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  1. /*
  2.  * BMP parser
  3.  * Copyright (c) 2012 Paul B Mahol
  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.  * BMP parser
  25.  */
  26.  
  27. #include "libavutil/bswap.h"
  28. #include "libavutil/common.h"
  29.  
  30. #include "parser.h"
  31.  
  32. typedef struct BMPParseContext {
  33.     ParseContext pc;
  34.     uint32_t fsize;
  35.     uint32_t remaining_size;
  36. } BMPParseContext;
  37.  
  38. static int bmp_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  39.                      const uint8_t **poutbuf, int *poutbuf_size,
  40.                      const uint8_t *buf, int buf_size)
  41. {
  42.     BMPParseContext *bpc = s->priv_data;
  43.     uint64_t state = bpc->pc.state64;
  44.     int next = END_NOT_FOUND;
  45.     int i = 0;
  46.  
  47.     *poutbuf_size = 0;
  48.  
  49. restart:
  50.     if (bpc->pc.frame_start_found <= 2+4+4) {
  51.         for (; i < buf_size; i++) {
  52.             state = (state << 8) | buf[i];
  53.             if (bpc->pc.frame_start_found == 0) {
  54.                 if ((state >> 48) == (('B' << 8) | 'M')) {
  55.                     bpc->fsize = av_bswap32(state >> 16);
  56.                     bpc->pc.frame_start_found = 1;
  57.                 }
  58.             } else if (bpc->pc.frame_start_found == 2+4+4) {
  59. //                 unsigned hsize = av_bswap32(state>>32);
  60.                 unsigned ihsize = av_bswap32(state);
  61.                 if (ihsize < 12 || ihsize > 200) {
  62.                     bpc->pc.frame_start_found = 0;
  63.                     continue;
  64.                 }
  65.                 bpc->pc.frame_start_found++;
  66.                 bpc->remaining_size = bpc->fsize + i - 17;
  67.  
  68.                 if (bpc->pc.index + i > 17) {
  69.                     next = i - 17;
  70.                 } else
  71.                     goto restart;
  72.             } else if (bpc->pc.frame_start_found)
  73.                 bpc->pc.frame_start_found++;
  74.         }
  75.         bpc->pc.state64 = state;
  76.     } else {
  77.         if (bpc->remaining_size) {
  78.             i = FFMIN(bpc->remaining_size, buf_size);
  79.             bpc->remaining_size -= i;
  80.             if (bpc->remaining_size)
  81.                 goto flush;
  82.  
  83.             bpc->pc.frame_start_found = 0;
  84.             goto restart;
  85.         }
  86.     }
  87.  
  88. flush:
  89.     if (ff_combine_frame(&bpc->pc, next, &buf, &buf_size) < 0)
  90.         return buf_size;
  91.  
  92.     bpc->pc.frame_start_found = 0;
  93.  
  94.     *poutbuf      = buf;
  95.     *poutbuf_size = buf_size;
  96.     return next;
  97. }
  98.  
  99. AVCodecParser ff_bmp_parser = {
  100.     .codec_ids      = { AV_CODEC_ID_BMP },
  101.     .priv_data_size = sizeof(BMPParseContext),
  102.     .parser_parse   = bmp_parse,
  103.     .parser_close   = ff_parse_close,
  104. };
  105.