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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | * PNG parser |
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| 3 | * Copyright (c) 2009 Peter Holik |
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| 4 | * |
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| 5 | * This file is part of FFmpeg. |
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| 6 | * |
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| 7 | * FFmpeg is free software; you can redistribute it and/or |
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| 8 | * modify it under the terms of the GNU Lesser General Public |
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| 9 | * License as published by the Free Software Foundation; either |
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| 10 | * version 2.1 of the License, or (at your option) any later version. |
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| 11 | * |
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| 12 | * FFmpeg is distributed in the hope that it will be useful, |
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | * Lesser General Public License for more details. |
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| 16 | * |
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| 17 | * You should have received a copy of the GNU Lesser General Public |
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| 18 | * License along with FFmpeg; if not, write to the Free Software |
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 20 | */ |
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| 21 | |||
| 22 | /** |
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| 23 | * @file |
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| 24 | * PNG parser |
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| 25 | */ |
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| 26 | |||
| 27 | #include "parser.h" |
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| 28 | #include "png.h" |
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| 29 | |||
| 30 | typedef struct PNGParseContext |
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| 31 | { |
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| 32 | ParseContext pc; |
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| 33 | uint32_t index; |
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| 34 | uint32_t chunk_length; |
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| 35 | uint32_t remaining_size; |
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| 36 | } PNGParseContext; |
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| 37 | |||
| 38 | static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx, |
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| 39 | const uint8_t **poutbuf, int *poutbuf_size, |
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| 40 | const uint8_t *buf, int buf_size) |
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| 41 | { |
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| 42 | PNGParseContext *ppc = s->priv_data; |
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| 43 | int next = END_NOT_FOUND; |
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| 44 | int i = 0; |
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| 45 | |||
| 46 | s->pict_type = AV_PICTURE_TYPE_NONE; |
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| 47 | |||
| 48 | *poutbuf_size = 0; |
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| 49 | if (buf_size == 0) |
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| 50 | return 0; |
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| 51 | |||
| 52 | if (!ppc->pc.frame_start_found) { |
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| 53 | uint64_t state64 = ppc->pc.state64; |
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| 54 | for (; i < buf_size; i++) { |
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| 55 | state64 = (state64 << 8) | buf[i]; |
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| 56 | if (state64 == PNGSIG || state64 == MNGSIG) { |
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| 57 | i++; |
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| 58 | ppc->pc.frame_start_found = 1; |
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| 59 | break; |
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| 60 | } |
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| 61 | } |
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| 62 | ppc->pc.state64 = state64; |
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| 63 | } else |
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| 64 | if (ppc->remaining_size) { |
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| 65 | i = FFMIN(ppc->remaining_size, buf_size); |
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| 66 | ppc->remaining_size -= i; |
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| 67 | if (ppc->remaining_size) |
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| 68 | goto flush; |
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| 69 | if (ppc->index == -1) { |
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| 70 | next = i; |
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| 71 | goto flush; |
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| 72 | } |
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| 73 | } |
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| 74 | |||
| 75 | for (;ppc->pc.frame_start_found && i < buf_size; i++) { |
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| 76 | ppc->pc.state = (ppc->pc.state<<8) | buf[i]; |
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| 77 | if (ppc->index == 3) { |
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| 78 | ppc->chunk_length = ppc->pc.state; |
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| 79 | if (ppc->chunk_length > 0x7fffffff) { |
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| 80 | ppc->index = ppc->pc.frame_start_found = 0; |
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| 81 | goto flush; |
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| 82 | } |
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| 83 | ppc->chunk_length += 4; |
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| 84 | } else if (ppc->index == 7) { |
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| 85 | if (ppc->chunk_length >= buf_size - i) |
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| 86 | ppc->remaining_size = ppc->chunk_length - buf_size + i + 1; |
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| 87 | if (ppc->pc.state == MKBETAG('I', 'E', 'N', 'D')) { |
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| 88 | if (ppc->remaining_size) |
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| 89 | ppc->index = -1; |
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| 90 | else |
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| 91 | next = ppc->chunk_length + i + 1; |
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| 92 | break; |
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| 93 | } else { |
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| 94 | ppc->index = 0; |
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| 95 | if (ppc->remaining_size) |
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| 96 | break; |
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| 97 | else |
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| 98 | i += ppc->chunk_length; |
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| 99 | continue; |
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| 100 | } |
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| 101 | } |
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| 102 | ppc->index++; |
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| 103 | } |
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| 104 | flush: |
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| 105 | if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0) |
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| 106 | return buf_size; |
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| 107 | |||
| 108 | ppc->index = ppc->pc.frame_start_found = 0; |
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| 109 | |||
| 110 | *poutbuf = buf; |
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| 111 | *poutbuf_size = buf_size; |
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| 112 | return next; |
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| 113 | } |
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| 114 | |||
| 115 | AVCodecParser ff_png_parser = { |
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| 116 | .codec_ids = { AV_CODEC_ID_PNG }, |
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| 117 | .priv_data_size = sizeof(PNGParseContext), |
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| 118 | .parser_parse = png_parse, |
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| 119 | .parser_close = ff_parse_close, |
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| 120 | }; |