| // Copyright 2020 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| pub status "#bad animation sequence number" |
| pub status "#bad checksum" |
| pub status "#bad chunk" |
| pub status "#bad filter" |
| pub status "#bad header" |
| pub status "#bad text chunk (not Latin-1)" |
| pub status "#missing palette" |
| pub status "#unsupported PNG compression method" |
| pub status "#unsupported PNG file" |
| |
| pri status "#internal error: inconsistent I/O" |
| pri status "#internal error: inconsistent chunk type" |
| pri status "#internal error: inconsistent frame bounds" |
| pri status "#internal error: inconsistent workbuf length" |
| pri status "#internal error: zlib decoder did not exhaust its input" |
| |
| pub const DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE : base.u64 = 0 |
| |
| // DECODER_SRC_IO_BUFFER_LENGTH_MIN_INCL is the minimum length of the src |
| // wuffs_base__io_buffer passed to the decoder. |
| pub const DECODER_SRC_IO_BUFFER_LENGTH_MIN_INCL : base.u64 = 8 |
| |
| // ANCILLARY_BIT is the upper/lower case bit on the chunk type's first byte (in |
| // little-endian order). |
| pri const ANCILLARY_BIT : base.u32 = 0x0000_0020 |
| |
| // INTERLACING holds the Adam7 interlacing pattern, involving 7 passes: |
| // 1 6 4 6 2 6 4 6 |
| // 7 7 7 7 7 7 7 7 |
| // 5 6 5 6 5 6 5 6 |
| // 7 7 7 7 7 7 7 7 |
| // 3 6 4 6 3 6 4 6 |
| // 7 7 7 7 7 7 7 7 |
| // 5 6 5 6 5 6 5 6 |
| // 7 7 7 7 7 7 7 7 |
| // |
| // The six elements of each inner array are: |
| // 0: log2(x_stride) |
| // 1: x_stride - x_offset - 1 |
| // 2: x_offset |
| // 3: log2(y_stride) |
| // 4: y_stride - y_offset - 1 |
| // 5: y_offset |
| pri const INTERLACING : array[8] array[6] base.u8[..= 7] = [ |
| [0, 0, 0, 0, 0, 0], // non-interlaced; xy_stride=1, xy_offset=0 |
| [3, 7, 0, 3, 7, 0], // interlace_pass == 1 |
| [3, 3, 4, 3, 7, 0], // interlace_pass == 2 |
| [2, 3, 0, 3, 3, 4], // interlace_pass == 3 |
| [2, 1, 2, 2, 3, 0], // interlace_pass == 4 |
| [1, 1, 0, 2, 1, 2], // interlace_pass == 5 |
| [1, 0, 1, 1, 1, 0], // interlace_pass == 6 |
| [0, 0, 0, 1, 0, 1], // interlace_pass == 7 |
| ] |
| |
| // LOW_BIT_DEPTH_MULTIPLIERS holds multipliers that convert D-bit values into |
| // 8-bit values, for depth D. |
| pri const LOW_BIT_DEPTH_MULTIPLIERS : array[8] base.u8 = [ |
| 0, |
| 0b1111_1111, // depth == 1 |
| 0b0101_0101, // depth == 2 |
| 0, |
| 0b0001_0001, // depth == 4 |
| 0, |
| 0, |
| 0, |
| ] |
| |
| // LOW_BIT_DEPTH_NUM_PACKS holds the number of smaller-than-1-byte units that |
| // are packed into each byte. |
| pri const LOW_BIT_DEPTH_NUM_PACKS : array[8] base.u8 = [ |
| 0, |
| 8, // depth == 1 |
| 4, // depth == 2 |
| 0, |
| 2, // depth == 4 |
| 0, |
| 0, |
| 0, |
| ] |
| |
| // NUM_CHANNELS holds the number of channels for each valid color type. |
| pri const NUM_CHANNELS : array[8] base.u8[..= 4] = [ |
| 1, // color_type == 0: Y |
| 0, |
| 3, // color_type == 2: RGB |
| 1, // color_type == 3: indexed |
| 2, // color_type == 4: YA |
| 0, |
| 4, // color_type == 6: RGBA |
| 0, |
| ] |
| |
| // LATIN_1 converts from printable Latin-1 (ISO/IEC 8859-1) to UTF-8 (encoded |
| // as little-endian u16). It was created by script/print-png-latin-1.go. |
| pri const LATIN_1 : array[256] base.u16 = [ |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, |
| 0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F, |
| 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, |
| 0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F, |
| 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, |
| 0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F, |
| 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, |
| 0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F, |
| 0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, |
| 0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F, |
| 0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, |
| 0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, |
| 0x0000, 0xA1C2, 0xA2C2, 0xA3C2, 0xA4C2, 0xA5C2, 0xA6C2, 0xA7C2, |
| 0xA8C2, 0xA9C2, 0xAAC2, 0xABC2, 0xACC2, 0xADC2, 0xAEC2, 0xAFC2, |
| 0xB0C2, 0xB1C2, 0xB2C2, 0xB3C2, 0xB4C2, 0xB5C2, 0xB6C2, 0xB7C2, |
| 0xB8C2, 0xB9C2, 0xBAC2, 0xBBC2, 0xBCC2, 0xBDC2, 0xBEC2, 0xBFC2, |
| 0x80C3, 0x81C3, 0x82C3, 0x83C3, 0x84C3, 0x85C3, 0x86C3, 0x87C3, |
| 0x88C3, 0x89C3, 0x8AC3, 0x8BC3, 0x8CC3, 0x8DC3, 0x8EC3, 0x8FC3, |
| 0x90C3, 0x91C3, 0x92C3, 0x93C3, 0x94C3, 0x95C3, 0x96C3, 0x97C3, |
| 0x98C3, 0x99C3, 0x9AC3, 0x9BC3, 0x9CC3, 0x9DC3, 0x9EC3, 0x9FC3, |
| 0xA0C3, 0xA1C3, 0xA2C3, 0xA3C3, 0xA4C3, 0xA5C3, 0xA6C3, 0xA7C3, |
| 0xA8C3, 0xA9C3, 0xAAC3, 0xABC3, 0xACC3, 0xADC3, 0xAEC3, 0xAFC3, |
| 0xB0C3, 0xB1C3, 0xB2C3, 0xB3C3, 0xB4C3, 0xB5C3, 0xB6C3, 0xB7C3, |
| 0xB8C3, 0xB9C3, 0xBAC3, 0xBBC3, 0xBCC3, 0xBDC3, 0xBEC3, 0xBFC3, |
| ] |