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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 "parser.h"
  29.  
  30. typedef struct BMPParseContext {
  31.     ParseContext pc;
  32.     uint32_t fsize;
  33.     uint32_t remaining_size;
  34. } BMPParseContext;
  35.  
  36. static int bmp_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  37.                      const uint8_t **poutbuf, int *poutbuf_size,
  38.                      const uint8_t *buf, int buf_size)
  39. {
  40.     BMPParseContext *bpc = s->priv_data;
  41.     uint64_t state = bpc->pc.state64;
  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.     if (buf_size == 0)
  49.         return 0;
  50.  
  51.     if (!bpc->pc.frame_start_found) {
  52.         for (; i < buf_size; i++) {
  53.             state = (state << 8) | buf[i];
  54.             if ((state >> 48) == (('B' << 8) | 'M')) {
  55.                 bpc->fsize = av_bswap32(state >> 16);
  56.                 bpc->pc.frame_start_found = 1;
  57.                 if (bpc->fsize > buf_size - i + 7)
  58.                     bpc->remaining_size = bpc->fsize - buf_size + i - 7;
  59.                 else
  60.                     next = bpc->fsize + i - 7;
  61.                 break;
  62.             }
  63.         }
  64.         bpc->pc.state64 = state;
  65.     } else {
  66.         if (bpc->remaining_size) {
  67.             i = FFMIN(bpc->remaining_size, buf_size);
  68.             bpc->remaining_size -= i;
  69.             if (bpc->remaining_size)
  70.                 goto flush;
  71.             next = i;
  72.         }
  73.     }
  74.  
  75. flush:
  76.     if (ff_combine_frame(&bpc->pc, next, &buf, &buf_size) < 0)
  77.         return buf_size;
  78.  
  79.     bpc->pc.frame_start_found = 0;
  80.  
  81.     *poutbuf      = buf;
  82.     *poutbuf_size = buf_size;
  83.     return next;
  84. }
  85.  
  86. AVCodecParser ff_bmp_parser = {
  87.     .codec_ids      = { AV_CODEC_ID_BMP },
  88.     .priv_data_size = sizeof(BMPParseContext),
  89.     .parser_parse   = bmp_parse,
  90.     .parser_close   = ff_parse_close,
  91. };
  92.