Merge pull request #241 from linkmauve/better-loader

Improve the loader a bit

1 files changed, 56 insertions, 53 deletions

diff --git a/src/core/loader/3dsx.cpp b/src/core/loader/3dsx.cpp
index 4d072871a..958dd03e8 100644
--- a/src/core/loader/3dsx.cpp
+++ b/src/core/loader/3dsx.cpp
@@ -13,11 +13,9 @@
 
 #include "3dsx.h"
 
-
 namespace Loader {
 
-
-/** 
+/**
  * File layout:
  * - File header
  * - Code, rodata and data relocation table headers
@@ -46,7 +44,6 @@ enum THREEDSX_Error {
 static const u32 RELOCBUFSIZE = 512;
 
 // File header
-static const u32 THREEDSX_MAGIC = 0x58534433; // '3DSX'
 #pragma pack(1)
 struct THREEDSX_Header
 {
@@ -64,9 +61,9 @@ struct THREEDSX_Header
 struct THREEDSX_RelocHdr
 {
     // # of absolute relocations (that is, fix address to post-relocation memory layout)
-    u32 cross_segment_absolute; 
+    u32 cross_segment_absolute;
     // # of cross-segment relative relocations (that is, 32bit signed offsets that need to be patched)
-    u32 cross_segment_relative; 
+    u32 cross_segment_relative;
     // more?
 
     // Relocations are written in this order:
@@ -88,12 +85,7 @@ struct THREEloadinfo
     u32 seg_sizes[3];
 };
 
-class THREEDSXReader {
-public:
-     static int Load3DSXFile(const std::string& filename, u32 base_addr);
-};
-
-static u32 TranslateAddr(u32 addr, THREEloadinfo *loadinfo, u32* offsets)
+static u32 TranslateAddr(u32 addr, const THREEloadinfo *loadinfo, u32* offsets)
 {
     if (addr < offsets[0])
         return loadinfo->seg_addrs[0] + addr;
@@ -102,12 +94,14 @@ static u32 TranslateAddr(u32 addr, THREEloadinfo *loadinfo, u32* offsets)
     return loadinfo->seg_addrs[2] + addr - offsets[1];
 }
 
-int THREEDSXReader::Load3DSXFile(const std::string& filename, u32 base_addr)
+static THREEDSX_Error Load3DSXFile(FileUtil::IOFile& file, u32 base_addr)
 {
-    FileUtil::IOFile file(filename, "rb");
-    if (!file.IsOpen()) {
+    if (!file.IsOpen())
         return ERROR_FILE;
-    }
+
+    // Reset read pointer in case this file has been read before.
+    file.Seek(0, SEEK_SET);
+
     THREEDSX_Header hdr;
     if (file.ReadBytes(&hdr, sizeof(hdr)) != sizeof(hdr))
         return ERROR_READ;
@@ -136,8 +130,9 @@ int THREEDSXReader::Load3DSXFile(const std::string& filename, u32 base_addr)
     // Read the relocation headers
     u32* relocs = (u32*)(loadinfo.seg_ptrs[2] + hdr.data_seg_size);
 
-    for (u32 current_segment = 0; current_segment < 3; current_segment++) {
-        if (file.ReadBytes(&relocs[current_segment*n_reloc_tables], n_reloc_tables * 4) != n_reloc_tables * 4)
+    for (unsigned current_segment : {0, 1, 2}) {
+        size_t size = n_reloc_tables * 4;
+        if (file.ReadBytes(&relocs[current_segment * n_reloc_tables], size) != size)
             return ERROR_READ;
     }
 
@@ -153,9 +148,9 @@ int THREEDSXReader::Load3DSXFile(const std::string& filename, u32 base_addr)
     memset((char*)loadinfo.seg_ptrs[2] + hdr.data_seg_size - hdr.bss_size, 0, hdr.bss_size);
 
     // Relocate the segments
-    for (u32 current_segment = 0; current_segment < 3; current_segment++) {
-        for (u32 current_segment_reloc_table = 0; current_segment_reloc_table < n_reloc_tables; current_segment_reloc_table++) {
-            u32 n_relocs = relocs[current_segment*n_reloc_tables + current_segment_reloc_table];
+    for (unsigned current_segment : {0, 1, 2}) {
+        for (unsigned current_segment_reloc_table = 0; current_segment_reloc_table < n_reloc_tables; current_segment_reloc_table++) {
+            u32 n_relocs = relocs[current_segment * n_reloc_tables + current_segment_reloc_table];
             if (current_segment_reloc_table >= 2) {
                 // We are not using this table - ignore it because we don't know what it dose
                 file.Seek(n_relocs*sizeof(THREEDSX_Reloc), SEEK_CUR);
@@ -164,29 +159,35 @@ int THREEDSXReader::Load3DSXFile(const std::string& filename, u32 base_addr)
             static THREEDSX_Reloc reloc_table[RELOCBUFSIZE];
 
             u32* pos = (u32*)loadinfo.seg_ptrs[current_segment];
-            u32* end_pos = pos + (loadinfo.seg_sizes[current_segment] / 4);
+            const u32* end_pos = pos + (loadinfo.seg_sizes[current_segment] / 4);
 
             while (n_relocs) {
                 u32 remaining = std::min(RELOCBUFSIZE, n_relocs);
                 n_relocs -= remaining;
 
-                if (file.ReadBytes(reloc_table, remaining*sizeof(THREEDSX_Reloc)) != remaining*sizeof(THREEDSX_Reloc))
+                if (file.ReadBytes(reloc_table, remaining * sizeof(THREEDSX_Reloc)) != remaining * sizeof(THREEDSX_Reloc))
                     return ERROR_READ;
 
-                for (u32 current_inprogress = 0; current_inprogress < remaining && pos < end_pos; current_inprogress++) {
-                    LOG_TRACE(Loader, "(t=%d,skip=%u,patch=%u)\n",
-                        current_segment_reloc_table, (u32)reloc_table[current_inprogress].skip, (u32)reloc_table[current_inprogress].patch);
-                    pos += reloc_table[current_inprogress].skip;
-                    s32 num_patches = reloc_table[current_inprogress].patch;
+                for (unsigned current_inprogress = 0; current_inprogress < remaining && pos < end_pos; current_inprogress++) {
+                    const auto& table = reloc_table[current_inprogress];
+                    LOG_TRACE(Loader, "(t=%d,skip=%u,patch=%u)\n", current_segment_reloc_table,
+                              (u32)table.skip, (u32)table.patch);
+                    pos += table.skip;
+                    s32 num_patches = table.patch;
                     while (0 < num_patches && pos < end_pos) {
                         u32 in_addr = (char*)pos - (char*)&all_mem[0];
                         u32 addr = TranslateAddr(*pos, &loadinfo, offsets);
                         LOG_TRACE(Loader, "Patching %08X <-- rel(%08X,%d) (%08X)\n",
-                            base_addr + in_addr, addr, current_segment_reloc_table, *pos);
+                                  base_addr + in_addr, addr, current_segment_reloc_table, *pos);
                         switch (current_segment_reloc_table) {
-                        case 0: *pos = (addr); break;
-                        case 1: *pos = (addr - in_addr); break;
-                        default: break; //this should never happen
+                        case 0:
+                            *pos = (addr);
+                            break;
+                        case 1:
+                            *pos = (addr - in_addr);
+                            break;
+                        default:
+                            break; //this should never happen
                         }
                         pos++;
                         num_patches--;
@@ -207,28 +208,30 @@ int THREEDSXReader::Load3DSXFile(const std::string& filename, u32 base_addr)
     return ERROR_NONE;
 }
 
-    /// AppLoader_DSX constructor
-    AppLoader_THREEDSX::AppLoader_THREEDSX(const std::string& filename) : filename(filename) {
-    }
+FileType AppLoader_THREEDSX::IdentifyType(FileUtil::IOFile& file) {
+    u32 magic;
+    file.Seek(0, SEEK_SET);
+    if (1 != file.ReadArray<u32>(&magic, 1))
+        return FileType::Error;
 
-    /// AppLoader_DSX destructor
-    AppLoader_THREEDSX::~AppLoader_THREEDSX() {
-    }
+    if (MakeMagic('3', 'D', 'S', 'X') == magic)
+        return FileType::THREEDSX;
 
-    /**
-    * Loads a 3DSX file
-    * @return Success on success, otherwise Error
-    */
-    ResultStatus AppLoader_THREEDSX::Load() {
-        LOG_INFO(Loader, "Loading 3DSX file %s...", filename.c_str());
-        FileUtil::IOFile file(filename, "rb");
-        if (file.IsOpen()) {
-            THREEDSXReader::Load3DSXFile(filename, 0x00100000);
-            Kernel::LoadExec(0x00100000);
-        } else {
-            return ResultStatus::Error;
-        }
-        return ResultStatus::Success;
-    }
+    return FileType::Error;
+}
+
+ResultStatus AppLoader_THREEDSX::Load() {
+    if (is_loaded)
+        return ResultStatus::ErrorAlreadyLoaded;
+
+    if (!file->IsOpen())
+        return ResultStatus::Error;
+
+    Load3DSXFile(*file, 0x00100000);
+    Kernel::LoadExec(0x00100000);
+
+    is_loaded = true;
+    return ResultStatus::Success;
+}
 
 } // namespace Loader