scan for DC coefficient
2288 if (stbi__jpeg_get_bit(j))
2289 data[0] += (short) (1 << j->succ_low);
2290 }
2291 return 1;
2292}
2293
2294// @OPTIMIZE: store non-zigzagged during the decode passes,
2295// and only de-zigzag when dequantizing
2296static int stbi__jpeg_decode_block_prog_ac(stbi__jpeg *j, short data[64], stbi__huffman *hac, stbi__int16 *fac)
2297{
2298 int k;
2299 if (j->spec_start == 0) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
2300
2301 if (j->succ_high == 0) {
2302 int shift = j->succ_low;
2303
2304 if (j->eob_run) {
2305 --j->eob_run;
2306 return 1;
2307 }
2308
2309 k = j->spec_start;
2310 do {
2311 unsigned int zig;
2312 int c,r,s;
2313 if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
2314 c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS)-1);
2315 r = fac[c];
2316 if (r) { // fast-AC path
2317 k += (r >> 4) & 15; // run
2318 s = r & 15; // combined length
2319 if (s > j->code_bits) return stbi__err("bad huffman code", "Combined length longer than code bits available");
2320 j->code_buffer <<= s;
2321 j->code_bits -= s;
2322 zig = stbi__jpeg_dezigzag[k++];
2323 data[zig] = (short) ((r >> 8) * (1 << shift));
2324 } else {
2325 int rs = stbi__jpeg_huff_decode(j, hac);
2326 if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
2327 s = rs & 15;
2328 r = rs >> 4;
2329 if (s == 0) {
2330 if (r < 15) {
2331 j->eob_run = (1 << r);
2332 if (r)
2333 j->eob_run += stbi__jpeg_get_bits(j, r);
2334 --j->eob_run;
2335 break;
2336 }
2337 k += 16;
2338 } else {
2339 k += r;
2340 zig = stbi__jpeg_dezigzag[k++];
2341 data[zig] = (short) (stbi__extend_receive(j,s) * (1 << shift));
2342 }
2343 }
2344 } while (k <= j->spec_end);
2345 } else {
2346 // refinement scan for these AC coefficients
2347
2348 short bit = (short) (1 << j->succ_low);
2349
2350 if (j->eob_run) {
2351 --j->eob_run;
2352 for (k = j->spec_start; k <= j->spec_end; ++k) {
2353 short *p = &data[stbi__jpeg_dezigzag[k]];
2354 if (*p != 0)
2355 if (stbi__jpeg_get_bit(j))
2356 if ((*p & bit)==0) {
2357 if (*p > 0)
2358 *p += bit;
2359 else
2360 *p -= bit;
2361 }
2362 }
2363 } else {
2364 k = j->spec_start;
2365 do {
2366 int r,s;
2367 int rs = stbi__jpeg_huff_decode(j, hac); // @OPTIMIZE see if we can use the fast path here, advance-by-r is so slow, eh
2368 if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
2369 s = rs & 15;
2370 r = rs >> 4;
2371 if (s == 0) {
2372 if (r < 15) {
2373 j->eob_run = (1 << r) - 1;
2374 if (r)
2375 j->eob_run += stbi__jpeg_get_bits(j, r);
2376 r = 64; // force end of block
2377 } else {
2378 // r=15 s=0 should write 16 0s, so we just do
2379 // a run of 15 0s and then write s (which is 0),
2380 // so we don't have to do anything special here
2381 }
2382 } else {
2383 if (s != 1) return stbi__err("bad huffman code", "Corrupt JPEG");
2384 // sign bit
2385 if (stbi__jpeg_get_bit(j))
2386 s = bit;
2387 else
2388 s = -bit;
2389 }
2390
2391 // advance by r
2392 while (k <= j->spec_end) {
2393 short *p = &data[stbi__jpeg_dezigzag[k++]];
2394 if (*p != 0) {
2395 if (stbi__jpeg_get_bit(j))
2396 if ((*p & bit)==0) {
2397 if (*p > 0)
2398 *p += bit;
2399 else
2400 *p -= bit;
2401 }
2402 } else {
2403 if (r == 0) {
2404 *p = (short) s;
2405 break;
2406 }
2407 --r;
2408 }
2409 }
2410 } while (k <= j->spec_end);
2411 }
2412 }
2413 return 1;
2414}
2415
2416// take a -128..127 value and stbi__clamp it and convert to 0..255
2417stbi_inline static stbi_uc stbi__clamp(int x)
2418{
2419 // trick to use a single test to catch both cases
2420 if ((unsigned int) x > 255) {
2421 if (x < 0) return 0;
2422 if (x > 255) return 255;
2423 }
2424 return (stbi_uc) x;
2425}
2426
2427#define stbi__f2f(x) ((int) (((x) * 4096 + 0.5)))
2428#define stbi__fsh(x) ((x) * 4096)
2429
2430// derived from jidctint -- DCT_ISLOW
2431#define STBI__IDCT_1D(s0,s1,s2,s3,s4,s5,s6,s7) \
2432 int t0,t1,t2,t3,p1,p2,p3,p4,p5,x0,x1,x2,x3; \
2433 p2 = s2; \
2434 p3 = s6; \
2435 p1 = (p2+p3) * stbi__f2f(0.5411961f); \
2436 t2 = p1 + p3*stbi__f2f(-1.847759065f); \
2437 t3 = p1 + p2*stbi__f2f( 0.765366865f); \
2438 p2 = s0; \
2439 p3 = s4; \
2440 t0 = stbi__fsh(p2+p3); \
2441 t1 = stbi__fsh(p2-p3); \
2442 x0 = t0+t3; \
2443 x3 = t0-t3; \
2444 x1 = t1+t2; \
2445 x2 = t1-t2; \
2446 t0 = s7; \
2447 t1 = s5; \
2448 t2 = s3; \
2449 t3 = s1; \
2450 p3 = t0+t2; \
2451 p4 = t1+t3; \
2452 p1 = t0+t3; \
2453 p2 = t1+t2; \
2454 p5 = (p3+p4)*stbi__f2f( 1.175875602f); \
2455 t0 = t0*stbi__f2f( 0.298631336f); \
2456 t1 = t1*stbi__f2f( 2.053119869f); \
2457 t2 = t2*stbi__f2f( 3.072711026f); \
2458 t3 = t3*stbi__f2f( 1.501321110f); \
2459 p1 = p5 + p1*stbi__f2f(-0.899976223f); \
2460 p2 = p5 + p2*stbi__f2f(-2.562915447f); \
2461 p3 = p3*stbi__f2f(-1.961570560f); \
2462 p4 = p4*stbi__f2f(-0.390180644f); \
2463 t3 += p1+p4; \
2464 t2 += p2+p3; \
2465 t1 += p2+p4; \
2466 t0 += p1+p3;
2467
2468static void stbi__idct_block(stbi_uc *out, int out_stride, short data[64])
2469{
2470 int i,val[64],*v=val;
2471 stbi_uc *o;
2472 short *d = data;
2473
2474 // columns
2475 for (i=0; i < 8; ++i,++d, ++v) {
2476 // if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing
2477 if (d[ 8]==0 && d[16]==0 && d[24]==0 && d[32]==0
2478 && d[40]==0 && d[48]==0 && d[56]==0) {
2479 // no shortcut 0 seconds
2480 // (1|2|3|4|5|6|7)==0 0 seconds
2481 // all separate -0.047 seconds
2482 // 1 && 2|3 && 4|5 && 6|7: -0.047 seconds
2483 int dcterm = d[0]*4;
2484 v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm;
2485 } else {
2486 STBI__IDCT_1D(d[ 0],d[ 8],d[16],d[24],d[32],d[40],d[48],d[56])
2487 // constants scaled things up by 1<<12; let's bring them back
2488 // down, but keep 2 extra bits of precision
2489 x0 += 512; x1 += 512; x2 += 512; x3 += 512;
2490 v[ 0] = (x0+t3) >> 10;
2491 v[56] = (x0-t3) >> 10;
2492 v[ 8] = (x1+t2) >> 10;
2493 v[48] = (x1-t2) >> 10;
2494 v[16] = (x2+t1) >> 10;
2495 v[40] = (x2-t1) >> 10;
2496 v[24] = (x3+t0) >> 10;
2497 v[32] = (x3-t0) >> 10;
2498 }
2499 }
2500
2501 for (i=0, v=val, o=out; i < 8; ++i,v+=8,o+=out_stride) {
2502 // no fast case since the first 1D IDCT spread components out
2503 STBI__IDCT_1D(v[0],v[1],v[2],v[3],v[4],v[5],v[6],v[7])
2504 // constants scaled things up by 1<<12, plus we had 1<<2 from first
2505 // loop, plus horizontal and vertical each scale by sqrt(8) so together
2506 // we've got an extra 1<<3, so 1<<17 total we need to remove.
2507 // so we want to round that, which means adding 0.5 * 1<<17,
2508 // aka 65536. Also, we'll end up with -128 to 127 that we want
2509 // to encode as 0..255 by adding 128, so we'll add that before the shift
2510 x0 += 65536 + (128<<17);
2511 x1 += 65536 + (128<<17);
2512 x2 += 65536 + (128<<17);
2513 x3 += 65536 + (128<<17);
2514 // tried computing the shifts into temps, or'ing the temps to see
2515 // if any were out of range, but that was slower
2516 o[0] = stbi__clamp((x0+t3) >> 17);
2517 o[7] = stbi__clamp((x0-t3) >> 17);
2518 o[1] = stbi__clamp((x1+t2) >> 17);
2519 o[6] = stbi__clamp((x1-t2) >> 17);
2520 o[2] = stbi__clamp((x2+t1) >> 17);
2521 o[5] = stbi__clamp((x2-t1) >> 17);
2522 o[3] = stbi__clamp((x3+t0) >> 17);
2523 o[4] = stbi__clamp((x3-t0) >> 17);
2524 }
2525}
2526
2527#ifdef STBI_SSE2
2528// sse2 integer IDCT. not the fastest possible implementation but it
2529// produces bit-identical results to the generic C version so it's
2530// fully "transparent".
2531static void stbi__idct_simd(stbi_uc *out, int out_stride, short data[64])
2532{
2533 // This is constructed to match our regular (generic) integer IDCT exactly.
2534 __m128i row0, row1, row2, row3, row4, row5, row6, row7;
2535 __m128i tmp;
2536
2537 // dot product constant: even elems=x, odd elems=y
2538 #define dct_const(x,y) _mm_setr_epi16((x),(y),(x),(y),(x),(y),(x),(y))
2539
2540 // out(0) = c0[even]*x + c0[odd]*y (c0, x, y 16-bit, out 32-bit)
2541 // out(1) = c1[even]*x + c1[odd]*y
2542 #define dct_rot(out0,out1, x,y,c0,c1) \
2543 __m128i c0##lo = _mm_unpacklo_epi16((x),(y)); \
2544 __m128i c0##hi = _mm_unpackhi_epi16((x),(y)); \
2545 __m128i out0##_l = _mm_madd_epi16(c0##lo, c0); \
2546 __m128i out0##_h = _mm_madd_epi16(c0##hi, c0); \
2547 __m128i out1##_l = _mm_madd_epi16(c0##lo, c1); \
2548 __m128i out1##_h = _mm_madd_epi16(c0##hi, c1)
2549
2550 // out = in << 12 (in 16-bit, out 32-bit)
2551 #define dct_widen(out, in) \
2552 __m128i out##_l = _mm_srai_epi32(_mm_unpacklo_epi16(_mm_setzero_si128(), (in)), 4); \
2553 __m128i out##_h = _mm_srai_epi32(_mm_unpackhi_epi16(_mm_setzero_si128(), (in)), 4)
2554
2555 // wide add
2556 #define dct_wadd(out, a, b) \
2557 __m128i out##_l = _mm_add_epi32(a##_l, b##_l); \
2558 __m128i out##_h = _mm_add_epi32(a##_h, b##_h)
2559
2560 // wide sub
2561 #define dct_wsub(out, a, b) \
2562 __m128i out##_l = _mm_sub_epi32(a##_l, b##_l); \
2563 __m128i out##_h = _mm_sub_epi32(a##_h, b##_h)
2564
2565 // butterfly a/b, add bias, then shift by "s" and pack
2566 #define dct_bfly32o(out0, out1, a,b,bias,s) \
2567 { \
2568 __m128i abiased_l = _mm_add_epi32(a##_l, bias); \
2569 __m128i abiased_h = _mm_add_epi32(a##_h, bias); \
2570 dct_wadd(sum, abiased, b); \
2571 dct_wsub(dif, abiased, b); \
2572 out0 = _mm_packs_epi32(_mm_srai_epi32(sum_l, s), _mm_srai_epi32(sum_h, s)); \
2573 out1 = _mm_packs_epi32(_mm_srai_epi32(dif_l, s), _mm_srai_epi32(dif_h, s)); \
2574 }
2575
2576 // 8-bit interleave step (for transposes)
2577 #define dct_interleave8(a, b) \
2578 tmp = a; \
2579 a = _mm_unpacklo_epi8(a, b); \
2580 b = _mm_unpackhi_epi8(tmp, b)
2581
2582 // 16-bit interleave step (for transposes)
2583 #define dct_interleave16(a, b) \
2584 tmp = a; \
2585 a = _mm_unpacklo_epi16(a, b); \
2586 b = _mm_unpackhi_epi16(tmp, b)
2587
2588 #define dct_pass(bias,shift) \
2589 { \
2590 /* even part */ \
2591 dct_rot(t2e,t3e, row2,row6, rot0_0,rot0_1); \
2592 __m128i sum04 = _mm_add_epi16(row0, row4); \
2593 __m128i dif04 = _mm_sub_epi16(row0, row4); \
2594 dct_widen(t0e, sum04); \
2595 dct_widen(t1e, dif04); \
2596 dct_wadd(x0, t0e, t3e); \
2597 dct_wsub(x3, t0e, t3e); \
2598 dct_wadd(x1, t1e, t2e); \
2599 dct_wsub(x2, t1e, t2e); \
2600 /* odd part */ \
2601 dct_rot(y0o,y2o, row7,row3, rot2_0,rot2_1); \
2602 dct_rot(y1o,y3o, row5,row1, rot3_0,rot3_1); \
2603 __m128i sum17 = _mm_add_epi16(row1, row7); \
2604 __m128i sum35 = _mm_add_epi16(row3, row5); \
2605 dct_rot(y4o,y5o, sum17,sum35, rot1_0,rot1_1); \
2606 dct_wadd(x4, y0o, y4o); \
2607 dct_wadd(x5, y1o, y5o); \
2608 dct_wadd(x6, y2o, y5o); \
2609 dct_wadd(x7, y3o, y4o); \
2610 dct_bfly32o(row0,row7, x0,x7,bias,shift); \
2611 dct_bfly32o(row1,row6, x1,x6,bias,shift); \
2612 dct_bfly32o(row2,row5, x2,x5,bias,shift); \
2613 dct_bfly32o(row3,row4, x3,x4,bias,shift); \
2614 }
2615
2616 __m128i rot0_0 = dct_const(stbi__f2f(0.5411961f), stbi__f2f(0.5411961f) + stbi__f2f(-1.847759065f));
2617 __m128i rot0_1 = dct_const(stbi__f2f(0.5411961f) + stbi__f2f( 0.765366865f), stbi__f2f(0.5411961f));
2618 __m128i rot1_0 = dct_const(stbi__f2f(1.175875602f) + stbi__f2f(-0.899976223f), stbi__f2f(1.175875602f));
2619 __m128i rot1_1 = dct_const(stbi__f2f(1.175875602f), stbi__f2f(1.175875602f) + stbi__f2f(-2.562915447f));
2620 __m128i rot2_0 = dct_const(stbi__f2f(-1.961570560f) + stbi__f2f( 0.298631336f), stbi__f2f(-1.961570560f));
2621 __m128i rot2_1 = dct_const(stbi__f2f(-1.961570560f), stbi__f2f(-1.961570560f) + stbi__f2f( 3.072711026f));
2622 __m128i rot3_0 = dct_const(stbi__f2f(-0.390180644f) + stbi__f2f( 2.053119869f), stbi__f2f(-0.390180644f));
2623 __m128i rot3_1 = dct_const(stbi__f2f(-0.390180644f), stbi__f2f(-0.390180644f) + stbi__f2f( 1.501321110f));
2624
2625 // rounding biases in column/row passes, see stbi__idct_block for explanation.
2626 __m128i bias_0 = _mm_set1_epi32(512);
2627 __m128i bias_1 = _mm_set1_epi32(65536 + (128<<17));
2628
2629 // load
2630 row0 = _mm_load_si128((const __m128i *) (data + 0*8));
2631 row1 = _mm_load_si128((const __m128i *) (data + 1*8));
2632 row2 = _mm_load_si128((const __m128i *) (data + 2*8));
2633 row3 = _mm_load_si128((const __m128i *) (data + 3*8));
2634 row4 = _mm_load_si128((const __m128i *) (data + 4*8));
2635 row5 = _mm_load_si128((const __m128i *) (data + 5*8));
2636 row6 = _mm_load_si128((const __m128i *) (data + 6*8));
2637 row7 = _mm_load_si128((const __m128i *) (data + 7*8));
2638
2639 // column pass
2640 dct_pass(bias_0, 10);
2641
2642 {
2643 // 16bit 8x8 transpose pass 1
2644 dct_interleave16(row0, row4);
2645 dct_interleave16(row1, row5);
2646 dct_interleave16(row2, row6);
2647 dct_interleave16(row3, row7);
2648
2649 // transpose pass 2
2650 dct_interleave16(row0, row2);
2651 dct_interleave16(row1, row3);
2652 dct_interleave16(row4, row6);
2653 dct_interleave16(row5, row7);
2654
2655 // transpose pass 3
2656 dct_interleave16(row0, row1);
2657 dct_interleave16(row2, row3);
2658 dct_interleave16(row4, row5);
2659 dct_interleave16(row6, row7);
2660 }
2661
2662 // row pass
2663 dct_pass(bias_1, 17);
2664
2665 {
2666 // pack
2667 __m128i p0 = _mm_packus_epi16(row0, row1); // a0a1a2a3...a7b0b1b2b3...b7
2668 __m128i p1 = _mm_packus_epi16(row2, row3);
2669 __m128i p2 = _mm_packus_epi16(row4, row5);
2670 __m128i p3 = _mm_packus_epi16(row6, row7);
2671
2672 // 8bit 8x8 transpose pass 1
2673 dct_interleave8(p0, p2); // a0e0a1e1...
2674 dct_interleave8(p1, p3); // c0g0c1g1...
2675
2676 // transpose pass 2
2677 dct_interleave8(p0, p1); // a0c0e0g0...
2678 dct_interleave8(p2, p3); // b0d0f0h0...
2679
2680 // transpose pass 3
2681 dct_interleave8(p0, p2); // a0b0c0d0...
2682 dct_interleave8(p1, p3); // a4b4c4d4...
2683
2684 // store
2685 _mm_storel_epi64((__m128i *) out, p0); out += out_stride;
2686 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p0, 0x4e)); out += out_stride;
2687 _mm_storel_epi64((__m128i *) out, p2); out += out_stride;
2688 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p2, 0x4e)); out += out_stride;
2689 _mm_storel_epi64((__m128i *) out, p1); out += out_stride;
2690 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p1, 0x4e)); out += out_stride;
2691 _mm_storel_epi64((__m128i *) out, p3); out += out_stride;
2692 _mm_storel_epi64((__m128i *) out, _mm_shuffle_epi32(p3, 0x4e));
2693 }
2694
2695#undef dct_const
2696#undef dct_rot
2697#undef dct_widen
2698#undef dct_wadd
2699#undef dct_wsub
2700#undef dct_bfly32o
2701#undef dct_interleave8
2702#undef dct_interleave16
2703#undef dct_pass
2704}
2705
2706#endif // STBI_SSE2
2707
2708#ifdef STBI_NEON
2709
2710// NEON integer IDCT. should produce bit-identical
2711// results to the generic C version.
2712static void stbi__idct_simd(stbi_uc *out, int out_stride, short data[64])
2713{
2714 int16x8_t row0, row1, row2, row3, row4, row5, row6, row7;
2715
2716 int16x4_t rot0_0 = vdup_n_s16(stbi__f2f(0.5411961f));
2717 int16x4_t rot0_1 = vdup_n_s16(stbi__f2f(-1.847759065f));
2718 int16x4_t rot0_2 = vdup_n_s16(stbi__f2f( 0.765366865f));
2719 int16x4_t rot1_0 = vdup_n_s16(stbi__f2f( 1.175875602f));
2720 int16x4_t rot1_1 = vdup_n_s16(stbi__f2f(-0.899976223f));
2721 int16x4_t rot1_2 = vdup_n_s16(stbi__f2f(-2.562915447f));
2722 int16x4_t rot2_0 = vdup_n_s16(stbi__f2f(-1.961570560f));
2723 int16x4_t rot2_1 = vdup_n_s16(stbi__f2f(-0.390180644f));
2724 int16x4_t rot3_0 = vdup_n_s16(stbi__f2f( 0.298631336f));
2725 int16x4_t rot3_1 = vdup_n_s16(stbi__f2f( 2.053119869f));
2726 int16x4_t rot3_2 = vdup_n_s16(stbi__f2f( 3.072711026f));
2727 int16x4_t rot3_3 = vdup_n_s16(stbi__f2f( 1.501321110f));
2728
2729#define dct_long_mul(out, inq, coeff) \
2730 int32x4_t out##_l = vmull_s16(vget_low_s16(inq), coeff); \
2731 int32x4_t out##_h = vmull_s16(vget_high_s16(inq), coeff)
2732
2733#define dct_long_mac(out, acc, inq, coeff) \
2734 int32x4_t out##_l = vmlal_s16(acc##_l, vget_low_s16(inq), coeff); \
2735 int32x4_t out##_h = vmlal_s16(acc##_h, vget_high_s16(inq), coeff)
2736
2737#define dct_widen(out, inq) \
2738 int32x4_t out##_l = vshll_n_s16(vget_low_s16(inq), 12); \
2739 int32x4_t out##_h = vshll_n_s16(vget_high_s16(inq), 12)
2740
2741// wide add
2742#define dct_wadd(out, a, b) \
2743 int32x4_t out##_l = vaddq_s32(a##_l, b##_l); \
2744 int32x4_t out##_h = vaddq_s32(a##_h, b##_h)
2745
2746// wide sub
2747#define dct_wsub(out, a, b) \
2748 int32x4_t out##_l = vsubq_s32(a##_l, b##_l); \
2749 int32x4_t out##_h = vsubq_s32(a##_h, b##_h)
2750
2751// butterfly a/b, then shift using "shiftop" by "s" and pack
2752#define dct_bfly32o(out0,out1, a,b,shiftop,s) \
2753 { \
2754 dct_wadd(sum, a, b); \
2755 dct_wsub(dif, a, b); \
2756 out0 = vcombine_s16(shiftop(sum_l, s), shiftop(sum_h, s)); \
2757 out1 = vcombine_s16(shiftop(dif_l, s), shiftop(dif_h, s)); \
2758 }
2759
2760#define dct_pass(shiftop, shift) \
2761 { \
2762 /* even part */ \
2763 int16x8_t sum26 = vaddq_s16(row2, row6); \
2764 dct_long_mul(p1e, sum26, rot0_0); \
2765 dct_long_mac(t2e, p1e, row6, rot0_1); \
2766 dct_long_mac(t3e, p1e, row2, rot0_2); \
2767 int16x8_t sum04 = vaddq_s16(row0, row4); \
2768 int16x8_t dif04 = vsubq_s16(row0, row4); \
2769 dct_widen(t0e, sum04); \
2770 dct_widen(t1e, dif04); \
2771 dct_wadd(x0, t0e, t3e); \
2772 dct_wsub(x3, t0e, t3e); \
2773 dct_wadd(x1, t1e, t2e); \
2774 dct_wsub(x2, t1e, t2e); \
2775 /* odd part */ \
2776 int16x8_t sum15 = vaddq_s16(row1, row5); \
2777 int16x8_t sum17 = vaddq_s16(row1, row7); \
2778 int16x8_t sum35 = vaddq_s16(row3, row5); \
2779 int16x8_t sum37 = vaddq_s16(row3, row7); \
2780 int16x8_t sumodd = vaddq_s16(sum17, sum35); \
2781 dct_long_mul(p5o, sumodd, rot1_0); \
2782 dct_long_mac(p1o, p5o, sum17, rot1_1); \
2783 dct_long_mac(p2o, p5o, sum35, rot1_2); \
2784 dct_long_mul(p3o, sum37, rot2_0); \
2785 dct_long_mul(p4o, sum15, rot2_1); \
2786 dct_wadd(sump13o, p1o, p3o); \
2787 dct_wadd(sump24o, p2o, p4o); \
2788 dct_wadd(sump23o, p2o, p3o); \
2789 dct_wadd(sump14o, p1o, p4o); \
2790 dct_long_mac(x4, sump13o, row7, rot3_0); \
2791 dct_long_mac(x5, sump24o, row5, rot3_1); \
2792 dct_long_mac(x6, sump23o, row3, rot3_2); \
2793 dct_long_mac(x7, sump14o, row1, rot3_3); \
2794 dct_bfly32o(row0,row7, x0,x7,shiftop,shift); \
2795 dct_bfly32o(row1,row6, x1,x6,shiftop,shift); \
2796 dct_bfly32o(row2,row5, x2,x5,shiftop,shift); \
2797 dct_bfly32o(row3,row4, x3,x4,shiftop,shift); \
2798 }
2799
2800 // load
2801 row0 = vld1q_s16(data + 0*8);
2802 row1 = vld1q_s16(data + 1*8);
2803 row2 = vld1q_s16(data + 2*8);
2804 row3 = vld1q_s16(data + 3*8);
2805 row4 = vld1q_s16(data + 4*8);
2806 row5 = vld1q_s16(data + 5*8);
2807 row6 = vld1q_s16(data + 6*8);
2808 row7 = vld1q_s16(data + 7*8);
2809
2810 // add DC bias
2811 row0 = vaddq_s16(row0, vsetq_lane_s16(1024, vdupq_n_s16(0), 0));
2812
2813 // column pass
2814 dct_pass(vrshrn_n_s32, 10);
2815
2816 // 16bit 8x8 transpose
2817 {
2818// these three map to a single VTRN.16, VTRN.32, and VSWP, respectively.
2819// whether compilers actually get this is another story, sadly.
2820#define dct_trn16(x, y) { int16x8x2_t t = vtrnq_s16(x, y); x = t.val[0]; y = t.val[1]; }
2821#define dct_trn32(x, y) { int32x4x2_t t = vtrnq_s32(vreinterpretq_s32_s16(x), vreinterpretq_s32_s16(y)); x = vreinterpretq_s16_s32(t.val[0]); y = vreinterpretq_s16_s32(t.val[1]); }
2822#define dct_trn64(x, y) { int16x8_t x0 = x; int16x8_t y0 = y; x = vcombine_s16(vget_low_s16(x0), vget_low_s16(y0)); y = vcombine_s16(vget_high_s16(x0), vget_high_s16(y0)); }
2823
2824 // pass 1
2825 dct_trn16(row0, row1); // a0b0a2b2a4b4a6b6
2826 dct_trn16(row2, row3);
2827 dct_trn16(row4, row5);
2828 dct_trn16(row6, row7);
2829
2830 // pass 2
2831 dct_trn32(row0, row2); // a0b0c0d0a4b4c4d4
2832 dct_trn32(row1, row3);
2833 dct_trn32(row4, row6);
2834 dct_trn32(row5, row7);
2835
2836 // pass 3
2837 dct_trn64(row0, row4); // a0b0c0d0e0f0g0h0
2838 dct_trn64(row1, row5);
2839 dct_trn64(row2, row6);
2840 dct_trn64(row3, row7);
2841
2842#undef dct_trn16
2843#undef dct_trn32
2844#undef dct_trn64
2845 }
2846
2847 // row pass
2848 // vrshrn_n_s32 only supports shifts up to 16, we need
2849 // 17. so do a non-rounding shift of 16 first then follow
2850 // up with a rounding shift by 1.
2851 dct_pass(vshrn_n_s32, 16);
2852
2853 {
2854 // pack and round
2855 uint8x8_t p0 = vqrshrun_n_s16(row0, 1);
2856 uint8x8_t p1 = vqrshrun_n_s16(row1, 1);
2857 uint8x8_t p2 = vqrshrun_n_s16(row2, 1);
2858 uint8x8_t p3 = vqrshrun_n_s16(row3, 1);
2859 uint8x8_t p4 = vqrshrun_n_s16(row4, 1);
2860 uint8x8_t p5 = vqrshrun_n_s16(row5, 1);
2861 uint8x8_t p6 = vqrshrun_n_s16(row6, 1);
2862 uint8x8_t p7 = vqrshrun_n_s16(row7, 1);
2863
2864 // again, these can translate into one instruction, but often don't.
2865#define dct_trn8_8(x, y) { uint8x8x2_t t = vtrn_u8(x, y); x = t.val[0]; y = t.val[1]; }
2866#define dct_trn8_16(x, y) { uint16x4x2_t t = vtrn_u16(vreinterpret_u16_u8(x), vreinterpret_u16_u8(y)); x = vreinterpret_u8_u16(t.val[0]); y = vreinterpret_u8_u16(t.val[1]); }
2867#define dct_trn8_32(x, y) { uint32x2x2_t t = vtrn_u32(vreinterpret_u32_u8(x), vreinterpret_u32_u8(y)); x = vreinterpret_u8_u32(t.val[0]); y = vreinterpret_u8_u32(t.val[1]); }
2868
2869 // sadly can't use interleaved stores here since we only write
2870 // 8 bytes to each scan line!
2871
2872 // 8x8 8-bit transpose pass 1
2873 dct_trn8_8(p0, p1);
2874 dct_trn8_8(p2, p3);
2875 dct_trn8_8(p4, p5);
2876 dct_trn8_8(p6, p7);
2877
2878 // pass 2
2879 dct_trn8_16(p0, p2);
2880 dct_trn8_16(p1, p3);
2881 dct_trn8_16(p4, p6);
2882 dct_trn8_16(p5, p7);
2883
2884 // pass 3
2885 dct_trn8_32(p0, p4);
2886 dct_trn8_32(p1, p5);
2887 dct_trn8_32(p2, p6);
2888 dct_trn8_32(p3, p7);
2889
2890 // store
2891 vst1_u8(out, p0); out += out_stride;
2892 vst1_u8(out, p1); out += out_stride;
2893 vst1_u8(out, p2); out += out_stride;
2894 vst1_u8(out, p3); out += out_stride;
2895 vst1_u8(out, p4); out += out_stride;
2896 vst1_u8(out, p5); out += out_stride;
2897 vst1_u8(out, p6); out += out_stride;
2898 vst1_u8(out, p7);
2899
2900#undef dct_trn8_8
2901#undef dct_trn8_16
2902#undef dct_trn8_32
2903 }
2904
2905#undef dct_long_mul
2906#undef dct_long_mac
2907#undef dct_widen
2908#undef dct_wadd
2909#undef dct_wsub
2910#undef dct_bfly32o
2911#undef dct_pass
2912}
2913
2914#endif // STBI_NEON
2915
2916#define STBI__MARKER_none 0xff
2917// if there's a pending marker from the entropy stream, return that
2918// otherwise, fetch from the stream and get a marker. if there's no
2919// marker, return 0xff, which is never a valid marker value
2920static stbi_uc stbi__get_marker(stbi__jpeg *j)
2921{
2922 stbi_uc x;
2923 if (j->marker != STBI__MARKER_none) { x = j->marker; j->marker = STBI__MARKER_none; return x; }
2924 x = stbi__get8(j->s);
2925 if (x != 0xff) return STBI__MARKER_none;
2926 while (x == 0xff)
2927 x = stbi__get8(j->s); // consume repeated 0xff fill bytes
2928 return x;
2929}
2930
2931// in each scan, we'll have scan_n components, and the order
2932// of the components is specified by order[]
2933#define STBI__RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7)
2934
2935// after a restart interval, stbi__jpeg_reset the entropy decoder and
2936// the dc prediction
2937static void stbi__jpeg_reset(stbi__jpeg *j)
2938{
2939 j->code_bits = 0;
2940 j->code_buffer = 0;
2941 j->nomore = 0;
2942 j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = j->img_comp[3].dc_pred = 0;
2943 j->marker = STBI__MARKER_none;
2944 j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff;
2945 j->eob_run = 0;
2946 // no more than 1<<31 MCUs if no restart_interal? that's plenty safe,
2947 // since we don't even allow 1<<30 pixels
2948}
2949
2950static int stbi__parse_entropy_coded_data(stbi__jpeg *z)
2951{
2952 stbi__jpeg_reset(z);
2953 if (!z->progressive) {
2954 if (z->scan_n == 1) {
2955 int i,j;
2956 STBI_SIMD_ALIGN(short, data[64]);
2957 int n = z->order[0];
2958 // non-interleaved data, we just need to process one block at a time,
2959 // in trivial scanline order
2960 // number of blocks to do just depends on how many actual "pixels" this
2961 // component has, independent of interleaved MCU blocking and such
2962 int w = (z->img_comp[n].x+7) >> 3;
2963 int h = (z->img_comp[n].y+7) >> 3;
2964 for (j=0; j < h; ++j) {
2965 for (i=0; i < w; ++i) {
2966 int ha = z->img_comp[n].ha;
2967 if (!stbi__jpeg_decode_block(z, data, z->huff_dc+z->img_comp[n].hd, z->huff_ac+ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq])) return 0;
2968 z->idct_block_kernel(z->img_comp[n].data+z->img_comp[n].w2*j*8+i*8, z->img_comp[n].w2, data);
2969 // every data block is an MCU, so countdown the restart interval
2970 if (--z->todo <= 0) {
2971 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
2972 // if it's NOT a restart, then just bail, so we get corrupt data
2973 // rather than no data
2974 if (!STBI__RESTART(z->marker)) return 1;
2975 stbi__jpeg_reset(z);
2976 }
2977 }
2978 }
2979 return 1;
2980 } else { // interleaved
2981 int i,j,k,x,y;
2982 STBI_SIMD_ALIGN(short, data[64]);
2983 for (j=0; j < z->img_mcu_y; ++j) {
2984 for (i=0; i < z->img_mcu_x; ++i) {
2985 // scan an interleaved mcu... process scan_n components in order
2986 for (k=0; k < z->scan_n; ++k) {
2987 int n = z->order[k];
2988 // scan out an mcu's worth of this component; that's just determined
2989 // by the basic H and V specified for the component
2990 for (y=0; y < z->img_comp[n].v; ++y) {
2991 for (x=0; x < z->img_comp[n].h; ++x) {
2992 int x2 = (i*z->img_comp[n].h + x)*8;
2993 int y2 = (j*z->img_comp[n].v + y)*8;
2994 int ha = z->img_comp[n].ha;
2995 if (!stbi__jpeg_decode_block(z, data, z->huff_dc+z->img_comp[n].hd, z->huff_ac+ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq])) return 0;
2996 z->idct_block_kernel(z->img_comp[n].data+z->img_comp[n].w2*y2+x2, z->img_comp[n].w2, data);
2997 }
2998 }
2999 }
3000 // after all interleaved components, that's an interleaved MCU,
3001 // so now count down the restart interval
3002 if (--z->todo <= 0) {
3003 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
3004 if (!STBI__RESTART(z->marker)) return 1;
3005 stbi__jpeg_reset(z);
3006 }
3007 }
3008 }
3009 return 1;
3010 }
3011 } else {
3012 if (z->scan_n == 1) {
3013 int i,j;
3014 int n = z->order[0];
3015 // non-interleaved data, we just need to process one block at a time,
3016 // in trivial scanline order
3017 // number of blocks to do just depends on how many actual "pixels" this
3018 // component has, independent of interleaved MCU blocking and such
3019 int w = (z->img_comp[n].x+7) >> 3;
3020 int h = (z->img_comp[n].y+7) >> 3;
3021 for (j=0; j < h; ++j) {
3022 for (i=0; i < w; ++i) {
3023 short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w);
3024 if (z->spec_start == 0) {
3025 if (!stbi__jpeg_decode_block_prog_dc(z, data, &z->huff_dc[z->img_comp[n].hd], n))
3026 return 0;
3027 } else {
3028 int ha = z->img_comp[n].ha;
3029 if (!stbi__jpeg_decode_block_prog_ac(z, data, &z->huff_ac[ha], z->fast_ac[ha]))
3030 return 0;
3031 }
3032 // every data block is an MCU, so countdown the restart interval
3033 if (--z->todo <= 0) {
3034 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
3035 if (!STBI__RESTART(z->marker)) return 1;
3036 stbi__jpeg_reset(z);
3037 }
3038 }
3039 }
3040 return 1;
3041 } else { // interleaved
3042 int i,j,k,x,y;
3043 for (j=0; j < z->img_mcu_y; ++j) {
3044 for (i=0; i < z->img_mcu_x; ++i) {
3045 // scan an interleaved mcu... process scan_n components in order
3046 for (k=0; k < z->scan_n; ++k) {
3047 int n = z->order[k];
3048 // scan out an mcu's worth of this component; that's just determined
3049 // by the basic H and V specified for the component
3050 for (y=0; y < z->img_comp[n].v; ++y) {
3051 for (x=0; x < z->img_comp[n].h; ++x) {
3052 int x2 = (i*z->img_comp[n].h + x);
3053 int y2 = (j*z->img_comp[n].v + y);
3054 short *data = z->img_comp[n].coeff + 64 * (x2 + y2 * z->img_comp[n].coeff_w);
3055 if (!stbi__jpeg_decode_block_prog_dc(z, data, &z->huff_dc[z->img_comp[n].hd], n))
3056 return 0;
3057 }
3058 }
3059 }
3060 // after all interleaved components, that's an interleaved MCU,
3061 // so now count down the restart interval
3062 if (--z->todo <= 0) {
3063 if (z->code_bits < 24) stbi__grow_buffer_unsafe(z);
3064 if (!STBI__RESTART(z->marker)) return 1;
3065 stbi__jpeg_reset(z);
3066 }
3067 }
3068 }
3069 return 1;
3070 }
3071 }
3072}
3073
3074static void stbi__jpeg_dequantize(short *data, stbi__uint16 *dequant)
3075{
3076 int i;
3077 for (i=0; i < 64; ++i)
3078 data[i] *= dequant[i];
3079}
3080
3081static void stbi__jpeg_finish(stbi__jpeg *z)
3082{
3083 if (z->progressive) {
3084 // dequantize and idct the data
3085 int i,j,n;
3086 for (n=0; n < z->s->img_n; ++n) {
3087 int w = (z->img_comp[n].x+7) >> 3;
3088 int h = (z->img_comp[n].y+7) >> 3;
3089 for (j=0; j < h; ++j) {
3090 for (i=0; i < w; ++i) {
3091 short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w);
3092 stbi__jpeg_dequantize(data, z->dequant[z->img_comp[n].tq]);
3093 z->idct_block_kernel(z->img_comp[n].data+z->img_comp[n].w2*j*8+i*8, z->img_comp[n].w2, data);
3094 }
3095 }
3096 }
3097 }
3098}
3099
3100static int stbi__process_marker(stbi__jpeg *z, int m)
3101{
3102 int L;
3103 switch (m) {
3104 case STBI__MARKER_none: // no marker found
3105 return stbi__err("expected marker","Corrupt JPEG");
3106
3107 case 0xDD: // DRI - specify restart interval
3108 if (stbi__get16be(z->s) != 4) return stbi__err("bad DRI len","Corrupt JPEG");
3109 z->restart_interval = stbi__get16be(z->s);
3110 return 1;
3111
3112 case 0xDB: // DQT - define quantization table
3113 L = stbi__get16be(z->s)-2;
3114 while (L > 0) {
3115 int q = stbi__get8(z->s);
3116 int p = q >> 4, sixteen = (p != 0);
3117 int t = q & 15,i;
3118 if (p != 0 && p != 1) return stbi__err("bad DQT type","Corrupt JPEG");
3119 if (t > 3) return stbi__err("bad DQT table","Corrupt JPEG");
3120
3121 for (i=0; i < 64; ++i)
3122 z->dequant[t][stbi__jpeg_dezigzag[i]] = (stbi__uint16)(sixteen ? stbi__get16be(z->s) : stbi__get8(z->s));
3123 L -= (sixteen ? 129 : 65);
3124 }
3125 return L==0;
3126
3127 case 0xC4: // DHT - define huffman table
3128 L = stbi__get16be(z->s)-2;
3129 while (L > 0) {
3130 stbi_uc *v;
3131 int sizes[16],i,n=0;
3132 int q = stbi__get8(z->s);
3133 int tc = q >> 4;
3134 int th = q & 15;
3135 if (tc > 1 || th > 3) return stbi__err("bad DHT header","Corrupt JPEG");
3136 for (i=0; i < 16; ++i) {
3137 sizes[i] = stbi__get8(z->s);
3138 n += sizes[i];
3139 }
3140 if(n > 256) return stbi__err("bad DHT header","Corrupt JPEG"); // Loop over i < n would write past end of values!
3141 L -= 17;
3142 if (tc == 0) {
3143 if (!stbi__build_huffman(z->huff_dc+th, sizes)) return 0;
3144 v = z->huff_dc[th].values;
3145 } else {
3146 if (!stbi__build_huffman(z->huff_ac+th, sizes)) return 0;
3147 v = z->huff_ac[th].values;
3148 }
3149 for (i=0; i < n; ++i)
3150 v[i] = stbi__get8(z->s);
3151 if (tc != 0)
3152 stbi__build_fast_ac(z->fast_ac[th], z->huff_ac + th);
3153 L -= n;
3154 }
3155 return L==0;
3156 }
3157
3158 // check for comment block or APP blocks
3159 if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE) {
3160 L = stbi__get16be(z->s);
3161 if (L < 2) {
3162 if (m == 0xFE)
3163 return stbi__err("bad COM len","Corrupt JPEG");
3164 else
3165 return stbi__err("bad APP len","Corrupt JPEG");
3166 }
3167 L -= 2;
3168
3169 if (m == 0xE0 && L >= 5) { // JFIF APP0 segment
3170 static const unsigned char tag[5] = {'J','F','I','F','\0'};
3171 int ok = 1;
3172 int i;
3173 for (i=0; i < 5; ++i)
3174 if (stbi__get8(z->s) != tag[i])
3175 ok = 0;
3176 L -= 5;
3177 if (ok)
3178 z->jfif = 1;
3179 } else if (m == 0xEE && L >= 12) { // Adobe APP14 segment
3180 static const unsigned char tag[6] = {'A','d','o','b','e','\0'};
3181 int ok = 1;
3182 int i;
3183 for (i=0; i < 6; ++i)
3184 if (stbi__get8(z->s) != tag[i])
3185 ok = 0;
3186 L -= 6;
3187 if (ok) {
3188 stbi__get8(z->s); // version
3189 stbi__get16be(z->s); // flags0
3190 stbi__get16be(z->s); // flags1
3191 z->app14_color_transform = stbi__get8(z->s); // color transform
3192 L -= 6;
3193 }
3194 }
3195
3196 stbi__skip(z->s, L);
3197 return 1;
3198 }
3199
3200 return stbi__err("unknown marker","Corrupt JPEG");
3201}
3202
3203// after we see SOS
3204static int stbi__process_scan_header(stbi__jpeg *z)
3205{
3206 int i;
3207 int Ls = stbi__get16be(z->s);
3208 z->scan_n = stbi__get8(z->s);
3209 if (z->scan_n < 1 || z->scan_n > 4 || z->scan_n > (int) z->s->img_n) return stbi__err("bad SOS component count","Corrupt JPEG");
3210 if (Ls != 6+2*z->scan_n) return stbi__err("bad SOS len","Corrupt JPEG");
3211 for (i=0; i < z->scan_n; ++i) {
3212 int id = stbi__get8(z->s), which;
3213 int q = stbi__get8(z->s);
3214 for (which = 0; which < z->s->img_n; ++which)
3215 if (z->img_comp[which].id == id)
3216 break;
3217 if (which == z->s->img_n) return 0; // no match
3218 z->img_comp[which].hd = q >> 4; if (z->img_comp[which].hd > 3) return stbi__err("bad DC huff","Corrupt JPEG");
3219 z->img_comp[which].ha = q & 15; if (z->img_comp[which].ha > 3) return stbi__err("bad AC huff","Corrupt JPEG");
3220 z->order[i] = which;
3221 }
3222
3223 {
3224 int aa;
3225 z->spec_start = stbi__get8(z->s);
3226 z->spec_end = stbi__get8(z->s); // should be 63, but might be 0
3227 aa = stbi__get8(z->s);
3228 z->succ_high = (aa >> 4);
3229 z->succ_low = (aa & 15);
3230 if (z->progressive) {
3231 if (z->spec_start > 63 || z->spec_end > 63 || z->spec_start > z->spec_end || z->succ_high > 13 || z->succ_low > 13)
3232 return stbi__err("bad SOS", "Corrupt JPEG");
3233 } else {
3234 if (z->spec_start != 0) return stbi__err("bad SOS","Corrupt JPEG");
3235 if (z->succ_high != 0 || z->succ_low != 0) return stbi__err("bad SOS","Corrupt JPEG");
3236 z->spec_end = 63;
3237 }
3238 }
3239
3240 return 1;
3241}
3242
3243static int stbi__free_jpeg_components(stbi__jpeg *z, int ncomp, int why)
3244{
3245 int i;
3246 for (i=0; i < ncomp; ++i) {
3247 if (z->img_comp[i].raw_data) {
3248 STBI_FREE(z->img_comp[i].raw_data);
3249 z->img_comp[i].raw_data = NULL;
3250 z->img_comp[i].data = NULL;
3251 }
3252 if (z->img_comp[i].raw_coeff) {
3253 STBI_FREE(z->img_comp[i].raw_coeff);
3254 z->img_comp[i].raw_coeff = 0;
3255 z->img_comp[i].coeff = 0;
3256 }
3257 if (z->img_comp[i].linebuf) {
3258 STBI_FREE(z->img_comp[i].linebuf);
3259 z->img_comp[i].linebuf = NULL;
3260 }
3261 }
3262 return why;
3263}
3264
3265static int stbi__process_frame_header(stbi__jpeg *z, int scan)
3266{
3267 stbi__context *s = z->s;
3268 int Lf,p,i,q, h_max=1,v_max=1,c;
3269 Lf = stbi__get16be(s); if (Lf < 11) return stbi__err("bad SOF len","Corrupt JPEG"); // JPEG
3270 p = stbi__get8(s); if (p != 8) return stbi__err("only 8-bit","JPEG format not supported: 8-bit only"); // JPEG baseline
3271 s->img_y = stbi__get16be(s); if (s->img_y == 0) return stbi__err("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
3272 s->img_x = stbi__get16be(s); if (s->img_x == 0) return stbi__err("0 width","Corrupt JPEG"); // JPEG requires
3273 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
3274 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
3275 c = stbi__get8(s);
3276 if (c != 3 && c != 1 && c != 4) return stbi__err("bad component count","Corrupt JPEG");
3277 s->img_n = c;
3278 for (i=0; i < c; ++i) {
3279 z->img_comp[i].data = NULL;
3280 z->img_comp[i].linebuf = NULL;
3281 }
3282
3283 if (Lf != 8+3*s->img_n) return stbi__err("bad SOF len","Corrupt JPEG");
3284
3285 z->rgb = 0;
3286 for (i=0; i < s->img_n; ++i) {
3287 static const unsigned char rgb[3] = { 'R', 'G', 'B' };
3288 z->img_comp[i].id = stbi__get8(s);
3289 if (s->img_n == 3 && z->img_comp[i].id == rgb[i])
3290 ++z->rgb;
3291 q = stbi__get8(s);
3292 z->img_comp[i].h = (q >> 4); if (!z->img_comp[i].h || z->img_comp[i].h > 4) return stbi__err("bad H","Corrupt JPEG");
3293 z->img_comp[i].v = q & 15; if (!z->img_comp[i].v || z->img_comp[i].v > 4) return stbi__err("bad V","Corrupt JPEG");
3294 z->img_comp[i].tq = stbi__get8(s); if (z->img_comp[i].tq > 3) return stbi__err("bad TQ","Corrupt JPEG");
3295 }
3296
3297 if (scan != STBI__SCAN_load) return 1;
3298
3299 if (!stbi__mad3sizes_valid(s->img_x, s->img_y, s->img_n, 0)) return stbi__err("too large", "Image too large to decode");
3300
3301 for (i=0; i < s->img_n; ++i) {
3302 if (z->img_comp[i].h > h_max) h_max = z->img_comp[i].h;
3303 if (z->img_comp[i].v > v_max) v_max = z->img_comp[i].v;
3304 }
3305
3306 // check that plane subsampling factors are integer ratios; our resamplers can't deal with fractional ratios
3307 // and I've never seen a non-corrupted JPEG file actually use them
3308 for (i=0; i < s->img_n; ++i) {
3309 if (h_max % z->img_comp[i].h != 0) return stbi__err("bad H","Corrupt JPEG");
3310 if (v_max % z->img_comp[i].v != 0) return stbi__err("bad V","Corrupt JPEG");
3311 }
3312
3313 // compute interleaved mcu info
3314 z->img_h_max = h_max;
3315 z->img_v_max = v_max;
3316 z->img_mcu_w = h_max * 8;
3317 z->img_mcu_h = v_max * 8;
3318 // these sizes can't be more than 17 bits
3319 z->img_mcu_x = (s->img_x + z->img_mcu_w-1) / z->img_mcu_w;
3320 z->img_mcu_y = (s->img_y + z->img_mcu_h-1) / z->img_mcu_h;
3321
3322 for (i=0; i < s->img_n; ++i) {
3323 // number of effective pixels (e.g. for non-interleaved MCU)
3324 z->img_comp[i].x = (s->img_x * z->img_comp[i].h + h_max-1) / h_max;
3325 z->img_comp[i].y = (s->img_y * z->img_comp[i].v + v_max-1) / v_max;
3326 // to simplify generation, we'll allocate enough memory to decode
3327 // the bogus oversized data from using interleaved MCUs and their
3328 // big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't
3329 // discard the extra data until colorspace conversion
3330 //
3331 // img_mcu_x, img_mcu_y: <=17 bits; comp[i].h and .v are <=4 (checked earlier)
3332 // so these muls can't overflow with 32-bit ints (which we require)
3333 z->img_comp[i].w2 = z->img_mcu_x * z->img_comp[i].h * 8;
3334 z->img_comp[i].h2 = z->img_mcu_y * z->img_comp[i].v * 8;
3335 z->img_comp[i].coeff = 0;
3336 z->img_comp[i].raw_coeff = 0;
3337 z->img_comp[i].linebuf = NULL;
3338 z->img_comp[i].raw_data = stbi__malloc_mad2(z->img_comp[i].w2, z->img_comp[i].h2, 15);
3339 if (z->img_comp[i].raw_data == NULL)
3340 return stbi__free_jpeg_components(z, i+1, stbi__err("outofmem", "Out of memory"));
3341 // align blocks for idct using mmx/sse
3342 z->img_comp[i].data = (stbi_uc*) (((size_t) z->img_comp[i].raw_data + 15) & ~15);
3343 if (z->progressive) {
3344 // w2, h2 are multiples of 8 (see above)
3345 z->img_comp[i].coeff_w = z->img_comp[i].w2 / 8;
3346 z->img_comp[i].coeff_h = z->img_comp[i].h2 / 8;
3347 z->img_comp[i].raw_coeff = stbi__malloc_mad3(z->img_comp[i].w2, z->img_comp[i].h2, sizeof(short), 15);
3348 if (z->img_comp[i].raw_coeff == NULL)
3349 return stbi__free_jpeg_components(z, i+1, stbi__err("outofmem", "Out of memory"));
3350 z->img_comp[i].coeff = (short*) (((size_t) z->img_comp[i].raw_coeff + 15) & ~15);
3351 }
3352 }
3353
3354 return 1;
3355}
3356
3357// use comparisons since in some cases we handle more than one case (e.g. SOF)
3358#define stbi__DNL(x) ((x) == 0xdc)
3359#define stbi__SOI(x) ((x) == 0xd8)
3360#define stbi__EOI(x) ((x) == 0xd9)
3361#define stbi__SOF(x) ((x) == 0xc0 || (x) == 0xc1 || (x) == 0xc2)
3362#define stbi__SOS(x) ((x) == 0xda)
3363
3364#define stbi__SOF_progressive(x) ((x) == 0xc2)
3365
3366static int stbi__decode_jpeg_header(stbi__jpeg *z, int scan)
3367{
3368 int m;
3369 z->jfif = 0;
3370 z->app14_color_transform = -1; // valid values are 0,1,2
3371 z->marker = STBI__MARKER_none; // initialize cached marker to empty
3372 m = stbi__get_marker(z);
3373 if (!stbi__SOI(m)) return stbi__err("no SOI","Corrupt JPEG");
3374 if (scan == STBI__SCAN_type) return 1;
3375 m = stbi__get_marker(z);
3376 while (!stbi__SOF(m)) {
3377 if (!stbi__process_marker(z,m)) return 0;
3378 m = stbi__get_marker(z);
3379 while (m == STBI__MARKER_none) {
3380 // some files have extra padding after their blocks, so ok, we'll scan
3381 if (stbi__at_eof(z->s)) return stbi__err("no SOF", "Corrupt JPEG");
3382 m = stbi__get_marker(z);
3383 }
3384 }
3385 z->progressive = stbi__SOF_progressive(m);
3386 if (!stbi__process_frame_header(z, scan)) return 0;
3387 return 1;
3388}
3389
3390static int stbi__skip_jpeg_junk_at_end(stbi__jpeg *j)
3391{
3392 // some JPEGs have junk at end, skip over it but if we find what looks
3393 // like a valid marker, resume there
3394 while (!stbi__at_eof(j->s)) {
3395 int x = stbi__get8(j->s);
3396 while (x == 255) { // might be a marker
3397 if (stbi__at_eof(j->s)) return STBI__MARKER_none;
3398 x = stbi__get8(j->s);
3399 if (x != 0x00 && x != 0xff) {
3400 // not a stuffed zero or lead-in to another marker, looks
3401 // like an actual marker, return it
3402 return x;
3403 }
3404 // stuffed zero has x=0 now which ends the loop, meaning we go
3405 // back to regular scan loop.
3406 // repeated 0xff keeps trying to read the next byte of the marker.
3407 }
3408 }
3409 return STBI__MARKER_none;
3410}
3411
3412// decode image to YCbCr format
3413static int stbi__decode_jpeg_image(stbi__jpeg *j)
3414{
3415 int m;
3416 for (m = 0; m < 4; m++) {
3417 j->img_comp[m].raw_data = NULL;
3418 j->img_comp[m].raw_coeff = NULL;
3419 }
3420 j->restart_interval = 0;
3421 if (!stbi__decode_jpeg_header(j, STBI__SCAN_load)) return 0;
3422 m = stbi__get_marker(j);
3423 while (!stbi__EOI(m)) {
3424 if (stbi__SOS(m)) {
3425 if (!stbi__process_scan_header(j)) return 0;
3426 if (!stbi__parse_entropy_coded_data(j)) return 0;
3427 if (j->marker == STBI__MARKER_none ) {
3428 j->marker = stbi__skip_jpeg_junk_at_end(j);
3429 // if we reach eof without hitting a marker, stbi__get_marker() below will fail and we'll eventually return 0
3430 }
3431 m = stbi__get_marker(j);
3432 if (STBI__RESTART(m))
3433 m = stbi__get_marker(j);
3434 } else if (stbi__DNL(m)) {
3435 int Ld = stbi__get16be(j->s);
3436 stbi__uint32 NL = stbi__get16be(j->s);
3437 if (Ld != 4) return stbi__err("bad DNL len", "Corrupt JPEG");
3438 if (NL != j->s->img_y) return stbi__err("bad DNL height", "Corrupt JPEG");
3439 m = stbi__get_marker(j);
3440 } else {
3441 if (!stbi__process_marker(j, m)) return 1;
3442 m = stbi__get_marker(j);
3443 }
3444 }
3445 if (j->progressive)
3446 stbi__jpeg_finish(j);
3447 return 1;
3448}
3449
3450// static jfif-centered resampling (across block boundaries)
3451
3452typedef stbi_uc *(*resample_row_func)(stbi_uc *out, stbi_uc *in0, stbi_uc *in1,
3453 int w, int hs);
3454
3455#define stbi__div4(x) ((stbi_uc) ((x) >> 2))
3456
3457static stbi_uc *resample_row_1(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3458{
3459 STBI_NOTUSED(out);
3460 STBI_NOTUSED(in_far);
3461 STBI_NOTUSED(w);
3462 STBI_NOTUSED(hs);
3463 return in_near;
3464}
3465
3466static stbi_uc* stbi__resample_row_v_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3467{
3468 // need to generate two samples vertically for every one in input
3469 int i;
3470 STBI_NOTUSED(hs);
3471 for (i=0; i < w; ++i)
3472 out[i] = stbi__div4(3*in_near[i] + in_far[i] + 2);
3473 return out;
3474}
3475
3476static stbi_uc* stbi__resample_row_h_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3477{
3478 // need to generate two samples horizontally for every one in input
3479 int i;
3480 stbi_uc *input = in_near;
3481
3482 if (w == 1) {
3483 // if only one sample, can't do any interpolation
3484 out[0] = out[1] = input[0];
3485 return out;
3486 }
3487
3488 out[0] = input[0];
3489 out[1] = stbi__div4(input[0]*3 + input[1] + 2);
3490 for (i=1; i < w-1; ++i) {
3491 int n = 3*input[i]+2;
3492 out[i*2+0] = stbi__div4(n+input[i-1]);
3493 out[i*2+1] = stbi__div4(n+input[i+1]);
3494 }
3495 out[i*2+0] = stbi__div4(input[w-2]*3 + input[w-1] + 2);
3496 out[i*2+1] = input[w-1];
3497
3498 STBI_NOTUSED(in_far);
3499 STBI_NOTUSED(hs);
3500
3501 return out;
3502}
3503
3504#define stbi__div16(x) ((stbi_uc) ((x) >> 4))
3505
3506static stbi_uc *stbi__resample_row_hv_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3507{
3508 // need to generate 2x2 samples for every one in input
3509 int i,t0,t1;
3510 if (w == 1) {
3511 out[0] = out[1] = stbi__div4(3*in_near[0] + in_far[0] + 2);
3512 return out;
3513 }
3514
3515 t1 = 3*in_near[0] + in_far[0];
3516 out[0] = stbi__div4(t1+2);
3517 for (i=1; i < w; ++i) {
3518 t0 = t1;
3519 t1 = 3*in_near[i]+in_far[i];
3520 out[i*2-1] = stbi__div16(3*t0 + t1 + 8);
3521 out[i*2 ] = stbi__div16(3*t1 + t0 + 8);
3522 }
3523 out[w*2-1] = stbi__div4(t1+2);
3524
3525 STBI_NOTUSED(hs);
3526
3527 return out;
3528}
3529
3530#if defined(STBI_SSE2) || defined(STBI_NEON)
3531static stbi_uc *stbi__resample_row_hv_2_simd(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3532{
3533 // need to generate 2x2 samples for every one in input
3534 int i=0,t0,t1;
3535
3536 if (w == 1) {
3537 out[0] = out[1] = stbi__div4(3*in_near[0] + in_far[0] + 2);
3538 return out;
3539 }
3540
3541 t1 = 3*in_near[0] + in_far[0];
3542 // process groups of 8 pixels for as long as we can.
3543 // note we can't handle the last pixel in a row in this loop
3544 // because we need to handle the filter boundary conditions.
3545 for (; i < ((w-1) & ~7); i += 8) {
3546#if defined(STBI_SSE2)
3547 // load and perform the vertical filtering pass
3548 // this uses 3*x + y = 4*x + (y - x)
3549 __m128i zero = _mm_setzero_si128();
3550 __m128i farb = _mm_loadl_epi64((__m128i *) (in_far + i));
3551 __m128i nearb = _mm_loadl_epi64((__m128i *) (in_near + i));
3552 __m128i farw = _mm_unpacklo_epi8(farb, zero);
3553 __m128i nearw = _mm_unpacklo_epi8(nearb, zero);
3554 __m128i diff = _mm_sub_epi16(farw, nearw);
3555 __m128i nears = _mm_slli_epi16(nearw, 2);
3556 __m128i curr = _mm_add_epi16(nears, diff); // current row
3557
3558 // horizontal filter works the same based on shifted vers of current
3559 // row. "prev" is current row shifted right by 1 pixel; we need to
3560 // insert the previous pixel value (from t1).
3561 // "next" is current row shifted left by 1 pixel, with first pixel
3562 // of next block of 8 pixels added in.
3563 __m128i prv0 = _mm_slli_si128(curr, 2);
3564 __m128i nxt0 = _mm_srli_si128(curr, 2);
3565 __m128i prev = _mm_insert_epi16(prv0, t1, 0);
3566 __m128i next = _mm_insert_epi16(nxt0, 3*in_near[i+8] + in_far[i+8], 7);
3567
3568 // horizontal filter, polyphase implementation since it's convenient:
3569 // even pixels = 3*cur + prev = cur*4 + (prev - cur)
3570 // odd pixels = 3*cur + next = cur*4 + (next - cur)
3571 // note the shared term.
3572 __m128i bias = _mm_set1_epi16(8);
3573 __m128i curs = _mm_slli_epi16(curr, 2);
3574 __m128i prvd = _mm_sub_epi16(prev, curr);
3575 __m128i nxtd = _mm_sub_epi16(next, curr);
3576 __m128i curb = _mm_add_epi16(curs, bias);
3577 __m128i even = _mm_add_epi16(prvd, curb);
3578 __m128i odd = _mm_add_epi16(nxtd, curb);
3579
3580 // interleave even and odd pixels, then undo scaling.
3581 __m128i int0 = _mm_unpacklo_epi16(even, odd);
3582 __m128i int1 = _mm_unpackhi_epi16(even, odd);
3583 __m128i de0 = _mm_srli_epi16(int0, 4);
3584 __m128i de1 = _mm_srli_epi16(int1, 4);
3585
3586 // pack and write output
3587 __m128i outv = _mm_packus_epi16(de0, de1);
3588 _mm_storeu_si128((__m128i *) (out + i*2), outv);
3589#elif defined(STBI_NEON)
3590 // load and perform the vertical filtering pass
3591 // this uses 3*x + y = 4*x + (y - x)
3592 uint8x8_t farb = vld1_u8(in_far + i);
3593 uint8x8_t nearb = vld1_u8(in_near + i);
3594 int16x8_t diff = vreinterpretq_s16_u16(vsubl_u8(farb, nearb));
3595 int16x8_t nears = vreinterpretq_s16_u16(vshll_n_u8(nearb, 2));
3596 int16x8_t curr = vaddq_s16(nears, diff); // current row
3597
3598 // horizontal filter works the same based on shifted vers of current
3599 // row. "prev" is current row shifted right by 1 pixel; we need to
3600 // insert the previous pixel value (from t1).
3601 // "next" is current row shifted left by 1 pixel, with first pixel
3602 // of next block of 8 pixels added in.
3603 int16x8_t prv0 = vextq_s16(curr, curr, 7);
3604 int16x8_t nxt0 = vextq_s16(curr, curr, 1);
3605 int16x8_t prev = vsetq_lane_s16(t1, prv0, 0);
3606 int16x8_t next = vsetq_lane_s16(3*in_near[i+8] + in_far[i+8], nxt0, 7);
3607
3608 // horizontal filter, polyphase implementation since it's convenient:
3609 // even pixels = 3*cur + prev = cur*4 + (prev - cur)
3610 // odd pixels = 3*cur + next = cur*4 + (next - cur)
3611 // note the shared term.
3612 int16x8_t curs = vshlq_n_s16(curr, 2);
3613 int16x8_t prvd = vsubq_s16(prev, curr);
3614 int16x8_t nxtd = vsubq_s16(next, curr);
3615 int16x8_t even = vaddq_s16(curs, prvd);
3616 int16x8_t odd = vaddq_s16(curs, nxtd);
3617
3618 // undo scaling and round, then store with even/odd phases interleaved
3619 uint8x8x2_t o;
3620 o.val[0] = vqrshrun_n_s16(even, 4);
3621 o.val[1] = vqrshrun_n_s16(odd, 4);
3622 vst2_u8(out + i*2, o);
3623#endif
3624
3625 // "previous" value for next iter
3626 t1 = 3*in_near[i+7] + in_far[i+7];
3627 }
3628
3629 t0 = t1;
3630 t1 = 3*in_near[i] + in_far[i];
3631 out[i*2] = stbi__div16(3*t1 + t0 + 8);
3632
3633 for (++i; i < w; ++i) {
3634 t0 = t1;
3635 t1 = 3*in_near[i]+in_far[i];
3636 out[i*2-1] = stbi__div16(3*t0 + t1 + 8);
3637 out[i*2 ] = stbi__div16(3*t1 + t0 + 8);
3638 }
3639 out[w*2-1] = stbi__div4(t1+2);
3640
3641 STBI_NOTUSED(hs);
3642
3643 return out;
3644}
3645#endif
3646
3647static stbi_uc *stbi__resample_row_generic(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
3648{
3649 // resample with nearest-neighbor
3650 int i,j;
3651 STBI_NOTUSED(in_far);
3652 for (i=0; i < w; ++i)
3653 for (j=0; j < hs; ++j)
3654 out[i*hs+j] = in_near[i];
3655 return out;
3656}
3657
3658// this is a reduced-precision calculation of YCbCr-to-RGB introduced
3659// to make sure the code produces the same results in both SIMD and scalar
3660#define stbi__float2fixed(x) (((int) ((x) * 4096.0f + 0.5f)) << 8)
3661static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step)
3662{
3663 int i;
3664 for (i=0; i < count; ++i) {
3665 int y_fixed = (y[i] << 20) + (1<<19); // rounding
3666 int r,g,b;
3667 int cr = pcr[i] - 128;
3668 int cb = pcb[i] - 128;
3669 r = y_fixed + cr* stbi__float2fixed(1.40200f);
3670 g = y_fixed + (cr*-stbi__float2fixed(0.71414f)) + ((cb*-stbi__float2fixed(0.34414f)) & 0xffff0000);
3671 b = y_fixed + cb* stbi__float2fixed(1.77200f);
3672 r >>= 20;
3673 g >>= 20;
3674 b >>= 20;
3675 if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; }
3676 if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; }
3677 if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; }
3678 out[0] = (stbi_uc)r;
3679 out[1] = (stbi_uc)g;
3680 out[2] = (stbi_uc)b;
3681 out[3] = 255;
3682 out += step;
3683 }
3684}
3685
3686#if defined(STBI_SSE2) || defined(STBI_NEON)
3687static void stbi__YCbCr_to_RGB_simd(stbi_uc *out, stbi_uc const *y, stbi_uc const *pcb, stbi_uc const *pcr, int count, int step)
3688{
3689 int i = 0;
3690
3691#ifdef STBI_SSE2
3692 // step == 3 is pretty ugly on the final interleave, and i'm not convinced
3693 // it's useful in practice (you wouldn't use it for textures, for example).
3694 // so just accelerate step == 4 case.
3695 if (step == 4) {
3696 // this is a fairly straightforward implementation and not super-optimized.
3697 __m128i signflip = _mm_set1_epi8(-0x80);
3698 __m128i cr_const0 = _mm_set1_epi16( (short) ( 1.40200f*4096.0f+0.5f));
3699 __m128i cr_const1 = _mm_set1_epi16( - (short) ( 0.71414f*4096.0f+0.5f));
3700 __m128i cb_const0 = _mm_set1_epi16( - (short) ( 0.34414f*4096.0f+0.5f));
3701 __m128i cb_const1 = _mm_set1_epi16( (short) ( 1.77200f*4096.0f+0.5f));
3702 __m128i y_bias = _mm_set1_epi8((char) (unsigned char) 128);
3703 __m128i xw = _mm_set1_epi16(255); // alpha channel
3704
3705 for (; i+7 < count; i += 8) {
3706 // load
3707 __m128i y_bytes = _mm_loadl_epi64((__m128i *) (y+i));
3708 __m128i cr_bytes = _mm_loadl_epi64((__m128i *) (pcr+i));
3709 __m128i cb_bytes = _mm_loadl_epi64((__m128i *) (pcb+i));
3710 __m128i cr_biased = _mm_xor_si128(cr_bytes, signflip); // -128
3711 __m128i cb_biased = _mm_xor_si128(cb_bytes, signflip); // -128
3712
3713 // unpack to short (and left-shift cr, cb by 8)
3714 __m128i yw = _mm_unpacklo_epi8(y_bias, y_bytes);
3715 __m128i crw = _mm_unpacklo_epi8(_mm_setzero_si128(), cr_biased);
3716 __m128i cbw = _mm_unpacklo_epi8(_mm_setzero_si128(), cb_biased);
3717
3718 // color transform
3719 __m128i yws = _mm_srli_epi16(yw, 4);
3720 __m128i cr0 = _mm_mulhi_epi16(cr_const0, crw);
3721 __m128i cb0 = _mm_mulhi_epi16(cb_const0, cbw);
3722 __m128i cb1 = _mm_mulhi_epi16(cbw, cb_const1);
3723 __m128i cr1 = _mm_mulhi_epi16(crw, cr_const1);
3724 __m128i rws = _mm_add_epi16(cr0, yws);
3725 __m128i gwt = _mm_add_epi16(cb0, yws);
3726 __m128i bws = _mm_add_epi16(yws, cb1);
3727 __m128i gws = _mm_add_epi16(gwt, cr1);
3728
3729 // descale
3730 __m128i rw = _mm_srai_epi16(rws, 4);
3731 __m128i bw = _mm_srai_epi16(bws, 4);
3732 __m128i gw = _mm_srai_epi16(gws, 4);
3733
3734 // back to byte, set up for transpose
3735 __m128i brb = _mm_packus_epi16(rw, bw);
3736 __m128i gxb = _mm_packus_epi16(gw, xw);
3737
3738 // transpose to interleave channels
3739 __m128i t0 = _mm_unpacklo_epi8(brb, gxb);
3740 __m128i t1 = _mm_unpackhi_epi8(brb, gxb);
3741 __m128i o0 = _mm_unpacklo_epi16(t0, t1);
3742 __m128i o1 = _mm_unpackhi_epi16(t0, t1);
3743
3744 // store
3745 _mm_storeu_si128((__m128i *) (out + 0), o0);
3746 _mm_storeu_si128((__m128i *) (out + 16), o1);
3747 out += 32;
3748 }
3749 }
3750#endif
3751
3752#ifdef STBI_NEON
3753 // in this version, step=3 support would be easy to add. but is there demand?
3754 if (step == 4) {
3755 // this is a fairly straightforward implementation and not super-optimized.
3756 uint8x8_t signflip = vdup_n_u8(0x80);
3757 int16x8_t cr_const0 = vdupq_n_s16( (short) ( 1.40200f*4096.0f+0.5f));
3758 int16x8_t cr_const1 = vdupq_n_s16( - (short) ( 0.71414f*4096.0f+0.5f));
3759 int16x8_t cb_const0 = vdupq_n_s16( - (short) ( 0.34414f*4096.0f+0.5f));
3760 int16x8_t cb_const1 = vdupq_n_s16( (short) ( 1.77200f*4096.0f+0.5f));
3761
3762 for (; i+7 < count; i += 8) {
3763 // load
3764 uint8x8_t y_bytes = vld1_u8(y + i);
3765 uint8x8_t cr_bytes = vld1_u8(pcr + i);
3766 uint8x8_t cb_bytes = vld1_u8(pcb + i);
3767 int8x8_t cr_biased = vreinterpret_s8_u8(vsub_u8(cr_bytes, signflip));
3768 int8x8_t cb_biased = vreinterpret_s8_u8(vsub_u8(cb_bytes, signflip));
3769
3770 // expand to s16
3771 int16x8_t yws = vreinterpretq_s16_u16(vshll_n_u8(y_bytes, 4));
3772 int16x8_t crw = vshll_n_s8(cr_biased, 7);
3773 int16x8_t cbw = vshll_n_s8(cb_biased, 7);
3774
3775 // color transform
3776 int16x8_t cr0 = vqdmulhq_s16(crw, cr_const0);
3777 int16x8_t cb0 = vqdmulhq_s16(cbw, cb_const0);
3778 int16x8_t cr1 = vqdmulhq_s16(crw, cr_const1);
3779 int16x8_t cb1 = vqdmulhq_s16(cbw, cb_const1);
3780 int16x8_t rws = vaddq_s16(yws, cr0);
3781 int16x8_t gws = vaddq_s16(vaddq_s16(yws, cb0), cr1);
3782 int16x8_t bws = vaddq_s16(yws, cb1);
3783
3784 // undo scaling, round, convert to byte
3785 uint8x8x4_t o;
3786 o.val[0] = vqrshrun_n_s16(rws, 4);
3787 o.val[1] = vqrshrun_n_s16(gws, 4);
3788 o.val[2] = vqrshrun_n_s16(bws, 4);
3789 o.val[3] = vdup_n_u8(255);
3790
3791 // store, interleaving r/g/b/a
3792 vst4_u8(out, o);
3793 out += 8*4;
3794 }
3795 }
3796#endif
3797
3798 for (; i < count; ++i) {
3799 int y_fixed = (y[i] << 20) + (1<<19); // rounding
3800 int r,g,b;
3801 int cr = pcr[i] - 128;
3802 int cb = pcb[i] - 128;
3803 r = y_fixed + cr* stbi__float2fixed(1.40200f);
3804 g = y_fixed + cr*-stbi__float2fixed(0.71414f) + ((cb*-stbi__float2fixed(0.34414f)) & 0xffff0000);
3805 b = y_fixed + cb* stbi__float2fixed(1.77200f);
3806 r >>= 20;
3807 g >>= 20;
3808 b >>= 20;
3809 if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; }
3810 if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; }
3811 if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; }
3812 out[0] = (stbi_uc)r;
3813 out[1] = (stbi_uc)g;
3814 out[2] = (stbi_uc)b;
3815 out[3] = 255;
3816 out += step;
3817 }
3818}
3819#endif
3820
3821// set up the kernels
3822static void stbi__setup_jpeg(stbi__jpeg *j)
3823{
3824 j->idct_block_kernel = stbi__idct_block;
3825 j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_row;
3826 j->resample_row_hv_2_kernel = stbi__resample_row_hv_2;
3827
3828#ifdef STBI_SSE2
3829 if (stbi__sse2_available()) {
3830 j->idct_block_kernel = stbi__idct_simd;
3831 j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
3832 j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
3833 }
3834#endif
3835
3836#ifdef STBI_NEON
3837 j->idct_block_kernel = stbi__idct_simd;
3838 j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
3839 j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
3840#endif
3841}
3842
3843// clean up the temporary component buffers
3844static void stbi__cleanup_jpeg(stbi__jpeg *j)
3845{
3846 stbi__free_jpeg_components(j, j->s->img_n, 0);
3847}
3848
3849typedef struct
3850{
3851 resample_row_func resample;
3852 stbi_uc *line0,*line1;
3853 int hs,vs; // expansion factor in each axis
3854 int w_lores; // horizontal pixels pre-expansion
3855 int ystep; // how far through vertical expansion we are
3856 int ypos; // which pre-expansion row we're on
3857} stbi__resample;
3858
3859// fast 0..255 * 0..255 => 0..255 rounded multiplication
3860static stbi_uc stbi__blinn_8x8(stbi_uc x, stbi_uc y)
3861{
3862 unsigned int t = x*y + 128;
3863 return (stbi_uc) ((t + (t >>8)) >> 8);
3864}
3865
3866static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp, int req_comp)
3867{
3868 int n, decode_n, is_rgb;
3869 z->s->img_n = 0; // make stbi__cleanup_jpeg safe
3870
3871 // validate req_comp
3872 if (req_comp < 0 || req_comp > 4) return stbi__errpuc("bad req_comp", "Internal error");
3873
3874 // load a jpeg image from whichever source, but leave in YCbCr format
3875 if (!stbi__decode_jpeg_image(z)) { stbi__cleanup_jpeg(z); return NULL; }
3876
3877 // determine actual number of components to generate
3878 n = req_comp ? req_comp : z->s->img_n >= 3 ? 3 : 1;
3879
3880 is_rgb = z->s->img_n == 3 && (z->rgb == 3 || (z->app14_color_transform == 0 && !z->jfif));
3881
3882 if (z->s->img_n == 3 && n < 3 && !is_rgb)
3883 decode_n = 1;
3884 else
3885 decode_n = z->s->img_n;
3886
3887 // nothing to do if no components requested; check this now to avoid
3888 // accessing uninitialized coutput[0] later
3889 if (decode_n <= 0) { stbi__cleanup_jpeg(z); return NULL; }
3890
3891 // resample and color-convert
3892 {
3893 int k;
3894 unsigned int i,j;
3895 stbi_uc *output;
3896 stbi_uc *coutput[4] = { NULL, NULL, NULL, NULL };
3897
3898 stbi__resample res_comp[4];
3899
3900 for (k=0; k < decode_n; ++k) {
3901 stbi__resample *r = &res_comp[k];
3902
3903 // allocate line buffer big enough for upsampling off the edges
3904 // with upsample factor of 4
3905 z->img_comp[k].linebuf = (stbi_uc *) stbi__malloc(z->s->img_x + 3);
3906 if (!z->img_comp[k].linebuf) { stbi__cleanup_jpeg(z); return stbi__errpuc("outofmem", "Out of memory"); }
3907
3908 r->hs = z->img_h_max / z->img_comp[k].h;
3909 r->vs = z->img_v_max / z->img_comp[k].v;
3910 r->ystep = r->vs >> 1;
3911 r->w_lores = (z->s->img_x + r->hs-1) / r->hs;
3912 r->ypos = 0;
3913 r->line0 = r->line1 = z->img_comp[k].data;
3914
3915 if (r->hs == 1 && r->vs == 1) r->resample = resample_row_1;
3916 else if (r->hs == 1 && r->vs == 2) r->resample = stbi__resample_row_v_2;
3917 else if (r->hs == 2 && r->vs == 1) r->resample = stbi__resample_row_h_2;
3918 else if (r->hs == 2 && r->vs == 2) r->resample = z->resample_row_hv_2_kernel;
3919 else r->resample = stbi__resample_row_generic;
3920 }
3921
3922 // can't error after this so, this is safe
3923 output = (stbi_uc *) stbi__malloc_mad3(n, z->s->img_x, z->s->img_y, 1);
3924 if (!output) { stbi__cleanup_jpeg(z); return stbi__errpuc("outofmem", "Out of memory"); }
3925
3926 // now go ahead and resample
3927 for (j=0; j < z->s->img_y; ++j) {
3928 stbi_uc *out = output + n * z->s->img_x * j;
3929 for (k=0; k < decode_n; ++k) {
3930 stbi__resample *r = &res_comp[k];
3931 int y_bot = r->ystep >= (r->vs >> 1);
3932 coutput[k] = r->resample(z->img_comp[k].linebuf,
3933 y_bot ? r->line1 : r->line0,
3934 y_bot ? r->line0 : r->line1,
3935 r->w_lores, r->hs);
3936 if (++r->ystep >= r->vs) {
3937 r->ystep = 0;
3938 r->line0 = r->line1;
3939 if (++r->ypos < z->img_comp[k].y)
3940 r->line1 += z->img_comp[k].w2;
3941 }
3942 }
3943 if (n >= 3) {
3944 stbi_uc *y = coutput[0];
3945 if (z->s->img_n == 3) {
3946 if (is_rgb) {
3947 for (i=0; i < z->s->img_x; ++i) {
3948 out[0] = y[i];
3949 out[1] = coutput[1][i];
3950 out[2] = coutput[2][i];
3951 out[3] = 255;
3952 out += n;
3953 }
3954 } else {
3955 z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
3956 }
3957 } else if (z->s->img_n == 4) {
3958 if (z->app14_color_transform == 0) { // CMYK
3959 for (i=0; i < z->s->img_x; ++i) {
3960 stbi_uc m = coutput[3][i];
3961 out[0] = stbi__blinn_8x8(coutput[0][i], m);
3962 out[1] = stbi__blinn_8x8(coutput[1][i], m);
3963 out[2] = stbi__blinn_8x8(coutput[2][i], m);
3964 out[3] = 255;
3965 out += n;
3966 }
3967 } else if (z->app14_color_transform == 2) { // YCCK
3968 z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
3969 for (i=0; i < z->s->img_x; ++i) {
3970 stbi_uc m = coutput[3][i];
3971 out[0] = stbi__blinn_8x8(255 - out[0], m);
3972 out[1] = stbi__blinn_8x8(255 - out[1], m);
3973 out[2] = stbi__blinn_8x8(255 - out[2], m);
3974 out += n;
3975 }
3976 } else { // YCbCr + alpha? Ignore the fourth channel for now
3977 z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
3978 }
3979 } else
3980 for (i=0; i < z->s->img_x; ++i) {
3981 out[0] = out[1] = out[2] = y[i];
3982 out[3] = 255; // not used if n==3
3983 out += n;
3984 }
3985 } else {
3986 if (is_rgb) {
3987 if (n == 1)
3988 for (i=0; i < z->s->img_x; ++i)
3989 *out++ = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]);
3990 else {
3991 for (i=0; i < z->s->img_x; ++i, out += 2) {
3992 out[0] = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]);
3993 out[1] = 255;
3994 }
3995 }
3996 } else if (z->s->img_n == 4 && z->app14_color_transform == 0) {
3997 for (i=0; i < z->s->img_x; ++i) {
3998 stbi_uc m = coutput[3][i];
3999 stbi_uc r = stbi__blinn_8x8(coutput[0][i], m);
4000 stbi_uc g = stbi__blinn_8x8(coutput[1][i], m);
4001 stbi_uc b = stbi__blinn_8x8(coutput[2][i], m);
4002 out[0] = stbi__compute_y(r, g, b);
4003 out[1] = 255;
4004 out += n;
4005 }
4006 } else if (z->s->img_n == 4 && z->app14_color_transform == 2) {
4007 for (i=0; i < z->s->img_x; ++i) {
4008 out[0] = stbi__blinn_8x8(255 - coutput[0][i], coutput[3][i]);
4009 out[1] = 255;
4010 out += n;
4011 }
4012 } else {
4013 stbi_uc *y = coutput[0];
4014 if (n == 1)
4015 for (i=0; i < z->s->img_x; ++i) out[i] = y[i];
4016 else
4017 for (i=0; i < z->s->img_x; ++i) { *out++ = y[i]; *out++ = 255; }
4018 }
4019 }
4020 }
4021 stbi__cleanup_jpeg(z);
4022 *out_x = z->s->img_x;
4023 *out_y = z->s->img_y;
4024 if (comp) *comp = z->s->img_n >= 3 ? 3 : 1; // report original components, not output
4025 return output;
4026 }
4027}
4028
4029static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
4030{
4031 unsigned char* result;
4032 stbi__jpeg* j = (stbi__jpeg*) stbi__malloc(sizeof(stbi__jpeg));
4033 if (!j) return stbi__errpuc("outofmem", "Out of memory");
4034 memset(j, 0, sizeof(stbi__jpeg));
4035 STBI_NOTUSED(ri);
4036 j->s = s;
4037 stbi__setup_jpeg(j);
4038 result = load_jpeg_image(j, x,y,comp,req_comp);
4039 STBI_FREE(j);
4040 return result;
4041}
4042
4043static int stbi__jpeg_test(stbi__context *s)
4044{
4045 int r;
4046 stbi__jpeg* j = (stbi__jpeg*)stbi__malloc(sizeof(stbi__jpeg));
4047 if (!j) return stbi__err("outofmem", "Out of memory");
4048 memset(j, 0, sizeof(stbi__jpeg));
4049 j->s = s;
4050 stbi__setup_jpeg(j);
4051 r = stbi__decode_jpeg_header(j, STBI__SCAN_type);
4052 stbi__rewind(s);
4053 STBI_FREE(j);
4054 return r;
4055}
4056
4057static int stbi__jpeg_info_raw(stbi__jpeg *j, int *x, int *y, int *comp)
4058{
4059 if (!stbi__decode_jpeg_header(j, STBI__SCAN_header)) {
4060 stbi__rewind( j->s );
4061 return 0;
4062 }
4063 if (x) *x = j->s->img_x;
4064 if (y) *y = j->s->img_y;
4065 if (comp) *comp = j->s->img_n >= 3 ? 3 : 1;
4066 return 1;
4067}
4068
4069static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp)
4070{
4071 int result;
4072 stbi__jpeg* j = (stbi__jpeg*) (stbi__malloc(sizeof(stbi__jpeg)));
4073 if (!j) return stbi__err("outofmem", "Out of memory");
4074 memset(j, 0, sizeof(stbi__jpeg));
4075 j->s = s;
4076 result = stbi__jpeg_info_raw(j, x, y, comp);
4077 STBI_FREE(j);
4078 return result;
4079}
4080#endif
4081
4082// public domain zlib decode v0.2 Sean Barrett 2006-11-18
4083// simple implementation
4084// - all input must be provided in an upfront buffer
4085// - all output is written to a single output buffer (can malloc/realloc)
4086// performance
4087// - fast huffman
4088
4089#ifndef STBI_NO_ZLIB
4090
4091// fast-way is faster to check than jpeg huffman, but slow way is slower
4092#define STBI__ZFAST_BITS 9 // accelerate all cases in default tables
4093#define STBI__ZFAST_MASK ((1 << STBI__ZFAST_BITS) - 1)
4094#define STBI__ZNSYMS 288 // number of symbols in literal/length alphabet
4095
4096// zlib-style huffman encoding
4097// (jpegs packs from left, zlib from right, so can't share code)
4098typedef struct
4099{
4100 stbi__uint16 fast[1 << STBI__ZFAST_BITS];
4101 stbi__uint16 firstcode[16];
4102 int maxcode[17];
4103 stbi__uint16 firstsymbol[16];
4104 stbi_uc size[STBI__ZNSYMS];
4105 stbi__uint16 value[STBI__ZNSYMS];
4106} stbi__zhuffman;
4107
4108stbi_inline static int stbi__bitreverse16(int n)
4109{
4110 n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1);
4111 n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2);
4112 n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4);
4113 n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8);
4114 return n;
4115}
4116
4117stbi_inline static int stbi__bit_reverse(int v, int bits)
4118{
4119 STBI_ASSERT(bits <= 16);
4120 // to bit reverse n bits, reverse 16 and shift
4121 // e.g. 11 bits, bit reverse and shift away 5
4122 return stbi__bitreverse16(v) >> (16-bits);
4123}
4124
4125static int stbi__zbuild_huffman(stbi__zhuffman *z, const stbi_uc *sizelist, int num)
4126{
4127 int i,k=0;
4128 int code, next_code[16], sizes[17];
4129
4130 // DEFLATE spec for generating codes
4131 memset(sizes, 0, sizeof(sizes));
4132 memset(z->fast, 0, sizeof(z->fast));
4133 for (i=0; i < num; ++i)
4134 ++sizes[sizelist[i]];
4135 sizes[0] = 0;
4136 for (i=1; i < 16; ++i)
4137 if (sizes[i] > (1 << i))
4138 return stbi__err("bad sizes", "Corrupt PNG");
4139 code = 0;
4140 for (i=1; i < 16; ++i) {
4141 next_code[i] = code;
4142 z->firstcode[i] = (stbi__uint16) code;
4143 z->firstsymbol[i] = (stbi__uint16) k;
4144 code = (code + sizes[i]);
4145 if (sizes[i])
4146 if (code-1 >= (1 << i)) return stbi__err("bad codelengths","Corrupt PNG");
4147 z->maxcode[i] = code << (16-i); // preshift for inner loop
4148 code <<= 1;
4149 k += sizes[i];
4150 }
4151 z->maxcode[16] = 0x10000; // sentinel
4152 for (i=0; i < num; ++i) {
4153 int s = sizelist[i];
4154 if (s) {
4155 int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s];
4156 stbi__uint16 fastv = (stbi__uint16) ((s << 9) | i);
4157 z->size [c] = (stbi_uc ) s;
4158 z->value[c] = (stbi__uint16) i;
4159 if (s <= STBI__ZFAST_BITS) {
4160 int j = stbi__bit_reverse(next_code[s],s);
4161 while (j < (1 << STBI__ZFAST_BITS)) {
4162 z->fast[j] = fastv;
4163 j += (1 << s);
4164 }
4165 }
4166 ++next_code[s];
4167 }
4168 }
4169 return 1;
4170}
4171
4172// zlib-from-memory implementation for PNG reading
4173// because PNG allows splitting the zlib stream arbitrarily,
4174// and it's annoying structurally to have PNG call ZLIB call PNG,
4175// we require PNG read all the IDATs and combine them into a single
4176// memory buffer
4177
4178typedef struct
4179{
4180 stbi_uc *zbuffer, *zbuffer_end;
4181 int num_bits;
4182 stbi__uint32 code_buffer;
4183
4184 char *zout;
4185 char *zout_start;
4186 char *zout_end;
4187 int z_expandable;
4188
4189 stbi__zhuffman z_length, z_distance;
4190} stbi__zbuf;
4191
4192stbi_inline static int stbi__zeof(stbi__zbuf *z)
4193{
4194 return (z->zbuffer >= z->zbuffer_end);
4195}
4196
4197stbi_inline static stbi_uc stbi__zget8(stbi__zbuf *z)
4198{
4199 return stbi__zeof(z) ? 0 : *z->zbuffer++;
4200}
4201
4202static void stbi__fill_bits(stbi__zbuf *z)
4203{
4204 do {
4205 if (z->code_buffer >= (1U << z->num_bits)) {
4206 z->zbuffer = z->zbuffer_end; /* treat this as EOF so we fail. */
4207 return;
4208 }
4209 z->code_buffer |= (unsigned int) stbi__zget8(z) << z->num_bits;
4210 z->num_bits += 8;
4211 } while (z->num_bits <= 24);
4212}
4213
4214stbi_inline static unsigned int stbi__zreceive(stbi__zbuf *z, int n)
4215{
4216 unsigned int k;
4217 if (z->num_bits < n) stbi__fill_bits(z);
4218 k = z->code_buffer & ((1 << n) - 1);
4219 z->code_buffer >>= n;
4220 z->num_bits -= n;
4221 return k;
4222}
4223
4224static int stbi__zhuffman_decode_slowpath(stbi__zbuf *a, stbi__zhuffman *z)
4225{
4226 int b,s,k;
4227 // not resolved by fast table, so compute it the slow way
4228 // use jpeg approach, which requires MSbits at top
4229 k = stbi__bit_reverse(a->code_buffer, 16);
4230 for (s=STBI__ZFAST_BITS+1; ; ++s)
4231 if (k < z->maxcode[s])
4232 break;
4233 if (s >= 16) return -1; // invalid code!
4234 // code size is s, so:
4235 b = (k >> (16-s)) - z->firstcode[s] + z->firstsymbol[s];
4236 if (b >= STBI__ZNSYMS) return -1; // some data was corrupt somewhere!
4237 if (z->size[b] != s) return -1; // was originally an assert, but report failure instead.
4238 a->code_buffer >>= s;
4239 a->num_bits -= s;
4240 return z->value[b];
4241}
4242
4243stbi_inline static int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z)
4244{
4245 int b,s;
4246 if (a->num_bits < 16) {
4247 if (stbi__zeof(a)) {
4248 return -1; /* report error for unexpected end of data. */
4249 }
4250 stbi__fill_bits(a);
4251 }
4252 b = z->fast[a->code_buffer & STBI__ZFAST_MASK];
4253 if (b) {
4254 s = b >> 9;
4255 a->code_buffer >>= s;
4256 a->num_bits -= s;
4257 return b & 511;
4258 }
4259 return stbi__zhuffman_decode_slowpath(a, z);
4260}
4261
4262static int stbi__zexpand(stbi__zbuf *z, char *zout, int n) // need to make room for n bytes
4263{
4264 char *q;
4265 unsigned int cur, limit, old_limit;
4266 z->zout = zout;
4267 if (!z->z_expandable) return stbi__err("output buffer limit","Corrupt PNG");
4268 cur = (unsigned int) (z->zout - z->zout_start);
4269 limit = old_limit = (unsigned) (z->zout_end - z->zout_start);
4270 if (UINT_MAX - cur < (unsigned) n) return stbi__err("outofmem", "Out of memory");
4271 while (cur + n > limit) {
4272 if(limit > UINT_MAX / 2) return stbi__err("outofmem", "Out of memory");
4273 limit *= 2;
4274 }
4275 q = (char *) STBI_REALLOC_SIZED(z->zout_start, old_limit, limit);
4276 STBI_NOTUSED(old_limit);
4277 if (q == NULL) return stbi__err("outofmem", "Out of memory");
4278 z->zout_start = q;
4279 z->zout = q + cur;
4280 z->zout_end = q + limit;
4281 return 1;
4282}
4283
4284static const int stbi__zlength_base[31] = {
4285 3,4,5,6,7,8,9,10,11,13,
4286 15,17,19,23,27,31,35,43,51,59,
4287 67,83,99,115,131,163,195,227,258,0,0 };
4288
4289static const int stbi__zlength_extra[31]=
4290{ 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0,0,0 };
4291
4292static const int stbi__zdist_base[32] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,
4293257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577,0,0};
4294
4295static const int stbi__zdist_extra[32] =
4296{ 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
4297
4298static int stbi__parse_huffman_block(stbi__zbuf *a)
4299{
4300 char *zout = a->zout;
4301 for(;;) {
4302 int z = stbi__zhuffman_decode(a, &a->z_length);
4303 if (z < 256) {
4304 if (z < 0) return stbi__err("bad huffman code","Corrupt PNG"); // error in huffman codes
4305 if (zout >= a->zout_end) {
4306 if (!stbi__zexpand(a, zout, 1)) return 0;
4307 zout = a->zout;
4308 }
4309 *zout++ = (char) z;
4310 } else {
4311 stbi_uc *p;
4312 int len,dist;
4313 if (z == 256) {
4314 a->zout = zout;
4315 return 1;
4316 }
4317 if (z >= 286) return stbi__err("bad huffman code","Corrupt PNG"); // per DEFLATE, length codes 286 and 287 must not appear in compressed data
4318 z -= 257;
4319 len = stbi__zlength_base[z];
4320 if (stbi__zlength_extra[z]) len += stbi__zreceive(a, stbi__zlength_extra[z]);
4321 z = stbi__zhuffman_decode(a, &a->z_distance);
4322 if (z < 0 || z >= 30) return stbi__err("bad huffman code","Corrupt PNG"); // per DEFLATE, distance codes 30 and 31 must not appear in compressed data
4323 dist = stbi__zdist_base[z];
4324 if (stbi__zdist_extra[z]) dist += stbi__zreceive(a, stbi__zdist_extra[z]);
4325 if (zout - a->zout_start < dist) return stbi__err("bad dist","Corrupt PNG");
4326 if (zout + len > a->zout_end) {
4327 if (!stbi__zexpand(a, zout, len)) return 0;
4328 zout = a->zout;
4329 }
4330 p = (stbi_uc *) (zout - dist);
4331 if (dist == 1) { // run of one byte; common in images.
4332 stbi_uc v = *p;
4333 if (len) { do *zout++ = v; while (--len); }
4334 } else {
4335 if (len) { do *zout++ = *p++; while (--len); }
4336 }
4337 }
4338 }
4339}
4340
4341static int stbi__compute_huffman_codes(stbi__zbuf *a)
4342{
4343 static const stbi_uc length_dezigzag[19] = { 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 };
4344 stbi__zhuffman z_codelength;
4345 stbi_uc lencodes[286+32+137];//padding for maximum single op
4346 stbi_uc codelength_sizes[19];
4347 int i,n;
4348
4349 int hlit = stbi__zreceive(a,5) + 257;
4350 int hdist = stbi__zreceive(a,5) + 1;
4351 int hclen = stbi__zreceive(a,4) + 4;
4352 int ntot = hlit + hdist;
4353
4354 memset(codelength_sizes, 0, sizeof(codelength_sizes));
4355 for (i=0; i < hclen; ++i) {
4356 int s = stbi__zreceive(a,3);
4357 codelength_sizes[length_dezigzag[i]] = (stbi_uc) s;
4358 }
4359 if (!stbi__zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0;
4360
4361 n = 0;
4362 while (n < ntot) {
4363 int c = stbi__zhuffman_decode(a, &z_codelength);
4364 if (c < 0 || c >= 19) return stbi__err("bad codelengths", "Corrupt PNG");
4365 if (c < 16)
4366 lencodes[n++] = (stbi_uc) c;
4367 else {
4368 stbi_uc fill = 0;
4369 if (c == 16) {
4370 c = stbi__zreceive(a,2)+3;
4371 if (n == 0) return stbi__err("bad codelengths", "Corrupt PNG");
4372 fill = lencodes[n-1];
4373 } else if (c == 17) {
4374 c = stbi__zreceive(a,3)+3;
4375 } else if (c == 18) {
4376 c = stbi__zreceive(a,7)+11;
4377 } else {
4378 return stbi__err("bad codelengths", "Corrupt PNG");
4379 }
4380 if (ntot - n < c) return stbi__err("bad codelengths", "Corrupt PNG");
4381 memset(lencodes+n, fill, c);
4382 n += c;
4383 }
4384 }
4385 if (n != ntot) return stbi__err("bad codelengths","Corrupt PNG");
4386 if (!stbi__zbuild_huffman(&a->z_length, lencodes, hlit)) return 0;
4387 if (!stbi__zbuild_huffman(&a->z_distance, lencodes+hlit, hdist)) return 0;
4388 return 1;
4389}
4390
4391static int stbi__parse_uncompressed_block(stbi__zbuf *a)
4392{
4393 stbi_uc header[4];
4394 int len,nlen,k;
4395 if (a->num_bits & 7)
4396 stbi__zreceive(a, a->num_bits & 7); // discard
4397 // drain the bit-packed data into header
4398 k = 0;
4399 while (a->num_bits > 0) {
4400 header[k++] = (stbi_uc) (a->code_buffer & 255); // suppress MSVC run-time check
4401 a->code_buffer >>= 8;
4402 a->num_bits -= 8;
4403 }
4404 if (a->num_bits < 0) return stbi__err("zlib corrupt","Corrupt PNG");
4405 // now fill header the normal way
4406 while (k < 4)
4407 header[k++] = stbi__zget8(a);
4408 len = header[1] * 256 + header[0];
4409 nlen = header[3] * 256 + header[2];
4410 if (nlen != (len ^ 0xffff)) return stbi__err("zlib corrupt","Corrupt PNG");
4411 if (a->zbuffer + len > a->zbuffer_end) return stbi__err("read past buffer","Corrupt PNG");
4412 if (a->zout + len > a->zout_end)
4413 if (!stbi__zexpand(a, a->zout, len)) return 0;
4414 memcpy(a->zout, a->zbuffer, len);
4415 a->zbuffer += len;
4416 a->zout += len;
4417 return 1;
4418}
4419
4420static int stbi__parse_zlib_header(stbi__zbuf *a)
4421{
4422 int cmf = stbi__zget8(a);
4423 int cm = cmf & 15;
4424 /* int cinfo = cmf >> 4; */
4425 int flg = stbi__zget8(a);
4426 if (stbi__zeof(a)) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec
4427 if ((cmf*256+flg) % 31 != 0) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec
4428 if (flg & 32) return stbi__err("no preset dict","Corrupt PNG"); // preset dictionary not allowed in png
4429 if (cm != 8) return stbi__err("bad compression","Corrupt PNG"); // DEFLATE required for png
4430 // window = 1 << (8 + cinfo)... but who cares, we fully buffer output
4431 return 1;
4432}
4433
4434static const stbi_uc stbi__zdefault_length[STBI__ZNSYMS] =
4435{
4436 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4437 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4438 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4439 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4440 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4441 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4442 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4443 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4444 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,8,8,8,8,8,8,8,8
4445};
4446static const stbi_uc stbi__zdefault_distance[32] =
4447{
4448 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5
4449};
4450/*
4451Init algorithm:
4452{
4453 int i; // use <= to match clearly with spec
4454 for (i=0; i <= 143; ++i) stbi__zdefault_length[i] = 8;
4455 for ( ; i <= 255; ++i) stbi__zdefault_length[i] = 9;
4456 for ( ; i <= 279; ++i) stbi__zdefault_length[i] = 7;
4457 for ( ; i <= 287; ++i) stbi__zdefault_length[i] = 8;
4458
4459 for (i=0; i <= 31; ++i) stbi__zdefault_distance[i] = 5;
4460}
4461*/
4462
4463static int stbi__parse_zlib(stbi__zbuf *a, int parse_header)
4464{
4465 int final, type;
4466 if (parse_header)
4467 if (!stbi__parse_zlib_header(a)) return 0;
4468 a->num_bits = 0;
4469 a->code_buffer = 0;
4470 do {
4471 final = stbi__zreceive(a,1);
4472 type = stbi__zreceive(a,2);
4473 if (type == 0) {
4474 if (!stbi__parse_uncompressed_block(a)) return 0;
4475 } else if (type == 3) {
4476 return 0;
4477 } else {
4478 if (type == 1) {
4479 // use fixed code lengths
4480 if (!stbi__zbuild_huffman(&a->z_length , stbi__zdefault_length , STBI__ZNSYMS)) return 0;
4481 if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance, 32)) return 0;
4482 } else {
4483 if (!stbi__compute_huffman_codes(a)) return 0;
4484 }
4485 if (!stbi__parse_huffman_block(a)) return 0;
4486 }
4487 } while (!final);
4488 return 1;
4489}
4490
4491static int stbi__do_zlib(stbi__zbuf *a, char *obuf, int olen, int exp, int parse_header)
4492{
4493 a->zout_start = obuf;
4494 a->zout = obuf;
4495 a->zout_end = obuf + olen;
4496 a->z_expandable = exp;
4497
4498 return stbi__parse_zlib(a, parse_header);
4499}
4500
4501STBIDEF char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen)
4502{
4503 stbi__zbuf a;
4504 char *p = (char *) stbi__malloc(initial_size);
4505 if (p == NULL) return NULL;
4506 a.zbuffer = (stbi_uc *) buffer;
4507 a.zbuffer_end = (stbi_uc *) buffer + len;
4508 if (stbi__do_zlib(&a, p, initial_size, 1, 1)) {
4509 if (outlen) *outlen = (int) (a.zout - a.zout_start);
4510 return a.zout_start;
4511 } else {
4512 STBI_FREE(a.zout_start);
4513 return NULL;
4514 }
4515}
4516
4517STBIDEF char *stbi_zlib_decode_malloc(char const *buffer, int len, int *outlen)
4518{
4519 return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen);
4520}
4521
4522STBIDEF char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header)
4523{
4524 stbi__zbuf a;
4525 char *p = (char *) stbi__malloc(initial_size);
4526 if (p == NULL) return NULL;
4527 a.zbuffer = (stbi_uc *) buffer;
4528 a.zbuffer_end = (stbi_uc *) buffer + len;
4529 if (stbi__do_zlib(&a, p, initial_size, 1, parse_header)) {
4530 if (outlen) *outlen = (int) (a.zout - a.zout_start);
4531 return a.zout_start;
4532 } else {
4533 STBI_FREE(a.zout_start);
4534 return NULL;
4535 }
4536}
4537
4538STBIDEF int stbi_zlib_decode_buffer(char *obuffer, int olen, char const *ibuffer, int ilen)
4539{
4540 stbi__zbuf a;
4541 a.zbuffer = (stbi_uc *) ibuffer;
4542 a.zbuffer_end = (stbi_uc *) ibuffer + ilen;
4543 if (stbi__do_zlib(&a, obuffer, olen, 0, 1))
4544 return (int) (a.zout - a.zout_start);
4545 else
4546 return -1;
4547}
4548
4549STBIDEF char *stbi_zlib_decode_noheader_malloc(char const *buffer, int len, int *outlen)
4550{
4551 stbi__zbuf a;
4552 char *p = (char *) stbi__malloc(16384);
4553 if (p == NULL) return NULL;
4554 a.zbuffer = (stbi_uc *) buffer;
4555 a.zbuffer_end = (stbi_uc *) buffer+len;
4556 if (stbi__do_zlib(&a, p, 16384, 1, 0)) {
4557 if (outlen) *outlen = (int) (a.zout - a.zout_start);
4558 return a.zout_start;
4559 } else {
4560 STBI_FREE(a.zout_start);
4561 return NULL;
4562 }
4563}
4564
4565STBIDEF int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen)
4566{
4567 stbi__zbuf a;
4568 a.zbuffer = (stbi_uc *) ibuffer;
4569 a.zbuffer_end = (stbi_uc *) ibuffer + ilen;
4570 if (stbi__do_zlib(&a, obuffer, olen, 0, 0))
4571 return (int) (a.zout - a.zout_start);
4572 else
4573 return -1;
4574}
4575#endif
4576
4577// public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18
4578// simple implementation
4579// - only 8-bit samples
4580// - no CRC checking
4581// - allocates lots of intermediate memory
4582// - avoids problem of streaming data between subsystems
4583// - avoids explicit window management
4584// performance
4585// - uses stb_zlib, a PD zlib implementation with fast huffman decoding
4586
4587#ifndef STBI_NO_PNG
4588typedef struct
4589{
4590 stbi__uint32 length;
4591 stbi__uint32 type;
4592} stbi__pngchunk;
4593
4594static stbi__pngchunk stbi__get_chunk_header(stbi__context *s)
4595{
4596 stbi__pngchunk c;
4597 c.length = stbi__get32be(s);
4598 c.type = stbi__get32be(s);
4599 return c;
4600}
4601
4602static int stbi__check_png_header(stbi__context *s)
4603{
4604 static const stbi_uc png_sig[8] = { 137,80,78,71,13,10,26,10 };
4605 int i;
4606 for (i=0; i < 8; ++i)
4607 if (stbi__get8(s) != png_sig[i]) return stbi__err("bad png sig","Not a PNG");
4608 return 1;
4609}
4610
4611typedef struct
4612{
4613 stbi__context *s;
4614 stbi_uc *idata, *expanded, *out;
4615 int depth;
4616} stbi__png;
4617
4618
4619enum {
4620 STBI__F_none=0,
4621 STBI__F_sub=1,
4622 STBI__F_up=2,
4623 STBI__F_avg=3,
4624 STBI__F_paeth=4,
4625 // synthetic filters used for first scanline to avoid needing a dummy row of 0s
4626 STBI__F_avg_first,
4627 STBI__F_paeth_first
4628};
4629
4630static stbi_uc first_row_filter[5] =
4631{
4632 STBI__F_none,
4633 STBI__F_sub,
4634 STBI__F_none,
4635 STBI__F_avg_first,
4636 STBI__F_paeth_first
4637};
4638
4639static int stbi__paeth(int a, int b, int c)
4640{
4641 int p = a + b - c;
4642 int pa = abs(p-a);
4643 int pb = abs(p-b);
4644 int pc = abs(p-c);
4645 if (pa <= pb && pa <= pc) return a;
4646 if (pb <= pc) return b;
4647 return c;
4648}
4649
4650static const stbi_uc stbi__depth_scale_table[9] = { 0, 0xff, 0x55, 0, 0x11, 0,0,0, 0x01 };
4651
4652// create the png data from post-deflated data
4653static int stbi__create_png_image_raw(stbi__png *a, stbi_uc *raw, stbi__uint32 raw_len, int out_n, stbi__uint32 x, stbi__uint32 y, int depth, int color)
4654{
4655 int bytes = (depth == 16? 2 : 1);
4656 stbi__context *s = a->s;
4657 stbi__uint32 i,j,stride = x*out_n*bytes;
4658 stbi__uint32 img_len, img_width_bytes;
4659 int k;
4660 int img_n = s->img_n; // copy it into a local for later
4661
4662 int output_bytes = out_n*bytes;
4663 int filter_bytes = img_n*bytes;
4664 int width = x;
4665
4666 STBI_ASSERT(out_n == s->img_n || out_n == s->img_n+1);
4667 a->out = (stbi_uc *) stbi__malloc_mad3(x, y, output_bytes, 0); // extra bytes to write off the end into
4668 if (!a->out) return stbi__err("outofmem", "Out of memory");
4669
4670 if (!stbi__mad3sizes_valid(img_n, x, depth, 7)) return stbi__err("too large", "Corrupt PNG");
4671 img_width_bytes = (((img_n * x * depth) + 7) >> 3);
4672 img_len = (img_width_bytes + 1) * y;
4673
4674 // we used to check for exact match between raw_len and img_len on non-interlaced PNGs,
4675 // but issue #276 reported a PNG in the wild that had extra data at the end (all zeros),
4676 // so just check for raw_len < img_len always.
4677 if (raw_len < img_len) return stbi__err("not enough pixels","Corrupt PNG");
4678
4679 for (j=0; j < y; ++j) {
4680 stbi_uc *cur = a->out + stride*j;
4681 stbi_uc *prior;
4682 int filter = *raw++;
4683
4684 if (filter > 4)
4685 return stbi__err("invalid filter","Corrupt PNG");
4686
4687 if (depth < 8) {
4688 if (img_width_bytes > x) return stbi__err("invalid width","Corrupt PNG");
4689 cur += x*out_n - img_width_bytes; // store output to the rightmost img_len bytes, so we can decode in place
4690 filter_bytes = 1;
4691 width = img_width_bytes;
4692 }
4693 prior = cur - stride; // bugfix: need to compute this after 'cur +=' computation above
4694
4695 // if first row, use special filter that doesn't sample previous row
4696 if (j == 0) filter = first_row_filter[filter];
4697
4698 // handle first byte explicitly
4699 for (k=0; k < filter_bytes; ++k) {
4700 switch (filter) {
4701 case STBI__F_none : cur[k] = raw[k]; break;
4702 case STBI__F_sub : cur[k] = raw[k]; break;
4703 case STBI__F_up : cur[k] = STBI__BYTECAST(raw[k] + prior[k]); break;
4704 case STBI__F_avg : cur[k] = STBI__BYTECAST(raw[k] + (prior[k]>>1)); break;
4705 case STBI__F_paeth : cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(0,prior[k],0)); break;
4706 case STBI__F_avg_first : cur[k] = raw[k]; break;
4707 case STBI__F_paeth_first: cur[k] = raw[k]; break;
4708 }
4709 }
4710
4711 if (depth == 8) {
4712 if (img_n != out_n)
4713 cur[img_n] = 255; // first pixel
4714 raw += img_n;
4715 cur += out_n;
4716 prior += out_n;
4717 } else if (depth == 16) {
4718 if (img_n != out_n) {
4719 cur[filter_bytes] = 255; // first pixel top byte
4720 cur[filter_bytes+1] = 255; // first pixel bottom byte
4721 }
4722 raw += filter_bytes;
4723 cur += output_bytes;
4724 prior += output_bytes;
4725 } else {
4726 raw += 1;
4727 cur += 1;
4728 prior += 1;
4729 }
4730
4731 // this is a little gross, so that we don't switch per-pixel or per-component
4732 if (depth < 8 || img_n == out_n) {
4733 int nk = (width - 1)*filter_bytes;
4734 #define STBI__CASE(f) \
4735 case f: \
4736 for (k=0; k < nk; ++k)
4737 switch (filter) {
4738 // "none" filter turns into a memcpy here; make that explicit.
4739 case STBI__F_none: memcpy(cur, raw, nk); break;
4740 STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k-filter_bytes]); } break;
4741 STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); } break;
4742 STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k-filter_bytes])>>1)); } break;
4743 STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k-filter_bytes],prior[k],prior[k-filter_bytes])); } break;
4744 STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k-filter_bytes] >> 1)); } break;
4745 STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k-filter_bytes],0,0)); } break;
4746 }
4747 #undef STBI__CASE
4748 raw += nk;
4749 } else {
4750 STBI_ASSERT(img_n+1 == out_n);
4751 #define STBI__CASE(f) \
4752 case f: \
4753 for (i=x-1; i >= 1; --i, cur[filter_bytes]=255,raw+=filter_bytes,cur+=output_bytes,prior+=output_bytes) \
4754 for (k=0; k < filter_bytes; ++k)
4755 switch (filter) {
4756 STBI__CASE(STBI__F_none) { cur[k] = raw[k]; } break;
4757 STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k- output_bytes]); } break;
4758 STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); } break;
4759 STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k- output_bytes])>>1)); } break;
4760 STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k- output_bytes],prior[k],prior[k- output_bytes])); } break;
4761 STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k- output_bytes] >> 1)); } break;
4762 STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k- output_bytes],0,0)); } break;
4763 }
4764 #undef STBI__CASE
4765
4766 // the loop above sets the high byte of the pixels' alpha, but for
4767 // 16 bit png files we also need the low byte set. we'll do that here.
4768 if (depth == 16) {
4769 cur = a->out + stride*j; // start at the beginning of the row again
4770 for (i=0; i < x; ++i,cur+=output_bytes) {
4771 cur[filter_bytes+1] = 255;
4772 }
4773 }
4774 }
4775 }
4776
4777 // we make a separate pass to expand bits to pixels; for performance,
4778 // this could run two scanlines behind the above code, so it won't
4779 // intefere with filtering but will still be in the cache.
4780 if (depth < 8) {
4781 for (j=0; j < y; ++j) {
4782 stbi_uc *cur = a->out + stride*j;
4783 stbi_uc *in = a->out + stride*j + x*out_n - img_width_bytes;
4784 // unpack 1/2/4-bit into a 8-bit buffer. allows us to keep the common 8-bit path optimal at minimal cost for 1/2/4-bit
4785 // png guarante byte alignment, if width is not multiple of 8/4/2 we'll decode dummy trailing data that will be skipped in the later loop
4786 stbi_uc scale = (color == 0) ? stbi__depth_scale_table[depth] : 1; // scale grayscale values to 0..255 range
4787
4788 // note that the final byte might overshoot and write more data than desired.
4789 // we can allocate enough data that this never writes out of memory, but it
4790 // could also overwrite the next scanline. can it overwrite non-empty data
4791 // on the next scanline? yes, consider 1-pixel-wide scanlines with 1-bit-per-pixel.
4792 // so we need to explicitly clamp the final ones
4793
4794 if (depth == 4) {
4795 for (k=x*img_n; k >= 2; k-=2, ++in) {
4796 *cur++ = scale * ((*in >> 4) );
4797 *cur++ = scale * ((*in ) & 0x0f);
4798 }
4799 if (k > 0) *cur++ = scale * ((*in >> 4) );
4800 } else if (depth == 2) {
4801 for (k=x*img_n; k >= 4; k-=4, ++in) {
4802 *cur++ = scale * ((*in >> 6) );
4803 *cur++ = scale * ((*in >> 4) & 0x03);
4804 *cur++ = scale * ((*in >> 2) & 0x03);
4805 *cur++ = scale * ((*in ) & 0x03);
4806 }
4807 if (k > 0) *cur++ = scale * ((*in >> 6) );
4808 if (k > 1) *cur++ = scale * ((*in >> 4) & 0x03);
4809 if (k > 2) *cur++ = scale * ((*in >> 2) & 0x03);
4810 } else if (depth == 1) {
4811 for (k=x*img_n; k >= 8; k-=8, ++in) {
4812 *cur++ = scale * ((*in >> 7) );
4813 *cur++ = scale * ((*in >> 6) & 0x01);
4814 *cur++ = scale * ((*in >> 5) & 0x01);
4815 *cur++ = scale * ((*in >> 4) & 0x01);
4816 *cur++ = scale * ((*in >> 3) & 0x01);
4817 *cur++ = scale * ((*in >> 2) & 0x01);
4818 *cur++ = scale * ((*in >> 1) & 0x01);
4819 *cur++ = scale * ((*in ) & 0x01);
4820 }
4821 if (k > 0) *cur++ = scale * ((*in >> 7) );
4822 if (k > 1) *cur++ = scale * ((*in >> 6) & 0x01);
4823 if (k > 2) *cur++ = scale * ((*in >> 5) & 0x01);
4824 if (k > 3) *cur++ = scale * ((*in >> 4) & 0x01);
4825 if (k > 4) *cur++ = scale * ((*in >> 3) & 0x01);
4826 if (k > 5) *cur++ = scale * ((*in >> 2) & 0x01);
4827 if (k > 6) *cur++ = scale * ((*in >> 1) & 0x01);
4828 }
4829 if (img_n != out_n) {
4830 int q;
4831 // insert alpha = 255
4832 cur = a->out + stride*j;
4833 if (img_n == 1) {
4834 for (q=x-1; q >= 0; --q) {
4835 cur[q*2+1] = 255;
4836 cur[q*2+0] = cur[q];
4837 }
4838 } else {
4839 STBI_ASSERT(img_n == 3);
4840 for (q=x-1; q >= 0; --q) {
4841 cur[q*4+3] = 255;
4842 cur[q*4+2] = cur[q*3+2];
4843 cur[q*4+1] = cur[q*3+1];
4844 cur[q*4+0] = cur[q*3+0];
4845 }
4846 }
4847 }
4848 }
4849 } else if (depth == 16) {
4850 // force the image data from big-endian to platform-native.
4851 // this is done in a separate pass due to the decoding relying
4852 // on the data being untouched, but could probably be done
4853 // per-line during decode if care is taken.
4854 stbi_uc *cur = a->out;
4855 stbi__uint16 *cur16 = (stbi__uint16*)cur;
4856
4857 for(i=0; i < x*y*out_n; ++i,cur16++,cur+=2) {
4858 *cur16 = (cur[0] << 8) | cur[1];
4859 }
4860 }
4861
4862 return 1;
4863}
4864
4865static int stbi__create_png_image(stbi__png *a, stbi_uc *image_data, stbi__uint32 image_data_len, int out_n, int depth, int color, int interlaced)
4866{
4867 int bytes = (depth == 16 ? 2 : 1);
4868 int out_bytes = out_n * bytes;
4869 stbi_uc *final;
4870 int p;
4871 if (!interlaced)
4872 return stbi__create_png_image_raw(a, image_data, image_data_len, out_n, a->s->img_x, a->s->img_y, depth, color);
4873
4874 // de-interlacing
4875 final = (stbi_uc *) stbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0);
4876 if (!final) return stbi__err("outofmem", "Out of memory");
4877 for (p=0; p < 7; ++p) {
4878 int xorig[] = { 0,4,0,2,0,1,0 };
4879 int yorig[] = { 0,0,4,0,2,0,1 };
4880 int xspc[] = { 8,8,4,4,2,2,1 };
4881 int yspc[] = { 8,8,8,4,4,2,2 };
4882 int i,j,x,y;
4883 // pass1_x[4] = 0, pass1_x[5] = 1, pass1_x[12] = 1
4884 x = (a->s->img_x - xorig[p] + xspc[p]-1) / xspc[p];
4885 y = (a->s->img_y - yorig[p] + yspc[p]-1) / yspc[p];
4886 if (x && y) {
4887 stbi__uint32 img_len = ((((a->s->img_n * x * depth) + 7) >> 3) + 1) * y;
4888 if (!stbi__create_png_image_raw(a, image_data, image_data_len, out_n, x, y, depth, color)) {
4889 STBI_FREE(final);
4890 return 0;
4891 }
4892 for (j=0; j < y; ++j) {
4893 for (i=0; i < x; ++i) {
4894 int out_y = j*yspc[p]+yorig[p];
4895 int out_x = i*xspc[p]+xorig[p];
4896 memcpy(final + out_y*a->s->img_x*out_bytes + out_x*out_bytes,
4897 a->out + (j*x+i)*out_bytes, out_bytes);
4898 }
4899 }
4900 STBI_FREE(a->out);
4901 image_data += img_len;
4902 image_data_len -= img_len;
4903 }
4904 }
4905 a->out = final;
4906
4907 return 1;
4908}
4909
4910static int stbi__compute_transparency(stbi__png *z, stbi_uc tc[3], int out_n)
4911{
4912 stbi__context *s = z->s;
4913 stbi__uint32 i, pixel_count = s->img_x * s->img_y;
4914 stbi_uc *p = z->out;
4915
4916 // compute color-based transparency, assuming we've
4917 // already got 255 as the alpha value in the output
4918 STBI_ASSERT(out_n == 2 || out_n == 4);
4919
4920 if (out_n == 2) {
4921 for (i=0; i < pixel_count; ++i) {
4922 p[1] = (p[0] == tc[0] ? 0 : 255);
4923 p += 2;
4924 }
4925 } else {
4926 for (i=0; i < pixel_count; ++i) {
4927 if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
4928 p[3] = 0;
4929 p += 4;
4930 }
4931 }
4932 return 1;
4933}
4934
4935static int stbi__compute_transparency16(stbi__png *z, stbi__uint16 tc[3], int out_n)
4936{
4937 stbi__context *s = z->s;
4938 stbi__uint32 i, pixel_count = s->img_x * s->img_y;
4939 stbi__uint16 *p = (stbi__uint16*) z->out;
4940
4941 // compute color-based transparency, assuming we've
4942 // already got 65535 as the alpha value in the output
4943 STBI_ASSERT(out_n == 2 || out_n == 4);
4944
4945 if (out_n == 2) {
4946 for (i = 0; i < pixel_count; ++i) {
4947 p[1] = (p[0] == tc[0] ? 0 : 65535);
4948 p += 2;
4949 }
4950 } else {
4951 for (i = 0; i < pixel_count; ++i) {
4952 if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
4953 p[3] = 0;
4954 p += 4;
4955 }
4956 }
4957 return 1;
4958}
4959
4960static int stbi__expand_png_palette(stbi__png *a, stbi_uc *palette, int len, int pal_img_n)
4961{
4962 stbi__uint32 i, pixel_count = a->s->img_x * a->s->img_y;
4963 stbi_uc *p, *temp_out, *orig = a->out;
4964
4965 p = (stbi_uc *) stbi__malloc_mad2(pixel_count, pal_img_n, 0);
4966 if (p == NULL) return stbi__err("outofmem", "Out of memory");
4967
4968 // between here and free(out) below, exitting would leak
4969 temp_out = p;
4970
4971 if (pal_img_n == 3) {
4972 for (i=0; i < pixel_count; ++i) {
4973 int n = orig[i]*4;
4974 p[0] = palette[n ];
4975 p[1] = palette[n+1];
4976 p[2] = palette[n+2];
4977 p += 3;
4978 }
4979 } else {
4980 for (i=0; i < pixel_count; ++i) {
4981 int n = orig[i]*4;
4982 p[0] = palette[n ];
4983 p[1] = palette[n+1];
4984 p[2] = palette[n+2];
4985 p[3] = palette[n+3];
4986 p += 4;
4987 }
4988 }
4989 STBI_FREE(a->out);
4990 a->out = temp_out;
4991
4992 STBI_NOTUSED(len);
4993
4994 return 1;
4995}
4996
4997static int stbi__unpremultiply_on_load_global = 0;
4998static int stbi__de_iphone_flag_global = 0;
4999
5000STBIDEF void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply)
5001{
5002 stbi__unpremultiply_on_load_global = flag_true_if_should_unpremultiply;
5003}
5004
5005STBIDEF void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert)
5006{
5007 stbi__de_iphone_flag_global = flag_true_if_should_convert;
5008}
5009
5010#ifndef STBI_THREAD_LOCAL
5011#define stbi__unpremultiply_on_load stbi__unpremultiply_on_load_global
5012#define stbi__de_iphone_flag stbi__de_iphone_flag_global
5013#else
5014static STBI_THREAD_LOCAL int stbi__unpremultiply_on_load_local, stbi__unpremultiply_on_load_set;
5015static STBI_THREAD_LOCAL int stbi__de_iphone_flag_local, stbi__de_iphone_flag_set;
5016
5017STBIDEF void stbi_set_unpremultiply_on_load_thread(int flag_true_if_should_unpremultiply)
5018{
5019 stbi__unpremultiply_on_load_local = flag_true_if_should_unpremultiply;
5020 stbi__unpremultiply_on_load_set = 1;
5021}
5022
5023STBIDEF void stbi_convert_iphone_png_to_rgb_thread(int flag_true_if_should_convert)
5024{
5025 stbi__de_iphone_flag_local = flag_true_if_should_convert;
5026 stbi__de_iphone_flag_set = 1;
5027}
5028
5029#define stbi__unpremultiply_on_load (stbi__unpremultiply_on_load_set \
5030 ? stbi__unpremultiply_on_load_local \
5031 : stbi__unpremultiply_on_load_global)
5032#define stbi__de_iphone_flag (stbi__de_iphone_flag_set \
5033 ? stbi__de_iphone_flag_local \
5034 : stbi__de_iphone_flag_global)
5035#endif // STBI_THREAD_LOCAL
5036
5037static void stbi__de_iphone(stbi__png *z)
5038{
5039 stbi__context *s = z->s;
5040 stbi__uint32 i, pixel_count = s->img_x * s->img_y;
5041 stbi_uc *p = z->out;
5042
5043 if (s->img_out_n == 3) { // convert bgr to rgb
5044 for (i=0; i < pixel_count; ++i) {
5045 stbi_uc t = p[0];
5046 p[0] = p[2];
5047 p[2] = t;
5048 p += 3;
5049 }
5050 } else {
5051 STBI_ASSERT(s->img_out_n == 4);
5052 if (stbi__unpremultiply_on_load) {
5053 // convert bgr to rgb and unpremultiply
5054 for (i=0; i < pixel_count; ++i) {
5055 stbi_uc a = p[3];
5056 stbi_uc t = p[0];
5057 if (a) {
5058 stbi_uc half = a / 2;
5059 p[0] = (p[2] * 255 + half) / a;
5060 p[1] = (p[1] * 255 + half) / a;
5061 p[2] = ( t * 255 + half) / a;
5062 } else {
5063 p[0] = p[2];
5064 p[2] = t;
5065 }
5066 p += 4;
5067 }
5068 } else {
5069 // convert bgr to rgb
5070 for (i=0; i < pixel_count; ++i) {
5071 stbi_uc t = p[0];
5072 p[0] = p[2];
5073 p[2] = t;
5074 p += 4;
5075 }
5076 }
5077 }
5078}
5079
5080#define STBI__PNG_TYPE(a,b,c,d) (((unsigned) (a) << 24) + ((unsigned) (b) << 16) + ((unsigned) (c) << 8) + (unsigned) (d))
5081
5082static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
5083{
5084 stbi_uc palette[1024], pal_img_n=0;
5085 stbi_uc has_trans=0, tc[3]={0};
5086 stbi__uint16 tc16[3];
5087 stbi__uint32 ioff=0, idata_limit=0, i, pal_len=0;
5088 int first=1,k,interlace=0, color=0, is_iphone=0;
5089 stbi__context *s = z->s;
5090
5091 z->expanded = NULL;
5092 z->idata = NULL;
5093 z->out = NULL;
5094
5095 if (!stbi__check_png_header(s)) return 0;
5096
5097 if (scan == STBI__SCAN_type) return 1;
5098
5099 for (;;) {
5100 stbi__pngchunk c = stbi__get_chunk_header(s);
5101 switch (c.type) {
5102 case STBI__PNG_TYPE('C','g','B','I'):
5103 is_iphone = 1;
5104 stbi__skip(s, c.length);
5105 break;
5106 case STBI__PNG_TYPE('I','H','D','R'): {
5107 int comp,filter;
5108 if (!first) return stbi__err("multiple IHDR","Corrupt PNG");
5109 first = 0;
5110 if (c.length != 13) return stbi__err("bad IHDR len","Corrupt PNG");
5111 s->img_x = stbi__get32be(s);
5112 s->img_y = stbi__get32be(s);
5113 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
5114 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
5115 z->depth = stbi__get8(s); if (z->depth != 1 && z->depth != 2 && z->depth != 4 && z->depth != 8 && z->depth != 16) return stbi__err("1/2/4/8/16-bit only","PNG not supported: 1/2/4/8/16-bit only");
5116 color = stbi__get8(s); if (color > 6) return stbi__err("bad ctype","Corrupt PNG");
5117 if (color == 3 && z->depth == 16) return stbi__err("bad ctype","Corrupt PNG");
5118 if (color == 3) pal_img_n = 3; else if (color & 1) return stbi__err("bad ctype","Corrupt PNG");
5119 comp = stbi__get8(s); if (comp) return stbi__err("bad comp method","Corrupt PNG");
5120 filter= stbi__get8(s); if (filter) return stbi__err("bad filter method","Corrupt PNG");
5121 interlace = stbi__get8(s); if (interlace>1) return stbi__err("bad interlace method","Corrupt PNG");
5122 if (!s->img_x || !s->img_y) return stbi__err("0-pixel image","Corrupt PNG");
5123 if (!pal_img_n) {
5124 s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
5125 if ((1 << 30) / s->img_x / s->img_n < s->img_y) return stbi__err("too large", "Image too large to decode");
5126 } else {
5127 // if paletted, then pal_n is our final components, and
5128 // img_n is # components to decompress/filter.
5129 s->img_n = 1;
5130 if ((1 << 30) / s->img_x / 4 < s->img_y) return stbi__err("too large","Corrupt PNG");
5131 }
5132 // even with SCAN_header, have to scan to see if we have a tRNS
5133 break;
5134 }
5135
5136 case STBI__PNG_TYPE('P','L','T','E'): {
5137 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
5138 if (c.length > 256*3) return stbi__err("invalid PLTE","Corrupt PNG");
5139 pal_len = c.length / 3;
5140 if (pal_len * 3 != c.length) return stbi__err("invalid PLTE","Corrupt PNG");
5141 for (i=0; i < pal_len; ++i) {
5142 palette[i*4+0] = stbi__get8(s);
5143 palette[i*4+1] = stbi__get8(s);
5144 palette[i*4+2] = stbi__get8(s);
5145 palette[i*4+3] = 255;
5146 }
5147 break;
5148 }
5149
5150 case STBI__PNG_TYPE('t','R','N','S'): {
5151 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
5152 if (z->idata) return stbi__err("tRNS after IDAT","Corrupt PNG");
5153 if (pal_img_n) {
5154 if (scan == STBI__SCAN_header) { s->img_n = 4; return 1; }
5155 if (pal_len == 0) return stbi__err("tRNS before PLTE","Corrupt PNG");
5156 if (c.length > pal_len) return stbi__err("bad tRNS len","Corrupt PNG");
5157 pal_img_n = 4;
5158 for (i=0; i < c.length; ++i)
5159 palette[i*4+3] = stbi__get8(s);
5160 } else {
5161 if (!(s->img_n & 1)) return stbi__err("tRNS with alpha","Corrupt PNG");
5162 if (c.length != (stbi__uint32) s->img_n*2) return stbi__err("bad tRNS len","Corrupt PNG");
5163 has_trans = 1;
5164 // non-paletted with tRNS = constant alpha. if header-scanning, we can stop now.
5165 if (scan == STBI__SCAN_header) { ++s->img_n; return 1; }
5166 if (z->depth == 16) {
5167 for (k = 0; k < s->img_n; ++k) tc16[k] = (stbi__uint16)stbi__get16be(s); // copy the values as-is
5168 } else {
5169 for (k = 0; k < s->img_n; ++k) tc[k] = (stbi_uc)(stbi__get16be(s) & 255) * stbi__depth_scale_table[z->depth]; // non 8-bit images will be larger
5170 }
5171 }
5172 break;
5173 }
5174
5175 case STBI__PNG_TYPE('I','D','A','T'): {
5176 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
5177 if (pal_img_n && !pal_len) return stbi__err("no PLTE","Corrupt PNG");
5178 if (scan == STBI__SCAN_header) {
5179 // header scan definitely stops at first IDAT
5180 if (pal_img_n)
5181 s->img_n = pal_img_n;
5182 return 1;
5183 }
5184 if (c.length > (1u << 30)) return stbi__err("IDAT size limit", "IDAT section larger than 2^30 bytes");
5185 if ((int)(ioff + c.length) < (int)ioff) return 0;
5186 if (ioff + c.length > idata_limit) {
5187 stbi__uint32 idata_limit_old = idata_limit;
5188 stbi_uc *p;
5189 if (idata_limit == 0) idata_limit = c.length > 4096 ? c.length : 4096;
5190 while (ioff + c.length > idata_limit)
5191 idata_limit *= 2;
5192 STBI_NOTUSED(idata_limit_old);
5193 p = (stbi_uc *) STBI_REALLOC_SIZED(z->idata, idata_limit_old, idata_limit); if (p == NULL) return stbi__err("outofmem", "Out of memory");
5194 z->idata = p;
5195 }
5196 if (!stbi__getn(s, z->idata+ioff,c.length)) return stbi__err("outofdata","Corrupt PNG");
5197 ioff += c.length;
5198 break;
5199 }
5200
5201 case STBI__PNG_TYPE('I','E','N','D'): {
5202 stbi__uint32 raw_len, bpl;
5203 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
5204 if (scan != STBI__SCAN_load) return 1;
5205 if (z->idata == NULL) return stbi__err("no IDAT","Corrupt PNG");
5206 // initial guess for decoded data size to avoid unnecessary reallocs
5207 bpl = (s->img_x * z->depth + 7) / 8; // bytes per line, per component
5208 raw_len = bpl * s->img_y * s->img_n /* pixels */ + s->img_y /* filter mode per row */;
5209 z->expanded = (stbi_uc *) stbi_zlib_decode_malloc_guesssize_headerflag((char *) z->idata, ioff, raw_len, (int *) &raw_len, !is_iphone);
5210 if (z->expanded == NULL) return 0; // zlib should set error
5211 STBI_FREE(z->idata); z->idata = NULL;
5212 if ((req_comp == s->img_n+1 && req_comp != 3 && !pal_img_n) || has_trans)
5213 s->img_out_n = s->img_n+1;
5214 else
5215 s->img_out_n = s->img_n;
5216 if (!stbi__create_png_image(z, z->expanded, raw_len, s->img_out_n, z->depth, color, interlace)) return 0;
5217 if (has_trans) {
5218 if (z->depth == 16) {
5219 if (!stbi__compute_transparency16(z, tc16, s->img_out_n)) return 0;
5220 } else {
5221 if (!stbi__compute_transparency(z, tc, s->img_out_n)) return 0;
5222 }
5223 }
5224 if (is_iphone && stbi__de_iphone_flag && s->img_out_n > 2)
5225 stbi__de_iphone(z);
5226 if (pal_img_n) {
5227 // pal_img_n == 3 or 4
5228 s->img_n = pal_img_n; // record the actual colors we had
5229 s->img_out_n = pal_img_n;
5230 if (req_comp >= 3) s->img_out_n = req_comp;
5231 if (!stbi__expand_png_palette(z, palette, pal_len, s->img_out_n))
5232 return 0;
5233 } else if (has_trans) {
5234 // non-paletted image with tRNS -> source image has (constant) alpha
5235 ++s->img_n;
5236 }
5237 STBI_FREE(z->expanded); z->expanded = NULL;
5238 // end of PNG chunk, read and skip CRC
5239 stbi__get32be(s);
5240 return 1;
5241 }
5242
5243 default:
5244 // if critical, fail
5245 if (first) return stbi__err("first not IHDR", "Corrupt PNG");
5246 if ((c.type & (1 << 29)) == 0) {
5247 #ifndef STBI_NO_FAILURE_STRINGS
5248 // not threadsafe
5249 static char invalid_chunk[] = "XXXX PNG chunk not known";
5250 invalid_chunk[0] = STBI__BYTECAST(c.type >> 24);
5251 invalid_chunk[1] = STBI__BYTECAST(c.type >> 16);
5252 invalid_chunk[2] = STBI__BYTECAST(c.type >> 8);
5253 invalid_chunk[3] = STBI__BYTECAST(c.type >> 0);
5254 #endif
5255 return stbi__err(invalid_chunk, "PNG not supported: unknown PNG chunk type");
5256 }
5257 stbi__skip(s, c.length);
5258 break;
5259 }
5260 // end of PNG chunk, read and skip CRC
5261 stbi__get32be(s);
5262 }
5263}
5264
5265static void *stbi__do_png(stbi__png *p, int *x, int *y, int *n, int req_comp, stbi__result_info *ri)
5266{
5267 void *result=NULL;
5268 if (req_comp < 0 || req_comp > 4) return stbi__errpuc("bad req_comp", "Internal error");
5269 if (stbi__parse_png_file(p, STBI__SCAN_load, req_comp)) {
5270 if (p->depth <= 8)
5271 ri->bits_per_channel = 8;
5272 else if (p->depth == 16)
5273 ri->bits_per_channel = 16;
5274 else
5275 return stbi__errpuc("bad bits_per_channel", "PNG not supported: unsupported color depth");
5276 result = p->out;
5277 p->out = NULL;
5278 if (req_comp && req_comp != p->s->img_out_n) {
5279 if (ri->bits_per_channel == 8)
5280 result = stbi__convert_format((unsigned char *) result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
5281 else
5282 result = stbi__convert_format16((stbi__uint16 *) result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
5283 p->s->img_out_n = req_comp;
5284 if (result == NULL) return result;
5285 }
5286 *x = p->s->img_x;
5287 *y = p->s->img_y;
5288 if (n) *n = p->s->img_n;
5289 }
5290 STBI_FREE(p->out); p->out = NULL;
5291 STBI_FREE(p->expanded); p->expanded = NULL;
5292 STBI_FREE(p->idata); p->idata = NULL;
5293
5294 return result;
5295}
5296
5297static void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
5298{
5299 stbi__png p;
5300 p.s = s;
5301 return stbi__do_png(&p, x,y,comp,req_comp, ri);
5302}
5303
5304static int stbi__png_test(stbi__context *s)
5305{
5306 int r;
5307 r = stbi__check_png_header(s);
5308 stbi__rewind(s);
5309 return r;
5310}
5311
5312static int stbi__png_info_raw(stbi__png *p, int *x, int *y, int *comp)
5313{
5314 if (!stbi__parse_png_file(p, STBI__SCAN_header, 0)) {
5315 stbi__rewind( p->s );
5316 return 0;
5317 }
5318 if (x) *x = p->s->img_x;
5319 if (y) *y = p->s->img_y;
5320 if (comp) *comp = p->s->img_n;
5321 return 1;
5322}
5323
5324static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp)
5325{
5326 stbi__png p;
5327 p.s = s;
5328 return stbi__png_info_raw(&p, x, y, comp);
5329}
5330
5331static int stbi__png_is16(stbi__context *s)
5332{
5333 stbi__png p;
5334 p.s = s;
5335 if (!stbi__png_info_raw(&p, NULL, NULL, NULL))
5336 return 0;
5337 if (p.depth != 16) {
5338 stbi__rewind(p.s);
5339 return 0;
5340 }
5341 return 1;
5342}
5343#endif
5344
5345// Microsoft/Windows BMP image
5346
5347#ifndef STBI_NO_BMP
5348static int stbi__bmp_test_raw(stbi__context *s)
5349{
5350 int r;
5351 int sz;
5352 if (stbi__get8(s) != 'B') return 0;
5353 if (stbi__get8(s) != 'M') return 0;
5354 stbi__get32le(s); // discard filesize
5355 stbi__get16le(s); // discard reserved
5356 stbi__get16le(s); // discard reserved
5357 stbi__get32le(s); // discard data offset
5358 sz = stbi__get32le(s);
5359 r = (sz == 12 || sz == 40 || sz == 56 || sz == 108 || sz == 124);
5360 return r;
5361}
5362
5363static int stbi__bmp_test(stbi__context *s)
5364{
5365 int r = stbi__bmp_test_raw(s);
5366 stbi__rewind(s);
5367 return r;
5368}
5369
5370
5371// returns 0..31 for the highest set bit
5372static int stbi__high_bit(unsigned int z)
5373{
5374 int n=0;
5375 if (z == 0) return -1;
5376 if (z >= 0x10000) { n += 16; z >>= 16; }
5377 if (z >= 0x00100) { n += 8; z >>= 8; }
5378 if (z >= 0x00010) { n += 4; z >>= 4; }
5379 if (z >= 0x00004) { n += 2; z >>= 2; }
5380 if (z >= 0x00002) { n += 1;/* >>= 1;*/ }
5381 return n;
5382}
5383
5384static int stbi__bitcount(unsigned int a)
5385{
5386 a = (a & 0x55555555) + ((a >> 1) & 0x55555555); // max 2
5387 a = (a & 0x33333333) + ((a >> 2) & 0x33333333); // max 4
5388 a = (a + (a >> 4)) & 0x0f0f0f0f; // max 8 per 4, now 8 bits
5389 a = (a + (a >> 8)); // max 16 per 8 bits
5390 a = (a + (a >> 16)); // max 32 per 8 bits
5391 return a & 0xff;
5392}
5393
5394// extract an arbitrarily-aligned N-bit value (N=bits)
5395// from v, and then make it 8-bits long and fractionally
5396// extend it to full full range.
5397static int stbi__shiftsigned(unsigned int v, int shift, int bits)
5398{
5399 static unsigned int mul_table[9] = {
5400 0,
5401 0xff/*0b11111111*/, 0x55/*0b01010101*/, 0x49/*0b01001001*/, 0x11/*0b00010001*/,
5402 0x21/*0b00100001*/, 0x41/*0b01000001*/, 0x81/*0b10000001*/, 0x01/*0b00000001*/,
5403 };
5404 static unsigned int shift_table[9] = {
5405 0, 0,0,1,0,2,4,6,0,
5406 };
5407 if (shift < 0)
5408 v <<= -shift;
5409 else
5410 v >>= shift;
5411 STBI_ASSERT(v < 256);
5412 v >>= (8-bits);
5413 STBI_ASSERT(bits >= 0 && bits <= 8);
5414 return (int) ((unsigned) v * mul_table[bits]) >> shift_table[bits];
5415}
5416
5417typedef struct
5418{
5419 int bpp, offset, hsz;
5420 unsigned int mr,mg,mb,ma, all_a;
5421 int extra_read;
5422} stbi__bmp_data;
5423
5424static int stbi__bmp_set_mask_defaults(stbi__bmp_data *info, int compress)
5425{
5426 // BI_BITFIELDS specifies masks explicitly, don't override
5427 if (compress == 3)
5428 return 1;
5429
5430 if (compress == 0) {
5431 if (info->bpp == 16) {
5432 info->mr = 31u << 10;
5433 info->mg = 31u << 5;
5434 info->mb = 31u << 0;
5435 } else if (info->bpp == 32) {
5436 info->mr = 0xffu << 16;
5437 info->mg = 0xffu << 8;
5438 info->mb = 0xffu << 0;
5439 info->ma = 0xffu << 24;
5440 info->all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
5441 } else {
5442 // otherwise, use defaults, which is all-0
5443 info->mr = info->mg = info->mb = info->ma = 0;
5444 }
5445 return 1;
5446 }
5447 return 0; // error
5448}
5449
5450static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
5451{
5452 int hsz;
5453 if (stbi__get8(s) != 'B' || stbi__get8(s) != 'M') return stbi__errpuc("not BMP", "Corrupt BMP");
5454 stbi__get32le(s); // discard filesize
5455 stbi__get16le(s); // discard reserved
5456 stbi__get16le(s); // discard reserved
5457 info->offset = stbi__get32le(s);
5458 info->hsz = hsz = stbi__get32le(s);
5459 info->mr = info->mg = info->mb = info->ma = 0;
5460 info->extra_read = 14;
5461
5462 if (info->offset < 0) return stbi__errpuc("bad BMP", "bad BMP");
5463
5464 if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108 && hsz != 124) return stbi__errpuc("unknown BMP", "BMP type not supported: unknown");
5465 if (hsz == 12) {
5466 s->img_x = stbi__get16le(s);
5467 s->img_y = stbi__get16le(s);
5468 } else {
5469 s->img_x = stbi__get32le(s);
5470 s->img_y = stbi__get32le(s);
5471 }
5472 if (stbi__get16le(s) != 1) return stbi__errpuc("bad BMP", "bad BMP");
5473 info->bpp = stbi__get16le(s);
5474 if (hsz != 12) {
5475 int compress = stbi__get32le(s);
5476 if (compress == 1 || compress == 2) return stbi__errpuc("BMP RLE", "BMP type not supported: RLE");
5477 if (compress >= 4) return stbi__errpuc("BMP JPEG/PNG", "BMP type not supported: unsupported compression"); // this includes PNG/JPEG modes
5478 if (compress == 3 && info->bpp != 16 && info->bpp != 32) return stbi__errpuc("bad BMP", "bad BMP"); // bitfields requires 16 or 32 bits/pixel
5479 stbi__get32le(s); // discard sizeof
5480 stbi__get32le(s); // discard hres
5481 stbi__get32le(s); // discard vres
5482 stbi__get32le(s); // discard colorsused
5483 stbi__get32le(s); // discard max important
5484 if (hsz == 40 || hsz == 56) {
5485 if (hsz == 56) {
5486 stbi__get32le(s);
5487 stbi__get32le(s);
5488 stbi__get32le(s);
5489 stbi__get32le(s);
5490 }
5491 if (info->bpp == 16 || info->bpp == 32) {
5492 if (compress == 0) {
5493 stbi__bmp_set_mask_defaults(info, compress);
5494 } else if (compress == 3) {
5495 info->mr = stbi__get32le(s);
5496 info->mg = stbi__get32le(s);
5497 info->mb = stbi__get32le(s);
5498 info->extra_read += 12;
5499 // not documented, but generated by photoshop and handled by mspaint
5500 if (info->mr == info->mg && info->mg == info->mb) {
5501 // ?!?!?
5502 return stbi__errpuc("bad BMP", "bad BMP");
5503 }
5504 } else
5505 return stbi__errpuc("bad BMP", "bad BMP");
5506 }
5507 } else {
5508 // V4/V5 header
5509 int i;
5510 if (hsz != 108 && hsz != 124)
5511 return stbi__errpuc("bad BMP", "bad BMP");
5512 info->mr = stbi__get32le(s);
5513 info->mg = stbi__get32le(s);
5514 info->mb = stbi__get32le(s);
5515 info->ma = stbi__get32le(s);
5516 if (compress != 3) // override mr/mg/mb unless in BI_BITFIELDS mode, as per docs
5517 stbi__bmp_set_mask_defaults(info, compress);
5518 stbi__get32le(s); // discard color space
5519 for (i=0; i < 12; ++i)
5520 stbi__get32le(s); // discard color space parameters
5521 if (hsz == 124) {
5522 stbi__get32le(s); // discard rendering intent
5523 stbi__get32le(s); // discard offset of profile data
5524 stbi__get32le(s); // discard size of profile data
5525 stbi__get32le(s); // discard reserved
5526 }
5527 }
5528 }
5529 return (void *) 1;
5530}
5531
5532
5533static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
5534{
5535 stbi_uc *out;
5536 unsigned int mr=0,mg=0,mb=0,ma=0, all_a;
5537 stbi_uc pal[256][4];
5538 int psize=0,i,j,width;
5539 int flip_vertically, pad, target;
5540 stbi__bmp_data info;
5541 STBI_NOTUSED(ri);
5542
5543 info.all_a = 255;
5544 if (stbi__bmp_parse_header(s, &info) == NULL)
5545 return NULL; // error code already set
5546
5547 flip_vertically = ((int) s->img_y) > 0;
5548 s->img_y = abs((int) s->img_y);
5549
5550 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5551 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5552
5553 mr = info.mr;
5554 mg = info.mg;
5555 mb = info.mb;
5556 ma = info.ma;
5557 all_a = info.all_a;
5558
5559 if (info.hsz == 12) {
5560 if (info.bpp < 24)
5561 psize = (info.offset - info.extra_read - 24) / 3;
5562 } else {
5563 if (info.bpp < 16)
5564 psize = (info.offset - info.extra_read - info.hsz) >> 2;
5565 }
5566 if (psize == 0) {
5567 // accept some number of extra bytes after the header, but if the offset points either to before
5568 // the header ends or implies a large amount of extra data, reject the file as malformed
5569 int bytes_read_so_far = s->callback_already_read + (int)(s->img_buffer - s->img_buffer_original);
5570 int header_limit = 1024; // max we actually read is below 256 bytes currently.
5571 int extra_data_limit = 256*4; // what ordinarily goes here is a palette; 256 entries*4 bytes is its max size.
5572 if (bytes_read_so_far <= 0 || bytes_read_so_far > header_limit) {
5573 return stbi__errpuc("bad header", "Corrupt BMP");
5574 }
5575 // we established that bytes_read_so_far is positive and sensible.
5576 // the first half of this test rejects offsets that are either too small positives, or
5577 // negative, and guarantees that info.offset >= bytes_read_so_far > 0. this in turn
5578 // ensures the number computed in the second half of the test can't overflow.
5579 if (info.offset < bytes_read_so_far || info.offset - bytes_read_so_far > extra_data_limit) {
5580 return stbi__errpuc("bad offset", "Corrupt BMP");
5581 } else {
5582 stbi__skip(s, info.offset - bytes_read_so_far);
5583 }
5584 }
5585
5586 if (info.bpp == 24 && ma == 0xff000000)
5587 s->img_n = 3;
5588 else
5589 s->img_n = ma ? 4 : 3;
5590 if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
5591 target = req_comp;
5592 else
5593 target = s->img_n; // if they want monochrome, we'll post-convert
5594
5595 // sanity-check size
5596 if (!stbi__mad3sizes_valid(target, s->img_x, s->img_y, 0))
5597 return stbi__errpuc("too large", "Corrupt BMP");
5598
5599 out = (stbi_uc *) stbi__malloc_mad3(target, s->img_x, s->img_y, 0);
5600 if (!out) return stbi__errpuc("outofmem", "Out of memory");
5601 if (info.bpp < 16) {
5602 int z=0;
5603 if (psize == 0 || psize > 256) { STBI_FREE(out); return stbi__errpuc("invalid", "Corrupt BMP"); }
5604 for (i=0; i < psize; ++i) {
5605 pal[i][2] = stbi__get8(s);
5606 pal[i][1] = stbi__get8(s);
5607 pal[i][0] = stbi__get8(s);
5608 if (info.hsz != 12) stbi__get8(s);
5609 pal[i][3] = 255;
5610 }
5611 stbi__skip(s, info.offset - info.extra_read - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
5612 if (info.bpp == 1) width = (s->img_x + 7) >> 3;
5613 else if (info.bpp == 4) width = (s->img_x + 1) >> 1;
5614 else if (info.bpp == 8) width = s->img_x;
5615 else { STBI_FREE(out); return stbi__errpuc("bad bpp", "Corrupt BMP"); }
5616 pad = (-width)&3;
5617 if (info.bpp == 1) {
5618 for (j=0; j < (int) s->img_y; ++j) {
5619 int bit_offset = 7, v = stbi__get8(s);
5620 for (i=0; i < (int) s->img_x; ++i) {
5621 int color = (v>>bit_offset)&0x1;
5622 out[z++] = pal[color][0];
5623 out[z++] = pal[color][1];
5624 out[z++] = pal[color][2];
5625 if (target == 4) out[z++] = 255;
5626 if (i+1 == (int) s->img_x) break;
5627 if((--bit_offset) < 0) {
5628 bit_offset = 7;
5629 v = stbi__get8(s);
5630 }
5631 }
5632 stbi__skip(s, pad);
5633 }
5634 } else {
5635 for (j=0; j < (int) s->img_y; ++j) {
5636 for (i=0; i < (int) s->img_x; i += 2) {
5637 int v=stbi__get8(s),v2=0;
5638 if (info.bpp == 4) {
5639 v2 = v & 15;
5640 v >>= 4;
5641 }
5642 out[z++] = pal[v][0];
5643 out[z++] = pal[v][1];
5644 out[z++] = pal[v][2];
5645 if (target == 4) out[z++] = 255;
5646 if (i+1 == (int) s->img_x) break;
5647 v = (info.bpp == 8) ? stbi__get8(s) : v2;
5648 out[z++] = pal[v][0];
5649 out[z++] = pal[v][1];
5650 out[z++] = pal[v][2];
5651 if (target == 4) out[z++] = 255;
5652 }
5653 stbi__skip(s, pad);
5654 }
5655 }
5656 } else {
5657 int rshift=0,gshift=0,bshift=0,ashift=0,rcount=0,gcount=0,bcount=0,acount=0;
5658 int z = 0;
5659 int easy=0;
5660 stbi__skip(s, info.offset - info.extra_read - info.hsz);
5661 if (info.bpp == 24) width = 3 * s->img_x;
5662 else if (info.bpp == 16) width = 2*s->img_x;
5663 else /* bpp = 32 and pad = 0 */ width=0;
5664 pad = (-width) & 3;
5665 if (info.bpp == 24) {
5666 easy = 1;
5667 } else if (info.bpp == 32) {
5668 if (mb == 0xff && mg == 0xff00 && mr == 0x00ff0000 && ma == 0xff000000)
5669 easy = 2;
5670 }
5671 if (!easy) {
5672 if (!mr || !mg || !mb) { STBI_FREE(out); return stbi__errpuc("bad masks", "Corrupt BMP"); }
5673 // right shift amt to put high bit in position #7
5674 rshift = stbi__high_bit(mr)-7; rcount = stbi__bitcount(mr);
5675 gshift = stbi__high_bit(mg)-7; gcount = stbi__bitcount(mg);
5676 bshift = stbi__high_bit(mb)-7; bcount = stbi__bitcount(mb);
5677 ashift = stbi__high_bit(ma)-7; acount = stbi__bitcount(ma);
5678 if (rcount > 8 || gcount > 8 || bcount > 8 || acount > 8) { STBI_FREE(out); return stbi__errpuc("bad masks", "Corrupt BMP"); }
5679 }
5680 for (j=0; j < (int) s->img_y; ++j) {
5681 if (easy) {
5682 for (i=0; i < (int) s->img_x; ++i) {
5683 unsigned char a;
5684 out[z+2] = stbi__get8(s);
5685 out[z+1] = stbi__get8(s);
5686 out[z+0] = stbi__get8(s);
5687 z += 3;
5688 a = (easy == 2 ? stbi__get8(s) : 255);
5689 all_a |= a;
5690 if (target == 4) out[z++] = a;
5691 }
5692 } else {
5693 int bpp = info.bpp;
5694 for (i=0; i < (int) s->img_x; ++i) {
5695 stbi__uint32 v = (bpp == 16 ? (stbi__uint32) stbi__get16le(s) : stbi__get32le(s));
5696 unsigned int a;
5697 out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mr, rshift, rcount));
5698 out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mg, gshift, gcount));
5699 out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mb, bshift, bcount));
5700 a = (ma ? stbi__shiftsigned(v & ma, ashift, acount) : 255);
5701 all_a |= a;
5702 if (target == 4) out[z++] = STBI__BYTECAST(a);
5703 }
5704 }
5705 stbi__skip(s, pad);
5706 }
5707 }
5708
5709 // if alpha channel is all 0s, replace with all 255s
5710 if (target == 4 && all_a == 0)
5711 for (i=4*s->img_x*s->img_y-1; i >= 0; i -= 4)
5712 out[i] = 255;
5713
5714 if (flip_vertically) {
5715 stbi_uc t;
5716 for (j=0; j < (int) s->img_y>>1; ++j) {
5717 stbi_uc *p1 = out + j *s->img_x*target;
5718 stbi_uc *p2 = out + (s->img_y-1-j)*s->img_x*target;
5719 for (i=0; i < (int) s->img_x*target; ++i) {
5720 t = p1[i]; p1[i] = p2[i]; p2[i] = t;
5721 }
5722 }
5723 }
5724
5725 if (req_comp && req_comp != target) {
5726 out = stbi__convert_format(out, target, req_comp, s->img_x, s->img_y);
5727 if (out == NULL) return out; // stbi__convert_format frees input on failure
5728 }
5729
5730 *x = s->img_x;
5731 *y = s->img_y;
5732 if (comp) *comp = s->img_n;
5733 return out;
5734}
5735#endif
5736
5737// Targa Truevision - TGA
5738// by Jonathan Dummer
5739#ifndef STBI_NO_TGA
5740// returns STBI_rgb or whatever, 0 on error
5741static int stbi__tga_get_comp(int bits_per_pixel, int is_grey, int* is_rgb16)
5742{
5743 // only RGB or RGBA (incl. 16bit) or grey allowed
5744 if (is_rgb16) *is_rgb16 = 0;
5745 switch(bits_per_pixel) {
5746 case 8: return STBI_grey;
5747 case 16: if(is_grey) return STBI_grey_alpha;
5748 // fallthrough
5749 case 15: if(is_rgb16) *is_rgb16 = 1;
5750 return STBI_rgb;
5751 case 24: // fallthrough
5752 case 32: return bits_per_pixel/8;
5753 default: return 0;
5754 }
5755}
5756
5757static int stbi__tga_info(stbi__context *s, int *x, int *y, int *comp)
5758{
5759 int tga_w, tga_h, tga_comp, tga_image_type, tga_bits_per_pixel, tga_colormap_bpp;
5760 int sz, tga_colormap_type;
5761 stbi__get8(s); // discard Offset
5762 tga_colormap_type = stbi__get8(s); // colormap type
5763 if( tga_colormap_type > 1 ) {
5764 stbi__rewind(s);
5765 return 0; // only RGB or indexed allowed
5766 }
5767 tga_image_type = stbi__get8(s); // image type
5768 if ( tga_colormap_type == 1 ) { // colormapped (paletted) image
5769 if (tga_image_type != 1 && tga_image_type != 9) {
5770 stbi__rewind(s);
5771 return 0;
5772 }
5773 stbi__skip(s,4); // skip index of first colormap entry and number of entries
5774 sz = stbi__get8(s); // check bits per palette color entry
5775 if ( (sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32) ) {
5776 stbi__rewind(s);
5777 return 0;
5778 }
5779 stbi__skip(s,4); // skip image x and y origin
5780 tga_colormap_bpp = sz;
5781 } else { // "normal" image w/o colormap - only RGB or grey allowed, +/- RLE
5782 if ( (tga_image_type != 2) && (tga_image_type != 3) && (tga_image_type != 10) && (tga_image_type != 11) ) {
5783 stbi__rewind(s);
5784 return 0; // only RGB or grey allowed, +/- RLE
5785 }
5786 stbi__skip(s,9); // skip colormap specification and image x/y origin
5787 tga_colormap_bpp = 0;
5788 }
5789 tga_w = stbi__get16le(s);
5790 if( tga_w < 1 ) {
5791 stbi__rewind(s);
5792 return 0; // test width
5793 }
5794 tga_h = stbi__get16le(s);
5795 if( tga_h < 1 ) {
5796 stbi__rewind(s);
5797 return 0; // test height
5798 }
5799 tga_bits_per_pixel = stbi__get8(s); // bits per pixel
5800 stbi__get8(s); // ignore alpha bits
5801 if (tga_colormap_bpp != 0) {
5802 if((tga_bits_per_pixel != 8) && (tga_bits_per_pixel != 16)) {
5803 // when using a colormap, tga_bits_per_pixel is the size of the indexes
5804 // I don't think anything but 8 or 16bit indexes makes sense
5805 stbi__rewind(s);
5806 return 0;
5807 }
5808 tga_comp = stbi__tga_get_comp(tga_colormap_bpp, 0, NULL);
5809 } else {
5810 tga_comp = stbi__tga_get_comp(tga_bits_per_pixel, (tga_image_type == 3) || (tga_image_type == 11), NULL);
5811 }
5812 if(!tga_comp) {
5813 stbi__rewind(s);
5814 return 0;
5815 }
5816 if (x) *x = tga_w;
5817 if (y) *y = tga_h;
5818 if (comp) *comp = tga_comp;
5819 return 1; // seems to have passed everything
5820}
5821
5822static int stbi__tga_test(stbi__context *s)
5823{
5824 int res = 0;
5825 int sz, tga_color_type;
5826 stbi__get8(s); // discard Offset
5827 tga_color_type = stbi__get8(s); // color type
5828 if ( tga_color_type > 1 ) goto errorEnd; // only RGB or indexed allowed
5829 sz = stbi__get8(s); // image type
5830 if ( tga_color_type == 1 ) { // colormapped (paletted) image
5831 if (sz != 1 && sz != 9) goto errorEnd; // colortype 1 demands image type 1 or 9
5832 stbi__skip(s,4); // skip index of first colormap entry and number of entries
5833 sz = stbi__get8(s); // check bits per palette color entry
5834 if ( (sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32) ) goto errorEnd;
5835 stbi__skip(s,4); // skip image x and y origin
5836 } else { // "normal" image w/o colormap
5837 if ( (sz != 2) && (sz != 3) && (sz != 10) && (sz != 11) ) goto errorEnd; // only RGB or grey allowed, +/- RLE
5838 stbi__skip(s,9); // skip colormap specification and image x/y origin
5839 }
5840 if ( stbi__get16le(s) < 1 ) goto errorEnd; // test width
5841 if ( stbi__get16le(s) < 1 ) goto errorEnd; // test height
5842 sz = stbi__get8(s); // bits per pixel
5843 if ( (tga_color_type == 1) && (sz != 8) && (sz != 16) ) goto errorEnd; // for colormapped images, bpp is size of an index
5844 if ( (sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32) ) goto errorEnd;
5845
5846 res = 1; // if we got this far, everything's good and we can return 1 instead of 0
5847
5848errorEnd:
5849 stbi__rewind(s);
5850 return res;
5851}
5852
5853// read 16bit value and convert to 24bit RGB
5854static void stbi__tga_read_rgb16(stbi__context *s, stbi_uc* out)
5855{
5856 stbi__uint16 px = (stbi__uint16)stbi__get16le(s);
5857 stbi__uint16 fiveBitMask = 31;
5858 // we have 3 channels with 5bits each
5859 int r = (px >> 10) & fiveBitMask;
5860 int g = (px >> 5) & fiveBitMask;
5861 int b = px & fiveBitMask;
5862 // Note that this saves the data in RGB(A) order, so it doesn't need to be swapped later
5863 out[0] = (stbi_uc)((r * 255)/31);
5864 out[1] = (stbi_uc)((g * 255)/31);
5865 out[2] = (stbi_uc)((b * 255)/31);
5866
5867 // some people claim that the most significant bit might be used for alpha
5868 // (possibly if an alpha-bit is set in the "image descriptor byte")
5869 // but that only made 16bit test images completely translucent..
5870 // so let's treat all 15 and 16bit TGAs as RGB with no alpha.
5871}
5872
5873static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
5874{
5875 // read in the TGA header stuff
5876 int tga_offset = stbi__get8(s);
5877 int tga_indexed = stbi__get8(s);
5878 int tga_image_type = stbi__get8(s);
5879 int tga_is_RLE = 0;
5880 int tga_palette_start = stbi__get16le(s);
5881 int tga_palette_len = stbi__get16le(s);
5882 int tga_palette_bits = stbi__get8(s);
5883 int tga_x_origin = stbi__get16le(s);
5884 int tga_y_origin = stbi__get16le(s);
5885 int tga_width = stbi__get16le(s);
5886 int tga_height = stbi__get16le(s);
5887 int tga_bits_per_pixel = stbi__get8(s);
5888 int tga_comp, tga_rgb16=0;
5889 int tga_inverted = stbi__get8(s);
5890 // int tga_alpha_bits = tga_inverted & 15; // the 4 lowest bits - unused (useless?)
5891 // image data
5892 unsigned char *tga_data;
5893 unsigned char *tga_palette = NULL;
5894 int i, j;
5895 unsigned char raw_data[4] = {0};
5896 int RLE_count = 0;
5897 int RLE_repeating = 0;
5898 int read_next_pixel = 1;
5899 STBI_NOTUSED(ri);
5900 STBI_NOTUSED(tga_x_origin); // @TODO
5901 STBI_NOTUSED(tga_y_origin); // @TODO
5902
5903 if (tga_height > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5904 if (tga_width > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
5905
5906 // do a tiny bit of precessing
5907 if ( tga_image_type >= 8 )
5908 {
5909 tga_image_type -= 8;
5910 tga_is_RLE = 1;
5911 }
5912 tga_inverted = 1 - ((tga_inverted >> 5) & 1);
5913
5914 // If I'm paletted, then I'll use the number of bits from the palette
5915 if ( tga_indexed ) tga_comp = stbi__tga_get_comp(tga_palette_bits, 0, &tga_rgb16);
5916 else tga_comp = stbi__tga_get_comp(tga_bits_per_pixel, (tga_image_type == 3), &tga_rgb16);
5917
5918 if(!tga_comp) // shouldn't really happen, stbi__tga_test() should have ensured basic consistency
5919 return stbi__errpuc("bad format", "Can't find out TGA pixelformat");
5920
5921 // tga info
5922 *x = tga_width;
5923 *y = tga_height;
5924 if (comp) *comp = tga_comp;
5925
5926 if (!stbi__mad3sizes_valid(tga_width, tga_height, tga_comp, 0))
5927 return stbi__errpuc("too large", "Corrupt TGA");
5928
5929 tga_data = (unsigned char*)stbi__malloc_mad3(tga_width, tga_height, tga_comp, 0);
5930 if (!tga_data) return stbi__errpuc("outofmem", "Out of memory");
5931
5932 // skip to the data's starting position (offset usually = 0)
5933 stbi__skip(s, tga_offset );
5934
5935 if ( !tga_indexed && !tga_is_RLE && !tga_rgb16 ) {
5936 for (i=0; i < tga_height; ++i) {
5937 int row = tga_inverted ? tga_height -i - 1 : i;
5938 stbi_uc *tga_row = tga_data + row*tga_width*tga_comp;
5939 stbi__getn(s, tga_row, tga_width * tga_comp);
5940 }
5941 } else {
5942 // do I need to load a palette?
5943 if ( tga_indexed)
5944 {
5945 if (tga_palette_len == 0) { /* you have to have at least one entry! */
5946 STBI_FREE(tga_data);
5947 return stbi__errpuc("bad palette", "Corrupt TGA");
5948 }
5949
5950 // any data to skip? (offset usually = 0)
5951 stbi__skip(s, tga_palette_start );
5952 // load the palette
5953 tga_palette = (unsigned char*)stbi__malloc_mad2(tga_palette_len, tga_comp, 0);
5954 if (!tga_palette) {
5955 STBI_FREE(tga_data);
5956 return stbi__errpuc("outofmem", "Out of memory");
5957 }
5958 if (tga_rgb16) {
5959 stbi_uc *pal_entry = tga_palette;
5960 STBI_ASSERT(tga_comp == STBI_rgb);
5961 for (i=0; i < tga_palette_len; ++i) {
5962 stbi__tga_read_rgb16(s, pal_entry);
5963 pal_entry += tga_comp;
5964 }
5965 } else if (!stbi__getn(s, tga_palette, tga_palette_len * tga_comp)) {
5966 STBI_FREE(tga_data);
5967 STBI_FREE(tga_palette);
5968 return stbi__errpuc("bad palette", "Corrupt TGA");
5969 }
5970 }
5971 // load the data
5972 for (i=0; i < tga_width * tga_height; ++i)
5973 {
5974 // if I'm in RLE mode, do I need to get a RLE stbi__pngchunk?
5975 if ( tga_is_RLE )
5976 {
5977 if ( RLE_count == 0 )
5978 {
5979 // yep, get the next byte as a RLE command
5980 int RLE_cmd = stbi__get8(s);
5981 RLE_count = 1 + (RLE_cmd & 127);
5982 RLE_repeating = RLE_cmd >> 7;
5983 read_next_pixel = 1;
5984 } else if ( !RLE_repeating )
5985 {
5986 read_next_pixel = 1;
5987 }
5988 } else
5989 {
5990 read_next_pixel = 1;
5991 }
5992 // OK, if I need to read a pixel, do it now
5993 if ( read_next_pixel )
5994 {
5995 // load however much data we did have
5996 if ( tga_indexed )
5997 {
5998 // read in index, then perform the lookup
5999 int pal_idx = (tga_bits_per_pixel == 8) ? stbi__get8(s) : stbi__get16le(s);
6000 if ( pal_idx >= tga_palette_len ) {
6001 // invalid index
6002 pal_idx = 0;
6003 }
6004 pal_idx *= tga_comp;
6005 for (j = 0; j < tga_comp; ++j) {
6006 raw_data[j] = tga_palette[pal_idx+j];
6007 }
6008 } else if(tga_rgb16) {
6009 STBI_ASSERT(tga_comp == STBI_rgb);
6010 stbi__tga_read_rgb16(s, raw_data);
6011 } else {
6012 // read in the data raw
6013 for (j = 0; j < tga_comp; ++j) {
6014 raw_data[j] = stbi__get8(s);
6015 }
6016 }
6017 // clear the reading flag for the next pixel
6018 read_next_pixel = 0;
6019 } // end of reading a pixel
6020
6021 // copy data
6022 for (j = 0; j < tga_comp; ++j)
6023 tga_data[i*tga_comp+j] = raw_data[j];
6024
6025 // in case we're in RLE mode, keep counting down
6026 --RLE_count;
6027 }
6028 // do I need to invert the image?
6029 if ( tga_inverted )
6030 {
6031 for (j = 0; j*2 < tga_height; ++j)
6032 {
6033 int index1 = j * tga_width * tga_comp;
6034 int index2 = (tga_height - 1 - j) * tga_width * tga_comp;
6035 for (i = tga_width * tga_comp; i > 0; --i)
6036 {
6037 unsigned char temp = tga_data[index1];
6038 tga_data[index1] = tga_data[index2];
6039 tga_data[index2] = temp;
6040 ++index1;
6041 ++index2;
6042 }
6043 }
6044 }
6045 // clear my palette, if I had one
6046 if ( tga_palette != NULL )
6047 {
6048 STBI_FREE( tga_palette );
6049 }
6050 }
6051
6052 // swap RGB - if the source data was RGB16, it already is in the right order
6053 if (tga_comp >= 3 && !tga_rgb16)
6054 {
6055 unsigned char* tga_pixel = tga_data;
6056 for (i=0; i < tga_width * tga_height; ++i)
6057 {
6058 unsigned char temp = tga_pixel[0];
6059 tga_pixel[0] = tga_pixel[2];
6060 tga_pixel[2] = temp;
6061 tga_pixel += tga_comp;
6062 }
6063 }
6064
6065 // convert to target component count
6066 if (req_comp && req_comp != tga_comp)
6067 tga_data = stbi__convert_format(tga_data, tga_comp, req_comp, tga_width, tga_height);
6068
6069 // the things I do to get rid of an error message, and yet keep
6070 // Microsoft's C compilers happy... [8^(
6071 tga_palette_start = tga_palette_len = tga_palette_bits =
6072 tga_x_origin = tga_y_origin = 0;
6073 STBI_NOTUSED(tga_palette_start);
6074 // OK, done
6075 return tga_data;
6076}
6077#endif
6078
6079// *************************************************************************************************
6080// Photoshop PSD loader -- PD by Thatcher Ulrich, integration by Nicolas Schulz, tweaked by STB
6081
6082#ifndef STBI_NO_PSD
6083static int stbi__psd_test(stbi__context *s)
6084{
6085 int r = (stbi__get32be(s) == 0x38425053);
6086 stbi__rewind(s);
6087 return r;
6088}
6089
6090static int stbi__psd_decode_rle(stbi__context *s, stbi_uc *p, int pixelCount)
6091{
6092 int count, nleft, len;
6093
6094 count = 0;
6095 while ((nleft = pixelCount - count) > 0) {
6096 len = stbi__get8(s);
6097 if (len == 128) {
6098 // No-op.
6099 } else if (len < 128) {
6100 // Copy next len+1 bytes literally.
6101 len++;
6102 if (len > nleft) return 0; // corrupt data
6103 count += len;
6104 while (len) {
6105 *p = stbi__get8(s);
6106 p += 4;
6107 len--;
6108 }
6109 } else if (len > 128) {
6110 stbi_uc val;
6111 // Next -len+1 bytes in the dest are replicated from next source byte.
6112 // (Interpret len as a negative 8-bit int.)
6113 len = 257 - len;
6114 if (len > nleft) return 0; // corrupt data
6115 val = stbi__get8(s);
6116 count += len;
6117 while (len) {
6118 *p = val;
6119 p += 4;
6120 len--;
6121 }
6122 }
6123 }
6124
6125 return 1;
6126}
6127
6128static void *stbi__psd_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
6129{
6130 int pixelCount;
6131 int channelCount, compression;
6132 int channel, i;
6133 int bitdepth;
6134 int w,h;
6135 stbi_uc *out;
6136 STBI_NOTUSED(ri);
6137
6138 // Check identifier
6139 if (stbi__get32be(s) != 0x38425053) // "8BPS"
6140 return stbi__errpuc("not PSD", "Corrupt PSD image");
6141
6142 // Check file type version.
6143 if (stbi__get16be(s) != 1)
6144 return stbi__errpuc("wrong version", "Unsupported version of PSD image");
6145
6146 // Skip 6 reserved bytes.
6147 stbi__skip(s, 6 );
6148
6149 // Read the number of channels (R, G, B, A, etc).
6150 channelCount = stbi__get16be(s);
6151 if (channelCount < 0 || channelCount > 16)
6152 return stbi__errpuc("wrong channel count", "Unsupported number of channels in PSD image");
6153
6154 // Read the rows and columns of the image.
6155 h = stbi__get32be(s);
6156 w = stbi__get32be(s);
6157
6158 if (h > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
6159 if (w > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
6160
6161 // Make sure the depth is 8 bits.
6162 bitdepth = stbi__get16be(s);
6163 if (bitdepth != 8 && bitdepth != 16)
6164 return stbi__errpuc("unsupported bit depth", "PSD bit depth is not 8 or 16 bit");
6165
6166 // Make sure the color mode is RGB.
6167 // Valid options are:
6168 // 0: Bitmap
6169 // 1: Grayscale
6170 // 2: Indexed color
6171 // 3: RGB color
6172 // 4: CMYK color
6173 // 7: Multichannel
6174 // 8: Duotone
6175 // 9: Lab color
6176 if (stbi__get16be(s) != 3)
6177 return stbi__errpuc("wrong color format", "PSD is not in RGB color format");
6178
6179 // Skip the Mode Data. (It's the palette for indexed color; other info for other modes.)
6180 stbi__skip(s,stbi__get32be(s) );
6181
6182 // Skip the image resources. (resolution, pen tool paths, etc)
6183 stbi__skip(s, stbi__get32be(s) );
6184
6185 // Skip the reserved data.
6186 stbi__skip(s, stbi__get32be(s) );
6187
6188 // Find out if the data is compressed.
6189 // Known values:
6190 // 0: no compression
6191 // 1: RLE compressed
6192 compression = stbi__get16be(s);
6193 if (compression > 1)
6194 return stbi__errpuc("bad compression", "PSD has an unknown compression format");
6195
6196 // Check size
6197 if (!stbi__mad3sizes_valid(4, w, h, 0))
6198 return stbi__errpuc("too large", "Corrupt PSD");
6199
6200 // Create the destination image.
6201
6202 if (!compression && bitdepth == 16 && bpc == 16) {
6203 out = (stbi_uc *) stbi__malloc_mad3(8, w, h, 0);
6204 ri->bits_per_channel = 16;
6205 } else
6206 out = (stbi_uc *) stbi__malloc(4 * w*h);
6207
6208 if (!out) return stbi__errpuc("outofmem", "Out of memory");
6209 pixelCount = w*h;
6210
6211 // Initialize the data to zero.
6212 //memset( out, 0, pixelCount * 4 );
6213
6214 // Finally, the image data.
6215 if (compression) {
6216 // RLE as used by .PSD and .TIFF
6217 // Loop until you get the number of unpacked bytes you are expecting:
6218 // Read the next source byte into n.
6219 // If n is between 0 and 127 inclusive, copy the next n+1 bytes literally.
6220 // Else if n is between -127 and -1 inclusive, copy the next byte -n+1 times.
6221 // Else if n is 128, noop.
6222 // Endloop
6223
6224 // The RLE-compressed data is preceded by a 2-byte data count for each row in the data,
6225 // which we're going to just skip.
6226 stbi__skip(s, h * channelCount * 2 );
6227
6228 // Read the RLE data by channel.
6229 for (channel = 0; channel < 4; channel++) {
6230 stbi_uc *p;
6231
6232 p = out+channel;
6233 if (channel >= channelCount) {
6234 // Fill this channel with default data.
6235 for (i = 0; i < pixelCount; i++, p += 4)
6236 *p = (channel == 3 ? 255 : 0);
6237 } else {
6238 // Read the RLE data.
6239 if (!stbi__psd_decode_rle(s, p, pixelCount)) {
6240 STBI_FREE(out);
6241 return stbi__errpuc("corrupt", "bad RLE data");
6242 }
6243 }
6244 }
6245
6246 } else {
6247 // We're at the raw image data. It's each channel in order (Red, Green, Blue, Alpha, ...)
6248 // where each channel consists of an 8-bit (or 16-bit) value for each pixel in the image.
6249
6250 // Read the data by channel.
6251 for (channel = 0; channel < 4; channel++) {
6252 if (channel >= channelCount) {
6253 // Fill this channel with default data.
6254 if (bitdepth == 16 && bpc == 16) {
6255 stbi__uint16 *q = ((stbi__uint16 *) out) + channel;
6256 stbi__uint16 val = channel == 3 ? 65535 : 0;
6257 for (i = 0; i < pixelCount; i++, q += 4)
6258 *q = val;
6259 } else {
6260 stbi_uc *p = out+channel;
6261 stbi_uc val = channel == 3 ? 255 : 0;
6262 for (i = 0; i < pixelCount; i++, p += 4)
6263 *p = val;
6264 }
6265 } else {
6266 if (ri->bits_per_channel == 16) { // output bpc
6267 stbi__uint16 *q = ((stbi__uint16 *) out) + channel;
6268 for (i = 0; i < pixelCount; i++, q += 4)
6269 *q = (stbi__uint16) stbi__get16be(s);
6270 } else {
6271 stbi_uc *p = out+channel;
6272 if (bitdepth == 16) { // input bpc
6273 for (i = 0; i < pixelCount; i++, p += 4)
6274 *p = (stbi_uc) (stbi__get16be(s) >> 8);
6275 } else {
6276 for (i = 0; i < pixelCount; i++, p += 4)
6277 *p = stbi__get8(s);
6278 }
6279 }
6280 }
6281 }
6282 }
6283
6284 // remove weird white matte from PSD
6285 if (channelCount >= 4) {
6286 if (ri->bits_per_channel == 16) {
6287 for (i=0; i < w*h; ++i) {
6288 stbi__uint16 *pixel = (stbi__uint16 *) out + 4*i;
6289 if (pixel[3] != 0 && pixel[3] != 65535) {
6290 float a = pixel[3] / 65535.0f;
6291 float ra = 1.0f / a;
6292 float inv_a = 65535.0f * (1 - ra);
6293 pixel[0] = (stbi__uint16) (pixel[0]*ra + inv_a);
6294 pixel[1] = (stbi__uint16) (pixel[1]*ra + inv_a);
6295 pixel[2] = (stbi__uint16) (pixel[2]*ra + inv_a);
6296 }
6297 }
6298 } else {
6299 for (i=0; i < w*h; ++i) {
6300 unsigned char *pixel = out + 4*i;
6301 if (pixel[3] != 0 && pixel[3] != 255) {
6302 float a = pixel[3] / 255.0f;
6303 float ra = 1.0f / a;
6304 float inv_a = 255.0f * (1 - ra);
6305 pixel[0] = (unsigned char) (pixel[0]*ra + inv_a);
6306 pixel[1] = (unsigned char) (pixel[1]*ra + inv_a);
6307 pixel[2] = (unsigned char) (pixel[2]*ra + inv_a);
6308 }
6309 }
6310 }
6311 }
6312
6313 // convert to desired output format
6314 if (req_comp && req_comp != 4) {
6315 if (ri->bits_per_channel == 16)
6316 out = (stbi_uc *) stbi__convert_format16((stbi__uint16 *) out, 4, req_comp, w, h);
6317 else
6318 out = stbi__convert_format(out, 4, req_comp, w, h);
6319 if (out == NULL) return out; // stbi__convert_format frees input on failure
6320 }
6321
6322 if (comp) *comp = 4;
6323 *y = h;
6324 *x = w;
6325
6326 return out;
6327}
6328#endif
6329
6330// *************************************************************************************************
6331// Softimage PIC loader
6332// by Tom Seddon
6333//
6334// See http://softimage.wiki.softimage.com/index.php/INFO:_PIC_file_format
6335// See http://ozviz.wasp.uwa.edu.au/~pbourke/dataformats/softimagepic/
6336
6337#ifndef STBI_NO_PIC
6338static int stbi__pic_is4(stbi__context *s,const char *str)
6339{
6340 int i;
6341 for (i=0; i<4; ++i)
6342 if (stbi__get8(s) != (stbi_uc)str[i])
6343 return 0;
6344
6345 return 1;
6346}
6347
6348static int stbi__pic_test_core(stbi__context *s)
6349{
6350 int i;
6351
6352 if (!stbi__pic_is4(s,"\x53\x80\xF6\x34"))
6353 return 0;
6354
6355 for(i=0;i<84;++i)
6356 stbi__get8(s);
6357
6358 if (!stbi__pic_is4(s,"PICT"))
6359 return 0;
6360
6361 return 1;
6362}
6363
6364typedef struct
6365{
6366 stbi_uc size,type,channel;
6367} stbi__pic_packet;
6368
6369static stbi_uc *stbi__readval(stbi__context *s, int channel, stbi_uc *dest)
6370{
6371 int mask=0x80, i;
6372
6373 for (i=0; i<4; ++i, mask>>=1) {
6374 if (channel & mask) {
6375 if (stbi__at_eof(s)) return stbi__errpuc("bad file","PIC file too short");
6376 dest[i]=stbi__get8(s);
6377 }
6378 }
6379
6380 return dest;
6381}
6382
6383static void stbi__copyval(int channel,stbi_uc *dest,const stbi_uc *src)
6384{
6385 int mask=0x80,i;
6386
6387 for (i=0;i<4; ++i, mask>>=1)
6388 if (channel&mask)
6389 dest[i]=src[i];
6390}
6391
6392static stbi_uc *stbi__pic_load_core(stbi__context *s,int width,int height,int *comp, stbi_uc *result)
6393{
6394 int act_comp=0,num_packets=0,y,chained;
6395 stbi__pic_packet packets[10];
6396
6397 // this will (should...) cater for even some bizarre stuff like having data
6398 // for the same channel in multiple packets.
6399 do {
6400 stbi__pic_packet *packet;
6401
6402 if (num_packets==sizeof(packets)/sizeof(packets[0]))
6403 return stbi__errpuc("bad format","too many packets");
6404
6405 packet = &packets[num_packets++];
6406
6407 chained = stbi__get8(s);
6408 packet->size = stbi__get8(s);
6409 packet->type = stbi__get8(s);
6410 packet->channel = stbi__get8(s);
6411
6412 act_comp |= packet->channel;
6413
6414 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (reading packets)");
6415 if (packet->size != 8) return stbi__errpuc("bad format","packet isn't 8bpp");
6416 } while (chained);
6417
6418 *comp = (act_comp & 0x10 ? 4 : 3); // has alpha channel?
6419
6420 for(y=0; y<height; ++y) {
6421 int packet_idx;
6422
6423 for(packet_idx=0; packet_idx < num_packets; ++packet_idx) {
6424 stbi__pic_packet *packet = &packets[packet_idx];
6425 stbi_uc *dest = result+y*width*4;
6426
6427 switch (packet->type) {
6428 default:
6429 return stbi__errpuc("bad format","packet has bad compression type");
6430
6431 case 0: {//uncompressed
6432 int x;
6433
6434 for(x=0;x<width;++x, dest+=4)
6435 if (!stbi__readval(s,packet->channel,dest))
6436 return 0;
6437 break;
6438 }
6439
6440 case 1://Pure RLE
6441 {
6442 int left=width, i;
6443
6444 while (left>0) {
6445 stbi_uc count,value[4];
6446
6447 count=stbi__get8(s);
6448 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (pure read count)");
6449
6450 if (count > left)
6451 count = (stbi_uc) left;
6452
6453 if (!stbi__readval(s,packet->channel,value)) return 0;
6454
6455 for(i=0; i<count; ++i,dest+=4)
6456 stbi__copyval(packet->channel,dest,value);
6457 left -= count;
6458 }
6459 }
6460 break;
6461
6462 case 2: {//Mixed RLE
6463 int left=width;
6464 while (left>0) {
6465 int count = stbi__get8(s), i;
6466 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (mixed read count)");
6467
6468 if (count >= 128) { // Repeated
6469 stbi_uc value[4];
6470
6471 if (count==128)
6472 count = stbi__get16be(s);
6473 else
6474 count -= 127;
6475 if (count > left)
6476 return stbi__errpuc("bad file","scanline overrun");
6477
6478 if (!stbi__readval(s,packet->channel,value))
6479 return 0;
6480
6481 for(i=0;i<count;++i, dest += 4)
6482 stbi__copyval(packet->channel,dest,value);
6483 } else { // Raw
6484 ++count;
6485 if (count>left) return stbi__errpuc("bad file","scanline overrun");
6486
6487 for(i=0;i<count;++i, dest+=4)
6488 if (!stbi__readval(s,packet->channel,dest))
6489 return 0;
6490 }
6491 left-=count;
6492 }
6493 break;
6494 }
6495 }
6496 }
6497 }
6498
6499 return result;
6500}
6501
6502static void *stbi__pic_load(stbi__context *s,int *px,int *py,int *comp,int req_comp, stbi__result_info *ri)
6503{
6504 stbi_uc *result;
6505 int i, x,y, internal_comp;
6506 STBI_NOTUSED(ri);
6507
6508 if (!comp) comp = &internal_comp;
6509
6510 for (i=0; i<92; ++i)
6511 stbi__get8(s);
6512
6513 x = stbi__get16be(s);
6514 y = stbi__get16be(s);
6515
6516 if (y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
6517 if (x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
6518
6519 if (stbi__at_eof(s)) return stbi__errpuc("bad file","file too short (pic header)");
6520 if (!stbi__mad3sizes_valid(x, y, 4, 0)) return stbi__errpuc("too large", "PIC image too large to decode");
6521
6522 stbi__get32be(s); //skip `ratio'
6523 stbi__get16be(s); //skip `fields'
6524 stbi__get16be(s); //skip `pad'
6525
6526 // intermediate buffer is RGBA
6527 result = (stbi_uc *) stbi__malloc_mad3(x, y, 4, 0);
6528 if (!result) return stbi__errpuc("outofmem", "Out of memory");
6529 memset(result, 0xff, x*y*4);
6530
6531 if (!stbi__pic_load_core(s,x,y,comp, result)) {
6532 STBI_FREE(result);
6533 result=0;
6534 }
6535 *px = x;
6536 *py = y;
6537 if (req_comp == 0) req_comp = *comp;
6538 result=stbi__convert_format(result,4,req_comp,x,y);
6539
6540 return result;
6541}
6542
6543static int stbi__pic_test(stbi__context *s)
6544{
6545 int r = stbi__pic_test_core(s);
6546 stbi__rewind(s);
6547 return r;
6548}
6549#endif
6550
6551// *************************************************************************************************
6552// GIF loader -- public domain by Jean-Marc Lienher -- simplified/shrunk by stb
6553
6554#ifndef STBI_NO_GIF
6555typedef struct
6556{
6557 stbi__int16 prefix;
6558 stbi_uc first;
6559 stbi_uc suffix;
6560} stbi__gif_lzw;
6561
6562typedef struct
6563{
6564 int w,h;
6565 stbi_uc *out; // output buffer (always 4 components)
6566 stbi_uc *background; // The current "background" as far as a gif is concerned
6567 stbi_uc *history;
6568 int flags, bgindex, ratio, transparent, eflags;
6569 stbi_uc pal[256][4];
6570 stbi_uc lpal[256][4];
6571 stbi__gif_lzw codes[8192];
6572 stbi_uc *color_table;
6573 int parse, step;
6574 int lflags;
6575 int start_x, start_y;
6576 int max_x, max_y;
6577 int cur_x, cur_y;
6578 int line_size;
6579 int delay;
6580} stbi__gif;
6581
6582static int stbi__gif_test_raw(stbi__context *s)
6583{
6584 int sz;
6585 if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8') return 0;
6586 sz = stbi__get8(s);
6587 if (sz != '9' && sz != '7') return 0;
6588 if (stbi__get8(s) != 'a') return 0;
6589 return 1;
6590}
6591
6592static int stbi__gif_test(stbi__context *s)
6593{
6594 int r = stbi__gif_test_raw(s);
6595 stbi__rewind(s);
6596 return r;
6597}
6598
6599static void stbi__gif_parse_colortable(stbi__context *s, stbi_uc pal[256][4], int num_entries, int transp)
6600{
6601 int i;
6602 for (i=0; i < num_entries; ++i) {
6603 pal[i][2] = stbi__get8(s);
6604 pal[i][1] = stbi__get8(s);
6605 pal[i][0] = stbi__get8(s);
6606 pal[i][3] = transp == i ? 0 : 255;
6607 }
6608}
6609
6610static int stbi__gif_header(stbi__context *s, stbi__gif *g, int *comp, int is_info)
6611{
6612 stbi_uc version;
6613 if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8')
6614 return stbi__err("not GIF", "Corrupt GIF");
6615
6616 version = stbi__get8(s);
6617 if (version != '7' && version != '9') return stbi__err("not GIF", "Corrupt GIF");
6618 if (stbi__get8(s) != 'a') return stbi__err("not GIF", "Corrupt GIF");
6619
6620 stbi__g_failure_reason = "";
6621 g->w = stbi__get16le(s);
6622 g->h = stbi__get16le(s);
6623 g->flags = stbi__get8(s);
6624 g->bgindex = stbi__get8(s);
6625 g->ratio = stbi__get8(s);
6626 g->transparent = -1;
6627
6628 if (g->w > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
6629 if (g->h > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
6630
6631 if (comp != 0) *comp = 4; // can't actually tell whether it's 3 or 4 until we parse the comments
6632
6633 if (is_info) return 1;
6634
6635 if (g->flags & 0x80)
6636 stbi__gif_parse_colortable(s,g->pal, 2 << (g->flags & 7), -1);
6637
6638 return 1;
6639}
6640
6641static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp)
6642{
6643 stbi__gif* g = (stbi__gif*) stbi__malloc(sizeof(stbi__gif));
6644 if (!g) return stbi__err("outofmem", "Out of memory");
6645 if (!stbi__gif_header(s, g, comp, 1)) {
6646 STBI_FREE(g);
6647 stbi__rewind( s );
6648 return 0;
6649 }
6650 if (x) *x = g->w;
6651 if (y) *y = g->h;
6652 STBI_FREE(g);
6653 return 1;
6654}
6655
6656static void stbi__out_gif_code(stbi__gif *g, stbi__uint16 code)
6657{
6658 stbi_uc *p, *c;
6659 int idx;
6660
6661 // recurse to decode the prefixes, since the linked-list is backwards,
6662 // and working backwards through an interleaved image would be nasty
6663 if (g->codes[code].prefix >= 0)
6664 stbi__out_gif_code(g, g->codes[code].prefix);
6665
6666 if (g->cur_y >= g->max_y) return;
6667
6668 idx = g->cur_x + g->cur_y;
6669 p = &g->out[idx];
6670 g->history[idx / 4] = 1;
6671
6672 c = &g->color_table[g->codes[code].suffix * 4];
6673 if (c[3] > 128) { // don't render transparent pixels;
6674 p[0] = c[2];
6675 p[1] = c[1];
6676 p[2] = c[0];
6677 p[3] = c[3];
6678 }
6679 g->cur_x += 4;
6680
6681 if (g->cur_x >= g->max_x) {
6682 g->cur_x = g->start_x;
6683 g->cur_y += g->step;
6684
6685 while (g->cur_y >= g->max_y && g->parse > 0) {
6686 g->step = (1 << g->parse) * g->line_size;
6687 g->cur_y = g->start_y + (g->step >> 1);
6688 --g->parse;
6689 }
6690 }
6691}
6692
6693static stbi_uc *stbi__process_gif_raster(stbi__context *s, stbi__gif *g)
6694{
6695 stbi_uc lzw_cs;
6696 stbi__int32 len, init_code;
6697 stbi__uint32 first;
6698 stbi__int32 codesize, codemask, avail, oldcode, bits, valid_bits, clear;
6699 stbi__gif_lzw *p;
6700
6701 lzw_cs = stbi__get8(s);
6702 if (lzw_cs > 12) return NULL;
6703 clear = 1 << lzw_cs;
6704 first = 1;
6705 codesize = lzw_cs + 1;
6706 codemask = (1 << codesize) - 1;
6707 bits = 0;
6708 valid_bits = 0;
6709 for (init_code = 0; init_code < clear; init_code++) {
6710 g->codes[init_code].prefix = -1;
6711 g->codes[init_code].first = (stbi_uc) init_code;
6712 g->codes[init_code].suffix = (stbi_uc) init_code;
6713 }
6714
6715 // support no starting clear code
6716 avail = clear+2;
6717 oldcode = -1;
6718
6719 len = 0;
6720 for(;;) {
6721 if (valid_bits < codesize) {
6722 if (len == 0) {
6723 len = stbi__get8(s); // start new block
6724 if (len == 0)
6725 return g->out;
6726 }
6727 --len;
6728 bits |= (stbi__int32) stbi__get8(s) << valid_bits;
6729 valid_bits += 8;
6730 } else {
6731 stbi__int32 code = bits & codemask;
6732 bits >>= codesize;
6733 valid_bits -= codesize;
6734 // @OPTIMIZE: is there some way we can accelerate the non-clear path?
6735 if (code == clear) { // clear code
6736 codesize = lzw_cs + 1;
6737 codemask = (1 << codesize) - 1;
6738 avail = clear + 2;
6739 oldcode = -1;
6740 first = 0;
6741 } else if (code == clear + 1) { // end of stream code
6742 stbi__skip(s, len);
6743 while ((len = stbi__get8(s)) > 0)
6744 stbi__skip(s,len);
6745 return g->out;
6746 } else if (code <= avail) {
6747 if (first) {
6748 return stbi__errpuc("no clear code", "Corrupt GIF");
6749 }
6750
6751 if (oldcode >= 0) {
6752 p = &g->codes[avail++];
6753 if (avail > 8192) {
6754 return stbi__errpuc("too many codes", "Corrupt GIF");
6755 }
6756
6757 p->prefix = (stbi__int16) oldcode;
6758 p->first = g->codes[oldcode].first;
6759 p->suffix = (code == avail) ? p->first : g->codes[code].first;
6760 } else if (code == avail)
6761 return stbi__errpuc("illegal code in raster", "Corrupt GIF");
6762
6763 stbi__out_gif_code(g, (stbi__uint16) code);
6764
6765 if ((avail & codemask) == 0 && avail <= 0x0FFF) {
6766 codesize++;
6767 codemask = (1 << codesize) - 1;
6768 }
6769
6770 oldcode = code;
6771 } else {
6772 return stbi__errpuc("illegal code in raster", "Corrupt GIF");
6773 }
6774 }
6775 }
6776}
6777
6778// this function is designed to support animated gifs, although stb_image doesn't support it
6779// two back is the image from two frames ago, used for a very specific disposal format
6780static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp, stbi_uc *two_back)
6781{
6782 int dispose;
6783 int first_frame;
6784 int pi;
6785 int pcount;
6786 STBI_NOTUSED(req_comp);
6787
6788 // on first frame, any non-written pixels get the background colour (non-transparent)
6789 first_frame = 0;
6790 if (g->out == 0) {
6791 if (!stbi__gif_header(s, g, comp,0)) return 0; // stbi__g_failure_reason set by stbi__gif_header
6792 if (!stbi__mad3sizes_valid(4, g->w, g->h, 0))
6793 return stbi__errpuc("too large", "GIF image is too large");
6794 pcount = g->w * g->h;
6795 g->out = (stbi_uc *) stbi__malloc(4 * pcount);
6796 g->background = (stbi_uc *) stbi__malloc(4 * pcount);
6797 g->history = (stbi_uc *) stbi__malloc(pcount);
6798 if (!g->out || !g->background || !g->history)
6799 return stbi__errpuc("outofmem", "Out of memory");
6800
6801 // image is treated as "transparent" at the start - ie, nothing overwrites the current background;
6802 // background colour is only used for pixels that are not rendered first frame, after that "background"
6803 // color refers to the color that was there the previous frame.
6804 memset(g->out, 0x00, 4 * pcount);
6805 memset(g->background, 0x00, 4 * pcount); // state of the background (starts transparent)
6806 memset(g->history, 0x00, pcount); // pixels that were affected previous frame
6807 first_frame = 1;
6808 } else {
6809 // second frame - how do we dispose of the previous one?
6810 dispose = (g->eflags & 0x1C) >> 2;
6811 pcount = g->w * g->h;
6812
6813 if ((dispose == 3) && (two_back == 0)) {
6814 dispose = 2; // if I don't have an image to revert back to, default to the old background
6815 }
6816
6817 if (dispose == 3) { // use previous graphic
6818 for (pi = 0; pi < pcount; ++pi) {
6819 if (g->history[pi]) {
6820 memcpy( &g->out[pi * 4], &two_back[pi * 4], 4 );
6821 }
6822 }
6823 } else if (dispose == 2) {
6824 // restore what was changed last frame to background before that frame;
6825 for (pi = 0; pi < pcount; ++pi) {
6826 if (g->history[pi]) {
6827 memcpy( &g->out[pi * 4], &g->background[pi * 4], 4 );
6828 }
6829 }
6830 } else {
6831 // This is a non-disposal case eithe way, so just
6832 // leave the pixels as is, and they will become the new background
6833 // 1: do not dispose
6834 // 0: not specified.
6835 }
6836
6837 // background is what out is after the undoing of the previou frame;
6838 memcpy( g->background, g->out, 4 * g->w * g->h );
6839 }
6840
6841 // clear my history;
6842 memset( g->history, 0x00, g->w * g->h ); // pixels that were affected previous frame
6843
6844 for (;;) {
6845 int tag = stbi__get8(s);
6846 switch (tag) {
6847 case 0x2C: /* Image Descriptor */
6848 {
6849 stbi__int32 x, y, w, h;
6850 stbi_uc *o;
6851
6852 x = stbi__get16le(s);
6853 y = stbi__get16le(s);
6854 w = stbi__get16le(s);
6855 h = stbi__get16le(s);
6856 if (((x + w) > (g->w)) || ((y + h) > (g->h)))
6857 return stbi__errpuc("bad Image Descriptor", "Corrupt GIF");
6858
6859 g->line_size = g->w * 4;
6860 g->start_x = x * 4;
6861 g->start_y = y * g->line_size;
6862 g->max_x = g->start_x + w * 4;
6863 g->max_y = g->start_y + h * g->line_size;
6864 g->cur_x = g->start_x;
6865 g->cur_y = g->start_y;
6866
6867 // if the width of the specified rectangle is 0, that means
6868 // we may not see *any* pixels or the image is malformed;
6869 // to make sure this is caught, move the current y down to
6870 // max_y (which is what out_gif_code checks).
6871 if (w == 0)
6872 g->cur_y = g->max_y;
6873
6874 g->lflags = stbi__get8(s);
6875
6876 if (g->lflags & 0x40) {
6877 g->step = 8 * g->line_size; // first interlaced spacing
6878 g->parse = 3;
6879 } else {
6880 g->step = g->line_size;
6881 g->parse = 0;
6882 }
6883
6884 if (g->lflags & 0x80) {
6885 stbi__gif_parse_colortable(s,g->lpal, 2 << (g->lflags & 7), g->eflags & 0x01 ? g->transparent : -1);
6886 g->color_table = (stbi_uc *) g->lpal;
6887 } else if (g->flags & 0x80) {
6888 g->color_table = (stbi_uc *) g->pal;
6889 } else
6890 return stbi__errpuc("missing color table", "Corrupt GIF");
6891
6892 o = stbi__process_gif_raster(s, g);
6893 if (!o) return NULL;
6894
6895 // if this was the first frame,
6896 pcount = g->w * g->h;
6897 if (first_frame && (g->bgindex > 0)) {
6898 // if first frame, any pixel not drawn to gets the background color
6899 for (pi = 0; pi < pcount; ++pi) {
6900 if (g->history[pi] == 0) {
6901 g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be;
6902 memcpy( &g->out[pi * 4], &g->pal[g->bgindex], 4 );
6903 }
6904 }
6905 }
6906
6907 return o;
6908 }
6909
6910 case 0x21: // Comment Extension.
6911 {
6912 int len;
6913 int ext = stbi__get8(s);
6914 if (ext == 0xF9) { // Graphic Control Extension.
6915 len = stbi__get8(s);
6916 if (len == 4) {
6917 g->eflags = stbi__get8(s);
6918 g->delay = 10 * stbi__get16le(s); // delay - 1/100th of a second, saving as 1/1000ths.
6919
6920 // unset old transparent
6921 if (g->transparent >= 0) {
6922 g->pal[g->transparent][3] = 255;
6923 }
6924 if (g->eflags & 0x01) {
6925 g->transparent = stbi__get8(s);
6926 if (g->transparent >= 0) {
6927 g->pal[g->transparent][3] = 0;
6928 }
6929 } else {
6930 // don't need transparent
6931 stbi__skip(s, 1);
6932 g->transparent = -1;
6933 }
6934 } else {
6935 stbi__skip(s, len);
6936 break;
6937 }
6938 }
6939 while ((len = stbi__get8(s)) != 0) {
6940 stbi__skip(s, len);
6941 }
6942 break;
6943 }
6944
6945 case 0x3B: // gif stream termination code
6946 return (stbi_uc *) s; // using '1' causes warning on some compilers
6947
6948 default:
6949 return stbi__errpuc("unknown code", "Corrupt GIF");
6950 }
6951 }
6952}
6953
6954static void *stbi__load_gif_main_outofmem(stbi__gif *g, stbi_uc *out, int **delays)
6955{
6956 STBI_FREE(g->out);
6957 STBI_FREE(g->history);
6958 STBI_FREE(g->background);
6959
6960 if (out) STBI_FREE(out);
6961 if (delays && *delays) STBI_FREE(*delays);
6962 return stbi__errpuc("outofmem", "Out of memory");
6963}
6964
6965static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
6966{
6967 if (stbi__gif_test(s)) {
6968 int layers = 0;
6969 stbi_uc *u = 0;
6970 stbi_uc *out = 0;
6971 stbi_uc *two_back = 0;
6972 stbi__gif g;
6973 int stride;
6974 int out_size = 0;
6975 int delays_size = 0;
6976
6977 STBI_NOTUSED(out_size);
6978 STBI_NOTUSED(delays_size);
6979
6980 memset(&g, 0, sizeof(g));
6981 if (delays) {
6982 *delays = 0;
6983 }
6984
6985 do {
6986 u = stbi__gif_load_next(s, &g, comp, req_comp, two_back);
6987 if (u == (stbi_uc *) s) u = 0; // end of animated gif marker
6988
6989 if (u) {
6990 *x = g.w;
6991 *y = g.h;
6992 ++layers;
6993 stride = g.w * g.h * 4;
6994
6995 if (out) {
6996 void *tmp = (stbi_uc*) STBI_REALLOC_SIZED( out, out_size, layers * stride );
6997 if (!tmp)
6998 return stbi__load_gif_main_outofmem(&g, out, delays);
6999 else {
7000 out = (stbi_uc*) tmp;
7001 out_size = layers * stride;
7002 }
7003
7004 if (delays) {
7005 int *new_delays = (int*) STBI_REALLOC_SIZED( *delays, delays_size, sizeof(int) * layers );
7006 if (!new_delays)
7007 return stbi__load_gif_main_outofmem(&g, out, delays);
7008 *delays = new_delays;
7009 delays_size = layers * sizeof(int);
7010 }
7011 } else {
7012 out = (stbi_uc*)stbi__malloc( layers * stride );
7013 if (!out)
7014 return stbi__load_gif_main_outofmem(&g, out, delays);
7015 out_size = layers * stride;
7016 if (delays) {
7017 *delays = (int*) stbi__malloc( layers * sizeof(int) );
7018 if (!*delays)
7019 return stbi__load_gif_main_outofmem(&g, out, delays);
7020 delays_size = layers * sizeof(int);
7021 }
7022 }
7023 memcpy( out + ((layers - 1) * stride), u, stride );
7024 if (layers >= 2) {
7025 two_back = out - 2 * stride;
7026 }
7027
7028 if (delays) {
7029 (*delays)[layers - 1U] = g.delay;
7030 }
7031 }
7032 } while (u != 0);
7033
7034 // free temp buffer;
7035 STBI_FREE(g.out);
7036 STBI_FREE(g.history);
7037 STBI_FREE(g.background);
7038
7039 // do the final conversion after loading everything;
7040 if (req_comp && req_comp != 4)
7041 out = stbi__convert_format(out, 4, req_comp, layers * g.w, g.h);
7042
7043 *z = layers;
7044 return out;
7045 } else {
7046 return stbi__errpuc("not GIF", "Image was not as a gif type.");
7047 }
7048}
7049
7050static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
7051{
7052 stbi_uc *u = 0;
7053 stbi__gif g;
7054 memset(&g, 0, sizeof(g));
7055 STBI_NOTUSED(ri);
7056
7057 u = stbi__gif_load_next(s, &g, comp, req_comp, 0);
7058 if (u == (stbi_uc *) s) u = 0; // end of animated gif marker
7059 if (u) {
7060 *x = g.w;
7061 *y = g.h;
7062
7063 // moved conversion to after successful load so that the same
7064 // can be done for multiple frames.
7065 if (req_comp && req_comp != 4)
7066 u = stbi__convert_format(u, 4, req_comp, g.w, g.h);
7067 } else if (g.out) {
7068 // if there was an error and we allocated an image buffer, free it!
7069 STBI_FREE(g.out);
7070 }
7071
7072 // free buffers needed for multiple frame loading;
7073 STBI_FREE(g.history);
7074 STBI_FREE(g.background);
7075
7076 return u;
7077}
7078
7079static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp)
7080{
7081 return stbi__gif_info_raw(s,x,y,comp);
7082}
7083#endif
7084
7085// *************************************************************************************************
7086// Radiance RGBE HDR loader
7087// originally by Nicolas Schulz
7088#ifndef STBI_NO_HDR
7089static int stbi__hdr_test_core(stbi__context *s, const char *signature)
7090{
7091 int i;
7092 for (i=0; signature[i]; ++i)
7093 if (stbi__get8(s) != signature[i])
7094 return 0;
7095 stbi__rewind(s);
7096 return 1;
7097}
7098
7099static int stbi__hdr_test(stbi__context* s)
7100{
7101 int r = stbi__hdr_test_core(s, "#?RADIANCE\n");
7102 stbi__rewind(s);
7103 if(!r) {
7104 r = stbi__hdr_test_core(s, "#?RGBE\n");
7105 stbi__rewind(s);
7106 }
7107 return r;
7108}
7109
7110#define STBI__HDR_BUFLEN 1024
7111static char *stbi__hdr_gettoken(stbi__context *z, char *buffer)
7112{
7113 int len=0;
7114 char c = '\0';
7115
7116 c = (char) stbi__get8(z);
7117
7118 while (!stbi__at_eof(z) && c != '\n') {
7119 buffer[len++] = c;
7120 if (len == STBI__HDR_BUFLEN-1) {
7121 // flush to end of line
7122 while (!stbi__at_eof(z) && stbi__get8(z) != '\n')
7123 ;
7124 break;
7125 }
7126 c = (char) stbi__get8(z);
7127 }
7128
7129 buffer[len] = 0;
7130 return buffer;
7131}
7132
7133static void stbi__hdr_convert(float *output, stbi_uc *input, int req_comp)
7134{
7135 if ( input[3] != 0 ) {
7136 float f1;
7137 // Exponent
7138 f1 = (float) ldexp(1.0f, input[3] - (int)(128 + 8));
7139 if (req_comp <= 2)
7140 output[0] = (input[0] + input[1] + input[2]) * f1 / 3;
7141 else {
7142 output[0] = input[0] * f1;
7143 output[1] = input[1] * f1;
7144 output[2] = input[2] * f1;
7145 }
7146 if (req_comp == 2) output[1] = 1;
7147 if (req_comp == 4) output[3] = 1;
7148 } else {
7149 switch (req_comp) {
7150 case 4: output[3] = 1; /* fallthrough */
7151 case 3: output[0] = output[1] = output[2] = 0;
7152 break;
7153 case 2: output[1] = 1; /* fallthrough */
7154 case 1: output[0] = 0;
7155 break;
7156 }
7157 }
7158}
7159
7160static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
7161{
7162 char buffer[STBI__HDR_BUFLEN];
7163 char *token;
7164 int valid = 0;
7165 int width, height;
7166 stbi_uc *scanline;
7167 float *hdr_data;
7168 int len;
7169 unsigned char count, value;
7170 int i, j, k, c1,c2, z;
7171 const char *headerToken;
7172 STBI_NOTUSED(ri);
7173
7174 // Check identifier
7175 headerToken = stbi__hdr_gettoken(s,buffer);
7176 if (strcmp(headerToken, "#?RADIANCE") != 0 && strcmp(headerToken, "#?RGBE") != 0)
7177 return stbi__errpf("not HDR", "Corrupt HDR image");
7178
7179 // Parse header
7180 for(;;) {
7181 token = stbi__hdr_gettoken(s,buffer);
7182 if (token[0] == 0) break;
7183 if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0) valid = 1;
7184 }
7185
7186 if (!valid) return stbi__errpf("unsupported format", "Unsupported HDR format");
7187
7188 // Parse width and height
7189 // can't use sscanf() if we're not using stdio!
7190 token = stbi__hdr_gettoken(s,buffer);
7191 if (strncmp(token, "-Y ", 3)) return stbi__errpf("unsupported data layout", "Unsupported HDR format");
7192 token += 3;
7193 height = (int) strtol(token, &token, 10);
7194 while (*token == ' ') ++token;
7195 if (strncmp(token, "+X ", 3)) return stbi__errpf("unsupported data layout", "Unsupported HDR format");
7196 token += 3;
7197 width = (int) strtol(token, NULL, 10);
7198
7199 if (height > STBI_MAX_DIMENSIONS) return stbi__errpf("too large","Very large image (corrupt?)");
7200 if (width > STBI_MAX_DIMENSIONS) return stbi__errpf("too large","Very large image (corrupt?)");
7201
7202 *x = width;
7203 *y = height;
7204
7205 if (comp) *comp = 3;
7206 if (req_comp == 0) req_comp = 3;
7207
7208 if (!stbi__mad4sizes_valid(width, height, req_comp, sizeof(float), 0))
7209 return stbi__errpf("too large", "HDR image is too large");
7210
7211 // Read data
7212 hdr_data = (float *) stbi__malloc_mad4(width, height, req_comp, sizeof(float), 0);
7213 if (!hdr_data)
7214 return stbi__errpf("outofmem", "Out of memory");
7215
7216 // Load image data
7217 // image data is stored as some number of sca
7218 if ( width < 8 || width >= 32768) {
7219 // Read flat data
7220 for (j=0; j < height; ++j) {
7221 for (i=0; i < width; ++i) {
7222 stbi_uc rgbe[4];
7223 main_decode_loop:
7224 stbi__getn(s, rgbe, 4);
7225 stbi__hdr_convert(hdr_data + j * width * req_comp + i * req_comp, rgbe, req_comp);
7226 }
7227 }
7228 } else {
7229 // Read RLE-encoded data
7230 scanline = NULL;
7231
7232 for (j = 0; j < height; ++j) {
7233 c1 = stbi__get8(s);
7234 c2 = stbi__get8(s);
7235 len = stbi__get8(s);
7236 if (c1 != 2 || c2 != 2 || (len & 0x80)) {
7237 // not run-length encoded, so we have to actually use THIS data as a decoded
7238 // pixel (note this can't be a valid pixel--one of RGB must be >= 128)
7239 stbi_uc rgbe[4];
7240 rgbe[0] = (stbi_uc) c1;
7241 rgbe[1] = (stbi_uc) c2;
7242 rgbe[2] = (stbi_uc) len;
7243 rgbe[3] = (stbi_uc) stbi__get8(s);
7244 stbi__hdr_convert(hdr_data, rgbe, req_comp);
7245 i = 1;
7246 j = 0;
7247 STBI_FREE(scanline);
7248 goto main_decode_loop; // yes, this makes no sense
7249 }
7250 len <<= 8;
7251 len |= stbi__get8(s);
7252 if (len != width) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("invalid decoded scanline length", "corrupt HDR"); }
7253 if (scanline == NULL) {
7254 scanline = (stbi_uc *) stbi__malloc_mad2(width, 4, 0);
7255 if (!scanline) {
7256 STBI_FREE(hdr_data);
7257 return stbi__errpf("outofmem", "Out of memory");
7258 }
7259 }
7260
7261 for (k = 0; k < 4; ++k) {
7262 int nleft;
7263 i = 0;
7264 while ((nleft = width - i) > 0) {
7265 count = stbi__get8(s);
7266 if (count > 128) {
7267 // Run
7268 value = stbi__get8(s);
7269 count -= 128;
7270 if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
7271 for (z = 0; z < count; ++z)
7272 scanline[i++ * 4 + k] = value;
7273 } else {
7274 // Dump
7275 if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
7276 for (z = 0; z < count; ++z)
7277 scanline[i++ * 4 + k] = stbi__get8(s);
7278 }
7279 }
7280 }
7281 for (i=0; i < width; ++i)
7282 stbi__hdr_convert(hdr_data+(j*width + i)*req_comp, scanline + i*4, req_comp);
7283 }
7284 if (scanline)
7285 STBI_FREE(scanline);
7286 }
7287
7288 return hdr_data;
7289}
7290
7291static int stbi__hdr_info(stbi__context *s, int *x, int *y, int *comp)
7292{
7293 char buffer[STBI__HDR_BUFLEN];
7294 char *token;
7295 int valid = 0;
7296 int dummy;
7297
7298 if (!x) x = &dummy;
7299 if (!y) y = &dummy;
7300 if (!comp) comp = &dummy;
7301
7302 if (stbi__hdr_test(s) == 0) {
7303 stbi__rewind( s );
7304 return 0;
7305 }
7306
7307 for(;;) {
7308 token = stbi__hdr_gettoken(s,buffer);
7309 if (token[0] == 0) break;
7310 if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0) valid = 1;
7311 }
7312
7313 if (!valid) {
7314 stbi__rewind( s );
7315 return 0;
7316 }
7317 token = stbi__hdr_gettoken(s,buffer);
7318 if (strncmp(token, "-Y ", 3)) {
7319 stbi__rewind( s );
7320 return 0;
7321 }
7322 token += 3;
7323 *y = (int) strtol(token, &token, 10);
7324 while (*token == ' ') ++token;
7325 if (strncmp(token, "+X ", 3)) {
7326 stbi__rewind( s );
7327 return 0;
7328 }
7329 token += 3;
7330 *x = (int) strtol(token, NULL, 10);
7331 *comp = 3;
7332 return 1;
7333}
7334#endif // STBI_NO_HDR
7335
7336#ifndef STBI_NO_BMP
7337static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp)
7338{
7339 void *p;
7340 stbi__bmp_data info;
7341
7342 info.all_a = 255;
7343 p = stbi__bmp_parse_header(s, &info);
7344 if (p == NULL) {
7345 stbi__rewind( s );
7346 return 0;
7347 }
7348 if (x) *x = s->img_x;
7349 if (y) *y = s->img_y;
7350 if (comp) {
7351 if (info.bpp == 24 && info.ma == 0xff000000)
7352 *comp = 3;
7353 else
7354 *comp = info.ma ? 4 : 3;
7355 }
7356 return 1;
7357}
7358#endif
7359
7360#ifndef STBI_NO_PSD
7361static int stbi__psd_info(stbi__context *s, int *x, int *y, int *comp)
7362{
7363 int channelCount, dummy, depth;
7364 if (!x) x = &dummy;
7365 if (!y) y = &dummy;
7366 if (!comp) comp = &dummy;
7367 if (stbi__get32be(s) != 0x38425053) {
7368 stbi__rewind( s );
7369 return 0;
7370 }
7371 if (stbi__get16be(s) != 1) {
7372 stbi__rewind( s );
7373 return 0;
7374 }
7375 stbi__skip(s, 6);
7376 channelCount = stbi__get16be(s);
7377 if (channelCount < 0 || channelCount > 16) {
7378 stbi__rewind( s );
7379 return 0;
7380 }
7381 *y = stbi__get32be(s);
7382 *x = stbi__get32be(s);
7383 depth = stbi__get16be(s);
7384 if (depth != 8 && depth != 16) {
7385 stbi__rewind( s );
7386 return 0;
7387 }
7388 if (stbi__get16be(s) != 3) {
7389 stbi__rewind( s );
7390 return 0;
7391 }
7392 *comp = 4;
7393 return 1;
7394}
7395
7396static int stbi__psd_is16(stbi__context *s)
7397{
7398 int channelCount, depth;
7399 if (stbi__get32be(s) != 0x38425053) {
7400 stbi__rewind( s );
7401 return 0;
7402 }
7403 if (stbi__get16be(s) != 1) {
7404 stbi__rewind( s );
7405 return 0;
7406 }
7407 stbi__skip(s, 6);
7408 channelCount = stbi__get16be(s);
7409 if (channelCount < 0 || channelCount > 16) {
7410 stbi__rewind( s );
7411 return 0;
7412 }
7413 STBI_NOTUSED(stbi__get32be(s));
7414 STBI_NOTUSED(stbi__get32be(s));
7415 depth = stbi__get16be(s);
7416 if (depth != 16) {
7417 stbi__rewind( s );
7418 return 0;
7419 }
7420 return 1;
7421}
7422#endif
7423
7424#ifndef STBI_NO_PIC
7425static int stbi__pic_info(stbi__context *s, int *x, int *y, int *comp)
7426{
7427 int act_comp=0,num_packets=0,chained,dummy;
7428 stbi__pic_packet packets[10];
7429
7430 if (!x) x = &dummy;
7431 if (!y) y = &dummy;
7432 if (!comp) comp = &dummy;
7433
7434 if (!stbi__pic_is4(s,"\x53\x80\xF6\x34")) {
7435 stbi__rewind(s);
7436 return 0;
7437 }
7438
7439 stbi__skip(s, 88);
7440
7441 *x = stbi__get16be(s);
7442 *y = stbi__get16be(s);
7443 if (stbi__at_eof(s)) {
7444 stbi__rewind( s);
7445 return 0;
7446 }
7447 if ( (*x) != 0 && (1 << 28) / (*x) < (*y)) {
7448 stbi__rewind( s );
7449 return 0;
7450 }
7451
7452 stbi__skip(s, 8);
7453
7454 do {
7455 stbi__pic_packet *packet;
7456
7457 if (num_packets==sizeof(packets)/sizeof(packets[0]))
7458 return 0;
7459
7460 packet = &packets[num_packets++];
7461 chained = stbi__get8(s);
7462 packet->size = stbi__get8(s);
7463 packet->type = stbi__get8(s);
7464 packet->channel = stbi__get8(s);
7465 act_comp |= packet->channel;
7466
7467 if (stbi__at_eof(s)) {
7468 stbi__rewind( s );
7469 return 0;
7470 }
7471 if (packet->size != 8) {
7472 stbi__rewind( s );
7473 return 0;
7474 }
7475 } while (chained);
7476
7477 *comp = (act_comp & 0x10 ? 4 : 3);
7478
7479 return 1;
7480}
7481#endif
7482
7483// *************************************************************************************************
7484// Portable Gray Map and Portable Pixel Map loader
7485// by Ken Miller
7486//
7487// PGM: http://netpbm.sourceforge.net/doc/pgm.html
7488// PPM: http://netpbm.sourceforge.net/doc/ppm.html
7489//
7490// Known limitations:
7491// Does not support comments in the header section
7492// Does not support ASCII image data (formats P2 and P3)
7493
7494#ifndef STBI_NO_PNM
7495
7496static int stbi__pnm_test(stbi__context *s)
7497{
7498 char p, t;
7499 p = (char) stbi__get8(s);
7500 t = (char) stbi__get8(s);
7501 if (p != 'P' || (t != '5' && t != '6')) {
7502 stbi__rewind( s );
7503 return 0;
7504 }
7505 return 1;
7506}
7507
7508static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
7509{
7510 stbi_uc *out;
7511 STBI_NOTUSED(ri);
7512
7513 ri->bits_per_channel = stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n);
7514 if (ri->bits_per_channel == 0)
7515 return 0;
7516
7517 if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
7518 if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
7519
7520 *x = s->img_x;
7521 *y = s->img_y;
7522 if (comp) *comp = s->img_n;
7523
7524 if (!stbi__mad4sizes_valid(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0))
7525 return stbi__errpuc("too large", "PNM too large");
7526
7527 out = (stbi_uc *) stbi__malloc_mad4(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0);
7528 if (!out) return stbi__errpuc("outofmem", "Out of memory");
7529 if (!stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8))) {
7530 STBI_FREE(out);
7531 return stbi__errpuc("bad PNM", "PNM file truncated");
7532 }
7533
7534 if (req_comp && req_comp != s->img_n) {
7535 if (ri->bits_per_channel == 16) {
7536 out = (stbi_uc *) stbi__convert_format16((stbi__uint16 *) out, s->img_n, req_comp, s->img_x, s->img_y);
7537 } else {
7538 out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
7539 }
7540 if (out == NULL) return out; // stbi__convert_format frees input on failure
7541 }
7542 return out;
7543}
7544
7545static int stbi__pnm_isspace(char c)
7546{
7547 return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r';
7548}
7549
7550static void stbi__pnm_skip_whitespace(stbi__context *s, char *c)
7551{
7552 for (;;) {
7553 while (!stbi__at_eof(s) && stbi__pnm_isspace(*c))
7554 *c = (char) stbi__get8(s);
7555
7556 if (stbi__at_eof(s) || *c != '#')
7557 break;
7558
7559 while (!stbi__at_eof(s) && *c != '\n' && *c != '\r' )
7560 *c = (char) stbi__get8(s);
7561 }
7562}
7563
7564static int stbi__pnm_isdigit(char c)
7565{
7566 return c >= '0' && c <= '9';
7567}
7568
7569static int stbi__pnm_getinteger(stbi__context *s, char *c)
7570{
7571 int value = 0;
7572
7573 while (!stbi__at_eof(s) && stbi__pnm_isdigit(*c)) {
7574 value = value*10 + (*c - '0');
7575 *c = (char) stbi__get8(s);
7576 if((value > 214748364) || (value == 214748364 && *c > '7'))
7577 return stbi__err("integer parse overflow", "Parsing an integer in the PPM header overflowed a 32-bit int");
7578 }
7579
7580 return value;
7581}
7582
7583static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp)
7584{
7585 int maxv, dummy;
7586 char c, p, t;
7587
7588 if (!x) x = &dummy;
7589 if (!y) y = &dummy;
7590 if (!comp) comp = &dummy;
7591
7592 stbi__rewind(s);
7593
7594 // Get identifier
7595 p = (char) stbi__get8(s);
7596 t = (char) stbi__get8(s);
7597 if (p != 'P' || (t != '5' && t != '6')) {
7598 stbi__rewind(s);
7599 return 0;
7600 }
7601
7602 *comp = (t == '6') ? 3 : 1; // '5' is 1-component .pgm; '6' is 3-component .ppm
7603
7604 c = (char) stbi__get8(s);
7605 stbi__pnm_skip_whitespace(s, &c);
7606
7607 *x = stbi__pnm_getinteger(s, &c); // read width
7608 if(*x == 0)
7609 return stbi__err("invalid width", "PPM image header had zero or overflowing width");
7610 stbi__pnm_skip_whitespace(s, &c);
7611
7612 *y = stbi__pnm_getinteger(s, &c); // read height
7613 if (*y == 0)
7614 return stbi__err("invalid width", "PPM image header had zero or overflowing width");
7615 stbi__pnm_skip_whitespace(s, &c);
7616
7617 maxv = stbi__pnm_getinteger(s, &c); // read max value
7618 if (maxv > 65535)
7619 return stbi__err("max value > 65535", "PPM image supports only 8-bit and 16-bit images");
7620 else if (maxv > 255)
7621 return 16;
7622 else
7623 return 8;
7624}
7625
7626static int stbi__pnm_is16(stbi__context *s)
7627{
7628 if (stbi__pnm_info(s, NULL, NULL, NULL) == 16)
7629 return 1;
7630 return 0;
7631}
7632#endif
7633
7634static int stbi__info_main(stbi__context *s, int *x, int *y, int *comp)
7635{
7636 #ifndef STBI_NO_JPEG
7637 if (stbi__jpeg_info(s, x, y, comp)) return 1;
7638 #endif
7639
7640 #ifndef STBI_NO_PNG
7641 if (stbi__png_info(s, x, y, comp)) return 1;
7642 #endif
7643
7644 #ifndef STBI_NO_GIF
7645 if (stbi__gif_info(s, x, y, comp)) return 1;
7646 #endif
7647
7648 #ifndef STBI_NO_BMP
7649 if (stbi__bmp_info(s, x, y, comp)) return 1;
7650 #endif
7651
7652 #ifndef STBI_NO_PSD
7653 if (stbi__psd_info(s, x, y, comp)) return 1;
7654 #endif
7655
7656 #ifndef STBI_NO_PIC
7657 if (stbi__pic_info(s, x, y, comp)) return 1;
7658 #endif
7659
7660 #ifndef STBI_NO_PNM
7661 if (stbi__pnm_info(s, x, y, comp)) return 1;
7662 #endif
7663
7664 #ifndef STBI_NO_HDR
7665 if (stbi__hdr_info(s, x, y, comp)) return 1;
7666 #endif
7667
7668 // test tga last because it's a crappy test!
7669 #ifndef STBI_NO_TGA
7670 if (stbi__tga_info(s, x, y, comp))
7671 return 1;
7672 #endif
7673 return stbi__err("unknown image type", "Image not of any known type, or corrupt");
7674}
7675
7676static int stbi__is_16_main(stbi__context *s)
7677{
7678 #ifndef STBI_NO_PNG
7679 if (stbi__png_is16(s)) return 1;
7680 #endif
7681
7682 #ifndef STBI_NO_PSD
7683 if (stbi__psd_is16(s)) return 1;
7684 #endif
7685
7686 #ifndef STBI_NO_PNM
7687 if (stbi__pnm_is16(s)) return 1;
7688 #endif
7689 return 0;
7690}
7691
7692#ifndef STBI_NO_STDIO
7693STBIDEF int stbi_info(char const *filename, int *x, int *y, int *comp)
7694{
7695 FILE *f = stbi__fopen(filename, "rb");
7696 int result;
7697 if (!f) return stbi__err("can't fopen", "Unable to open file");
7698 result = stbi_info_from_file(f, x, y, comp);
7699 fclose(f);
7700 return result;
7701}
7702
7703STBIDEF int stbi_info_from_file(FILE *f, int *x, int *y, int *comp)
7704{
7705 int r;
7706 stbi__context s;
7707 long pos = ftell(f);
7708 stbi__start_file(&s, f);
7709 r = stbi__info_main(&s,x,y,comp);
7710 fseek(f,pos,SEEK_SET);
7711 return r;
7712}
7713
7714STBIDEF int stbi_is_16_bit(char const *filename)
7715{
7716 FILE *f = stbi__fopen(filename, "rb");
7717 int result;
7718 if (!f) return stbi__err("can't fopen", "Unable to open file");
7719 result = stbi_is_16_bit_from_file(f);
7720 fclose(f);
7721 return result;
7722}
7723
7724STBIDEF int stbi_is_16_bit_from_file(FILE *f)
7725{
7726 int r;
7727 stbi__context s;
7728 long pos = ftell(f);
7729 stbi__start_file(&s, f);
7730 r = stbi__is_16_main(&s);
7731 fseek(f,pos,SEEK_SET);
7732 return r;
7733}
7734#endif // !STBI_NO_STDIO
7735
7736STBIDEF int stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp)
7737{
7738 stbi__context s;
7739 stbi__start_mem(&s,buffer,len);
7740 return stbi__info_main(&s,x,y,comp);
7741}
7742
7743STBIDEF int stbi_info_from_callbacks(stbi_io_callbacks const *c, void *user, int *x, int *y, int *comp)
7744{
7745 stbi__context s;
7746 stbi__start_callbacks(&s, (stbi_io_callbacks *) c, user);
7747 return stbi__info_main(&s,x,y,comp);
7748}
7749
7750STBIDEF int stbi_is_16_bit_from_memory(stbi_uc const *buffer, int len)
7751{
7752 stbi__context s;
7753 stbi__start_mem(&s,buffer,len);
7754 return stbi__is_16_main(&s);
7755}
7756
7757STBIDEF int stbi_is_16_bit_from_callbacks(stbi_io_callbacks const *c, void *user)
7758{
7759 stbi__context s;
7760 stbi__start_callbacks(&s, (stbi_io_callbacks *) c, user);
7761 return stbi__is_16_main(&s);
7762}
7763
7764#endif // STB_IMAGE_IMPLEMENTATION
7765
7766/* 548/*
7767 revision history: 549 revision history:
7768 2.20 (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs 550 2.20 (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
diff --git a/externals/stb/stb_image_resize.cpp b/externals/stb/stb_image_resize.cpp
new file mode 100644
index 000000000..6f023629e
--- /dev/null
+++ b/externals/stb/stb_image_resize.cpp
@@ -0,0 +1,2282 @@
1// SPDX-FileCopyrightText: Jorge L Rodriguez
2// SPDX-License-Identifier: MIT
3
4/* stb_image_resize - v0.97 - public domain image resizing
5 by Jorge L Rodriguez (@VinoBS) - 2014
6 http://github.com/nothings/stb
7
8 CONTRIBUTORS
9 Jorge L Rodriguez: Implementation
10 Sean Barrett: API design, optimizations
11 Aras Pranckevicius: bugfix
12 Nathan Reed: warning fixes
13
14 REVISIONS
15 0.97 (2020-02-02) fixed warning
16 0.96 (2019-03-04) fixed warnings
17 0.95 (2017-07-23) fixed warnings
18 0.94 (2017-03-18) fixed warnings
19 0.93 (2017-03-03) fixed bug with certain combinations of heights
20 0.92 (2017-01-02) fix integer overflow on large (>2GB) images
21 0.91 (2016-04-02) fix warnings; fix handling of subpixel regions
22 0.90 (2014-09-17) first released version
23
24 LICENSE
25 See end of file for license information.
26
27 TODO
28 Don't decode all of the image data when only processing a partial tile
29 Don't use full-width decode buffers when only processing a partial tile
30 When processing wide images, break processing into tiles so data fits in L1 cache
31 Installable filters?
32 Resize that respects alpha test coverage
33 (Reference code: FloatImage::alphaTestCoverage and FloatImage::scaleAlphaToCoverage:
34 https://code.google.com/p/nvidia-texture-tools/source/browse/trunk/src/nvimage/FloatImage.cpp )
35*/
36
37#include <stb_image_resize.h>
38
39#ifndef STBIR_ASSERT
40#include <assert.h>
41#define STBIR_ASSERT(x) assert(x)
42#endif
43
44// For memset
45#include <string.h>
46
47#include <math.h>
48
49#ifndef STBIR_MALLOC
50#include <stdlib.h>
51// use comma operator to evaluate c, to avoid "unused parameter" warnings
52#define STBIR_MALLOC(size,c) ((void)(c), malloc(size))
53#define STBIR_FREE(ptr,c) ((void)(c), free(ptr))
54#endif
55
56#ifndef _MSC_VER
57#ifdef __cplusplus
58#define stbir__inline inline
59#else
60#define stbir__inline
61#endif
62#else
63#define stbir__inline __forceinline
64#endif
65
66
67// should produce compiler error if size is wrong
68typedef unsigned char stbir__validate_uint32[sizeof(stbir_uint32) == 4 ? 1 : -1];
69
70#ifdef _MSC_VER
71#define STBIR__NOTUSED(v) (void)(v)
72#else
73#define STBIR__NOTUSED(v) (void)sizeof(v)
74#endif
75
76#define STBIR__ARRAY_SIZE(a) (sizeof((a))/sizeof((a)[0]))
77
78#ifndef STBIR_DEFAULT_FILTER_UPSAMPLE
79#define STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM
80#endif
81
82#ifndef STBIR_DEFAULT_FILTER_DOWNSAMPLE
83#define STBIR_DEFAULT_FILTER_DOWNSAMPLE STBIR_FILTER_MITCHELL
84#endif
85
86#ifndef STBIR_PROGRESS_REPORT
87#define STBIR_PROGRESS_REPORT(float_0_to_1)
88#endif
89
90#ifndef STBIR_MAX_CHANNELS
91#define STBIR_MAX_CHANNELS 64
92#endif
93
94#if STBIR_MAX_CHANNELS > 65536
95#error "Too many channels; STBIR_MAX_CHANNELS must be no more than 65536."
96// because we store the indices in 16-bit variables
97#endif
98
99// This value is added to alpha just before premultiplication to avoid
100// zeroing out color values. It is equivalent to 2^-80. If you don't want
101// that behavior (it may interfere if you have floating point images with
102// very small alpha values) then you can define STBIR_NO_ALPHA_EPSILON to
103// disable it.
104#ifndef STBIR_ALPHA_EPSILON
105#define STBIR_ALPHA_EPSILON ((float)1 / (1 << 20) / (1 << 20) / (1 << 20) / (1 << 20))
106#endif
107
108
109
110#ifdef _MSC_VER
111#define STBIR__UNUSED_PARAM(v) (void)(v)
112#else
113#define STBIR__UNUSED_PARAM(v) (void)sizeof(v)
114#endif
115
116// must match stbir_datatype
117static unsigned char stbir__type_size[] = {
118 1, // STBIR_TYPE_UINT8
119 2, // STBIR_TYPE_UINT16
120 4, // STBIR_TYPE_UINT32
121 4, // STBIR_TYPE_FLOAT
122};
123
124// Kernel function centered at 0
125typedef float (stbir__kernel_fn)(float x, float scale);
126typedef float (stbir__support_fn)(float scale);
127
128typedef struct
129{
130 stbir__kernel_fn* kernel;
131 stbir__support_fn* support;
132} stbir__filter_info;
133
134// When upsampling, the contributors are which source pixels contribute.
135// When downsampling, the contributors are which destination pixels are contributed to.
136typedef struct
137{
138 int n0; // First contributing pixel
139 int n1; // Last contributing pixel
140} stbir__contributors;
141
142typedef struct
143{
144 const void* input_data;
145 int input_w;
146 int input_h;
147 int input_stride_bytes;
148
149 void* output_data;
150 int output_w;
151 int output_h;
152 int output_stride_bytes;
153
154 float s0, t0, s1, t1;
155
156 float horizontal_shift; // Units: output pixels
157 float vertical_shift; // Units: output pixels
158 float horizontal_scale;
159 float vertical_scale;
160
161 int channels;
162 int alpha_channel;
163 stbir_uint32 flags;
164 stbir_datatype type;
165 stbir_filter horizontal_filter;
166 stbir_filter vertical_filter;
167 stbir_edge edge_horizontal;
168 stbir_edge edge_vertical;
169 stbir_colorspace colorspace;
170
171 stbir__contributors* horizontal_contributors;
172 float* horizontal_coefficients;
173
174 stbir__contributors* vertical_contributors;
175 float* vertical_coefficients;
176
177 int decode_buffer_pixels;
178 float* decode_buffer;
179
180 float* horizontal_buffer;
181
182 // cache these because ceil/floor are inexplicably showing up in profile
183 int horizontal_coefficient_width;
184 int vertical_coefficient_width;
185 int horizontal_filter_pixel_width;
186 int vertical_filter_pixel_width;
187 int horizontal_filter_pixel_margin;
188 int vertical_filter_pixel_margin;
189 int horizontal_num_contributors;
190 int vertical_num_contributors;
191
192 int ring_buffer_length_bytes; // The length of an individual entry in the ring buffer. The total number of ring buffers is stbir__get_filter_pixel_width(filter)
193 int ring_buffer_num_entries; // Total number of entries in the ring buffer.
194 int ring_buffer_first_scanline;
195 int ring_buffer_last_scanline;
196 int ring_buffer_begin_index; // first_scanline is at this index in the ring buffer
197 float* ring_buffer;
198
199 float* encode_buffer; // A temporary buffer to store floats so we don't lose precision while we do multiply-adds.
200
201 int horizontal_contributors_size;
202 int horizontal_coefficients_size;
203 int vertical_contributors_size;
204 int vertical_coefficients_size;
205 int decode_buffer_size;
206 int horizontal_buffer_size;
207 int ring_buffer_size;
208 int encode_buffer_size;
209} stbir__info;
210
211
212static const float stbir__max_uint8_as_float = 255.0f;
213static const float stbir__max_uint16_as_float = 65535.0f;
214static const double stbir__max_uint32_as_float = 4294967295.0;
215
216
217static stbir__inline int stbir__min(int a, int b)
218{
219 return a < b ? a : b;
220}
221
222static stbir__inline float stbir__saturate(float x)
223{
224 if (x < 0)
225 return 0;
226
227 if (x > 1)
228 return 1;
229
230 return x;
231}
232
233#ifdef STBIR_SATURATE_INT
234static stbir__inline stbir_uint8 stbir__saturate8(int x)
235{
236 if ((unsigned int) x <= 255)
237 return x;
238
239 if (x < 0)
240 return 0;
241
242 return 255;
243}
244
245static stbir__inline stbir_uint16 stbir__saturate16(int x)
246{
247 if ((unsigned int) x <= 65535)
248 return x;
249
250 if (x < 0)
251 return 0;
252
253 return 65535;
254}
255#endif
256
257static float stbir__srgb_uchar_to_linear_float[256] = {
258 0.000000f, 0.000304f, 0.000607f, 0.000911f, 0.001214f, 0.001518f, 0.001821f, 0.002125f, 0.002428f, 0.002732f, 0.003035f,
259 0.003347f, 0.003677f, 0.004025f, 0.004391f, 0.004777f, 0.005182f, 0.005605f, 0.006049f, 0.006512f, 0.006995f, 0.007499f,
260 0.008023f, 0.008568f, 0.009134f, 0.009721f, 0.010330f, 0.010960f, 0.011612f, 0.012286f, 0.012983f, 0.013702f, 0.014444f,
261 0.015209f, 0.015996f, 0.016807f, 0.017642f, 0.018500f, 0.019382f, 0.020289f, 0.021219f, 0.022174f, 0.023153f, 0.024158f,
262 0.025187f, 0.026241f, 0.027321f, 0.028426f, 0.029557f, 0.030713f, 0.031896f, 0.033105f, 0.034340f, 0.035601f, 0.036889f,
263 0.038204f, 0.039546f, 0.040915f, 0.042311f, 0.043735f, 0.045186f, 0.046665f, 0.048172f, 0.049707f, 0.051269f, 0.052861f,
264 0.054480f, 0.056128f, 0.057805f, 0.059511f, 0.061246f, 0.063010f, 0.064803f, 0.066626f, 0.068478f, 0.070360f, 0.072272f,
265 0.074214f, 0.076185f, 0.078187f, 0.080220f, 0.082283f, 0.084376f, 0.086500f, 0.088656f, 0.090842f, 0.093059f, 0.095307f,
266 0.097587f, 0.099899f, 0.102242f, 0.104616f, 0.107023f, 0.109462f, 0.111932f, 0.114435f, 0.116971f, 0.119538f, 0.122139f,
267 0.124772f, 0.127438f, 0.130136f, 0.132868f, 0.135633f, 0.138432f, 0.141263f, 0.144128f, 0.147027f, 0.149960f, 0.152926f,
268 0.155926f, 0.158961f, 0.162029f, 0.165132f, 0.168269f, 0.171441f, 0.174647f, 0.177888f, 0.181164f, 0.184475f, 0.187821f,
269 0.191202f, 0.194618f, 0.198069f, 0.201556f, 0.205079f, 0.208637f, 0.212231f, 0.215861f, 0.219526f, 0.223228f, 0.226966f,
270 0.230740f, 0.234551f, 0.238398f, 0.242281f, 0.246201f, 0.250158f, 0.254152f, 0.258183f, 0.262251f, 0.266356f, 0.270498f,
271 0.274677f, 0.278894f, 0.283149f, 0.287441f, 0.291771f, 0.296138f, 0.300544f, 0.304987f, 0.309469f, 0.313989f, 0.318547f,
272 0.323143f, 0.327778f, 0.332452f, 0.337164f, 0.341914f, 0.346704f, 0.351533f, 0.356400f, 0.361307f, 0.366253f, 0.371238f,
273 0.376262f, 0.381326f, 0.386430f, 0.391573f, 0.396755f, 0.401978f, 0.407240f, 0.412543f, 0.417885f, 0.423268f, 0.428691f,
274 0.434154f, 0.439657f, 0.445201f, 0.450786f, 0.456411f, 0.462077f, 0.467784f, 0.473532f, 0.479320f, 0.485150f, 0.491021f,
275 0.496933f, 0.502887f, 0.508881f, 0.514918f, 0.520996f, 0.527115f, 0.533276f, 0.539480f, 0.545725f, 0.552011f, 0.558340f,
276 0.564712f, 0.571125f, 0.577581f, 0.584078f, 0.590619f, 0.597202f, 0.603827f, 0.610496f, 0.617207f, 0.623960f, 0.630757f,
277 0.637597f, 0.644480f, 0.651406f, 0.658375f, 0.665387f, 0.672443f, 0.679543f, 0.686685f, 0.693872f, 0.701102f, 0.708376f,
278 0.715694f, 0.723055f, 0.730461f, 0.737911f, 0.745404f, 0.752942f, 0.760525f, 0.768151f, 0.775822f, 0.783538f, 0.791298f,
279 0.799103f, 0.806952f, 0.814847f, 0.822786f, 0.830770f, 0.838799f, 0.846873f, 0.854993f, 0.863157f, 0.871367f, 0.879622f,
280 0.887923f, 0.896269f, 0.904661f, 0.913099f, 0.921582f, 0.930111f, 0.938686f, 0.947307f, 0.955974f, 0.964686f, 0.973445f,
281 0.982251f, 0.991102f, 1.0f
282};
283
284static float stbir__srgb_to_linear(float f)
285{
286 if (f <= 0.04045f)
287 return f / 12.92f;
288 else
289 return (float)pow((f + 0.055f) / 1.055f, 2.4f);
290}
291
292static float stbir__linear_to_srgb(float f)
293{
294 if (f <= 0.0031308f)
295 return f * 12.92f;
296 else
297 return 1.055f * (float)pow(f, 1 / 2.4f) - 0.055f;
298}
299
300#ifndef STBIR_NON_IEEE_FLOAT
301// From https://gist.github.com/rygorous/2203834
302
303typedef union
304{
305 stbir_uint32 u;
306 float f;
307} stbir__FP32;
308
309static const stbir_uint32 fp32_to_srgb8_tab4[104] = {
310 0x0073000d, 0x007a000d, 0x0080000d, 0x0087000d, 0x008d000d, 0x0094000d, 0x009a000d, 0x00a1000d,
311 0x00a7001a, 0x00b4001a, 0x00c1001a, 0x00ce001a, 0x00da001a, 0x00e7001a, 0x00f4001a, 0x0101001a,
312 0x010e0033, 0x01280033, 0x01410033, 0x015b0033, 0x01750033, 0x018f0033, 0x01a80033, 0x01c20033,
313 0x01dc0067, 0x020f0067, 0x02430067, 0x02760067, 0x02aa0067, 0x02dd0067, 0x03110067, 0x03440067,
314 0x037800ce, 0x03df00ce, 0x044600ce, 0x04ad00ce, 0x051400ce, 0x057b00c5, 0x05dd00bc, 0x063b00b5,
315 0x06970158, 0x07420142, 0x07e30130, 0x087b0120, 0x090b0112, 0x09940106, 0x0a1700fc, 0x0a9500f2,
316 0x0b0f01cb, 0x0bf401ae, 0x0ccb0195, 0x0d950180, 0x0e56016e, 0x0f0d015e, 0x0fbc0150, 0x10630143,
317 0x11070264, 0x1238023e, 0x1357021d, 0x14660201, 0x156601e9, 0x165a01d3, 0x174401c0, 0x182401af,
318 0x18fe0331, 0x1a9602fe, 0x1c1502d2, 0x1d7e02ad, 0x1ed4028d, 0x201a0270, 0x21520256, 0x227d0240,
319 0x239f0443, 0x25c003fe, 0x27bf03c4, 0x29a10392, 0x2b6a0367, 0x2d1d0341, 0x2ebe031f, 0x304d0300,
320 0x31d105b0, 0x34a80555, 0x37520507, 0x39d504c5, 0x3c37048b, 0x3e7c0458, 0x40a8042a, 0x42bd0401,
321 0x44c20798, 0x488e071e, 0x4c1c06b6, 0x4f76065d, 0x52a50610, 0x55ac05cc, 0x5892058f, 0x5b590559,
322 0x5e0c0a23, 0x631c0980, 0x67db08f6, 0x6c55087f, 0x70940818, 0x74a007bd, 0x787d076c, 0x7c330723,
323};
324
325static stbir_uint8 stbir__linear_to_srgb_uchar(float in)
326{
327 static const stbir__FP32 almostone = { 0x3f7fffff }; // 1-eps
328 static const stbir__FP32 minval = { (127-13) << 23 };
329 stbir_uint32 tab,bias,scale,t;
330 stbir__FP32 f;
331
332 // Clamp to [2^(-13), 1-eps]; these two values map to 0 and 1, respectively.
333 // The tests are carefully written so that NaNs map to 0, same as in the reference
334 // implementation.
335 if (!(in > minval.f)) // written this way to catch NaNs
336 in = minval.f;
337 if (in > almostone.f)
338 in = almostone.f;
339
340 // Do the table lookup and unpack bias, scale
341 f.f = in;
342 tab = fp32_to_srgb8_tab4[(f.u - minval.u) >> 20];
343 bias = (tab >> 16) << 9;
344 scale = tab & 0xffff;
345
346 // Grab next-highest mantissa bits and perform linear interpolation
347 t = (f.u >> 12) & 0xff;
348 return (unsigned char) ((bias + scale*t) >> 16);
349}
350
351#else
352// sRGB transition values, scaled by 1<<28
353static int stbir__srgb_offset_to_linear_scaled[256] =
354{
355 0, 40738, 122216, 203693, 285170, 366648, 448125, 529603,
356 611080, 692557, 774035, 855852, 942009, 1033024, 1128971, 1229926,
357 1335959, 1447142, 1563542, 1685229, 1812268, 1944725, 2082664, 2226148,
358 2375238, 2529996, 2690481, 2856753, 3028870, 3206888, 3390865, 3580856,
359 3776916, 3979100, 4187460, 4402049, 4622919, 4850123, 5083710, 5323731,
360 5570236, 5823273, 6082892, 6349140, 6622065, 6901714, 7188133, 7481369,
361 7781466, 8088471, 8402427, 8723380, 9051372, 9386448, 9728650, 10078021,
362 10434603, 10798439, 11169569, 11548036, 11933879, 12327139, 12727857, 13136073,
363 13551826, 13975156, 14406100, 14844697, 15290987, 15745007, 16206795, 16676389,
364 17153826, 17639142, 18132374, 18633560, 19142734, 19659934, 20185196, 20718552,
365 21260042, 21809696, 22367554, 22933648, 23508010, 24090680, 24681686, 25281066,
366 25888850, 26505076, 27129772, 27762974, 28404716, 29055026, 29713942, 30381490,
367 31057708, 31742624, 32436272, 33138682, 33849884, 34569912, 35298800, 36036568,
368 36783260, 37538896, 38303512, 39077136, 39859796, 40651528, 41452360, 42262316,
369 43081432, 43909732, 44747252, 45594016, 46450052, 47315392, 48190064, 49074096,
370 49967516, 50870356, 51782636, 52704392, 53635648, 54576432, 55526772, 56486700,
371 57456236, 58435408, 59424248, 60422780, 61431036, 62449032, 63476804, 64514376,
372 65561776, 66619028, 67686160, 68763192, 69850160, 70947088, 72053992, 73170912,
373 74297864, 75434880, 76581976, 77739184, 78906536, 80084040, 81271736, 82469648,
374 83677792, 84896192, 86124888, 87363888, 88613232, 89872928, 91143016, 92423512,
375 93714432, 95015816, 96327688, 97650056, 98982952, 100326408, 101680440, 103045072,
376 104420320, 105806224, 107202800, 108610064, 110028048, 111456776, 112896264, 114346544,
377 115807632, 117279552, 118762328, 120255976, 121760536, 123276016, 124802440, 126339832,
378 127888216, 129447616, 131018048, 132599544, 134192112, 135795792, 137410592, 139036528,
379 140673648, 142321952, 143981456, 145652208, 147334208, 149027488, 150732064, 152447968,
380 154175200, 155913792, 157663776, 159425168, 161197984, 162982240, 164777968, 166585184,
381 168403904, 170234160, 172075968, 173929344, 175794320, 177670896, 179559120, 181458992,
382 183370528, 185293776, 187228736, 189175424, 191133888, 193104112, 195086128, 197079968,
383 199085648, 201103184, 203132592, 205173888, 207227120, 209292272, 211369392, 213458480,
384 215559568, 217672656, 219797792, 221934976, 224084240, 226245600, 228419056, 230604656,
385 232802400, 235012320, 237234432, 239468736, 241715280, 243974080, 246245120, 248528464,
386 250824112, 253132064, 255452368, 257785040, 260130080, 262487520, 264857376, 267239664,
387};
388
389static stbir_uint8 stbir__linear_to_srgb_uchar(float f)
390{
391 int x = (int) (f * (1 << 28)); // has headroom so you don't need to clamp
392 int v = 0;
393 int i;
394
395 // Refine the guess with a short binary search.
396 i = v + 128; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
397 i = v + 64; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
398 i = v + 32; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
399 i = v + 16; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
400 i = v + 8; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
401 i = v + 4; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
402 i = v + 2; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
403 i = v + 1; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
404
405 return (stbir_uint8) v;
406}
407#endif
408
409static float stbir__filter_trapezoid(float x, float scale)
410{
411 float halfscale = scale / 2;
412 float t = 0.5f + halfscale;
413 STBIR_ASSERT(scale <= 1);
414
415 x = (float)fabs(x);
416
417 if (x >= t)
418 return 0;
419 else
420 {
421 float r = 0.5f - halfscale;
422 if (x <= r)
423 return 1;
424 else
425 return (t - x) / scale;
426 }
427}
428
429static float stbir__support_trapezoid(float scale)
430{
431 STBIR_ASSERT(scale <= 1);
432 return 0.5f + scale / 2;
433}
434
435static float stbir__filter_triangle(float x, float s)
436{
437 STBIR__UNUSED_PARAM(s);
438
439 x = (float)fabs(x);
440
441 if (x <= 1.0f)
442 return 1 - x;
443 else
444 return 0;
445}
446
447static float stbir__filter_cubic(float x, float s)
448{
449 STBIR__UNUSED_PARAM(s);
450
451 x = (float)fabs(x);
452
453 if (x < 1.0f)
454 return (4 + x*x*(3*x - 6))/6;
455 else if (x < 2.0f)
456 return (8 + x*(-12 + x*(6 - x)))/6;
457
458 return (0.0f);
459}
460
461static float stbir__filter_catmullrom(float x, float s)
462{
463 STBIR__UNUSED_PARAM(s);
464
465 x = (float)fabs(x);
466
467 if (x < 1.0f)
468 return 1 - x*x*(2.5f - 1.5f*x);
469 else if (x < 2.0f)
470 return 2 - x*(4 + x*(0.5f*x - 2.5f));
471
472 return (0.0f);
473}
474
475static float stbir__filter_mitchell(float x, float s)
476{
477 STBIR__UNUSED_PARAM(s);
478
479 x = (float)fabs(x);
480
481 if (x < 1.0f)
482 return (16 + x*x*(21 * x - 36))/18;
483 else if (x < 2.0f)
484 return (32 + x*(-60 + x*(36 - 7*x)))/18;
485
486 return (0.0f);
487}
488
489static float stbir__support_zero(float s)
490{
491 STBIR__UNUSED_PARAM(s);
492 return 0;
493}
494
495static float stbir__support_one(float s)
496{
497 STBIR__UNUSED_PARAM(s);
498 return 1;
499}
500
501static float stbir__support_two(float s)
502{
503 STBIR__UNUSED_PARAM(s);
504 return 2;
505}
506
507static stbir__filter_info stbir__filter_info_table[] = {
508 { NULL, stbir__support_zero },
509 { stbir__filter_trapezoid, stbir__support_trapezoid },
510 { stbir__filter_triangle, stbir__support_one },
511 { stbir__filter_cubic, stbir__support_two },
512 { stbir__filter_catmullrom, stbir__support_two },
513 { stbir__filter_mitchell, stbir__support_two },
514};
515
516stbir__inline static int stbir__use_upsampling(float ratio)
517{
518 return ratio > 1;
519}
520
521stbir__inline static int stbir__use_width_upsampling(stbir__info* stbir_info)
522{
523 return stbir__use_upsampling(stbir_info->horizontal_scale);
524}
525
526stbir__inline static int stbir__use_height_upsampling(stbir__info* stbir_info)
527{
528 return stbir__use_upsampling(stbir_info->vertical_scale);
529}
530
531// This is the maximum number of input samples that can affect an output sample
532// with the given filter
533static int stbir__get_filter_pixel_width(stbir_filter filter, float scale)
534{
535 STBIR_ASSERT(filter != 0);
536 STBIR_ASSERT(filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
537
538 if (stbir__use_upsampling(scale))
539 return (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2);
540 else
541 return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2 / scale);
542}
543
544// This is how much to expand buffers to account for filters seeking outside
545// the image boundaries.
546static int stbir__get_filter_pixel_margin(stbir_filter filter, float scale)
547{
548 return stbir__get_filter_pixel_width(filter, scale) / 2;
549}
550
551static int stbir__get_coefficient_width(stbir_filter filter, float scale)
552{
553 if (stbir__use_upsampling(scale))
554 return (int)ceil(stbir__filter_info_table[filter].support(1 / scale) * 2);
555 else
556 return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2);
557}
558
559static int stbir__get_contributors(float scale, stbir_filter filter, int input_size, int output_size)
560{
561 if (stbir__use_upsampling(scale))
562 return output_size;
563 else
564 return (input_size + stbir__get_filter_pixel_margin(filter, scale) * 2);
565}
566
567static int stbir__get_total_horizontal_coefficients(stbir__info* info)
568{
569 return info->horizontal_num_contributors
570 * stbir__get_coefficient_width (info->horizontal_filter, info->horizontal_scale);
571}
572
573static int stbir__get_total_vertical_coefficients(stbir__info* info)
574{
575 return info->vertical_num_contributors
576 * stbir__get_coefficient_width (info->vertical_filter, info->vertical_scale);
577}
578
579static stbir__contributors* stbir__get_contributor(stbir__contributors* contributors, int n)
580{
581 return &contributors[n];
582}
583
584// For perf reasons this code is duplicated in stbir__resample_horizontal_upsample/downsample,
585// if you change it here change it there too.
586static float* stbir__get_coefficient(float* coefficients, stbir_filter filter, float scale, int n, int c)
587{
588 int width = stbir__get_coefficient_width(filter, scale);
589 return &coefficients[width*n + c];
590}
591
592static int stbir__edge_wrap_slow(stbir_edge edge, int n, int max)
593{
594 switch (edge)
595 {
596 case STBIR_EDGE_ZERO:
597 return 0; // we'll decode the wrong pixel here, and then overwrite with 0s later
598
599 case STBIR_EDGE_CLAMP:
600 if (n < 0)
601 return 0;
602
603 if (n >= max)
604 return max - 1;
605
606 return n; // NOTREACHED
607
608 case STBIR_EDGE_REFLECT:
609 {
610 if (n < 0)
611 {
612 if (n < max)
613 return -n;
614 else
615 return max - 1;
616 }
617
618 if (n >= max)
619 {
620 int max2 = max * 2;
621 if (n >= max2)
622 return 0;
623 else
624 return max2 - n - 1;
625 }
626
627 return n; // NOTREACHED
628 }
629
630 case STBIR_EDGE_WRAP:
631 if (n >= 0)
632 return (n % max);
633 else
634 {
635 int m = (-n) % max;
636
637 if (m != 0)
638 m = max - m;
639
640 return (m);
641 }
642 // NOTREACHED
643
644 default:
645 STBIR_ASSERT(!"Unimplemented edge type");
646 return 0;
647 }
648}
649
650stbir__inline static int stbir__edge_wrap(stbir_edge edge, int n, int max)
651{
652 // avoid per-pixel switch
653 if (n >= 0 && n < max)
654 return n;
655 return stbir__edge_wrap_slow(edge, n, max);
656}
657
658// What input pixels contribute to this output pixel?
659static void stbir__calculate_sample_range_upsample(int n, float out_filter_radius, float scale_ratio, float out_shift, int* in_first_pixel, int* in_last_pixel, float* in_center_of_out)
660{
661 float out_pixel_center = (float)n + 0.5f;
662 float out_pixel_influence_lowerbound = out_pixel_center - out_filter_radius;
663 float out_pixel_influence_upperbound = out_pixel_center + out_filter_radius;
664
665 float in_pixel_influence_lowerbound = (out_pixel_influence_lowerbound + out_shift) / scale_ratio;
666 float in_pixel_influence_upperbound = (out_pixel_influence_upperbound + out_shift) / scale_ratio;
667
668 *in_center_of_out = (out_pixel_center + out_shift) / scale_ratio;
669 *in_first_pixel = (int)(floor(in_pixel_influence_lowerbound + 0.5));
670 *in_last_pixel = (int)(floor(in_pixel_influence_upperbound - 0.5));
671}
672
673// What output pixels does this input pixel contribute to?
674static void stbir__calculate_sample_range_downsample(int n, float in_pixels_radius, float scale_ratio, float out_shift, int* out_first_pixel, int* out_last_pixel, float* out_center_of_in)
675{
676 float in_pixel_center = (float)n + 0.5f;
677 float in_pixel_influence_lowerbound = in_pixel_center - in_pixels_radius;
678 float in_pixel_influence_upperbound = in_pixel_center + in_pixels_radius;
679
680 float out_pixel_influence_lowerbound = in_pixel_influence_lowerbound * scale_ratio - out_shift;
681 float out_pixel_influence_upperbound = in_pixel_influence_upperbound * scale_ratio - out_shift;
682
683 *out_center_of_in = in_pixel_center * scale_ratio - out_shift;
684 *out_first_pixel = (int)(floor(out_pixel_influence_lowerbound + 0.5));
685 *out_last_pixel = (int)(floor(out_pixel_influence_upperbound - 0.5));
686}
687
688static void stbir__calculate_coefficients_upsample(stbir_filter filter, float scale, int in_first_pixel, int in_last_pixel, float in_center_of_out, stbir__contributors* contributor, float* coefficient_group)
689{
690 int i;
691 float total_filter = 0;
692 float filter_scale;
693
694 STBIR_ASSERT(in_last_pixel - in_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2)); // Taken directly from stbir__get_coefficient_width() which we can't call because we don't know if we're horizontal or vertical.
695
696 contributor->n0 = in_first_pixel;
697 contributor->n1 = in_last_pixel;
698
699 STBIR_ASSERT(contributor->n1 >= contributor->n0);
700
701 for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
702 {
703 float in_pixel_center = (float)(i + in_first_pixel) + 0.5f;
704 coefficient_group[i] = stbir__filter_info_table[filter].kernel(in_center_of_out - in_pixel_center, 1 / scale);
705
706 // If the coefficient is zero, skip it. (Don't do the <0 check here, we want the influence of those outside pixels.)
707 if (i == 0 && !coefficient_group[i])
708 {
709 contributor->n0 = ++in_first_pixel;
710 i--;
711 continue;
712 }
713
714 total_filter += coefficient_group[i];
715 }
716
717 // NOTE(fg): Not actually true in general, nor is there any reason to expect it should be.
718 // It would be true in exact math but is at best approximately true in floating-point math,
719 // and it would not make sense to try and put actual bounds on this here because it depends
720 // on the image aspect ratio which can get pretty extreme.
721 //STBIR_ASSERT(stbir__filter_info_table[filter].kernel((float)(in_last_pixel + 1) + 0.5f - in_center_of_out, 1/scale) == 0);
722
723 STBIR_ASSERT(total_filter > 0.9);
724 STBIR_ASSERT(total_filter < 1.1f); // Make sure it's not way off.
725
726 // Make sure the sum of all coefficients is 1.
727 filter_scale = 1 / total_filter;
728
729 for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
730 coefficient_group[i] *= filter_scale;
731
732 for (i = in_last_pixel - in_first_pixel; i >= 0; i--)
733 {
734 if (coefficient_group[i])
735 break;
736
737 // This line has no weight. We can skip it.
738 contributor->n1 = contributor->n0 + i - 1;
739 }
740}
741
742static void stbir__calculate_coefficients_downsample(stbir_filter filter, float scale_ratio, int out_first_pixel, int out_last_pixel, float out_center_of_in, stbir__contributors* contributor, float* coefficient_group)
743{
744 int i;
745
746 STBIR_ASSERT(out_last_pixel - out_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(scale_ratio) * 2)); // Taken directly from stbir__get_coefficient_width() which we can't call because we don't know if we're horizontal or vertical.
747
748 contributor->n0 = out_first_pixel;
749 contributor->n1 = out_last_pixel;
750
751 STBIR_ASSERT(contributor->n1 >= contributor->n0);
752
753 for (i = 0; i <= out_last_pixel - out_first_pixel; i++)
754 {
755 float out_pixel_center = (float)(i + out_first_pixel) + 0.5f;
756 float x = out_pixel_center - out_center_of_in;
757 coefficient_group[i] = stbir__filter_info_table[filter].kernel(x, scale_ratio) * scale_ratio;
758 }
759
760 // NOTE(fg): Not actually true in general, nor is there any reason to expect it should be.
761 // It would be true in exact math but is at best approximately true in floating-point math,
762 // and it would not make sense to try and put actual bounds on this here because it depends
763 // on the image aspect ratio which can get pretty extreme.
764 //STBIR_ASSERT(stbir__filter_info_table[filter].kernel((float)(out_last_pixel + 1) + 0.5f - out_center_of_in, scale_ratio) == 0);
765
766 for (i = out_last_pixel - out_first_pixel; i >= 0; i--)
767 {
768 if (coefficient_group[i])
769 break;
770
771 // This line has no weight. We can skip it.
772 contributor->n1 = contributor->n0 + i - 1;
773 }
774}
775
776static void stbir__normalize_downsample_coefficients(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, int input_size, int output_size)
777{
778 int num_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size);
779 int num_coefficients = stbir__get_coefficient_width(filter, scale_ratio);
780 int i, j;
781 int skip;
782
783 for (i = 0; i < output_size; i++)
784 {
785 float scale;
786 float total = 0;
787
788 for (j = 0; j < num_contributors; j++)
789 {
790 if (i >= contributors[j].n0 && i <= contributors[j].n1)
791 {
792 float coefficient = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0);
793 total += coefficient;
794 }
795 else if (i < contributors[j].n0)
796 break;
797 }
798
799 STBIR_ASSERT(total > 0.9f);
800 STBIR_ASSERT(total < 1.1f);
801
802 scale = 1 / total;
803
804 for (j = 0; j < num_contributors; j++)
805 {
806 if (i >= contributors[j].n0 && i <= contributors[j].n1)
807 *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0) *= scale;
808 else if (i < contributors[j].n0)
809 break;
810 }
811 }
812
813 // Optimize: Skip zero coefficients and contributions outside of image bounds.
814 // Do this after normalizing because normalization depends on the n0/n1 values.
815 for (j = 0; j < num_contributors; j++)
816 {
817 int range, max, width;
818
819 skip = 0;
820 while (*stbir__get_coefficient(coefficients, filter, scale_ratio, j, skip) == 0)
821 skip++;
822
823 contributors[j].n0 += skip;
824
825 while (contributors[j].n0 < 0)
826 {
827 contributors[j].n0++;
828 skip++;
829 }
830
831 range = contributors[j].n1 - contributors[j].n0 + 1;
832 max = stbir__min(num_coefficients, range);
833
834 width = stbir__get_coefficient_width(filter, scale_ratio);
835 for (i = 0; i < max; i++)
836 {
837 if (i + skip >= width)
838 break;
839
840 *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i) = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i + skip);
841 }
842
843 continue;
844 }
845
846 // Using min to avoid writing into invalid pixels.
847 for (i = 0; i < num_contributors; i++)
848 contributors[i].n1 = stbir__min(contributors[i].n1, output_size - 1);
849}
850
851// Each scan line uses the same kernel values so we should calculate the kernel
852// values once and then we can use them for every scan line.
853static void stbir__calculate_filters(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, float shift, int input_size, int output_size)
854{
855 int n;
856 int total_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size);
857
858 if (stbir__use_upsampling(scale_ratio))
859 {
860 float out_pixels_radius = stbir__filter_info_table[filter].support(1 / scale_ratio) * scale_ratio;
861
862 // Looping through out pixels
863 for (n = 0; n < total_contributors; n++)
864 {
865 float in_center_of_out; // Center of the current out pixel in the in pixel space
866 int in_first_pixel, in_last_pixel;
867
868 stbir__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, shift, &in_first_pixel, &in_last_pixel, &in_center_of_out);
869
870 stbir__calculate_coefficients_upsample(filter, scale_ratio, in_first_pixel, in_last_pixel, in_center_of_out, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0));
871 }
872 }
873 else
874 {
875 float in_pixels_radius = stbir__filter_info_table[filter].support(scale_ratio) / scale_ratio;
876
877 // Looping through in pixels
878 for (n = 0; n < total_contributors; n++)
879 {
880 float out_center_of_in; // Center of the current out pixel in the in pixel space
881 int out_first_pixel, out_last_pixel;
882 int n_adjusted = n - stbir__get_filter_pixel_margin(filter, scale_ratio);
883
884 stbir__calculate_sample_range_downsample(n_adjusted, in_pixels_radius, scale_ratio, shift, &out_first_pixel, &out_last_pixel, &out_center_of_in);
885
886 stbir__calculate_coefficients_downsample(filter, scale_ratio, out_first_pixel, out_last_pixel, out_center_of_in, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0));
887 }
888
889 stbir__normalize_downsample_coefficients(contributors, coefficients, filter, scale_ratio, input_size, output_size);
890 }
891}
892
893static float* stbir__get_decode_buffer(stbir__info* stbir_info)
894{
895 // The 0 index of the decode buffer starts after the margin. This makes
896 // it okay to use negative indexes on the decode buffer.
897 return &stbir_info->decode_buffer[stbir_info->horizontal_filter_pixel_margin * stbir_info->channels];
898}
899
900#define STBIR__DECODE(type, colorspace) ((int)(type) * (STBIR_MAX_COLORSPACES) + (int)(colorspace))
901
902static void stbir__decode_scanline(stbir__info* stbir_info, int n)
903{
904 int c;
905 int channels = stbir_info->channels;
906 int alpha_channel = stbir_info->alpha_channel;
907 int type = stbir_info->type;
908 int colorspace = stbir_info->colorspace;
909 int input_w = stbir_info->input_w;
910 size_t input_stride_bytes = stbir_info->input_stride_bytes;
911 float* decode_buffer = stbir__get_decode_buffer(stbir_info);
912 stbir_edge edge_horizontal = stbir_info->edge_horizontal;
913 stbir_edge edge_vertical = stbir_info->edge_vertical;
914 size_t in_buffer_row_offset = stbir__edge_wrap(edge_vertical, n, stbir_info->input_h) * input_stride_bytes;
915 const void* input_data = (char *) stbir_info->input_data + in_buffer_row_offset;
916 int max_x = input_w + stbir_info->horizontal_filter_pixel_margin;
917 int decode = STBIR__DECODE(type, colorspace);
918
919 int x = -stbir_info->horizontal_filter_pixel_margin;
920
921 // special handling for STBIR_EDGE_ZERO because it needs to return an item that doesn't appear in the input,
922 // and we want to avoid paying overhead on every pixel if not STBIR_EDGE_ZERO
923 if (edge_vertical == STBIR_EDGE_ZERO && (n < 0 || n >= stbir_info->input_h))
924 {
925 for (; x < max_x; x++)
926 for (c = 0; c < channels; c++)
927 decode_buffer[x*channels + c] = 0;
928 return;
929 }
930
931 switch (decode)
932 {
933 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
934 for (; x < max_x; x++)
935 {
936 int decode_pixel_index = x * channels;
937 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
938 for (c = 0; c < channels; c++)
939 decode_buffer[decode_pixel_index + c] = ((float)((const unsigned char*)input_data)[input_pixel_index + c]) / stbir__max_uint8_as_float;
940 }
941 break;
942
943 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
944 for (; x < max_x; x++)
945 {
946 int decode_pixel_index = x * channels;
947 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
948 for (c = 0; c < channels; c++)
949 decode_buffer[decode_pixel_index + c] = stbir__srgb_uchar_to_linear_float[((const unsigned char*)input_data)[input_pixel_index + c]];
950
951 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
952 decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned char*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint8_as_float;
953 }
954 break;
955
956 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
957 for (; x < max_x; x++)
958 {
959 int decode_pixel_index = x * channels;
960 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
961 for (c = 0; c < channels; c++)
962 decode_buffer[decode_pixel_index + c] = ((float)((const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float;
963 }
964 break;
965
966 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
967 for (; x < max_x; x++)
968 {
969 int decode_pixel_index = x * channels;
970 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
971 for (c = 0; c < channels; c++)
972 decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((float)((const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float);
973
974 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
975 decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned short*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint16_as_float;
976 }
977 break;
978
979 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
980 for (; x < max_x; x++)
981 {
982 int decode_pixel_index = x * channels;
983 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
984 for (c = 0; c < channels; c++)
985 decode_buffer[decode_pixel_index + c] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float);
986 }
987 break;
988
989 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
990 for (; x < max_x; x++)
991 {
992 int decode_pixel_index = x * channels;
993 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
994 for (c = 0; c < channels; c++)
995 decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear((float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float));
996
997 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
998 decode_buffer[decode_pixel_index + alpha_channel] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint32_as_float);
999 }
1000 break;
1001
1002 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
1003 for (; x < max_x; x++)
1004 {
1005 int decode_pixel_index = x * channels;
1006 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1007 for (c = 0; c < channels; c++)
1008 decode_buffer[decode_pixel_index + c] = ((const float*)input_data)[input_pixel_index + c];
1009 }
1010 break;
1011
1012 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
1013 for (; x < max_x; x++)
1014 {
1015 int decode_pixel_index = x * channels;
1016 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1017 for (c = 0; c < channels; c++)
1018 decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((const float*)input_data)[input_pixel_index + c]);
1019
1020 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1021 decode_buffer[decode_pixel_index + alpha_channel] = ((const float*)input_data)[input_pixel_index + alpha_channel];
1022 }
1023
1024 break;
1025
1026 default:
1027 STBIR_ASSERT(!"Unknown type/colorspace/channels combination.");
1028 break;
1029 }
1030
1031 if (!(stbir_info->flags & STBIR_FLAG_ALPHA_PREMULTIPLIED))
1032 {
1033 for (x = -stbir_info->horizontal_filter_pixel_margin; x < max_x; x++)
1034 {
1035 int decode_pixel_index = x * channels;
1036
1037 // If the alpha value is 0 it will clobber the color values. Make sure it's not.
1038 float alpha = decode_buffer[decode_pixel_index + alpha_channel];
1039#ifndef STBIR_NO_ALPHA_EPSILON
1040 if (stbir_info->type != STBIR_TYPE_FLOAT) {
1041 alpha += STBIR_ALPHA_EPSILON;
1042 decode_buffer[decode_pixel_index + alpha_channel] = alpha;
1043 }
1044#endif
1045 for (c = 0; c < channels; c++)
1046 {
1047 if (c == alpha_channel)
1048 continue;
1049
1050 decode_buffer[decode_pixel_index + c] *= alpha;
1051 }
1052 }
1053 }
1054
1055 if (edge_horizontal == STBIR_EDGE_ZERO)
1056 {
1057 for (x = -stbir_info->horizontal_filter_pixel_margin; x < 0; x++)
1058 {
1059 for (c = 0; c < channels; c++)
1060 decode_buffer[x*channels + c] = 0;
1061 }
1062 for (x = input_w; x < max_x; x++)
1063 {
1064 for (c = 0; c < channels; c++)
1065 decode_buffer[x*channels + c] = 0;
1066 }
1067 }
1068}
1069
1070static float* stbir__get_ring_buffer_entry(float* ring_buffer, int index, int ring_buffer_length)
1071{
1072 return &ring_buffer[index * ring_buffer_length];
1073}
1074
1075static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n)
1076{
1077 int ring_buffer_index;
1078 float* ring_buffer;
1079
1080 stbir_info->ring_buffer_last_scanline = n;
1081
1082 if (stbir_info->ring_buffer_begin_index < 0)
1083 {
1084 ring_buffer_index = stbir_info->ring_buffer_begin_index = 0;
1085 stbir_info->ring_buffer_first_scanline = n;
1086 }
1087 else
1088 {
1089 ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline)) % stbir_info->ring_buffer_num_entries;
1090 STBIR_ASSERT(ring_buffer_index != stbir_info->ring_buffer_begin_index);
1091 }
1092
1093 ring_buffer = stbir__get_ring_buffer_entry(stbir_info->ring_buffer, ring_buffer_index, stbir_info->ring_buffer_length_bytes / sizeof(float));
1094 memset(ring_buffer, 0, stbir_info->ring_buffer_length_bytes);
1095
1096 return ring_buffer;
1097}
1098
1099
1100static void stbir__resample_horizontal_upsample(stbir__info* stbir_info, float* output_buffer)
1101{
1102 int x, k;
1103 int output_w = stbir_info->output_w;
1104 int channels = stbir_info->channels;
1105 float* decode_buffer = stbir__get_decode_buffer(stbir_info);
1106 stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
1107 float* horizontal_coefficients = stbir_info->horizontal_coefficients;
1108 int coefficient_width = stbir_info->horizontal_coefficient_width;
1109
1110 for (x = 0; x < output_w; x++)
1111 {
1112 int n0 = horizontal_contributors[x].n0;
1113 int n1 = horizontal_contributors[x].n1;
1114
1115 int out_pixel_index = x * channels;
1116 int coefficient_group = coefficient_width * x;
1117 int coefficient_counter = 0;
1118
1119 STBIR_ASSERT(n1 >= n0);
1120 STBIR_ASSERT(n0 >= -stbir_info->horizontal_filter_pixel_margin);
1121 STBIR_ASSERT(n1 >= -stbir_info->horizontal_filter_pixel_margin);
1122 STBIR_ASSERT(n0 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin);
1123 STBIR_ASSERT(n1 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin);
1124
1125 switch (channels) {
1126 case 1:
1127 for (k = n0; k <= n1; k++)
1128 {
1129 int in_pixel_index = k * 1;
1130 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1131 STBIR_ASSERT(coefficient != 0);
1132 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1133 }
1134 break;
1135 case 2:
1136 for (k = n0; k <= n1; k++)
1137 {
1138 int in_pixel_index = k * 2;
1139 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1140 STBIR_ASSERT(coefficient != 0);
1141 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1142 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1143 }
1144 break;
1145 case 3:
1146 for (k = n0; k <= n1; k++)
1147 {
1148 int in_pixel_index = k * 3;
1149 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1150 STBIR_ASSERT(coefficient != 0);
1151 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1152 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1153 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1154 }
1155 break;
1156 case 4:
1157 for (k = n0; k <= n1; k++)
1158 {
1159 int in_pixel_index = k * 4;
1160 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1161 STBIR_ASSERT(coefficient != 0);
1162 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1163 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1164 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1165 output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
1166 }
1167 break;
1168 default:
1169 for (k = n0; k <= n1; k++)
1170 {
1171 int in_pixel_index = k * channels;
1172 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1173 int c;
1174 STBIR_ASSERT(coefficient != 0);
1175 for (c = 0; c < channels; c++)
1176 output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
1177 }
1178 break;
1179 }
1180 }
1181}
1182
1183static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, float* output_buffer)
1184{
1185 int x, k;
1186 int input_w = stbir_info->input_w;
1187 int channels = stbir_info->channels;
1188 float* decode_buffer = stbir__get_decode_buffer(stbir_info);
1189 stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
1190 float* horizontal_coefficients = stbir_info->horizontal_coefficients;
1191 int coefficient_width = stbir_info->horizontal_coefficient_width;
1192 int filter_pixel_margin = stbir_info->horizontal_filter_pixel_margin;
1193 int max_x = input_w + filter_pixel_margin * 2;
1194
1195 STBIR_ASSERT(!stbir__use_width_upsampling(stbir_info));
1196
1197 switch (channels) {
1198 case 1:
1199 for (x = 0; x < max_x; x++)
1200 {
1201 int n0 = horizontal_contributors[x].n0;
1202 int n1 = horizontal_contributors[x].n1;
1203
1204 int in_x = x - filter_pixel_margin;
1205 int in_pixel_index = in_x * 1;
1206 int max_n = n1;
1207 int coefficient_group = coefficient_width * x;
1208
1209 for (k = n0; k <= max_n; k++)
1210 {
1211 int out_pixel_index = k * 1;
1212 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1213 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1214 }
1215 }
1216 break;
1217
1218 case 2:
1219 for (x = 0; x < max_x; x++)
1220 {
1221 int n0 = horizontal_contributors[x].n0;
1222 int n1 = horizontal_contributors[x].n1;
1223
1224 int in_x = x - filter_pixel_margin;
1225 int in_pixel_index = in_x * 2;
1226 int max_n = n1;
1227 int coefficient_group = coefficient_width * x;
1228
1229 for (k = n0; k <= max_n; k++)
1230 {
1231 int out_pixel_index = k * 2;
1232 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1233 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1234 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1235 }
1236 }
1237 break;
1238
1239 case 3:
1240 for (x = 0; x < max_x; x++)
1241 {
1242 int n0 = horizontal_contributors[x].n0;
1243 int n1 = horizontal_contributors[x].n1;
1244
1245 int in_x = x - filter_pixel_margin;
1246 int in_pixel_index = in_x * 3;
1247 int max_n = n1;
1248 int coefficient_group = coefficient_width * x;
1249
1250 for (k = n0; k <= max_n; k++)
1251 {
1252 int out_pixel_index = k * 3;
1253 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1254 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1255 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1256 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1257 }
1258 }
1259 break;
1260
1261 case 4:
1262 for (x = 0; x < max_x; x++)
1263 {
1264 int n0 = horizontal_contributors[x].n0;
1265 int n1 = horizontal_contributors[x].n1;
1266
1267 int in_x = x - filter_pixel_margin;
1268 int in_pixel_index = in_x * 4;
1269 int max_n = n1;
1270 int coefficient_group = coefficient_width * x;
1271
1272 for (k = n0; k <= max_n; k++)
1273 {
1274 int out_pixel_index = k * 4;
1275 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1276 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1277 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1278 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1279 output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
1280 }
1281 }
1282 break;
1283
1284 default:
1285 for (x = 0; x < max_x; x++)
1286 {
1287 int n0 = horizontal_contributors[x].n0;
1288 int n1 = horizontal_contributors[x].n1;
1289
1290 int in_x = x - filter_pixel_margin;
1291 int in_pixel_index = in_x * channels;
1292 int max_n = n1;
1293 int coefficient_group = coefficient_width * x;
1294
1295 for (k = n0; k <= max_n; k++)
1296 {
1297 int c;
1298 int out_pixel_index = k * channels;
1299 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1300 for (c = 0; c < channels; c++)
1301 output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
1302 }
1303 }
1304 break;
1305 }
1306}
1307
1308static void stbir__decode_and_resample_upsample(stbir__info* stbir_info, int n)
1309{
1310 // Decode the nth scanline from the source image into the decode buffer.
1311 stbir__decode_scanline(stbir_info, n);
1312
1313 // Now resample it into the ring buffer.
1314 if (stbir__use_width_upsampling(stbir_info))
1315 stbir__resample_horizontal_upsample(stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n));
1316 else
1317 stbir__resample_horizontal_downsample(stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n));
1318
1319 // Now it's sitting in the ring buffer ready to be used as source for the vertical sampling.
1320}
1321
1322static void stbir__decode_and_resample_downsample(stbir__info* stbir_info, int n)
1323{
1324 // Decode the nth scanline from the source image into the decode buffer.
1325 stbir__decode_scanline(stbir_info, n);
1326
1327 memset(stbir_info->horizontal_buffer, 0, stbir_info->output_w * stbir_info->channels * sizeof(float));
1328
1329 // Now resample it into the horizontal buffer.
1330 if (stbir__use_width_upsampling(stbir_info))
1331 stbir__resample_horizontal_upsample(stbir_info, stbir_info->horizontal_buffer);
1332 else
1333 stbir__resample_horizontal_downsample(stbir_info, stbir_info->horizontal_buffer);
1334
1335 // Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers.
1336}
1337
1338// Get the specified scan line from the ring buffer.
1339static float* stbir__get_ring_buffer_scanline(int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_num_entries, int ring_buffer_length)
1340{
1341 int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_num_entries;
1342 return stbir__get_ring_buffer_entry(ring_buffer, ring_buffer_index, ring_buffer_length);
1343}
1344
1345
1346static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void *output_buffer, float *encode_buffer, int channels, int alpha_channel, int decode)
1347{
1348 int x;
1349 int n;
1350 int num_nonalpha;
1351 stbir_uint16 nonalpha[STBIR_MAX_CHANNELS];
1352
1353 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_PREMULTIPLIED))
1354 {
1355 for (x=0; x < num_pixels; ++x)
1356 {
1357 int pixel_index = x*channels;
1358
1359 float alpha = encode_buffer[pixel_index + alpha_channel];
1360 float reciprocal_alpha = alpha ? 1.0f / alpha : 0;
1361
1362 // unrolling this produced a 1% slowdown upscaling a large RGBA linear-space image on my machine - stb
1363 for (n = 0; n < channels; n++)
1364 if (n != alpha_channel)
1365 encode_buffer[pixel_index + n] *= reciprocal_alpha;
1366
1367 // We added in a small epsilon to prevent the color channel from being deleted with zero alpha.
1368 // Because we only add it for integer types, it will automatically be discarded on integer
1369 // conversion, so we don't need to subtract it back out (which would be problematic for
1370 // numeric precision reasons).
1371 }
1372 }
1373
1374 // build a table of all channels that need colorspace correction, so
1375 // we don't perform colorspace correction on channels that don't need it.
1376 for (x = 0, num_nonalpha = 0; x < channels; ++x)
1377 {
1378 if (x != alpha_channel || (stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE))
1379 {
1380 nonalpha[num_nonalpha++] = (stbir_uint16)x;
1381 }
1382 }
1383
1384 #define STBIR__ROUND_INT(f) ((int) ((f)+0.5))
1385 #define STBIR__ROUND_UINT(f) ((stbir_uint32) ((f)+0.5))
1386
1387 #ifdef STBIR__SATURATE_INT
1388 #define STBIR__ENCODE_LINEAR8(f) stbir__saturate8 (STBIR__ROUND_INT((f) * stbir__max_uint8_as_float ))
1389 #define STBIR__ENCODE_LINEAR16(f) stbir__saturate16(STBIR__ROUND_INT((f) * stbir__max_uint16_as_float))
1390 #else
1391 #define STBIR__ENCODE_LINEAR8(f) (unsigned char ) STBIR__ROUND_INT(stbir__saturate(f) * stbir__max_uint8_as_float )
1392 #define STBIR__ENCODE_LINEAR16(f) (unsigned short) STBIR__ROUND_INT(stbir__saturate(f) * stbir__max_uint16_as_float)
1393 #endif
1394
1395 switch (decode)
1396 {
1397 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
1398 for (x=0; x < num_pixels; ++x)
1399 {
1400 int pixel_index = x*channels;
1401
1402 for (n = 0; n < channels; n++)
1403 {
1404 int index = pixel_index + n;
1405 ((unsigned char*)output_buffer)[index] = STBIR__ENCODE_LINEAR8(encode_buffer[index]);
1406 }
1407 }
1408 break;
1409
1410 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
1411 for (x=0; x < num_pixels; ++x)
1412 {
1413 int pixel_index = x*channels;
1414
1415 for (n = 0; n < num_nonalpha; n++)
1416 {
1417 int index = pixel_index + nonalpha[n];
1418 ((unsigned char*)output_buffer)[index] = stbir__linear_to_srgb_uchar(encode_buffer[index]);
1419 }
1420
1421 if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE))
1422 ((unsigned char *)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR8(encode_buffer[pixel_index+alpha_channel]);
1423 }
1424 break;
1425
1426 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
1427 for (x=0; x < num_pixels; ++x)
1428 {
1429 int pixel_index = x*channels;
1430
1431 for (n = 0; n < channels; n++)
1432 {
1433 int index = pixel_index + n;
1434 ((unsigned short*)output_buffer)[index] = STBIR__ENCODE_LINEAR16(encode_buffer[index]);
1435 }
1436 }
1437 break;
1438
1439 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
1440 for (x=0; x < num_pixels; ++x)
1441 {
1442 int pixel_index = x*channels;
1443
1444 for (n = 0; n < num_nonalpha; n++)
1445 {
1446 int index = pixel_index + nonalpha[n];
1447 ((unsigned short*)output_buffer)[index] = (unsigned short)STBIR__ROUND_INT(stbir__linear_to_srgb(stbir__saturate(encode_buffer[index])) * stbir__max_uint16_as_float);
1448 }
1449
1450 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1451 ((unsigned short*)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR16(encode_buffer[pixel_index + alpha_channel]);
1452 }
1453
1454 break;
1455
1456 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
1457 for (x=0; x < num_pixels; ++x)
1458 {
1459 int pixel_index = x*channels;
1460
1461 for (n = 0; n < channels; n++)
1462 {
1463 int index = pixel_index + n;
1464 ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT(((double)stbir__saturate(encode_buffer[index])) * stbir__max_uint32_as_float);
1465 }
1466 }
1467 break;
1468
1469 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
1470 for (x=0; x < num_pixels; ++x)
1471 {
1472 int pixel_index = x*channels;
1473
1474 for (n = 0; n < num_nonalpha; n++)
1475 {
1476 int index = pixel_index + nonalpha[n];
1477 ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[index]))) * stbir__max_uint32_as_float);
1478 }
1479
1480 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1481 ((unsigned int*)output_buffer)[pixel_index + alpha_channel] = (unsigned int)STBIR__ROUND_INT(((double)stbir__saturate(encode_buffer[pixel_index + alpha_channel])) * stbir__max_uint32_as_float);
1482 }
1483 break;
1484
1485 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
1486 for (x=0; x < num_pixels; ++x)
1487 {
1488 int pixel_index = x*channels;
1489
1490 for (n = 0; n < channels; n++)
1491 {
1492 int index = pixel_index + n;
1493 ((float*)output_buffer)[index] = encode_buffer[index];
1494 }
1495 }
1496 break;
1497
1498 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
1499 for (x=0; x < num_pixels; ++x)
1500 {
1501 int pixel_index = x*channels;
1502
1503 for (n = 0; n < num_nonalpha; n++)
1504 {
1505 int index = pixel_index + nonalpha[n];
1506 ((float*)output_buffer)[index] = stbir__linear_to_srgb(encode_buffer[index]);
1507 }
1508
1509 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1510 ((float*)output_buffer)[pixel_index + alpha_channel] = encode_buffer[pixel_index + alpha_channel];
1511 }
1512 break;
1513
1514 default:
1515 STBIR_ASSERT(!"Unknown type/colorspace/channels combination.");
1516 break;
1517 }
1518}
1519
1520static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n)
1521{
1522 int x, k;
1523 int output_w = stbir_info->output_w;
1524 stbir__contributors* vertical_contributors = stbir_info->vertical_contributors;
1525 float* vertical_coefficients = stbir_info->vertical_coefficients;
1526 int channels = stbir_info->channels;
1527 int alpha_channel = stbir_info->alpha_channel;
1528 int type = stbir_info->type;
1529 int colorspace = stbir_info->colorspace;
1530 int ring_buffer_entries = stbir_info->ring_buffer_num_entries;
1531 void* output_data = stbir_info->output_data;
1532 float* encode_buffer = stbir_info->encode_buffer;
1533 int decode = STBIR__DECODE(type, colorspace);
1534 int coefficient_width = stbir_info->vertical_coefficient_width;
1535 int coefficient_counter;
1536 int contributor = n;
1537
1538 float* ring_buffer = stbir_info->ring_buffer;
1539 int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
1540 int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
1541 int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
1542
1543 int n0,n1, output_row_start;
1544 int coefficient_group = coefficient_width * contributor;
1545
1546 n0 = vertical_contributors[contributor].n0;
1547 n1 = vertical_contributors[contributor].n1;
1548
1549 output_row_start = n * stbir_info->output_stride_bytes;
1550
1551 STBIR_ASSERT(stbir__use_height_upsampling(stbir_info));
1552
1553 memset(encode_buffer, 0, output_w * sizeof(float) * channels);
1554
1555 // I tried reblocking this for better cache usage of encode_buffer
1556 // (using x_outer, k, x_inner), but it lost speed. -- stb
1557
1558 coefficient_counter = 0;
1559 switch (channels) {
1560 case 1:
1561 for (k = n0; k <= n1; k++)
1562 {
1563 int coefficient_index = coefficient_counter++;
1564 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1565 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1566 for (x = 0; x < output_w; ++x)
1567 {
1568 int in_pixel_index = x * 1;
1569 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1570 }
1571 }
1572 break;
1573 case 2:
1574 for (k = n0; k <= n1; k++)
1575 {
1576 int coefficient_index = coefficient_counter++;
1577 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1578 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1579 for (x = 0; x < output_w; ++x)
1580 {
1581 int in_pixel_index = x * 2;
1582 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1583 encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
1584 }
1585 }
1586 break;
1587 case 3:
1588 for (k = n0; k <= n1; k++)
1589 {
1590 int coefficient_index = coefficient_counter++;
1591 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1592 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1593 for (x = 0; x < output_w; ++x)
1594 {
1595 int in_pixel_index = x * 3;
1596 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1597 encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
1598 encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient;
1599 }
1600 }
1601 break;
1602 case 4:
1603 for (k = n0; k <= n1; k++)
1604 {
1605 int coefficient_index = coefficient_counter++;
1606 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1607 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1608 for (x = 0; x < output_w; ++x)
1609 {
1610 int in_pixel_index = x * 4;
1611 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1612 encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
1613 encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient;
1614 encode_buffer[in_pixel_index + 3] += ring_buffer_entry[in_pixel_index + 3] * coefficient;
1615 }
1616 }
1617 break;
1618 default:
1619 for (k = n0; k <= n1; k++)
1620 {
1621 int coefficient_index = coefficient_counter++;
1622 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1623 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1624 for (x = 0; x < output_w; ++x)
1625 {
1626 int in_pixel_index = x * channels;
1627 int c;
1628 for (c = 0; c < channels; c++)
1629 encode_buffer[in_pixel_index + c] += ring_buffer_entry[in_pixel_index + c] * coefficient;
1630 }
1631 }
1632 break;
1633 }
1634 stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, encode_buffer, channels, alpha_channel, decode);
1635}
1636
1637static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n)
1638{
1639 int x, k;
1640 int output_w = stbir_info->output_w;
1641 stbir__contributors* vertical_contributors = stbir_info->vertical_contributors;
1642 float* vertical_coefficients = stbir_info->vertical_coefficients;
1643 int channels = stbir_info->channels;
1644 int ring_buffer_entries = stbir_info->ring_buffer_num_entries;
1645 float* horizontal_buffer = stbir_info->horizontal_buffer;
1646 int coefficient_width = stbir_info->vertical_coefficient_width;
1647 int contributor = n + stbir_info->vertical_filter_pixel_margin;
1648
1649 float* ring_buffer = stbir_info->ring_buffer;
1650 int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
1651 int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
1652 int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
1653 int n0,n1;
1654
1655 n0 = vertical_contributors[contributor].n0;
1656 n1 = vertical_contributors[contributor].n1;
1657
1658 STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info));
1659
1660 for (k = n0; k <= n1; k++)
1661 {
1662 int coefficient_index = k - n0;
1663 int coefficient_group = coefficient_width * contributor;
1664 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1665
1666 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1667
1668 switch (channels) {
1669 case 1:
1670 for (x = 0; x < output_w; x++)
1671 {
1672 int in_pixel_index = x * 1;
1673 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
1674 }
1675 break;
1676 case 2:
1677 for (x = 0; x < output_w; x++)
1678 {
1679 int in_pixel_index = x * 2;
1680 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
1681 ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
1682 }
1683 break;
1684 case 3:
1685 for (x = 0; x < output_w; x++)
1686 {
1687 int in_pixel_index = x * 3;
1688 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
1689 ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
1690 ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient;
1691 }
1692 break;
1693 case 4:
1694 for (x = 0; x < output_w; x++)
1695 {
1696 int in_pixel_index = x * 4;
1697 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
1698 ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
1699 ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient;
1700 ring_buffer_entry[in_pixel_index + 3] += horizontal_buffer[in_pixel_index + 3] * coefficient;
1701 }
1702 break;
1703 default:
1704 for (x = 0; x < output_w; x++)
1705 {
1706 int in_pixel_index = x * channels;
1707
1708 int c;
1709 for (c = 0; c < channels; c++)
1710 ring_buffer_entry[in_pixel_index + c] += horizontal_buffer[in_pixel_index + c] * coefficient;
1711 }
1712 break;
1713 }
1714 }
1715}
1716
1717static void stbir__buffer_loop_upsample(stbir__info* stbir_info)
1718{
1719 int y;
1720 float scale_ratio = stbir_info->vertical_scale;
1721 float out_scanlines_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(1/scale_ratio) * scale_ratio;
1722
1723 STBIR_ASSERT(stbir__use_height_upsampling(stbir_info));
1724
1725 for (y = 0; y < stbir_info->output_h; y++)
1726 {
1727 float in_center_of_out = 0; // Center of the current out scanline in the in scanline space
1728 int in_first_scanline = 0, in_last_scanline = 0;
1729
1730 stbir__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, stbir_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out);
1731
1732 STBIR_ASSERT(in_last_scanline - in_first_scanline + 1 <= stbir_info->ring_buffer_num_entries);
1733
1734 if (stbir_info->ring_buffer_begin_index >= 0)
1735 {
1736 // Get rid of whatever we don't need anymore.
1737 while (in_first_scanline > stbir_info->ring_buffer_first_scanline)
1738 {
1739 if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
1740 {
1741 // We just popped the last scanline off the ring buffer.
1742 // Reset it to the empty state.
1743 stbir_info->ring_buffer_begin_index = -1;
1744 stbir_info->ring_buffer_first_scanline = 0;
1745 stbir_info->ring_buffer_last_scanline = 0;
1746 break;
1747 }
1748 else
1749 {
1750 stbir_info->ring_buffer_first_scanline++;
1751 stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries;
1752 }
1753 }
1754 }
1755
1756 // Load in new ones.
1757 if (stbir_info->ring_buffer_begin_index < 0)
1758 stbir__decode_and_resample_upsample(stbir_info, in_first_scanline);
1759
1760 while (in_last_scanline > stbir_info->ring_buffer_last_scanline)
1761 stbir__decode_and_resample_upsample(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
1762
1763 // Now all buffers should be ready to write a row of vertical sampling.
1764 stbir__resample_vertical_upsample(stbir_info, y);
1765
1766 STBIR_PROGRESS_REPORT((float)y / stbir_info->output_h);
1767 }
1768}
1769
1770static void stbir__empty_ring_buffer(stbir__info* stbir_info, int first_necessary_scanline)
1771{
1772 int output_stride_bytes = stbir_info->output_stride_bytes;
1773 int channels = stbir_info->channels;
1774 int alpha_channel = stbir_info->alpha_channel;
1775 int type = stbir_info->type;
1776 int colorspace = stbir_info->colorspace;
1777 int output_w = stbir_info->output_w;
1778 void* output_data = stbir_info->output_data;
1779 int decode = STBIR__DECODE(type, colorspace);
1780
1781 float* ring_buffer = stbir_info->ring_buffer;
1782 int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
1783
1784 if (stbir_info->ring_buffer_begin_index >= 0)
1785 {
1786 // Get rid of whatever we don't need anymore.
1787 while (first_necessary_scanline > stbir_info->ring_buffer_first_scanline)
1788 {
1789 if (stbir_info->ring_buffer_first_scanline >= 0 && stbir_info->ring_buffer_first_scanline < stbir_info->output_h)
1790 {
1791 int output_row_start = stbir_info->ring_buffer_first_scanline * output_stride_bytes;
1792 float* ring_buffer_entry = stbir__get_ring_buffer_entry(ring_buffer, stbir_info->ring_buffer_begin_index, ring_buffer_length);
1793 stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, ring_buffer_entry, channels, alpha_channel, decode);
1794 STBIR_PROGRESS_REPORT((float)stbir_info->ring_buffer_first_scanline / stbir_info->output_h);
1795 }
1796
1797 if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
1798 {
1799 // We just popped the last scanline off the ring buffer.
1800 // Reset it to the empty state.
1801 stbir_info->ring_buffer_begin_index = -1;
1802 stbir_info->ring_buffer_first_scanline = 0;
1803 stbir_info->ring_buffer_last_scanline = 0;
1804 break;
1805 }
1806 else
1807 {
1808 stbir_info->ring_buffer_first_scanline++;
1809 stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries;
1810 }
1811 }
1812 }
1813}
1814
1815static void stbir__buffer_loop_downsample(stbir__info* stbir_info)
1816{
1817 int y;
1818 float scale_ratio = stbir_info->vertical_scale;
1819 int output_h = stbir_info->output_h;
1820 float in_pixels_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(scale_ratio) / scale_ratio;
1821 int pixel_margin = stbir_info->vertical_filter_pixel_margin;
1822 int max_y = stbir_info->input_h + pixel_margin;
1823
1824 STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info));
1825
1826 for (y = -pixel_margin; y < max_y; y++)
1827 {
1828 float out_center_of_in; // Center of the current out scanline in the in scanline space
1829 int out_first_scanline, out_last_scanline;
1830
1831 stbir__calculate_sample_range_downsample(y, in_pixels_radius, scale_ratio, stbir_info->vertical_shift, &out_first_scanline, &out_last_scanline, &out_center_of_in);
1832
1833 STBIR_ASSERT(out_last_scanline - out_first_scanline + 1 <= stbir_info->ring_buffer_num_entries);
1834
1835 if (out_last_scanline < 0 || out_first_scanline >= output_h)
1836 continue;
1837
1838 stbir__empty_ring_buffer(stbir_info, out_first_scanline);
1839
1840 stbir__decode_and_resample_downsample(stbir_info, y);
1841
1842 // Load in new ones.
1843 if (stbir_info->ring_buffer_begin_index < 0)
1844 stbir__add_empty_ring_buffer_entry(stbir_info, out_first_scanline);
1845
1846 while (out_last_scanline > stbir_info->ring_buffer_last_scanline)
1847 stbir__add_empty_ring_buffer_entry(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
1848
1849 // Now the horizontal buffer is ready to write to all ring buffer rows.
1850 stbir__resample_vertical_downsample(stbir_info, y);
1851 }
1852
1853 stbir__empty_ring_buffer(stbir_info, stbir_info->output_h);
1854}
1855
1856static void stbir__setup(stbir__info *info, int input_w, int input_h, int output_w, int output_h, int channels)
1857{
1858 info->input_w = input_w;
1859 info->input_h = input_h;
1860 info->output_w = output_w;
1861 info->output_h = output_h;
1862 info->channels = channels;
1863}
1864
1865static void stbir__calculate_transform(stbir__info *info, float s0, float t0, float s1, float t1, float *transform)
1866{
1867 info->s0 = s0;
1868 info->t0 = t0;
1869 info->s1 = s1;
1870 info->t1 = t1;
1871
1872 if (transform)
1873 {
1874 info->horizontal_scale = transform[0];
1875 info->vertical_scale = transform[1];
1876 info->horizontal_shift = transform[2];
1877 info->vertical_shift = transform[3];
1878 }
1879 else
1880 {
1881 info->horizontal_scale = ((float)info->output_w / info->input_w) / (s1 - s0);
1882 info->vertical_scale = ((float)info->output_h / info->input_h) / (t1 - t0);
1883
1884 info->horizontal_shift = s0 * info->output_w / (s1 - s0);
1885 info->vertical_shift = t0 * info->output_h / (t1 - t0);
1886 }
1887}
1888
1889static void stbir__choose_filter(stbir__info *info, stbir_filter h_filter, stbir_filter v_filter)
1890{
1891 if (h_filter == 0)
1892 h_filter = stbir__use_upsampling(info->horizontal_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
1893 if (v_filter == 0)
1894 v_filter = stbir__use_upsampling(info->vertical_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
1895 info->horizontal_filter = h_filter;
1896 info->vertical_filter = v_filter;
1897}
1898
1899static stbir_uint32 stbir__calculate_memory(stbir__info *info)
1900{
1901 int pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
1902 int filter_height = stbir__get_filter_pixel_width(info->vertical_filter, info->vertical_scale);
1903
1904 info->horizontal_num_contributors = stbir__get_contributors(info->horizontal_scale, info->horizontal_filter, info->input_w, info->output_w);
1905 info->vertical_num_contributors = stbir__get_contributors(info->vertical_scale , info->vertical_filter , info->input_h, info->output_h);
1906
1907 // One extra entry because floating point precision problems sometimes cause an extra to be necessary.
1908 info->ring_buffer_num_entries = filter_height + 1;
1909
1910 info->horizontal_contributors_size = info->horizontal_num_contributors * sizeof(stbir__contributors);
1911 info->horizontal_coefficients_size = stbir__get_total_horizontal_coefficients(info) * sizeof(float);
1912 info->vertical_contributors_size = info->vertical_num_contributors * sizeof(stbir__contributors);
1913 info->vertical_coefficients_size = stbir__get_total_vertical_coefficients(info) * sizeof(float);
1914 info->decode_buffer_size = (info->input_w + pixel_margin * 2) * info->channels * sizeof(float);
1915 info->horizontal_buffer_size = info->output_w * info->channels * sizeof(float);
1916 info->ring_buffer_size = info->output_w * info->channels * info->ring_buffer_num_entries * sizeof(float);
1917 info->encode_buffer_size = info->output_w * info->channels * sizeof(float);
1918
1919 STBIR_ASSERT(info->horizontal_filter != 0);
1920 STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
1921 STBIR_ASSERT(info->vertical_filter != 0);
1922 STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
1923
1924 if (stbir__use_height_upsampling(info))
1925 // The horizontal buffer is for when we're downsampling the height and we
1926 // can't output the result of sampling the decode buffer directly into the
1927 // ring buffers.
1928 info->horizontal_buffer_size = 0;
1929 else
1930 // The encode buffer is to retain precision in the height upsampling method
1931 // and isn't used when height downsampling.
1932 info->encode_buffer_size = 0;
1933
1934 return info->horizontal_contributors_size + info->horizontal_coefficients_size
1935 + info->vertical_contributors_size + info->vertical_coefficients_size
1936 + info->decode_buffer_size + info->horizontal_buffer_size
1937 + info->ring_buffer_size + info->encode_buffer_size;
1938}
1939
1940static int stbir__resize_allocated(stbir__info *info,
1941 const void* input_data, int input_stride_in_bytes,
1942 void* output_data, int output_stride_in_bytes,
1943 int alpha_channel, stbir_uint32 flags, stbir_datatype type,
1944 stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace,
1945 void* tempmem, size_t tempmem_size_in_bytes)
1946{
1947 size_t memory_required = stbir__calculate_memory(info);
1948
1949 int width_stride_input = input_stride_in_bytes ? input_stride_in_bytes : info->channels * info->input_w * stbir__type_size[type];
1950 int width_stride_output = output_stride_in_bytes ? output_stride_in_bytes : info->channels * info->output_w * stbir__type_size[type];
1951
1952#ifdef STBIR_DEBUG_OVERWRITE_TEST
1953#define OVERWRITE_ARRAY_SIZE 8
1954 unsigned char overwrite_output_before_pre[OVERWRITE_ARRAY_SIZE];
1955 unsigned char overwrite_tempmem_before_pre[OVERWRITE_ARRAY_SIZE];
1956 unsigned char overwrite_output_after_pre[OVERWRITE_ARRAY_SIZE];
1957 unsigned char overwrite_tempmem_after_pre[OVERWRITE_ARRAY_SIZE];
1958
1959 size_t begin_forbidden = width_stride_output * (info->output_h - 1) + info->output_w * info->channels * stbir__type_size[type];
1960 memcpy(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
1961 memcpy(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE);
1962 memcpy(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
1963 memcpy(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE);
1964#endif
1965
1966 STBIR_ASSERT(info->channels >= 0);
1967 STBIR_ASSERT(info->channels <= STBIR_MAX_CHANNELS);
1968
1969 if (info->channels < 0 || info->channels > STBIR_MAX_CHANNELS)
1970 return 0;
1971
1972 STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
1973 STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
1974
1975 if (info->horizontal_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
1976 return 0;
1977 if (info->vertical_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
1978 return 0;
1979
1980 if (alpha_channel < 0)
1981 flags |= STBIR_FLAG_ALPHA_USES_COLORSPACE | STBIR_FLAG_ALPHA_PREMULTIPLIED;
1982
1983 if (!(flags&STBIR_FLAG_ALPHA_USES_COLORSPACE) || !(flags&STBIR_FLAG_ALPHA_PREMULTIPLIED)) {
1984 STBIR_ASSERT(alpha_channel >= 0 && alpha_channel < info->channels);
1985 }
1986
1987 if (alpha_channel >= info->channels)
1988 return 0;
1989
1990 STBIR_ASSERT(tempmem);
1991
1992 if (!tempmem)
1993 return 0;
1994
1995 STBIR_ASSERT(tempmem_size_in_bytes >= memory_required);
1996
1997 if (tempmem_size_in_bytes < memory_required)
1998 return 0;
1999
2000 memset(tempmem, 0, tempmem_size_in_bytes);
2001
2002 info->input_data = input_data;
2003 info->input_stride_bytes = width_stride_input;
2004
2005 info->output_data = output_data;
2006 info->output_stride_bytes = width_stride_output;
2007
2008 info->alpha_channel = alpha_channel;
2009 info->flags = flags;
2010 info->type = type;
2011 info->edge_horizontal = edge_horizontal;
2012 info->edge_vertical = edge_vertical;
2013 info->colorspace = colorspace;
2014
2015 info->horizontal_coefficient_width = stbir__get_coefficient_width (info->horizontal_filter, info->horizontal_scale);
2016 info->vertical_coefficient_width = stbir__get_coefficient_width (info->vertical_filter , info->vertical_scale );
2017 info->horizontal_filter_pixel_width = stbir__get_filter_pixel_width (info->horizontal_filter, info->horizontal_scale);
2018 info->vertical_filter_pixel_width = stbir__get_filter_pixel_width (info->vertical_filter , info->vertical_scale );
2019 info->horizontal_filter_pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
2020 info->vertical_filter_pixel_margin = stbir__get_filter_pixel_margin(info->vertical_filter , info->vertical_scale );
2021
2022 info->ring_buffer_length_bytes = info->output_w * info->channels * sizeof(float);
2023 info->decode_buffer_pixels = info->input_w + info->horizontal_filter_pixel_margin * 2;
2024
2025#define STBIR__NEXT_MEMPTR(current, newtype) (newtype*)(((unsigned char*)current) + current##_size)
2026
2027 info->horizontal_contributors = (stbir__contributors *) tempmem;
2028 info->horizontal_coefficients = STBIR__NEXT_MEMPTR(info->horizontal_contributors, float);
2029 info->vertical_contributors = STBIR__NEXT_MEMPTR(info->horizontal_coefficients, stbir__contributors);
2030 info->vertical_coefficients = STBIR__NEXT_MEMPTR(info->vertical_contributors, float);
2031 info->decode_buffer = STBIR__NEXT_MEMPTR(info->vertical_coefficients, float);
2032
2033 if (stbir__use_height_upsampling(info))
2034 {
2035 info->horizontal_buffer = NULL;
2036 info->ring_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
2037 info->encode_buffer = STBIR__NEXT_MEMPTR(info->ring_buffer, float);
2038
2039 STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->encode_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
2040 }
2041 else
2042 {
2043 info->horizontal_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
2044 info->ring_buffer = STBIR__NEXT_MEMPTR(info->horizontal_buffer, float);
2045 info->encode_buffer = NULL;
2046
2047 STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->ring_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
2048 }
2049
2050#undef STBIR__NEXT_MEMPTR
2051
2052 // This signals that the ring buffer is empty
2053 info->ring_buffer_begin_index = -1;
2054
2055 stbir__calculate_filters(info->horizontal_contributors, info->horizontal_coefficients, info->horizontal_filter, info->horizontal_scale, info->horizontal_shift, info->input_w, info->output_w);
2056 stbir__calculate_filters(info->vertical_contributors, info->vertical_coefficients, info->vertical_filter, info->vertical_scale, info->vertical_shift, info->input_h, info->output_h);
2057
2058 STBIR_PROGRESS_REPORT(0);
2059
2060 if (stbir__use_height_upsampling(info))
2061 stbir__buffer_loop_upsample(info);
2062 else
2063 stbir__buffer_loop_downsample(info);
2064
2065 STBIR_PROGRESS_REPORT(1);
2066
2067#ifdef STBIR_DEBUG_OVERWRITE_TEST
2068 STBIR_ASSERT(memcmp(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
2069 STBIR_ASSERT(memcmp(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE) == 0);
2070 STBIR_ASSERT(memcmp(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
2071 STBIR_ASSERT(memcmp(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE) == 0);
2072#endif
2073
2074 return 1;
2075}
2076
2077
2078static int stbir__resize_arbitrary(
2079 void *alloc_context,
2080 const void* input_data, int input_w, int input_h, int input_stride_in_bytes,
2081 void* output_data, int output_w, int output_h, int output_stride_in_bytes,
2082 float s0, float t0, float s1, float t1, float *transform,
2083 int channels, int alpha_channel, stbir_uint32 flags, stbir_datatype type,
2084 stbir_filter h_filter, stbir_filter v_filter,
2085 stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace)
2086{
2087 stbir__info info;
2088 int result;
2089 size_t memory_required;
2090 void* extra_memory;
2091
2092 stbir__setup(&info, input_w, input_h, output_w, output_h, channels);
2093 stbir__calculate_transform(&info, s0,t0,s1,t1,transform);
2094 stbir__choose_filter(&info, h_filter, v_filter);
2095 memory_required = stbir__calculate_memory(&info);
2096 extra_memory = STBIR_MALLOC(memory_required, alloc_context);
2097
2098 if (!extra_memory)
2099 return 0;
2100
2101 result = stbir__resize_allocated(&info, input_data, input_stride_in_bytes,
2102 output_data, output_stride_in_bytes,
2103 alpha_channel, flags, type,
2104 edge_horizontal, edge_vertical,
2105 colorspace, extra_memory, memory_required);
2106
2107 STBIR_FREE(extra_memory, alloc_context);
2108
2109 return result;
2110}
2111
2112STBIRDEF int stbir_resize_uint8( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2113 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2114 int num_channels)
2115{
2116 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2117 output_pixels, output_w, output_h, output_stride_in_bytes,
2118 0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2119 STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
2120}
2121
2122STBIRDEF int stbir_resize_float( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2123 float *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2124 int num_channels)
2125{
2126 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2127 output_pixels, output_w, output_h, output_stride_in_bytes,
2128 0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_FLOAT, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2129 STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
2130}
2131
2132STBIRDEF int stbir_resize_uint8_srgb(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2133 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2134 int num_channels, int alpha_channel, int flags)
2135{
2136 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2137 output_pixels, output_w, output_h, output_stride_in_bytes,
2138 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2139 STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB);
2140}
2141
2142STBIRDEF int stbir_resize_uint8_srgb_edgemode(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2143 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2144 int num_channels, int alpha_channel, int flags,
2145 stbir_edge edge_wrap_mode)
2146{
2147 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2148 output_pixels, output_w, output_h, output_stride_in_bytes,
2149 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2150 edge_wrap_mode, edge_wrap_mode, STBIR_COLORSPACE_SRGB);
2151}
2152
2153STBIRDEF int stbir_resize_uint8_generic( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2154 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2155 int num_channels, int alpha_channel, int flags,
2156 stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
2157 void *alloc_context)
2158{
2159 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2160 output_pixels, output_w, output_h, output_stride_in_bytes,
2161 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, filter, filter,
2162 edge_wrap_mode, edge_wrap_mode, space);
2163}
2164
2165STBIRDEF int stbir_resize_uint16_generic(const stbir_uint16 *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2166 stbir_uint16 *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
2167 int num_channels, int alpha_channel, int flags,
2168 stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
2169 void *alloc_context)
2170{
2171 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2172 output_pixels, output_w, output_h, output_stride_in_bytes,
2173 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT16, filter, filter,
2174 edge_wrap_mode, edge_wrap_mode, space);
2175}
2176
2177
2178STBIRDEF int stbir_resize_float_generic( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2179 float *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
2180 int num_channels, int alpha_channel, int flags,
2181 stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
2182 void *alloc_context)
2183{
2184 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2185 output_pixels, output_w, output_h, output_stride_in_bytes,
2186 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_FLOAT, filter, filter,
2187 edge_wrap_mode, edge_wrap_mode, space);
2188}
2189
2190
2191STBIRDEF int stbir_resize( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2192 void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2193 stbir_datatype datatype,
2194 int num_channels, int alpha_channel, int flags,
2195 stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
2196 stbir_filter filter_horizontal, stbir_filter filter_vertical,
2197 stbir_colorspace space, void *alloc_context)
2198{
2199 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2200 output_pixels, output_w, output_h, output_stride_in_bytes,
2201 0,0,1,1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
2202 edge_mode_horizontal, edge_mode_vertical, space);
2203}
2204
2205
2206STBIRDEF int stbir_resize_subpixel(const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2207 void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2208 stbir_datatype datatype,
2209 int num_channels, int alpha_channel, int flags,
2210 stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
2211 stbir_filter filter_horizontal, stbir_filter filter_vertical,
2212 stbir_colorspace space, void *alloc_context,
2213 float x_scale, float y_scale,
2214 float x_offset, float y_offset)
2215{
2216 float transform[4];
2217 transform[0] = x_scale;
2218 transform[1] = y_scale;
2219 transform[2] = x_offset;
2220 transform[3] = y_offset;
2221 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2222 output_pixels, output_w, output_h, output_stride_in_bytes,
2223 0,0,1,1,transform,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
2224 edge_mode_horizontal, edge_mode_vertical, space);
2225}
2226
2227STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2228 void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2229 stbir_datatype datatype,
2230 int num_channels, int alpha_channel, int flags,
2231 stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
2232 stbir_filter filter_horizontal, stbir_filter filter_vertical,
2233 stbir_colorspace space, void *alloc_context,
2234 float s0, float t0, float s1, float t1)
2235{
2236 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2237 output_pixels, output_w, output_h, output_stride_in_bytes,
2238 s0,t0,s1,t1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
2239 edge_mode_horizontal, edge_mode_vertical, space);
2240}
2241
2242/*
2243------------------------------------------------------------------------------
2244This software is available under 2 licenses -- choose whichever you prefer.
2245------------------------------------------------------------------------------
2246ALTERNATIVE A - MIT License
2247Copyright (c) 2017 Sean Barrett
2248Permission is hereby granted, free of charge, to any person obtaining a copy of
2249this software and associated documentation files (the "Software"), to deal in
2250the Software without restriction, including without limitation the rights to
2251use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
2252of the Software, and to permit persons to whom the Software is furnished to do
2253so, subject to the following conditions:
2254The above copyright notice and this permission notice shall be included in all
2255copies or substantial portions of the Software.
2256THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
2257IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
2258FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
2259AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
2260LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
2261OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
2262SOFTWARE.
2263------------------------------------------------------------------------------
2264ALTERNATIVE B - Public Domain (www.unlicense.org)
2265This is free and unencumbered software released into the public domain.
2266Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
2267software, either in source code form or as a compiled binary, for any purpose,
2268commercial or non-commercial, and by any means.
2269In jurisdictions that recognize copyright laws, the author or authors of this
2270software dedicate any and all copyright interest in the software to the public
2271domain. We make this dedication for the benefit of the public at large and to
2272the detriment of our heirs and successors. We intend this dedication to be an
2273overt act of relinquishment in perpetuity of all present and future rights to
2274this software under copyright law.
2275THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
2276IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
2277FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
2278AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
2279ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
2280WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
2281------------------------------------------------------------------------------
2282*/
diff --git a/externals/stb/stb_image_resize.h b/externals/stb/stb_image_resize.h
index 073ba20d9..3107e0670 100644
--- a/externals/stb/stb_image_resize.h
+++ b/externals/stb/stb_image_resize.h
@@ -1,4 +1,4 @@
1// SPDX-FileCopyrightText: stb http://nothings.org/stb 1// SPDX-FileCopyrightText: Jorge L Rodriguez
2// SPDX-License-Identifier: MIT 2// SPDX-License-Identifier: MIT
3 3
4/* stb_image_resize - v0.97 - public domain image resizing 4/* stb_image_resize - v0.97 - public domain image resizing
@@ -383,2217 +383,6 @@ STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int
383//// end header file ///////////////////////////////////////////////////// 383//// end header file /////////////////////////////////////////////////////
384#endif // STBIR_INCLUDE_STB_IMAGE_RESIZE_H 384#endif // STBIR_INCLUDE_STB_IMAGE_RESIZE_H
385 385
386
387
388
389
390#ifdef STB_IMAGE_RESIZE_IMPLEMENTATION
391
392#ifndef STBIR_ASSERT
393#include <assert.h>
394#define STBIR_ASSERT(x) assert(x)
395#endif
396
397// For memset
398#include <string.h>
399
400#include <math.h>
401
402#ifndef STBIR_MALLOC
403#include <stdlib.h>
404// use comma operator to evaluate c, to avoid "unused parameter" warnings
405#define STBIR_MALLOC(size,c) ((void)(c), malloc(size))
406#define STBIR_FREE(ptr,c) ((void)(c), free(ptr))
407#endif
408
409#ifndef _MSC_VER
410#ifdef __cplusplus
411#define stbir__inline inline
412#else
413#define stbir__inline
414#endif
415#else
416#define stbir__inline __forceinline
417#endif
418
419
420// should produce compiler error if size is wrong
421typedef unsigned char stbir__validate_uint32[sizeof(stbir_uint32) == 4 ? 1 : -1];
422
423#ifdef _MSC_VER
424#define STBIR__NOTUSED(v) (void)(v)
425#else
426#define STBIR__NOTUSED(v) (void)sizeof(v)
427#endif
428
429#define STBIR__ARRAY_SIZE(a) (sizeof((a))/sizeof((a)[0]))
430
431#ifndef STBIR_DEFAULT_FILTER_UPSAMPLE
432#define STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM
433#endif
434
435#ifndef STBIR_DEFAULT_FILTER_DOWNSAMPLE
436#define STBIR_DEFAULT_FILTER_DOWNSAMPLE STBIR_FILTER_MITCHELL
437#endif
438
439#ifndef STBIR_PROGRESS_REPORT
440#define STBIR_PROGRESS_REPORT(float_0_to_1)
441#endif
442
443#ifndef STBIR_MAX_CHANNELS
444#define STBIR_MAX_CHANNELS 64
445#endif
446
447#if STBIR_MAX_CHANNELS > 65536
448#error "Too many channels; STBIR_MAX_CHANNELS must be no more than 65536."
449// because we store the indices in 16-bit variables
450#endif
451
452// This value is added to alpha just before premultiplication to avoid
453// zeroing out color values. It is equivalent to 2^-80. If you don't want
454// that behavior (it may interfere if you have floating point images with
455// very small alpha values) then you can define STBIR_NO_ALPHA_EPSILON to
456// disable it.
457#ifndef STBIR_ALPHA_EPSILON
458#define STBIR_ALPHA_EPSILON ((float)1 / (1 << 20) / (1 << 20) / (1 << 20) / (1 << 20))
459#endif
460
461
462
463#ifdef _MSC_VER
464#define STBIR__UNUSED_PARAM(v) (void)(v)
465#else
466#define STBIR__UNUSED_PARAM(v) (void)sizeof(v)
467#endif
468
469// must match stbir_datatype
470static unsigned char stbir__type_size[] = {
471 1, // STBIR_TYPE_UINT8
472 2, // STBIR_TYPE_UINT16
473 4, // STBIR_TYPE_UINT32
474 4, // STBIR_TYPE_FLOAT
475};
476
477// Kernel function centered at 0
478typedef float (stbir__kernel_fn)(float x, float scale);
479typedef float (stbir__support_fn)(float scale);
480
481typedef struct
482{
483 stbir__kernel_fn* kernel;
484 stbir__support_fn* support;
485} stbir__filter_info;
486
487// When upsampling, the contributors are which source pixels contribute.
488// When downsampling, the contributors are which destination pixels are contributed to.
489typedef struct
490{
491 int n0; // First contributing pixel
492 int n1; // Last contributing pixel
493} stbir__contributors;
494
495typedef struct
496{
497 const void* input_data;
498 int input_w;
499 int input_h;
500 int input_stride_bytes;
501
502 void* output_data;
503 int output_w;
504 int output_h;
505 int output_stride_bytes;
506
507 float s0, t0, s1, t1;
508
509 float horizontal_shift; // Units: output pixels
510 float vertical_shift; // Units: output pixels
511 float horizontal_scale;
512 float vertical_scale;
513
514 int channels;
515 int alpha_channel;
516 stbir_uint32 flags;
517 stbir_datatype type;
518 stbir_filter horizontal_filter;
519 stbir_filter vertical_filter;
520 stbir_edge edge_horizontal;
521 stbir_edge edge_vertical;
522 stbir_colorspace colorspace;
523
524 stbir__contributors* horizontal_contributors;
525 float* horizontal_coefficients;
526
527 stbir__contributors* vertical_contributors;
528 float* vertical_coefficients;
529
530 int decode_buffer_pixels;
531 float* decode_buffer;
532
533 float* horizontal_buffer;
534
535 // cache these because ceil/floor are inexplicably showing up in profile
536 int horizontal_coefficient_width;
537 int vertical_coefficient_width;
538 int horizontal_filter_pixel_width;
539 int vertical_filter_pixel_width;
540 int horizontal_filter_pixel_margin;
541 int vertical_filter_pixel_margin;
542 int horizontal_num_contributors;
543 int vertical_num_contributors;
544
545 int ring_buffer_length_bytes; // The length of an individual entry in the ring buffer. The total number of ring buffers is stbir__get_filter_pixel_width(filter)
546 int ring_buffer_num_entries; // Total number of entries in the ring buffer.
547 int ring_buffer_first_scanline;
548 int ring_buffer_last_scanline;
549 int ring_buffer_begin_index; // first_scanline is at this index in the ring buffer
550 float* ring_buffer;
551
552 float* encode_buffer; // A temporary buffer to store floats so we don't lose precision while we do multiply-adds.
553
554 int horizontal_contributors_size;
555 int horizontal_coefficients_size;
556 int vertical_contributors_size;
557 int vertical_coefficients_size;
558 int decode_buffer_size;
559 int horizontal_buffer_size;
560 int ring_buffer_size;
561 int encode_buffer_size;
562} stbir__info;
563
564
565static const float stbir__max_uint8_as_float = 255.0f;
566static const float stbir__max_uint16_as_float = 65535.0f;
567static const double stbir__max_uint32_as_float = 4294967295.0;
568
569
570static stbir__inline int stbir__min(int a, int b)
571{
572 return a < b ? a : b;
573}
574
575static stbir__inline float stbir__saturate(float x)
576{
577 if (x < 0)
578 return 0;
579
580 if (x > 1)
581 return 1;
582
583 return x;
584}
585
586#ifdef STBIR_SATURATE_INT
587static stbir__inline stbir_uint8 stbir__saturate8(int x)
588{
589 if ((unsigned int) x <= 255)
590 return x;
591
592 if (x < 0)
593 return 0;
594
595 return 255;
596}
597
598static stbir__inline stbir_uint16 stbir__saturate16(int x)
599{
600 if ((unsigned int) x <= 65535)
601 return x;
602
603 if (x < 0)
604 return 0;
605
606 return 65535;
607}
608#endif
609
610static float stbir__srgb_uchar_to_linear_float[256] = {
611 0.000000f, 0.000304f, 0.000607f, 0.000911f, 0.001214f, 0.001518f, 0.001821f, 0.002125f, 0.002428f, 0.002732f, 0.003035f,
612 0.003347f, 0.003677f, 0.004025f, 0.004391f, 0.004777f, 0.005182f, 0.005605f, 0.006049f, 0.006512f, 0.006995f, 0.007499f,
613 0.008023f, 0.008568f, 0.009134f, 0.009721f, 0.010330f, 0.010960f, 0.011612f, 0.012286f, 0.012983f, 0.013702f, 0.014444f,
614 0.015209f, 0.015996f, 0.016807f, 0.017642f, 0.018500f, 0.019382f, 0.020289f, 0.021219f, 0.022174f, 0.023153f, 0.024158f,
615 0.025187f, 0.026241f, 0.027321f, 0.028426f, 0.029557f, 0.030713f, 0.031896f, 0.033105f, 0.034340f, 0.035601f, 0.036889f,
616 0.038204f, 0.039546f, 0.040915f, 0.042311f, 0.043735f, 0.045186f, 0.046665f, 0.048172f, 0.049707f, 0.051269f, 0.052861f,
617 0.054480f, 0.056128f, 0.057805f, 0.059511f, 0.061246f, 0.063010f, 0.064803f, 0.066626f, 0.068478f, 0.070360f, 0.072272f,
618 0.074214f, 0.076185f, 0.078187f, 0.080220f, 0.082283f, 0.084376f, 0.086500f, 0.088656f, 0.090842f, 0.093059f, 0.095307f,
619 0.097587f, 0.099899f, 0.102242f, 0.104616f, 0.107023f, 0.109462f, 0.111932f, 0.114435f, 0.116971f, 0.119538f, 0.122139f,
620 0.124772f, 0.127438f, 0.130136f, 0.132868f, 0.135633f, 0.138432f, 0.141263f, 0.144128f, 0.147027f, 0.149960f, 0.152926f,
621 0.155926f, 0.158961f, 0.162029f, 0.165132f, 0.168269f, 0.171441f, 0.174647f, 0.177888f, 0.181164f, 0.184475f, 0.187821f,
622 0.191202f, 0.194618f, 0.198069f, 0.201556f, 0.205079f, 0.208637f, 0.212231f, 0.215861f, 0.219526f, 0.223228f, 0.226966f,
623 0.230740f, 0.234551f, 0.238398f, 0.242281f, 0.246201f, 0.250158f, 0.254152f, 0.258183f, 0.262251f, 0.266356f, 0.270498f,
624 0.274677f, 0.278894f, 0.283149f, 0.287441f, 0.291771f, 0.296138f, 0.300544f, 0.304987f, 0.309469f, 0.313989f, 0.318547f,
625 0.323143f, 0.327778f, 0.332452f, 0.337164f, 0.341914f, 0.346704f, 0.351533f, 0.356400f, 0.361307f, 0.366253f, 0.371238f,
626 0.376262f, 0.381326f, 0.386430f, 0.391573f, 0.396755f, 0.401978f, 0.407240f, 0.412543f, 0.417885f, 0.423268f, 0.428691f,
627 0.434154f, 0.439657f, 0.445201f, 0.450786f, 0.456411f, 0.462077f, 0.467784f, 0.473532f, 0.479320f, 0.485150f, 0.491021f,
628 0.496933f, 0.502887f, 0.508881f, 0.514918f, 0.520996f, 0.527115f, 0.533276f, 0.539480f, 0.545725f, 0.552011f, 0.558340f,
629 0.564712f, 0.571125f, 0.577581f, 0.584078f, 0.590619f, 0.597202f, 0.603827f, 0.610496f, 0.617207f, 0.623960f, 0.630757f,
630 0.637597f, 0.644480f, 0.651406f, 0.658375f, 0.665387f, 0.672443f, 0.679543f, 0.686685f, 0.693872f, 0.701102f, 0.708376f,
631 0.715694f, 0.723055f, 0.730461f, 0.737911f, 0.745404f, 0.752942f, 0.760525f, 0.768151f, 0.775822f, 0.783538f, 0.791298f,
632 0.799103f, 0.806952f, 0.814847f, 0.822786f, 0.830770f, 0.838799f, 0.846873f, 0.854993f, 0.863157f, 0.871367f, 0.879622f,
633 0.887923f, 0.896269f, 0.904661f, 0.913099f, 0.921582f, 0.930111f, 0.938686f, 0.947307f, 0.955974f, 0.964686f, 0.973445f,
634 0.982251f, 0.991102f, 1.0f
635};
636
637static float stbir__srgb_to_linear(float f)
638{
639 if (f <= 0.04045f)
640 return f / 12.92f;
641 else
642 return (float)pow((f + 0.055f) / 1.055f, 2.4f);
643}
644
645static float stbir__linear_to_srgb(float f)
646{
647 if (f <= 0.0031308f)
648 return f * 12.92f;
649 else
650 return 1.055f * (float)pow(f, 1 / 2.4f) - 0.055f;
651}
652
653#ifndef STBIR_NON_IEEE_FLOAT
654// From https://gist.github.com/rygorous/2203834
655
656typedef union
657{
658 stbir_uint32 u;
659 float f;
660} stbir__FP32;
661
662static const stbir_uint32 fp32_to_srgb8_tab4[104] = {
663 0x0073000d, 0x007a000d, 0x0080000d, 0x0087000d, 0x008d000d, 0x0094000d, 0x009a000d, 0x00a1000d,
664 0x00a7001a, 0x00b4001a, 0x00c1001a, 0x00ce001a, 0x00da001a, 0x00e7001a, 0x00f4001a, 0x0101001a,
665 0x010e0033, 0x01280033, 0x01410033, 0x015b0033, 0x01750033, 0x018f0033, 0x01a80033, 0x01c20033,
666 0x01dc0067, 0x020f0067, 0x02430067, 0x02760067, 0x02aa0067, 0x02dd0067, 0x03110067, 0x03440067,
667 0x037800ce, 0x03df00ce, 0x044600ce, 0x04ad00ce, 0x051400ce, 0x057b00c5, 0x05dd00bc, 0x063b00b5,
668 0x06970158, 0x07420142, 0x07e30130, 0x087b0120, 0x090b0112, 0x09940106, 0x0a1700fc, 0x0a9500f2,
669 0x0b0f01cb, 0x0bf401ae, 0x0ccb0195, 0x0d950180, 0x0e56016e, 0x0f0d015e, 0x0fbc0150, 0x10630143,
670 0x11070264, 0x1238023e, 0x1357021d, 0x14660201, 0x156601e9, 0x165a01d3, 0x174401c0, 0x182401af,
671 0x18fe0331, 0x1a9602fe, 0x1c1502d2, 0x1d7e02ad, 0x1ed4028d, 0x201a0270, 0x21520256, 0x227d0240,
672 0x239f0443, 0x25c003fe, 0x27bf03c4, 0x29a10392, 0x2b6a0367, 0x2d1d0341, 0x2ebe031f, 0x304d0300,
673 0x31d105b0, 0x34a80555, 0x37520507, 0x39d504c5, 0x3c37048b, 0x3e7c0458, 0x40a8042a, 0x42bd0401,
674 0x44c20798, 0x488e071e, 0x4c1c06b6, 0x4f76065d, 0x52a50610, 0x55ac05cc, 0x5892058f, 0x5b590559,
675 0x5e0c0a23, 0x631c0980, 0x67db08f6, 0x6c55087f, 0x70940818, 0x74a007bd, 0x787d076c, 0x7c330723,
676};
677
678static stbir_uint8 stbir__linear_to_srgb_uchar(float in)
679{
680 static const stbir__FP32 almostone = { 0x3f7fffff }; // 1-eps
681 static const stbir__FP32 minval = { (127-13) << 23 };
682 stbir_uint32 tab,bias,scale,t;
683 stbir__FP32 f;
684
685 // Clamp to [2^(-13), 1-eps]; these two values map to 0 and 1, respectively.
686 // The tests are carefully written so that NaNs map to 0, same as in the reference
687 // implementation.
688 if (!(in > minval.f)) // written this way to catch NaNs
689 in = minval.f;
690 if (in > almostone.f)
691 in = almostone.f;
692
693 // Do the table lookup and unpack bias, scale
694 f.f = in;
695 tab = fp32_to_srgb8_tab4[(f.u - minval.u) >> 20];
696 bias = (tab >> 16) << 9;
697 scale = tab & 0xffff;
698
699 // Grab next-highest mantissa bits and perform linear interpolation
700 t = (f.u >> 12) & 0xff;
701 return (unsigned char) ((bias + scale*t) >> 16);
702}
703
704#else
705// sRGB transition values, scaled by 1<<28
706static int stbir__srgb_offset_to_linear_scaled[256] =
707{
708 0, 40738, 122216, 203693, 285170, 366648, 448125, 529603,
709 611080, 692557, 774035, 855852, 942009, 1033024, 1128971, 1229926,
710 1335959, 1447142, 1563542, 1685229, 1812268, 1944725, 2082664, 2226148,
711 2375238, 2529996, 2690481, 2856753, 3028870, 3206888, 3390865, 3580856,
712 3776916, 3979100, 4187460, 4402049, 4622919, 4850123, 5083710, 5323731,
713 5570236, 5823273, 6082892, 6349140, 6622065, 6901714, 7188133, 7481369,
714 7781466, 8088471, 8402427, 8723380, 9051372, 9386448, 9728650, 10078021,
715 10434603, 10798439, 11169569, 11548036, 11933879, 12327139, 12727857, 13136073,
716 13551826, 13975156, 14406100, 14844697, 15290987, 15745007, 16206795, 16676389,
717 17153826, 17639142, 18132374, 18633560, 19142734, 19659934, 20185196, 20718552,
718 21260042, 21809696, 22367554, 22933648, 23508010, 24090680, 24681686, 25281066,
719 25888850, 26505076, 27129772, 27762974, 28404716, 29055026, 29713942, 30381490,
720 31057708, 31742624, 32436272, 33138682, 33849884, 34569912, 35298800, 36036568,
721 36783260, 37538896, 38303512, 39077136, 39859796, 40651528, 41452360, 42262316,
722 43081432, 43909732, 44747252, 45594016, 46450052, 47315392, 48190064, 49074096,
723 49967516, 50870356, 51782636, 52704392, 53635648, 54576432, 55526772, 56486700,
724 57456236, 58435408, 59424248, 60422780, 61431036, 62449032, 63476804, 64514376,
725 65561776, 66619028, 67686160, 68763192, 69850160, 70947088, 72053992, 73170912,
726 74297864, 75434880, 76581976, 77739184, 78906536, 80084040, 81271736, 82469648,
727 83677792, 84896192, 86124888, 87363888, 88613232, 89872928, 91143016, 92423512,
728 93714432, 95015816, 96327688, 97650056, 98982952, 100326408, 101680440, 103045072,
729 104420320, 105806224, 107202800, 108610064, 110028048, 111456776, 112896264, 114346544,
730 115807632, 117279552, 118762328, 120255976, 121760536, 123276016, 124802440, 126339832,
731 127888216, 129447616, 131018048, 132599544, 134192112, 135795792, 137410592, 139036528,
732 140673648, 142321952, 143981456, 145652208, 147334208, 149027488, 150732064, 152447968,
733 154175200, 155913792, 157663776, 159425168, 161197984, 162982240, 164777968, 166585184,
734 168403904, 170234160, 172075968, 173929344, 175794320, 177670896, 179559120, 181458992,
735 183370528, 185293776, 187228736, 189175424, 191133888, 193104112, 195086128, 197079968,
736 199085648, 201103184, 203132592, 205173888, 207227120, 209292272, 211369392, 213458480,
737 215559568, 217672656, 219797792, 221934976, 224084240, 226245600, 228419056, 230604656,
738 232802400, 235012320, 237234432, 239468736, 241715280, 243974080, 246245120, 248528464,
739 250824112, 253132064, 255452368, 257785040, 260130080, 262487520, 264857376, 267239664,
740};
741
742static stbir_uint8 stbir__linear_to_srgb_uchar(float f)
743{
744 int x = (int) (f * (1 << 28)); // has headroom so you don't need to clamp
745 int v = 0;
746 int i;
747
748 // Refine the guess with a short binary search.
749 i = v + 128; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
750 i = v + 64; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
751 i = v + 32; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
752 i = v + 16; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
753 i = v + 8; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
754 i = v + 4; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
755 i = v + 2; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
756 i = v + 1; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
757
758 return (stbir_uint8) v;
759}
760#endif
761
762static float stbir__filter_trapezoid(float x, float scale)
763{
764 float halfscale = scale / 2;
765 float t = 0.5f + halfscale;
766 STBIR_ASSERT(scale <= 1);
767
768 x = (float)fabs(x);
769
770 if (x >= t)
771 return 0;
772 else
773 {
774 float r = 0.5f - halfscale;
775 if (x <= r)
776 return 1;
777 else
778 return (t - x) / scale;
779 }
780}
781
782static float stbir__support_trapezoid(float scale)
783{
784 STBIR_ASSERT(scale <= 1);
785 return 0.5f + scale / 2;
786}
787
788static float stbir__filter_triangle(float x, float s)
789{
790 STBIR__UNUSED_PARAM(s);
791
792 x = (float)fabs(x);
793
794 if (x <= 1.0f)
795 return 1 - x;
796 else
797 return 0;
798}
799
800static float stbir__filter_cubic(float x, float s)
801{
802 STBIR__UNUSED_PARAM(s);
803
804 x = (float)fabs(x);
805
806 if (x < 1.0f)
807 return (4 + x*x*(3*x - 6))/6;
808 else if (x < 2.0f)
809 return (8 + x*(-12 + x*(6 - x)))/6;
810
811 return (0.0f);
812}
813
814static float stbir__filter_catmullrom(float x, float s)
815{
816 STBIR__UNUSED_PARAM(s);
817
818 x = (float)fabs(x);
819
820 if (x < 1.0f)
821 return 1 - x*x*(2.5f - 1.5f*x);
822 else if (x < 2.0f)
823 return 2 - x*(4 + x*(0.5f*x - 2.5f));
824
825 return (0.0f);
826}
827
828static float stbir__filter_mitchell(float x, float s)
829{
830 STBIR__UNUSED_PARAM(s);
831
832 x = (float)fabs(x);
833
834 if (x < 1.0f)
835 return (16 + x*x*(21 * x - 36))/18;
836 else if (x < 2.0f)
837 return (32 + x*(-60 + x*(36 - 7*x)))/18;
838
839 return (0.0f);
840}
841
842static float stbir__support_zero(float s)
843{
844 STBIR__UNUSED_PARAM(s);
845 return 0;
846}
847
848static float stbir__support_one(float s)
849{
850 STBIR__UNUSED_PARAM(s);
851 return 1;
852}
853
854static float stbir__support_two(float s)
855{
856 STBIR__UNUSED_PARAM(s);
857 return 2;
858}
859
860static stbir__filter_info stbir__filter_info_table[] = {
861 { NULL, stbir__support_zero },
862 { stbir__filter_trapezoid, stbir__support_trapezoid },
863 { stbir__filter_triangle, stbir__support_one },
864 { stbir__filter_cubic, stbir__support_two },
865 { stbir__filter_catmullrom, stbir__support_two },
866 { stbir__filter_mitchell, stbir__support_two },
867};
868
869stbir__inline static int stbir__use_upsampling(float ratio)
870{
871 return ratio > 1;
872}
873
874stbir__inline static int stbir__use_width_upsampling(stbir__info* stbir_info)
875{
876 return stbir__use_upsampling(stbir_info->horizontal_scale);
877}
878
879stbir__inline static int stbir__use_height_upsampling(stbir__info* stbir_info)
880{
881 return stbir__use_upsampling(stbir_info->vertical_scale);
882}
883
884// This is the maximum number of input samples that can affect an output sample
885// with the given filter
886static int stbir__get_filter_pixel_width(stbir_filter filter, float scale)
887{
888 STBIR_ASSERT(filter != 0);
889 STBIR_ASSERT(filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
890
891 if (stbir__use_upsampling(scale))
892 return (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2);
893 else
894 return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2 / scale);
895}
896
897// This is how much to expand buffers to account for filters seeking outside
898// the image boundaries.
899static int stbir__get_filter_pixel_margin(stbir_filter filter, float scale)
900{
901 return stbir__get_filter_pixel_width(filter, scale) / 2;
902}
903
904static int stbir__get_coefficient_width(stbir_filter filter, float scale)
905{
906 if (stbir__use_upsampling(scale))
907 return (int)ceil(stbir__filter_info_table[filter].support(1 / scale) * 2);
908 else
909 return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2);
910}
911
912static int stbir__get_contributors(float scale, stbir_filter filter, int input_size, int output_size)
913{
914 if (stbir__use_upsampling(scale))
915 return output_size;
916 else
917 return (input_size + stbir__get_filter_pixel_margin(filter, scale) * 2);
918}
919
920static int stbir__get_total_horizontal_coefficients(stbir__info* info)
921{
922 return info->horizontal_num_contributors
923 * stbir__get_coefficient_width (info->horizontal_filter, info->horizontal_scale);
924}
925
926static int stbir__get_total_vertical_coefficients(stbir__info* info)
927{
928 return info->vertical_num_contributors
929 * stbir__get_coefficient_width (info->vertical_filter, info->vertical_scale);
930}
931
932static stbir__contributors* stbir__get_contributor(stbir__contributors* contributors, int n)
933{
934 return &contributors[n];
935}
936
937// For perf reasons this code is duplicated in stbir__resample_horizontal_upsample/downsample,
938// if you change it here change it there too.
939static float* stbir__get_coefficient(float* coefficients, stbir_filter filter, float scale, int n, int c)
940{
941 int width = stbir__get_coefficient_width(filter, scale);
942 return &coefficients[width*n + c];
943}
944
945static int stbir__edge_wrap_slow(stbir_edge edge, int n, int max)
946{
947 switch (edge)
948 {
949 case STBIR_EDGE_ZERO:
950 return 0; // we'll decode the wrong pixel here, and then overwrite with 0s later
951
952 case STBIR_EDGE_CLAMP:
953 if (n < 0)
954 return 0;
955
956 if (n >= max)
957 return max - 1;
958
959 return n; // NOTREACHED
960
961 case STBIR_EDGE_REFLECT:
962 {
963 if (n < 0)
964 {
965 if (n < max)
966 return -n;
967 else
968 return max - 1;
969 }
970
971 if (n >= max)
972 {
973 int max2 = max * 2;
974 if (n >= max2)
975 return 0;
976 else
977 return max2 - n - 1;
978 }
979
980 return n; // NOTREACHED
981 }
982
983 case STBIR_EDGE_WRAP:
984 if (n >= 0)
985 return (n % max);
986 else
987 {
988 int m = (-n) % max;
989
990 if (m != 0)
991 m = max - m;
992
993 return (m);
994 }
995 // NOTREACHED
996
997 default:
998 STBIR_ASSERT(!"Unimplemented edge type");
999 return 0;
1000 }
1001}
1002
1003stbir__inline static int stbir__edge_wrap(stbir_edge edge, int n, int max)
1004{
1005 // avoid per-pixel switch
1006 if (n >= 0 && n < max)
1007 return n;
1008 return stbir__edge_wrap_slow(edge, n, max);
1009}
1010
1011// What input pixels contribute to this output pixel?
1012static void stbir__calculate_sample_range_upsample(int n, float out_filter_radius, float scale_ratio, float out_shift, int* in_first_pixel, int* in_last_pixel, float* in_center_of_out)
1013{
1014 float out_pixel_center = (float)n + 0.5f;
1015 float out_pixel_influence_lowerbound = out_pixel_center - out_filter_radius;
1016 float out_pixel_influence_upperbound = out_pixel_center + out_filter_radius;
1017
1018 float in_pixel_influence_lowerbound = (out_pixel_influence_lowerbound + out_shift) / scale_ratio;
1019 float in_pixel_influence_upperbound = (out_pixel_influence_upperbound + out_shift) / scale_ratio;
1020
1021 *in_center_of_out = (out_pixel_center + out_shift) / scale_ratio;
1022 *in_first_pixel = (int)(floor(in_pixel_influence_lowerbound + 0.5));
1023 *in_last_pixel = (int)(floor(in_pixel_influence_upperbound - 0.5));
1024}
1025
1026// What output pixels does this input pixel contribute to?
1027static void stbir__calculate_sample_range_downsample(int n, float in_pixels_radius, float scale_ratio, float out_shift, int* out_first_pixel, int* out_last_pixel, float* out_center_of_in)
1028{
1029 float in_pixel_center = (float)n + 0.5f;
1030 float in_pixel_influence_lowerbound = in_pixel_center - in_pixels_radius;
1031 float in_pixel_influence_upperbound = in_pixel_center + in_pixels_radius;
1032
1033 float out_pixel_influence_lowerbound = in_pixel_influence_lowerbound * scale_ratio - out_shift;
1034 float out_pixel_influence_upperbound = in_pixel_influence_upperbound * scale_ratio - out_shift;
1035
1036 *out_center_of_in = in_pixel_center * scale_ratio - out_shift;
1037 *out_first_pixel = (int)(floor(out_pixel_influence_lowerbound + 0.5));
1038 *out_last_pixel = (int)(floor(out_pixel_influence_upperbound - 0.5));
1039}
1040
1041static void stbir__calculate_coefficients_upsample(stbir_filter filter, float scale, int in_first_pixel, int in_last_pixel, float in_center_of_out, stbir__contributors* contributor, float* coefficient_group)
1042{
1043 int i;
1044 float total_filter = 0;
1045 float filter_scale;
1046
1047 STBIR_ASSERT(in_last_pixel - in_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2)); // Taken directly from stbir__get_coefficient_width() which we can't call because we don't know if we're horizontal or vertical.
1048
1049 contributor->n0 = in_first_pixel;
1050 contributor->n1 = in_last_pixel;
1051
1052 STBIR_ASSERT(contributor->n1 >= contributor->n0);
1053
1054 for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
1055 {
1056 float in_pixel_center = (float)(i + in_first_pixel) + 0.5f;
1057 coefficient_group[i] = stbir__filter_info_table[filter].kernel(in_center_of_out - in_pixel_center, 1 / scale);
1058
1059 // If the coefficient is zero, skip it. (Don't do the <0 check here, we want the influence of those outside pixels.)
1060 if (i == 0 && !coefficient_group[i])
1061 {
1062 contributor->n0 = ++in_first_pixel;
1063 i--;
1064 continue;
1065 }
1066
1067 total_filter += coefficient_group[i];
1068 }
1069
1070 // NOTE(fg): Not actually true in general, nor is there any reason to expect it should be.
1071 // It would be true in exact math but is at best approximately true in floating-point math,
1072 // and it would not make sense to try and put actual bounds on this here because it depends
1073 // on the image aspect ratio which can get pretty extreme.
1074 //STBIR_ASSERT(stbir__filter_info_table[filter].kernel((float)(in_last_pixel + 1) + 0.5f - in_center_of_out, 1/scale) == 0);
1075
1076 STBIR_ASSERT(total_filter > 0.9);
1077 STBIR_ASSERT(total_filter < 1.1f); // Make sure it's not way off.
1078
1079 // Make sure the sum of all coefficients is 1.
1080 filter_scale = 1 / total_filter;
1081
1082 for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
1083 coefficient_group[i] *= filter_scale;
1084
1085 for (i = in_last_pixel - in_first_pixel; i >= 0; i--)
1086 {
1087 if (coefficient_group[i])
1088 break;
1089
1090 // This line has no weight. We can skip it.
1091 contributor->n1 = contributor->n0 + i - 1;
1092 }
1093}
1094
1095static void stbir__calculate_coefficients_downsample(stbir_filter filter, float scale_ratio, int out_first_pixel, int out_last_pixel, float out_center_of_in, stbir__contributors* contributor, float* coefficient_group)
1096{
1097 int i;
1098
1099 STBIR_ASSERT(out_last_pixel - out_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(scale_ratio) * 2)); // Taken directly from stbir__get_coefficient_width() which we can't call because we don't know if we're horizontal or vertical.
1100
1101 contributor->n0 = out_first_pixel;
1102 contributor->n1 = out_last_pixel;
1103
1104 STBIR_ASSERT(contributor->n1 >= contributor->n0);
1105
1106 for (i = 0; i <= out_last_pixel - out_first_pixel; i++)
1107 {
1108 float out_pixel_center = (float)(i + out_first_pixel) + 0.5f;
1109 float x = out_pixel_center - out_center_of_in;
1110 coefficient_group[i] = stbir__filter_info_table[filter].kernel(x, scale_ratio) * scale_ratio;
1111 }
1112
1113 // NOTE(fg): Not actually true in general, nor is there any reason to expect it should be.
1114 // It would be true in exact math but is at best approximately true in floating-point math,
1115 // and it would not make sense to try and put actual bounds on this here because it depends
1116 // on the image aspect ratio which can get pretty extreme.
1117 //STBIR_ASSERT(stbir__filter_info_table[filter].kernel((float)(out_last_pixel + 1) + 0.5f - out_center_of_in, scale_ratio) == 0);
1118
1119 for (i = out_last_pixel - out_first_pixel; i >= 0; i--)
1120 {
1121 if (coefficient_group[i])
1122 break;
1123
1124 // This line has no weight. We can skip it.
1125 contributor->n1 = contributor->n0 + i - 1;
1126 }
1127}
1128
1129static void stbir__normalize_downsample_coefficients(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, int input_size, int output_size)
1130{
1131 int num_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size);
1132 int num_coefficients = stbir__get_coefficient_width(filter, scale_ratio);
1133 int i, j;
1134 int skip;
1135
1136 for (i = 0; i < output_size; i++)
1137 {
1138 float scale;
1139 float total = 0;
1140
1141 for (j = 0; j < num_contributors; j++)
1142 {
1143 if (i >= contributors[j].n0 && i <= contributors[j].n1)
1144 {
1145 float coefficient = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0);
1146 total += coefficient;
1147 }
1148 else if (i < contributors[j].n0)
1149 break;
1150 }
1151
1152 STBIR_ASSERT(total > 0.9f);
1153 STBIR_ASSERT(total < 1.1f);
1154
1155 scale = 1 / total;
1156
1157 for (j = 0; j < num_contributors; j++)
1158 {
1159 if (i >= contributors[j].n0 && i <= contributors[j].n1)
1160 *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0) *= scale;
1161 else if (i < contributors[j].n0)
1162 break;
1163 }
1164 }
1165
1166 // Optimize: Skip zero coefficients and contributions outside of image bounds.
1167 // Do this after normalizing because normalization depends on the n0/n1 values.
1168 for (j = 0; j < num_contributors; j++)
1169 {
1170 int range, max, width;
1171
1172 skip = 0;
1173 while (*stbir__get_coefficient(coefficients, filter, scale_ratio, j, skip) == 0)
1174 skip++;
1175
1176 contributors[j].n0 += skip;
1177
1178 while (contributors[j].n0 < 0)
1179 {
1180 contributors[j].n0++;
1181 skip++;
1182 }
1183
1184 range = contributors[j].n1 - contributors[j].n0 + 1;
1185 max = stbir__min(num_coefficients, range);
1186
1187 width = stbir__get_coefficient_width(filter, scale_ratio);
1188 for (i = 0; i < max; i++)
1189 {
1190 if (i + skip >= width)
1191 break;
1192
1193 *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i) = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i + skip);
1194 }
1195
1196 continue;
1197 }
1198
1199 // Using min to avoid writing into invalid pixels.
1200 for (i = 0; i < num_contributors; i++)
1201 contributors[i].n1 = stbir__min(contributors[i].n1, output_size - 1);
1202}
1203
1204// Each scan line uses the same kernel values so we should calculate the kernel
1205// values once and then we can use them for every scan line.
1206static void stbir__calculate_filters(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, float shift, int input_size, int output_size)
1207{
1208 int n;
1209 int total_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size);
1210
1211 if (stbir__use_upsampling(scale_ratio))
1212 {
1213 float out_pixels_radius = stbir__filter_info_table[filter].support(1 / scale_ratio) * scale_ratio;
1214
1215 // Looping through out pixels
1216 for (n = 0; n < total_contributors; n++)
1217 {
1218 float in_center_of_out; // Center of the current out pixel in the in pixel space
1219 int in_first_pixel, in_last_pixel;
1220
1221 stbir__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, shift, &in_first_pixel, &in_last_pixel, &in_center_of_out);
1222
1223 stbir__calculate_coefficients_upsample(filter, scale_ratio, in_first_pixel, in_last_pixel, in_center_of_out, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0));
1224 }
1225 }
1226 else
1227 {
1228 float in_pixels_radius = stbir__filter_info_table[filter].support(scale_ratio) / scale_ratio;
1229
1230 // Looping through in pixels
1231 for (n = 0; n < total_contributors; n++)
1232 {
1233 float out_center_of_in; // Center of the current out pixel in the in pixel space
1234 int out_first_pixel, out_last_pixel;
1235 int n_adjusted = n - stbir__get_filter_pixel_margin(filter, scale_ratio);
1236
1237 stbir__calculate_sample_range_downsample(n_adjusted, in_pixels_radius, scale_ratio, shift, &out_first_pixel, &out_last_pixel, &out_center_of_in);
1238
1239 stbir__calculate_coefficients_downsample(filter, scale_ratio, out_first_pixel, out_last_pixel, out_center_of_in, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0));
1240 }
1241
1242 stbir__normalize_downsample_coefficients(contributors, coefficients, filter, scale_ratio, input_size, output_size);
1243 }
1244}
1245
1246static float* stbir__get_decode_buffer(stbir__info* stbir_info)
1247{
1248 // The 0 index of the decode buffer starts after the margin. This makes
1249 // it okay to use negative indexes on the decode buffer.
1250 return &stbir_info->decode_buffer[stbir_info->horizontal_filter_pixel_margin * stbir_info->channels];
1251}
1252
1253#define STBIR__DECODE(type, colorspace) ((int)(type) * (STBIR_MAX_COLORSPACES) + (int)(colorspace))
1254
1255static void stbir__decode_scanline(stbir__info* stbir_info, int n)
1256{
1257 int c;
1258 int channels = stbir_info->channels;
1259 int alpha_channel = stbir_info->alpha_channel;
1260 int type = stbir_info->type;
1261 int colorspace = stbir_info->colorspace;
1262 int input_w = stbir_info->input_w;
1263 size_t input_stride_bytes = stbir_info->input_stride_bytes;
1264 float* decode_buffer = stbir__get_decode_buffer(stbir_info);
1265 stbir_edge edge_horizontal = stbir_info->edge_horizontal;
1266 stbir_edge edge_vertical = stbir_info->edge_vertical;
1267 size_t in_buffer_row_offset = stbir__edge_wrap(edge_vertical, n, stbir_info->input_h) * input_stride_bytes;
1268 const void* input_data = (char *) stbir_info->input_data + in_buffer_row_offset;
1269 int max_x = input_w + stbir_info->horizontal_filter_pixel_margin;
1270 int decode = STBIR__DECODE(type, colorspace);
1271
1272 int x = -stbir_info->horizontal_filter_pixel_margin;
1273
1274 // special handling for STBIR_EDGE_ZERO because it needs to return an item that doesn't appear in the input,
1275 // and we want to avoid paying overhead on every pixel if not STBIR_EDGE_ZERO
1276 if (edge_vertical == STBIR_EDGE_ZERO && (n < 0 || n >= stbir_info->input_h))
1277 {
1278 for (; x < max_x; x++)
1279 for (c = 0; c < channels; c++)
1280 decode_buffer[x*channels + c] = 0;
1281 return;
1282 }
1283
1284 switch (decode)
1285 {
1286 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
1287 for (; x < max_x; x++)
1288 {
1289 int decode_pixel_index = x * channels;
1290 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1291 for (c = 0; c < channels; c++)
1292 decode_buffer[decode_pixel_index + c] = ((float)((const unsigned char*)input_data)[input_pixel_index + c]) / stbir__max_uint8_as_float;
1293 }
1294 break;
1295
1296 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
1297 for (; x < max_x; x++)
1298 {
1299 int decode_pixel_index = x * channels;
1300 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1301 for (c = 0; c < channels; c++)
1302 decode_buffer[decode_pixel_index + c] = stbir__srgb_uchar_to_linear_float[((const unsigned char*)input_data)[input_pixel_index + c]];
1303
1304 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1305 decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned char*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint8_as_float;
1306 }
1307 break;
1308
1309 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
1310 for (; x < max_x; x++)
1311 {
1312 int decode_pixel_index = x * channels;
1313 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1314 for (c = 0; c < channels; c++)
1315 decode_buffer[decode_pixel_index + c] = ((float)((const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float;
1316 }
1317 break;
1318
1319 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
1320 for (; x < max_x; x++)
1321 {
1322 int decode_pixel_index = x * channels;
1323 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1324 for (c = 0; c < channels; c++)
1325 decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((float)((const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float);
1326
1327 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1328 decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned short*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint16_as_float;
1329 }
1330 break;
1331
1332 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
1333 for (; x < max_x; x++)
1334 {
1335 int decode_pixel_index = x * channels;
1336 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1337 for (c = 0; c < channels; c++)
1338 decode_buffer[decode_pixel_index + c] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float);
1339 }
1340 break;
1341
1342 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
1343 for (; x < max_x; x++)
1344 {
1345 int decode_pixel_index = x * channels;
1346 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1347 for (c = 0; c < channels; c++)
1348 decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear((float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float));
1349
1350 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1351 decode_buffer[decode_pixel_index + alpha_channel] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint32_as_float);
1352 }
1353 break;
1354
1355 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
1356 for (; x < max_x; x++)
1357 {
1358 int decode_pixel_index = x * channels;
1359 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1360 for (c = 0; c < channels; c++)
1361 decode_buffer[decode_pixel_index + c] = ((const float*)input_data)[input_pixel_index + c];
1362 }
1363 break;
1364
1365 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
1366 for (; x < max_x; x++)
1367 {
1368 int decode_pixel_index = x * channels;
1369 int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
1370 for (c = 0; c < channels; c++)
1371 decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((const float*)input_data)[input_pixel_index + c]);
1372
1373 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1374 decode_buffer[decode_pixel_index + alpha_channel] = ((const float*)input_data)[input_pixel_index + alpha_channel];
1375 }
1376
1377 break;
1378
1379 default:
1380 STBIR_ASSERT(!"Unknown type/colorspace/channels combination.");
1381 break;
1382 }
1383
1384 if (!(stbir_info->flags & STBIR_FLAG_ALPHA_PREMULTIPLIED))
1385 {
1386 for (x = -stbir_info->horizontal_filter_pixel_margin; x < max_x; x++)
1387 {
1388 int decode_pixel_index = x * channels;
1389
1390 // If the alpha value is 0 it will clobber the color values. Make sure it's not.
1391 float alpha = decode_buffer[decode_pixel_index + alpha_channel];
1392#ifndef STBIR_NO_ALPHA_EPSILON
1393 if (stbir_info->type != STBIR_TYPE_FLOAT) {
1394 alpha += STBIR_ALPHA_EPSILON;
1395 decode_buffer[decode_pixel_index + alpha_channel] = alpha;
1396 }
1397#endif
1398 for (c = 0; c < channels; c++)
1399 {
1400 if (c == alpha_channel)
1401 continue;
1402
1403 decode_buffer[decode_pixel_index + c] *= alpha;
1404 }
1405 }
1406 }
1407
1408 if (edge_horizontal == STBIR_EDGE_ZERO)
1409 {
1410 for (x = -stbir_info->horizontal_filter_pixel_margin; x < 0; x++)
1411 {
1412 for (c = 0; c < channels; c++)
1413 decode_buffer[x*channels + c] = 0;
1414 }
1415 for (x = input_w; x < max_x; x++)
1416 {
1417 for (c = 0; c < channels; c++)
1418 decode_buffer[x*channels + c] = 0;
1419 }
1420 }
1421}
1422
1423static float* stbir__get_ring_buffer_entry(float* ring_buffer, int index, int ring_buffer_length)
1424{
1425 return &ring_buffer[index * ring_buffer_length];
1426}
1427
1428static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n)
1429{
1430 int ring_buffer_index;
1431 float* ring_buffer;
1432
1433 stbir_info->ring_buffer_last_scanline = n;
1434
1435 if (stbir_info->ring_buffer_begin_index < 0)
1436 {
1437 ring_buffer_index = stbir_info->ring_buffer_begin_index = 0;
1438 stbir_info->ring_buffer_first_scanline = n;
1439 }
1440 else
1441 {
1442 ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline)) % stbir_info->ring_buffer_num_entries;
1443 STBIR_ASSERT(ring_buffer_index != stbir_info->ring_buffer_begin_index);
1444 }
1445
1446 ring_buffer = stbir__get_ring_buffer_entry(stbir_info->ring_buffer, ring_buffer_index, stbir_info->ring_buffer_length_bytes / sizeof(float));
1447 memset(ring_buffer, 0, stbir_info->ring_buffer_length_bytes);
1448
1449 return ring_buffer;
1450}
1451
1452
1453static void stbir__resample_horizontal_upsample(stbir__info* stbir_info, float* output_buffer)
1454{
1455 int x, k;
1456 int output_w = stbir_info->output_w;
1457 int channels = stbir_info->channels;
1458 float* decode_buffer = stbir__get_decode_buffer(stbir_info);
1459 stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
1460 float* horizontal_coefficients = stbir_info->horizontal_coefficients;
1461 int coefficient_width = stbir_info->horizontal_coefficient_width;
1462
1463 for (x = 0; x < output_w; x++)
1464 {
1465 int n0 = horizontal_contributors[x].n0;
1466 int n1 = horizontal_contributors[x].n1;
1467
1468 int out_pixel_index = x * channels;
1469 int coefficient_group = coefficient_width * x;
1470 int coefficient_counter = 0;
1471
1472 STBIR_ASSERT(n1 >= n0);
1473 STBIR_ASSERT(n0 >= -stbir_info->horizontal_filter_pixel_margin);
1474 STBIR_ASSERT(n1 >= -stbir_info->horizontal_filter_pixel_margin);
1475 STBIR_ASSERT(n0 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin);
1476 STBIR_ASSERT(n1 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin);
1477
1478 switch (channels) {
1479 case 1:
1480 for (k = n0; k <= n1; k++)
1481 {
1482 int in_pixel_index = k * 1;
1483 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1484 STBIR_ASSERT(coefficient != 0);
1485 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1486 }
1487 break;
1488 case 2:
1489 for (k = n0; k <= n1; k++)
1490 {
1491 int in_pixel_index = k * 2;
1492 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1493 STBIR_ASSERT(coefficient != 0);
1494 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1495 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1496 }
1497 break;
1498 case 3:
1499 for (k = n0; k <= n1; k++)
1500 {
1501 int in_pixel_index = k * 3;
1502 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1503 STBIR_ASSERT(coefficient != 0);
1504 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1505 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1506 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1507 }
1508 break;
1509 case 4:
1510 for (k = n0; k <= n1; k++)
1511 {
1512 int in_pixel_index = k * 4;
1513 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1514 STBIR_ASSERT(coefficient != 0);
1515 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1516 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1517 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1518 output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
1519 }
1520 break;
1521 default:
1522 for (k = n0; k <= n1; k++)
1523 {
1524 int in_pixel_index = k * channels;
1525 float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
1526 int c;
1527 STBIR_ASSERT(coefficient != 0);
1528 for (c = 0; c < channels; c++)
1529 output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
1530 }
1531 break;
1532 }
1533 }
1534}
1535
1536static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, float* output_buffer)
1537{
1538 int x, k;
1539 int input_w = stbir_info->input_w;
1540 int channels = stbir_info->channels;
1541 float* decode_buffer = stbir__get_decode_buffer(stbir_info);
1542 stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
1543 float* horizontal_coefficients = stbir_info->horizontal_coefficients;
1544 int coefficient_width = stbir_info->horizontal_coefficient_width;
1545 int filter_pixel_margin = stbir_info->horizontal_filter_pixel_margin;
1546 int max_x = input_w + filter_pixel_margin * 2;
1547
1548 STBIR_ASSERT(!stbir__use_width_upsampling(stbir_info));
1549
1550 switch (channels) {
1551 case 1:
1552 for (x = 0; x < max_x; x++)
1553 {
1554 int n0 = horizontal_contributors[x].n0;
1555 int n1 = horizontal_contributors[x].n1;
1556
1557 int in_x = x - filter_pixel_margin;
1558 int in_pixel_index = in_x * 1;
1559 int max_n = n1;
1560 int coefficient_group = coefficient_width * x;
1561
1562 for (k = n0; k <= max_n; k++)
1563 {
1564 int out_pixel_index = k * 1;
1565 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1566 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1567 }
1568 }
1569 break;
1570
1571 case 2:
1572 for (x = 0; x < max_x; x++)
1573 {
1574 int n0 = horizontal_contributors[x].n0;
1575 int n1 = horizontal_contributors[x].n1;
1576
1577 int in_x = x - filter_pixel_margin;
1578 int in_pixel_index = in_x * 2;
1579 int max_n = n1;
1580 int coefficient_group = coefficient_width * x;
1581
1582 for (k = n0; k <= max_n; k++)
1583 {
1584 int out_pixel_index = k * 2;
1585 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1586 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1587 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1588 }
1589 }
1590 break;
1591
1592 case 3:
1593 for (x = 0; x < max_x; x++)
1594 {
1595 int n0 = horizontal_contributors[x].n0;
1596 int n1 = horizontal_contributors[x].n1;
1597
1598 int in_x = x - filter_pixel_margin;
1599 int in_pixel_index = in_x * 3;
1600 int max_n = n1;
1601 int coefficient_group = coefficient_width * x;
1602
1603 for (k = n0; k <= max_n; k++)
1604 {
1605 int out_pixel_index = k * 3;
1606 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1607 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1608 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1609 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1610 }
1611 }
1612 break;
1613
1614 case 4:
1615 for (x = 0; x < max_x; x++)
1616 {
1617 int n0 = horizontal_contributors[x].n0;
1618 int n1 = horizontal_contributors[x].n1;
1619
1620 int in_x = x - filter_pixel_margin;
1621 int in_pixel_index = in_x * 4;
1622 int max_n = n1;
1623 int coefficient_group = coefficient_width * x;
1624
1625 for (k = n0; k <= max_n; k++)
1626 {
1627 int out_pixel_index = k * 4;
1628 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1629 output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
1630 output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
1631 output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
1632 output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
1633 }
1634 }
1635 break;
1636
1637 default:
1638 for (x = 0; x < max_x; x++)
1639 {
1640 int n0 = horizontal_contributors[x].n0;
1641 int n1 = horizontal_contributors[x].n1;
1642
1643 int in_x = x - filter_pixel_margin;
1644 int in_pixel_index = in_x * channels;
1645 int max_n = n1;
1646 int coefficient_group = coefficient_width * x;
1647
1648 for (k = n0; k <= max_n; k++)
1649 {
1650 int c;
1651 int out_pixel_index = k * channels;
1652 float coefficient = horizontal_coefficients[coefficient_group + k - n0];
1653 for (c = 0; c < channels; c++)
1654 output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
1655 }
1656 }
1657 break;
1658 }
1659}
1660
1661static void stbir__decode_and_resample_upsample(stbir__info* stbir_info, int n)
1662{
1663 // Decode the nth scanline from the source image into the decode buffer.
1664 stbir__decode_scanline(stbir_info, n);
1665
1666 // Now resample it into the ring buffer.
1667 if (stbir__use_width_upsampling(stbir_info))
1668 stbir__resample_horizontal_upsample(stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n));
1669 else
1670 stbir__resample_horizontal_downsample(stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n));
1671
1672 // Now it's sitting in the ring buffer ready to be used as source for the vertical sampling.
1673}
1674
1675static void stbir__decode_and_resample_downsample(stbir__info* stbir_info, int n)
1676{
1677 // Decode the nth scanline from the source image into the decode buffer.
1678 stbir__decode_scanline(stbir_info, n);
1679
1680 memset(stbir_info->horizontal_buffer, 0, stbir_info->output_w * stbir_info->channels * sizeof(float));
1681
1682 // Now resample it into the horizontal buffer.
1683 if (stbir__use_width_upsampling(stbir_info))
1684 stbir__resample_horizontal_upsample(stbir_info, stbir_info->horizontal_buffer);
1685 else
1686 stbir__resample_horizontal_downsample(stbir_info, stbir_info->horizontal_buffer);
1687
1688 // Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers.
1689}
1690
1691// Get the specified scan line from the ring buffer.
1692static float* stbir__get_ring_buffer_scanline(int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_num_entries, int ring_buffer_length)
1693{
1694 int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_num_entries;
1695 return stbir__get_ring_buffer_entry(ring_buffer, ring_buffer_index, ring_buffer_length);
1696}
1697
1698
1699static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void *output_buffer, float *encode_buffer, int channels, int alpha_channel, int decode)
1700{
1701 int x;
1702 int n;
1703 int num_nonalpha;
1704 stbir_uint16 nonalpha[STBIR_MAX_CHANNELS];
1705
1706 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_PREMULTIPLIED))
1707 {
1708 for (x=0; x < num_pixels; ++x)
1709 {
1710 int pixel_index = x*channels;
1711
1712 float alpha = encode_buffer[pixel_index + alpha_channel];
1713 float reciprocal_alpha = alpha ? 1.0f / alpha : 0;
1714
1715 // unrolling this produced a 1% slowdown upscaling a large RGBA linear-space image on my machine - stb
1716 for (n = 0; n < channels; n++)
1717 if (n != alpha_channel)
1718 encode_buffer[pixel_index + n] *= reciprocal_alpha;
1719
1720 // We added in a small epsilon to prevent the color channel from being deleted with zero alpha.
1721 // Because we only add it for integer types, it will automatically be discarded on integer
1722 // conversion, so we don't need to subtract it back out (which would be problematic for
1723 // numeric precision reasons).
1724 }
1725 }
1726
1727 // build a table of all channels that need colorspace correction, so
1728 // we don't perform colorspace correction on channels that don't need it.
1729 for (x = 0, num_nonalpha = 0; x < channels; ++x)
1730 {
1731 if (x != alpha_channel || (stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE))
1732 {
1733 nonalpha[num_nonalpha++] = (stbir_uint16)x;
1734 }
1735 }
1736
1737 #define STBIR__ROUND_INT(f) ((int) ((f)+0.5))
1738 #define STBIR__ROUND_UINT(f) ((stbir_uint32) ((f)+0.5))
1739
1740 #ifdef STBIR__SATURATE_INT
1741 #define STBIR__ENCODE_LINEAR8(f) stbir__saturate8 (STBIR__ROUND_INT((f) * stbir__max_uint8_as_float ))
1742 #define STBIR__ENCODE_LINEAR16(f) stbir__saturate16(STBIR__ROUND_INT((f) * stbir__max_uint16_as_float))
1743 #else
1744 #define STBIR__ENCODE_LINEAR8(f) (unsigned char ) STBIR__ROUND_INT(stbir__saturate(f) * stbir__max_uint8_as_float )
1745 #define STBIR__ENCODE_LINEAR16(f) (unsigned short) STBIR__ROUND_INT(stbir__saturate(f) * stbir__max_uint16_as_float)
1746 #endif
1747
1748 switch (decode)
1749 {
1750 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
1751 for (x=0; x < num_pixels; ++x)
1752 {
1753 int pixel_index = x*channels;
1754
1755 for (n = 0; n < channels; n++)
1756 {
1757 int index = pixel_index + n;
1758 ((unsigned char*)output_buffer)[index] = STBIR__ENCODE_LINEAR8(encode_buffer[index]);
1759 }
1760 }
1761 break;
1762
1763 case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
1764 for (x=0; x < num_pixels; ++x)
1765 {
1766 int pixel_index = x*channels;
1767
1768 for (n = 0; n < num_nonalpha; n++)
1769 {
1770 int index = pixel_index + nonalpha[n];
1771 ((unsigned char*)output_buffer)[index] = stbir__linear_to_srgb_uchar(encode_buffer[index]);
1772 }
1773
1774 if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE))
1775 ((unsigned char *)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR8(encode_buffer[pixel_index+alpha_channel]);
1776 }
1777 break;
1778
1779 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
1780 for (x=0; x < num_pixels; ++x)
1781 {
1782 int pixel_index = x*channels;
1783
1784 for (n = 0; n < channels; n++)
1785 {
1786 int index = pixel_index + n;
1787 ((unsigned short*)output_buffer)[index] = STBIR__ENCODE_LINEAR16(encode_buffer[index]);
1788 }
1789 }
1790 break;
1791
1792 case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
1793 for (x=0; x < num_pixels; ++x)
1794 {
1795 int pixel_index = x*channels;
1796
1797 for (n = 0; n < num_nonalpha; n++)
1798 {
1799 int index = pixel_index + nonalpha[n];
1800 ((unsigned short*)output_buffer)[index] = (unsigned short)STBIR__ROUND_INT(stbir__linear_to_srgb(stbir__saturate(encode_buffer[index])) * stbir__max_uint16_as_float);
1801 }
1802
1803 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1804 ((unsigned short*)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR16(encode_buffer[pixel_index + alpha_channel]);
1805 }
1806
1807 break;
1808
1809 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
1810 for (x=0; x < num_pixels; ++x)
1811 {
1812 int pixel_index = x*channels;
1813
1814 for (n = 0; n < channels; n++)
1815 {
1816 int index = pixel_index + n;
1817 ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT(((double)stbir__saturate(encode_buffer[index])) * stbir__max_uint32_as_float);
1818 }
1819 }
1820 break;
1821
1822 case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
1823 for (x=0; x < num_pixels; ++x)
1824 {
1825 int pixel_index = x*channels;
1826
1827 for (n = 0; n < num_nonalpha; n++)
1828 {
1829 int index = pixel_index + nonalpha[n];
1830 ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[index]))) * stbir__max_uint32_as_float);
1831 }
1832
1833 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1834 ((unsigned int*)output_buffer)[pixel_index + alpha_channel] = (unsigned int)STBIR__ROUND_INT(((double)stbir__saturate(encode_buffer[pixel_index + alpha_channel])) * stbir__max_uint32_as_float);
1835 }
1836 break;
1837
1838 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
1839 for (x=0; x < num_pixels; ++x)
1840 {
1841 int pixel_index = x*channels;
1842
1843 for (n = 0; n < channels; n++)
1844 {
1845 int index = pixel_index + n;
1846 ((float*)output_buffer)[index] = encode_buffer[index];
1847 }
1848 }
1849 break;
1850
1851 case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
1852 for (x=0; x < num_pixels; ++x)
1853 {
1854 int pixel_index = x*channels;
1855
1856 for (n = 0; n < num_nonalpha; n++)
1857 {
1858 int index = pixel_index + nonalpha[n];
1859 ((float*)output_buffer)[index] = stbir__linear_to_srgb(encode_buffer[index]);
1860 }
1861
1862 if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
1863 ((float*)output_buffer)[pixel_index + alpha_channel] = encode_buffer[pixel_index + alpha_channel];
1864 }
1865 break;
1866
1867 default:
1868 STBIR_ASSERT(!"Unknown type/colorspace/channels combination.");
1869 break;
1870 }
1871}
1872
1873static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n)
1874{
1875 int x, k;
1876 int output_w = stbir_info->output_w;
1877 stbir__contributors* vertical_contributors = stbir_info->vertical_contributors;
1878 float* vertical_coefficients = stbir_info->vertical_coefficients;
1879 int channels = stbir_info->channels;
1880 int alpha_channel = stbir_info->alpha_channel;
1881 int type = stbir_info->type;
1882 int colorspace = stbir_info->colorspace;
1883 int ring_buffer_entries = stbir_info->ring_buffer_num_entries;
1884 void* output_data = stbir_info->output_data;
1885 float* encode_buffer = stbir_info->encode_buffer;
1886 int decode = STBIR__DECODE(type, colorspace);
1887 int coefficient_width = stbir_info->vertical_coefficient_width;
1888 int coefficient_counter;
1889 int contributor = n;
1890
1891 float* ring_buffer = stbir_info->ring_buffer;
1892 int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
1893 int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
1894 int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
1895
1896 int n0,n1, output_row_start;
1897 int coefficient_group = coefficient_width * contributor;
1898
1899 n0 = vertical_contributors[contributor].n0;
1900 n1 = vertical_contributors[contributor].n1;
1901
1902 output_row_start = n * stbir_info->output_stride_bytes;
1903
1904 STBIR_ASSERT(stbir__use_height_upsampling(stbir_info));
1905
1906 memset(encode_buffer, 0, output_w * sizeof(float) * channels);
1907
1908 // I tried reblocking this for better cache usage of encode_buffer
1909 // (using x_outer, k, x_inner), but it lost speed. -- stb
1910
1911 coefficient_counter = 0;
1912 switch (channels) {
1913 case 1:
1914 for (k = n0; k <= n1; k++)
1915 {
1916 int coefficient_index = coefficient_counter++;
1917 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1918 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1919 for (x = 0; x < output_w; ++x)
1920 {
1921 int in_pixel_index = x * 1;
1922 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1923 }
1924 }
1925 break;
1926 case 2:
1927 for (k = n0; k <= n1; k++)
1928 {
1929 int coefficient_index = coefficient_counter++;
1930 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1931 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1932 for (x = 0; x < output_w; ++x)
1933 {
1934 int in_pixel_index = x * 2;
1935 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1936 encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
1937 }
1938 }
1939 break;
1940 case 3:
1941 for (k = n0; k <= n1; k++)
1942 {
1943 int coefficient_index = coefficient_counter++;
1944 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1945 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1946 for (x = 0; x < output_w; ++x)
1947 {
1948 int in_pixel_index = x * 3;
1949 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1950 encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
1951 encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient;
1952 }
1953 }
1954 break;
1955 case 4:
1956 for (k = n0; k <= n1; k++)
1957 {
1958 int coefficient_index = coefficient_counter++;
1959 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1960 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1961 for (x = 0; x < output_w; ++x)
1962 {
1963 int in_pixel_index = x * 4;
1964 encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
1965 encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
1966 encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient;
1967 encode_buffer[in_pixel_index + 3] += ring_buffer_entry[in_pixel_index + 3] * coefficient;
1968 }
1969 }
1970 break;
1971 default:
1972 for (k = n0; k <= n1; k++)
1973 {
1974 int coefficient_index = coefficient_counter++;
1975 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
1976 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
1977 for (x = 0; x < output_w; ++x)
1978 {
1979 int in_pixel_index = x * channels;
1980 int c;
1981 for (c = 0; c < channels; c++)
1982 encode_buffer[in_pixel_index + c] += ring_buffer_entry[in_pixel_index + c] * coefficient;
1983 }
1984 }
1985 break;
1986 }
1987 stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, encode_buffer, channels, alpha_channel, decode);
1988}
1989
1990static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n)
1991{
1992 int x, k;
1993 int output_w = stbir_info->output_w;
1994 stbir__contributors* vertical_contributors = stbir_info->vertical_contributors;
1995 float* vertical_coefficients = stbir_info->vertical_coefficients;
1996 int channels = stbir_info->channels;
1997 int ring_buffer_entries = stbir_info->ring_buffer_num_entries;
1998 float* horizontal_buffer = stbir_info->horizontal_buffer;
1999 int coefficient_width = stbir_info->vertical_coefficient_width;
2000 int contributor = n + stbir_info->vertical_filter_pixel_margin;
2001
2002 float* ring_buffer = stbir_info->ring_buffer;
2003 int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
2004 int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
2005 int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
2006 int n0,n1;
2007
2008 n0 = vertical_contributors[contributor].n0;
2009 n1 = vertical_contributors[contributor].n1;
2010
2011 STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info));
2012
2013 for (k = n0; k <= n1; k++)
2014 {
2015 int coefficient_index = k - n0;
2016 int coefficient_group = coefficient_width * contributor;
2017 float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
2018
2019 float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
2020
2021 switch (channels) {
2022 case 1:
2023 for (x = 0; x < output_w; x++)
2024 {
2025 int in_pixel_index = x * 1;
2026 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
2027 }
2028 break;
2029 case 2:
2030 for (x = 0; x < output_w; x++)
2031 {
2032 int in_pixel_index = x * 2;
2033 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
2034 ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
2035 }
2036 break;
2037 case 3:
2038 for (x = 0; x < output_w; x++)
2039 {
2040 int in_pixel_index = x * 3;
2041 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
2042 ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
2043 ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient;
2044 }
2045 break;
2046 case 4:
2047 for (x = 0; x < output_w; x++)
2048 {
2049 int in_pixel_index = x * 4;
2050 ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
2051 ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
2052 ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient;
2053 ring_buffer_entry[in_pixel_index + 3] += horizontal_buffer[in_pixel_index + 3] * coefficient;
2054 }
2055 break;
2056 default:
2057 for (x = 0; x < output_w; x++)
2058 {
2059 int in_pixel_index = x * channels;
2060
2061 int c;
2062 for (c = 0; c < channels; c++)
2063 ring_buffer_entry[in_pixel_index + c] += horizontal_buffer[in_pixel_index + c] * coefficient;
2064 }
2065 break;
2066 }
2067 }
2068}
2069
2070static void stbir__buffer_loop_upsample(stbir__info* stbir_info)
2071{
2072 int y;
2073 float scale_ratio = stbir_info->vertical_scale;
2074 float out_scanlines_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(1/scale_ratio) * scale_ratio;
2075
2076 STBIR_ASSERT(stbir__use_height_upsampling(stbir_info));
2077
2078 for (y = 0; y < stbir_info->output_h; y++)
2079 {
2080 float in_center_of_out = 0; // Center of the current out scanline in the in scanline space
2081 int in_first_scanline = 0, in_last_scanline = 0;
2082
2083 stbir__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, stbir_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out);
2084
2085 STBIR_ASSERT(in_last_scanline - in_first_scanline + 1 <= stbir_info->ring_buffer_num_entries);
2086
2087 if (stbir_info->ring_buffer_begin_index >= 0)
2088 {
2089 // Get rid of whatever we don't need anymore.
2090 while (in_first_scanline > stbir_info->ring_buffer_first_scanline)
2091 {
2092 if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
2093 {
2094 // We just popped the last scanline off the ring buffer.
2095 // Reset it to the empty state.
2096 stbir_info->ring_buffer_begin_index = -1;
2097 stbir_info->ring_buffer_first_scanline = 0;
2098 stbir_info->ring_buffer_last_scanline = 0;
2099 break;
2100 }
2101 else
2102 {
2103 stbir_info->ring_buffer_first_scanline++;
2104 stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries;
2105 }
2106 }
2107 }
2108
2109 // Load in new ones.
2110 if (stbir_info->ring_buffer_begin_index < 0)
2111 stbir__decode_and_resample_upsample(stbir_info, in_first_scanline);
2112
2113 while (in_last_scanline > stbir_info->ring_buffer_last_scanline)
2114 stbir__decode_and_resample_upsample(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
2115
2116 // Now all buffers should be ready to write a row of vertical sampling.
2117 stbir__resample_vertical_upsample(stbir_info, y);
2118
2119 STBIR_PROGRESS_REPORT((float)y / stbir_info->output_h);
2120 }
2121}
2122
2123static void stbir__empty_ring_buffer(stbir__info* stbir_info, int first_necessary_scanline)
2124{
2125 int output_stride_bytes = stbir_info->output_stride_bytes;
2126 int channels = stbir_info->channels;
2127 int alpha_channel = stbir_info->alpha_channel;
2128 int type = stbir_info->type;
2129 int colorspace = stbir_info->colorspace;
2130 int output_w = stbir_info->output_w;
2131 void* output_data = stbir_info->output_data;
2132 int decode = STBIR__DECODE(type, colorspace);
2133
2134 float* ring_buffer = stbir_info->ring_buffer;
2135 int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
2136
2137 if (stbir_info->ring_buffer_begin_index >= 0)
2138 {
2139 // Get rid of whatever we don't need anymore.
2140 while (first_necessary_scanline > stbir_info->ring_buffer_first_scanline)
2141 {
2142 if (stbir_info->ring_buffer_first_scanline >= 0 && stbir_info->ring_buffer_first_scanline < stbir_info->output_h)
2143 {
2144 int output_row_start = stbir_info->ring_buffer_first_scanline * output_stride_bytes;
2145 float* ring_buffer_entry = stbir__get_ring_buffer_entry(ring_buffer, stbir_info->ring_buffer_begin_index, ring_buffer_length);
2146 stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, ring_buffer_entry, channels, alpha_channel, decode);
2147 STBIR_PROGRESS_REPORT((float)stbir_info->ring_buffer_first_scanline / stbir_info->output_h);
2148 }
2149
2150 if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
2151 {
2152 // We just popped the last scanline off the ring buffer.
2153 // Reset it to the empty state.
2154 stbir_info->ring_buffer_begin_index = -1;
2155 stbir_info->ring_buffer_first_scanline = 0;
2156 stbir_info->ring_buffer_last_scanline = 0;
2157 break;
2158 }
2159 else
2160 {
2161 stbir_info->ring_buffer_first_scanline++;
2162 stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries;
2163 }
2164 }
2165 }
2166}
2167
2168static void stbir__buffer_loop_downsample(stbir__info* stbir_info)
2169{
2170 int y;
2171 float scale_ratio = stbir_info->vertical_scale;
2172 int output_h = stbir_info->output_h;
2173 float in_pixels_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(scale_ratio) / scale_ratio;
2174 int pixel_margin = stbir_info->vertical_filter_pixel_margin;
2175 int max_y = stbir_info->input_h + pixel_margin;
2176
2177 STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info));
2178
2179 for (y = -pixel_margin; y < max_y; y++)
2180 {
2181 float out_center_of_in; // Center of the current out scanline in the in scanline space
2182 int out_first_scanline, out_last_scanline;
2183
2184 stbir__calculate_sample_range_downsample(y, in_pixels_radius, scale_ratio, stbir_info->vertical_shift, &out_first_scanline, &out_last_scanline, &out_center_of_in);
2185
2186 STBIR_ASSERT(out_last_scanline - out_first_scanline + 1 <= stbir_info->ring_buffer_num_entries);
2187
2188 if (out_last_scanline < 0 || out_first_scanline >= output_h)
2189 continue;
2190
2191 stbir__empty_ring_buffer(stbir_info, out_first_scanline);
2192
2193 stbir__decode_and_resample_downsample(stbir_info, y);
2194
2195 // Load in new ones.
2196 if (stbir_info->ring_buffer_begin_index < 0)
2197 stbir__add_empty_ring_buffer_entry(stbir_info, out_first_scanline);
2198
2199 while (out_last_scanline > stbir_info->ring_buffer_last_scanline)
2200 stbir__add_empty_ring_buffer_entry(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
2201
2202 // Now the horizontal buffer is ready to write to all ring buffer rows.
2203 stbir__resample_vertical_downsample(stbir_info, y);
2204 }
2205
2206 stbir__empty_ring_buffer(stbir_info, stbir_info->output_h);
2207}
2208
2209static void stbir__setup(stbir__info *info, int input_w, int input_h, int output_w, int output_h, int channels)
2210{
2211 info->input_w = input_w;
2212 info->input_h = input_h;
2213 info->output_w = output_w;
2214 info->output_h = output_h;
2215 info->channels = channels;
2216}
2217
2218static void stbir__calculate_transform(stbir__info *info, float s0, float t0, float s1, float t1, float *transform)
2219{
2220 info->s0 = s0;
2221 info->t0 = t0;
2222 info->s1 = s1;
2223 info->t1 = t1;
2224
2225 if (transform)
2226 {
2227 info->horizontal_scale = transform[0];
2228 info->vertical_scale = transform[1];
2229 info->horizontal_shift = transform[2];
2230 info->vertical_shift = transform[3];
2231 }
2232 else
2233 {
2234 info->horizontal_scale = ((float)info->output_w / info->input_w) / (s1 - s0);
2235 info->vertical_scale = ((float)info->output_h / info->input_h) / (t1 - t0);
2236
2237 info->horizontal_shift = s0 * info->output_w / (s1 - s0);
2238 info->vertical_shift = t0 * info->output_h / (t1 - t0);
2239 }
2240}
2241
2242static void stbir__choose_filter(stbir__info *info, stbir_filter h_filter, stbir_filter v_filter)
2243{
2244 if (h_filter == 0)
2245 h_filter = stbir__use_upsampling(info->horizontal_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
2246 if (v_filter == 0)
2247 v_filter = stbir__use_upsampling(info->vertical_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
2248 info->horizontal_filter = h_filter;
2249 info->vertical_filter = v_filter;
2250}
2251
2252static stbir_uint32 stbir__calculate_memory(stbir__info *info)
2253{
2254 int pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
2255 int filter_height = stbir__get_filter_pixel_width(info->vertical_filter, info->vertical_scale);
2256
2257 info->horizontal_num_contributors = stbir__get_contributors(info->horizontal_scale, info->horizontal_filter, info->input_w, info->output_w);
2258 info->vertical_num_contributors = stbir__get_contributors(info->vertical_scale , info->vertical_filter , info->input_h, info->output_h);
2259
2260 // One extra entry because floating point precision problems sometimes cause an extra to be necessary.
2261 info->ring_buffer_num_entries = filter_height + 1;
2262
2263 info->horizontal_contributors_size = info->horizontal_num_contributors * sizeof(stbir__contributors);
2264 info->horizontal_coefficients_size = stbir__get_total_horizontal_coefficients(info) * sizeof(float);
2265 info->vertical_contributors_size = info->vertical_num_contributors * sizeof(stbir__contributors);
2266 info->vertical_coefficients_size = stbir__get_total_vertical_coefficients(info) * sizeof(float);
2267 info->decode_buffer_size = (info->input_w + pixel_margin * 2) * info->channels * sizeof(float);
2268 info->horizontal_buffer_size = info->output_w * info->channels * sizeof(float);
2269 info->ring_buffer_size = info->output_w * info->channels * info->ring_buffer_num_entries * sizeof(float);
2270 info->encode_buffer_size = info->output_w * info->channels * sizeof(float);
2271
2272 STBIR_ASSERT(info->horizontal_filter != 0);
2273 STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
2274 STBIR_ASSERT(info->vertical_filter != 0);
2275 STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
2276
2277 if (stbir__use_height_upsampling(info))
2278 // The horizontal buffer is for when we're downsampling the height and we
2279 // can't output the result of sampling the decode buffer directly into the
2280 // ring buffers.
2281 info->horizontal_buffer_size = 0;
2282 else
2283 // The encode buffer is to retain precision in the height upsampling method
2284 // and isn't used when height downsampling.
2285 info->encode_buffer_size = 0;
2286
2287 return info->horizontal_contributors_size + info->horizontal_coefficients_size
2288 + info->vertical_contributors_size + info->vertical_coefficients_size
2289 + info->decode_buffer_size + info->horizontal_buffer_size
2290 + info->ring_buffer_size + info->encode_buffer_size;
2291}
2292
2293static int stbir__resize_allocated(stbir__info *info,
2294 const void* input_data, int input_stride_in_bytes,
2295 void* output_data, int output_stride_in_bytes,
2296 int alpha_channel, stbir_uint32 flags, stbir_datatype type,
2297 stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace,
2298 void* tempmem, size_t tempmem_size_in_bytes)
2299{
2300 size_t memory_required = stbir__calculate_memory(info);
2301
2302 int width_stride_input = input_stride_in_bytes ? input_stride_in_bytes : info->channels * info->input_w * stbir__type_size[type];
2303 int width_stride_output = output_stride_in_bytes ? output_stride_in_bytes : info->channels * info->output_w * stbir__type_size[type];
2304
2305#ifdef STBIR_DEBUG_OVERWRITE_TEST
2306#define OVERWRITE_ARRAY_SIZE 8
2307 unsigned char overwrite_output_before_pre[OVERWRITE_ARRAY_SIZE];
2308 unsigned char overwrite_tempmem_before_pre[OVERWRITE_ARRAY_SIZE];
2309 unsigned char overwrite_output_after_pre[OVERWRITE_ARRAY_SIZE];
2310 unsigned char overwrite_tempmem_after_pre[OVERWRITE_ARRAY_SIZE];
2311
2312 size_t begin_forbidden = width_stride_output * (info->output_h - 1) + info->output_w * info->channels * stbir__type_size[type];
2313 memcpy(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
2314 memcpy(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE);
2315 memcpy(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
2316 memcpy(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE);
2317#endif
2318
2319 STBIR_ASSERT(info->channels >= 0);
2320 STBIR_ASSERT(info->channels <= STBIR_MAX_CHANNELS);
2321
2322 if (info->channels < 0 || info->channels > STBIR_MAX_CHANNELS)
2323 return 0;
2324
2325 STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
2326 STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
2327
2328 if (info->horizontal_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
2329 return 0;
2330 if (info->vertical_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
2331 return 0;
2332
2333 if (alpha_channel < 0)
2334 flags |= STBIR_FLAG_ALPHA_USES_COLORSPACE | STBIR_FLAG_ALPHA_PREMULTIPLIED;
2335
2336 if (!(flags&STBIR_FLAG_ALPHA_USES_COLORSPACE) || !(flags&STBIR_FLAG_ALPHA_PREMULTIPLIED)) {
2337 STBIR_ASSERT(alpha_channel >= 0 && alpha_channel < info->channels);
2338 }
2339
2340 if (alpha_channel >= info->channels)
2341 return 0;
2342
2343 STBIR_ASSERT(tempmem);
2344
2345 if (!tempmem)
2346 return 0;
2347
2348 STBIR_ASSERT(tempmem_size_in_bytes >= memory_required);
2349
2350 if (tempmem_size_in_bytes < memory_required)
2351 return 0;
2352
2353 memset(tempmem, 0, tempmem_size_in_bytes);
2354
2355 info->input_data = input_data;
2356 info->input_stride_bytes = width_stride_input;
2357
2358 info->output_data = output_data;
2359 info->output_stride_bytes = width_stride_output;
2360
2361 info->alpha_channel = alpha_channel;
2362 info->flags = flags;
2363 info->type = type;
2364 info->edge_horizontal = edge_horizontal;
2365 info->edge_vertical = edge_vertical;
2366 info->colorspace = colorspace;
2367
2368 info->horizontal_coefficient_width = stbir__get_coefficient_width (info->horizontal_filter, info->horizontal_scale);
2369 info->vertical_coefficient_width = stbir__get_coefficient_width (info->vertical_filter , info->vertical_scale );
2370 info->horizontal_filter_pixel_width = stbir__get_filter_pixel_width (info->horizontal_filter, info->horizontal_scale);
2371 info->vertical_filter_pixel_width = stbir__get_filter_pixel_width (info->vertical_filter , info->vertical_scale );
2372 info->horizontal_filter_pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
2373 info->vertical_filter_pixel_margin = stbir__get_filter_pixel_margin(info->vertical_filter , info->vertical_scale );
2374
2375 info->ring_buffer_length_bytes = info->output_w * info->channels * sizeof(float);
2376 info->decode_buffer_pixels = info->input_w + info->horizontal_filter_pixel_margin * 2;
2377
2378#define STBIR__NEXT_MEMPTR(current, newtype) (newtype*)(((unsigned char*)current) + current##_size)
2379
2380 info->horizontal_contributors = (stbir__contributors *) tempmem;
2381 info->horizontal_coefficients = STBIR__NEXT_MEMPTR(info->horizontal_contributors, float);
2382 info->vertical_contributors = STBIR__NEXT_MEMPTR(info->horizontal_coefficients, stbir__contributors);
2383 info->vertical_coefficients = STBIR__NEXT_MEMPTR(info->vertical_contributors, float);
2384 info->decode_buffer = STBIR__NEXT_MEMPTR(info->vertical_coefficients, float);
2385
2386 if (stbir__use_height_upsampling(info))
2387 {
2388 info->horizontal_buffer = NULL;
2389 info->ring_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
2390 info->encode_buffer = STBIR__NEXT_MEMPTR(info->ring_buffer, float);
2391
2392 STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->encode_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
2393 }
2394 else
2395 {
2396 info->horizontal_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
2397 info->ring_buffer = STBIR__NEXT_MEMPTR(info->horizontal_buffer, float);
2398 info->encode_buffer = NULL;
2399
2400 STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->ring_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
2401 }
2402
2403#undef STBIR__NEXT_MEMPTR
2404
2405 // This signals that the ring buffer is empty
2406 info->ring_buffer_begin_index = -1;
2407
2408 stbir__calculate_filters(info->horizontal_contributors, info->horizontal_coefficients, info->horizontal_filter, info->horizontal_scale, info->horizontal_shift, info->input_w, info->output_w);
2409 stbir__calculate_filters(info->vertical_contributors, info->vertical_coefficients, info->vertical_filter, info->vertical_scale, info->vertical_shift, info->input_h, info->output_h);
2410
2411 STBIR_PROGRESS_REPORT(0);
2412
2413 if (stbir__use_height_upsampling(info))
2414 stbir__buffer_loop_upsample(info);
2415 else
2416 stbir__buffer_loop_downsample(info);
2417
2418 STBIR_PROGRESS_REPORT(1);
2419
2420#ifdef STBIR_DEBUG_OVERWRITE_TEST
2421 STBIR_ASSERT(memcmp(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
2422 STBIR_ASSERT(memcmp(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE) == 0);
2423 STBIR_ASSERT(memcmp(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
2424 STBIR_ASSERT(memcmp(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE) == 0);
2425#endif
2426
2427 return 1;
2428}
2429
2430
2431static int stbir__resize_arbitrary(
2432 void *alloc_context,
2433 const void* input_data, int input_w, int input_h, int input_stride_in_bytes,
2434 void* output_data, int output_w, int output_h, int output_stride_in_bytes,
2435 float s0, float t0, float s1, float t1, float *transform,
2436 int channels, int alpha_channel, stbir_uint32 flags, stbir_datatype type,
2437 stbir_filter h_filter, stbir_filter v_filter,
2438 stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace)
2439{
2440 stbir__info info;
2441 int result;
2442 size_t memory_required;
2443 void* extra_memory;
2444
2445 stbir__setup(&info, input_w, input_h, output_w, output_h, channels);
2446 stbir__calculate_transform(&info, s0,t0,s1,t1,transform);
2447 stbir__choose_filter(&info, h_filter, v_filter);
2448 memory_required = stbir__calculate_memory(&info);
2449 extra_memory = STBIR_MALLOC(memory_required, alloc_context);
2450
2451 if (!extra_memory)
2452 return 0;
2453
2454 result = stbir__resize_allocated(&info, input_data, input_stride_in_bytes,
2455 output_data, output_stride_in_bytes,
2456 alpha_channel, flags, type,
2457 edge_horizontal, edge_vertical,
2458 colorspace, extra_memory, memory_required);
2459
2460 STBIR_FREE(extra_memory, alloc_context);
2461
2462 return result;
2463}
2464
2465STBIRDEF int stbir_resize_uint8( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2466 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2467 int num_channels)
2468{
2469 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2470 output_pixels, output_w, output_h, output_stride_in_bytes,
2471 0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2472 STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
2473}
2474
2475STBIRDEF int stbir_resize_float( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2476 float *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2477 int num_channels)
2478{
2479 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2480 output_pixels, output_w, output_h, output_stride_in_bytes,
2481 0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_FLOAT, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2482 STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
2483}
2484
2485STBIRDEF int stbir_resize_uint8_srgb(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2486 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2487 int num_channels, int alpha_channel, int flags)
2488{
2489 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2490 output_pixels, output_w, output_h, output_stride_in_bytes,
2491 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2492 STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB);
2493}
2494
2495STBIRDEF int stbir_resize_uint8_srgb_edgemode(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2496 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2497 int num_channels, int alpha_channel, int flags,
2498 stbir_edge edge_wrap_mode)
2499{
2500 return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
2501 output_pixels, output_w, output_h, output_stride_in_bytes,
2502 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
2503 edge_wrap_mode, edge_wrap_mode, STBIR_COLORSPACE_SRGB);
2504}
2505
2506STBIRDEF int stbir_resize_uint8_generic( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2507 unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2508 int num_channels, int alpha_channel, int flags,
2509 stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
2510 void *alloc_context)
2511{
2512 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2513 output_pixels, output_w, output_h, output_stride_in_bytes,
2514 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, filter, filter,
2515 edge_wrap_mode, edge_wrap_mode, space);
2516}
2517
2518STBIRDEF int stbir_resize_uint16_generic(const stbir_uint16 *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2519 stbir_uint16 *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
2520 int num_channels, int alpha_channel, int flags,
2521 stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
2522 void *alloc_context)
2523{
2524 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2525 output_pixels, output_w, output_h, output_stride_in_bytes,
2526 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT16, filter, filter,
2527 edge_wrap_mode, edge_wrap_mode, space);
2528}
2529
2530
2531STBIRDEF int stbir_resize_float_generic( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2532 float *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
2533 int num_channels, int alpha_channel, int flags,
2534 stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
2535 void *alloc_context)
2536{
2537 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2538 output_pixels, output_w, output_h, output_stride_in_bytes,
2539 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_FLOAT, filter, filter,
2540 edge_wrap_mode, edge_wrap_mode, space);
2541}
2542
2543
2544STBIRDEF int stbir_resize( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2545 void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2546 stbir_datatype datatype,
2547 int num_channels, int alpha_channel, int flags,
2548 stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
2549 stbir_filter filter_horizontal, stbir_filter filter_vertical,
2550 stbir_colorspace space, void *alloc_context)
2551{
2552 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2553 output_pixels, output_w, output_h, output_stride_in_bytes,
2554 0,0,1,1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
2555 edge_mode_horizontal, edge_mode_vertical, space);
2556}
2557
2558
2559STBIRDEF int stbir_resize_subpixel(const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2560 void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2561 stbir_datatype datatype,
2562 int num_channels, int alpha_channel, int flags,
2563 stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
2564 stbir_filter filter_horizontal, stbir_filter filter_vertical,
2565 stbir_colorspace space, void *alloc_context,
2566 float x_scale, float y_scale,
2567 float x_offset, float y_offset)
2568{
2569 float transform[4];
2570 transform[0] = x_scale;
2571 transform[1] = y_scale;
2572 transform[2] = x_offset;
2573 transform[3] = y_offset;
2574 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2575 output_pixels, output_w, output_h, output_stride_in_bytes,
2576 0,0,1,1,transform,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
2577 edge_mode_horizontal, edge_mode_vertical, space);
2578}
2579
2580STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
2581 void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
2582 stbir_datatype datatype,
2583 int num_channels, int alpha_channel, int flags,
2584 stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
2585 stbir_filter filter_horizontal, stbir_filter filter_vertical,
2586 stbir_colorspace space, void *alloc_context,
2587 float s0, float t0, float s1, float t1)
2588{
2589 return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
2590 output_pixels, output_w, output_h, output_stride_in_bytes,
2591 s0,t0,s1,t1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
2592 edge_mode_horizontal, edge_mode_vertical, space);
2593}
2594
2595#endif // STB_IMAGE_RESIZE_IMPLEMENTATION
2596
2597/* 386/*
2598------------------------------------------------------------------------------ 387------------------------------------------------------------------------------
2599This software is available under 2 licenses -- choose whichever you prefer. 388This software is available under 2 licenses -- choose whichever you prefer.