From 08be45bfeb85bc809a492b9d0147052a028dd8ec Mon Sep 17 00:00:00 2001 From: Jose Colon Rodriguez Date: Sun, 18 Feb 2024 11:21:49 -0400 Subject: Back to zg code_point. 4ms faster than Ghostty's Utf8Decoder --- src/Utf8Decoder.zig | 142 ---------------------------------------------------- 1 file changed, 142 deletions(-) delete mode 100644 src/Utf8Decoder.zig (limited to 'src/Utf8Decoder.zig') diff --git a/src/Utf8Decoder.zig b/src/Utf8Decoder.zig deleted file mode 100644 index 6bb0d98..0000000 --- a/src/Utf8Decoder.zig +++ /dev/null @@ -1,142 +0,0 @@ -//! DFA-based non-allocating error-replacing UTF-8 decoder. -//! -//! This implementation is based largely on the excellent work of -//! Bjoern Hoehrmann, with slight modifications to support error- -//! replacement. -//! -//! For details on Bjoern's DFA-based UTF-8 decoder, see -//! http://bjoern.hoehrmann.de/utf-8/decoder/dfa (MIT licensed) -const UTF8Decoder = @This(); - -const std = @import("std"); -const testing = std.testing; - -const log = std.log.scoped(.utf8decoder); - -// zig fmt: off -const char_classes = [_]u4{ - 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, - 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, - 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, - 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, - 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, - 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, - 8,8,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, - 10,3,3,3,3,3,3,3,3,3,3,3,3,4,3,3, 11,6,6,6,5,8,8,8,8,8,8,8,8,8,8,8, -}; - -const transitions = [_]u8 { - 0,12,24,36,60,96,84,12,12,12,48,72, 12,12,12,12,12,12,12,12,12,12,12,12, - 12, 0,12,12,12,12,12, 0,12, 0,12,12, 12,24,12,12,12,12,12,24,12,24,12,12, - 12,12,12,12,12,12,12,24,12,12,12,12, 12,24,12,12,12,12,12,12,12,24,12,12, - 12,12,12,12,12,12,12,36,12,36,12,12, 12,36,12,12,12,12,12,36,12,36,12,12, - 12,36,12,12,12,12,12,12,12,12,12,12, -}; -// zig fmt: on - -// DFA states -const ACCEPT_STATE = 0; -const REJECT_STATE = 12; - -// This is where we accumulate our current codepoint. -accumulator: u21 = 0, -// The internal state of the DFA. -state: u8 = ACCEPT_STATE, - -/// Takes the next byte in the utf-8 sequence and emits a tuple of -/// - The codepoint that was generated, if there is one. -/// - A boolean that indicates whether the provided byte was consumed. -/// -/// The only case where the byte is not consumed is if an ill-formed -/// sequence is reached, in which case a replacement character will be -/// emitted and the byte will not be consumed. -/// -/// If the byte is not consumed, the caller is responsible for calling -/// again with the same byte before continuing. -pub inline fn next(self: *UTF8Decoder, byte: u8) struct { ?u21, bool } { - const char_class = char_classes[byte]; - - const initial_state = self.state; - - if (self.state != ACCEPT_STATE) { - self.accumulator <<= 6; - self.accumulator |= (byte & 0x3F); - } else { - self.accumulator = (@as(u21, 0xFF) >> char_class) & (byte); - } - - self.state = transitions[self.state + char_class]; - - if (self.state == ACCEPT_STATE) { - defer self.accumulator = 0; - - // Emit the fully decoded codepoint. - return .{ self.accumulator, true }; - } else if (self.state == REJECT_STATE) { - self.accumulator = 0; - self.state = ACCEPT_STATE; - // Emit a replacement character. If we rejected the first byte - // in a sequence, then it was consumed, otherwise it was not. - return .{ 0xFFFD, initial_state == ACCEPT_STATE }; - } else { - // Emit nothing, we're in the middle of a sequence. - return .{ null, true }; - } -} - -test "ASCII" { - var d: UTF8Decoder = .{}; - var out: [13]u8 = undefined; - for ("Hello, World!", 0..) |byte, i| { - const res = d.next(byte); - try testing.expect(res[1]); - if (res[0]) |codepoint| { - out[i] = @intCast(codepoint); - } - } - - try testing.expect(std.mem.eql(u8, &out, "Hello, World!")); -} - -test "Well formed utf-8" { - var d: UTF8Decoder = .{}; - var out: [4]u21 = undefined; - var i: usize = 0; - // 4 bytes, 3 bytes, 2 bytes, 1 byte - for ("๐Ÿ˜„โœครA") |byte| { - var consumed = false; - while (!consumed) { - const res = d.next(byte); - consumed = res[1]; - // There are no errors in this sequence, so - // every byte should be consumed first try. - try testing.expect(consumed == true); - if (res[0]) |codepoint| { - out[i] = codepoint; - i += 1; - } - } - } - - try testing.expect(std.mem.eql(u21, &out, &[_]u21{ 0x1F604, 0x2724, 0xC1, 0x41 })); -} - -test "Partially invalid utf-8" { - var d: UTF8Decoder = .{}; - var out: [5]u21 = undefined; - var i: usize = 0; - // Illegally terminated sequence, valid sequence, illegal surrogate pair. - for ("\xF0\x9F๐Ÿ˜„\xED\xA0\x80") |byte| { - var consumed = false; - while (!consumed) { - const res = d.next(byte); - consumed = res[1]; - if (res[0]) |codepoint| { - out[i] = codepoint; - i += 1; - } - } - } - - try testing.expect(std.mem.eql(u21, &out, &[_]u21{ 0xFFFD, 0x1F604, 0xFFFD, 0xFFFD, 0xFFFD })); -} -- cgit v1.2.3