repositories / deb_ffmpeg.git / blame
| Commit | Line | Data |
|---|---|---|
| 2ba45a60 DM |
1 | /* |
| 2 | * PNG parser | |
| 3 | * Copyright (c) 2009 Peter Holik | |
| 4 | * | |
| 5 | * This file is part of FFmpeg. | |
| 6 | * | |
| 7 | * FFmpeg is free software; you can redistribute it and/or | |
| 8 | * modify it under the terms of the GNU Lesser General Public | |
| 9 | * License as published by the Free Software Foundation; either | |
| 10 | * version 2.1 of the License, or (at your option) any later version. | |
| 11 | * | |
| 12 | * FFmpeg is distributed in the hope that it will be useful, | |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 15 | * Lesser General Public License for more details. | |
| 16 | * | |
| 17 | * You should have received a copy of the GNU Lesser General Public | |
| 18 | * License along with FFmpeg; if not, write to the Free Software | |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| 20 | */ | |
| 21 | ||
| 22 | /** | |
| 23 | * @file | |
| 24 | * PNG parser | |
| 25 | */ | |
| 26 | ||
| 27 | #include "parser.h" | |
| 28 | #include "png.h" | |
| 29 | ||
| 30 | typedef struct PNGParseContext { | |
| 31 | ParseContext pc; | |
| 32 | uint32_t chunk_pos; ///< position inside current chunk | |
| 33 | uint32_t chunk_length; ///< length of the current chunk | |
| 34 | uint32_t remaining_size; ///< remaining size of the current chunk | |
| 35 | } PNGParseContext; | |
| 36 | ||
| 37 | static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx, | |
| 38 | const uint8_t **poutbuf, int *poutbuf_size, | |
| 39 | const uint8_t *buf, int buf_size) | |
| 40 | { | |
| 41 | PNGParseContext *ppc = s->priv_data; | |
| 42 | int next = END_NOT_FOUND; | |
| 43 | int i = 0; | |
| 44 | ||
| 45 | s->pict_type = AV_PICTURE_TYPE_NONE; | |
| 46 | ||
| 47 | *poutbuf_size = 0; | |
| 48 | ||
| 49 | if (!ppc->pc.frame_start_found) { | |
| 50 | uint64_t state64 = ppc->pc.state64; | |
| 51 | for (; i < buf_size; i++) { | |
| 52 | state64 = (state64 << 8) | buf[i]; | |
| 53 | if (state64 == PNGSIG || state64 == MNGSIG) { | |
| 54 | i++; | |
| 55 | ppc->pc.frame_start_found = 1; | |
| 56 | break; | |
| 57 | } | |
| 58 | } | |
| 59 | ppc->pc.state64 = state64; | |
| 60 | } else if (ppc->remaining_size) { | |
| 61 | i = FFMIN(ppc->remaining_size, buf_size); | |
| 62 | ppc->remaining_size -= i; | |
| 63 | if (ppc->remaining_size) | |
| 64 | goto flush; | |
| 65 | if (ppc->chunk_pos == -1) { | |
| 66 | next = i; | |
| 67 | goto flush; | |
| 68 | } | |
| 69 | } | |
| 70 | ||
| 71 | for (; ppc->pc.frame_start_found && i < buf_size; i++) { | |
| 72 | ppc->pc.state = (ppc->pc.state << 8) | buf[i]; | |
| 73 | if (ppc->chunk_pos == 3) { | |
| 74 | ppc->chunk_length = ppc->pc.state; | |
| 75 | if (ppc->chunk_length > 0x7fffffff) { | |
| 76 | ppc->chunk_pos = ppc->pc.frame_start_found = 0; | |
| 77 | goto flush; | |
| 78 | } | |
| 79 | ppc->chunk_length += 4; | |
| 80 | } else if (ppc->chunk_pos == 7) { | |
| 81 | if (ppc->chunk_length >= buf_size - i) | |
| 82 | ppc->remaining_size = ppc->chunk_length - buf_size + i + 1; | |
| 83 | if (ppc->pc.state == MKBETAG('I', 'E', 'N', 'D')) { | |
| 84 | if (ppc->remaining_size) | |
| 85 | ppc->chunk_pos = -1; | |
| 86 | else | |
| 87 | next = ppc->chunk_length + i + 1; | |
| 88 | break; | |
| 89 | } else { | |
| 90 | ppc->chunk_pos = 0; | |
| 91 | if (ppc->remaining_size) | |
| 92 | break; | |
| 93 | else | |
| 94 | i += ppc->chunk_length; | |
| 95 | continue; | |
| 96 | } | |
| 97 | } | |
| 98 | ppc->chunk_pos++; | |
| 99 | } | |
| 100 | ||
| 101 | flush: | |
| 102 | if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0) | |
| 103 | return buf_size; | |
| 104 | ||
| 105 | ppc->chunk_pos = ppc->pc.frame_start_found = 0; | |
| 106 | ||
| 107 | *poutbuf = buf; | |
| 108 | *poutbuf_size = buf_size; | |
| 109 | return next; | |
| 110 | } | |
| 111 | ||
| 112 | AVCodecParser ff_png_parser = { | |
| 113 | .codec_ids = { AV_CODEC_ID_PNG }, | |
| 114 | .priv_data_size = sizeof(PNGParseContext), | |
| 115 | .parser_parse = png_parse, | |
| 116 | .parser_close = ff_parse_close, | |
| 117 | }; |