libavcodec/xiph.c

   1 /*
   2  * Copyright (C) 2007  FFmpeg Project
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "xiph.h"
  22
  23 int ff_split_xiph_headers(uint8_t *extradata, int extradata_size,
  24                           int first_header_size, uint8_t *header_start[3],
  25                           int header_len[3])
  26 {
  27     int i;
  28
  29     if (extradata_size >= 6 && AV_RB16(extradata) == first_header_size) {
  30         int overall_len = 6;
  31         for (i=0; i<3; i++) {
  32             header_len[i] = AV_RB16(extradata);
  33             extradata += 2;
  34             header_start[i] = extradata;
  35             extradata += header_len[i];
  36             if (overall_len > extradata_size - header_len[i])
  37                 return -1;
  38             overall_len += header_len[i];
  39         }
  40     } else if (extradata_size >= 3 && extradata_size < INT_MAX - 0x1ff && extradata[0] == 2) {
  41         int overall_len = 3;
  42         extradata++;
  43         for (i=0; i<2; i++, extradata++) {
  44             header_len[i] = 0;
  45             for (; overall_len < extradata_size && *extradata==0xff; extradata++) {
  46                 header_len[i] += 0xff;
  47                 overall_len   += 0xff + 1;
  48             }
  49             header_len[i] += *extradata;
  50             overall_len   += *extradata;
  51             if (overall_len > extradata_size)
  52                 return -1;
  53         }
  54         header_len[2] = extradata_size - overall_len;
  55         header_start[0] = extradata;
  56         header_start[1] = header_start[0] + header_len[0];
  57         header_start[2] = header_start[1] + header_len[1];
  58     } else {
  59         return -1;
  60     }
  61     return 0;
  62 }