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 "libavutil/intreadwrite.h"
  22 #include "xiph.h"
  23
  24 int ff_split_xiph_headers(uint8_t *extradata, int extradata_size,
  25                           int first_header_size, uint8_t *header_start[3],
  26                           int header_len[3])
  27 {
  28     int i;
  29
  30     if (extradata_size >= 6 && AV_RB16(extradata) == first_header_size) {
  31         int overall_len = 6;
  32         for (i=0; i<3; i++) {
  33             header_len[i] = AV_RB16(extradata);
  34             extradata += 2;
  35             header_start[i] = extradata;
  36             extradata += header_len[i];
  37             if (overall_len > extradata_size - header_len[i])
  38                 return -1;
  39             overall_len += header_len[i];
  40         }
  41     } else if (extradata_size >= 3 && extradata_size < INT_MAX - 0x1ff && extradata[0] == 2) {
  42         int overall_len = 3;
  43         extradata++;
  44         for (i=0; i<2; i++, extradata++) {
  45             header_len[i] = 0;
  46             for (; overall_len < extradata_size && *extradata==0xff; extradata++) {
  47                 header_len[i] += 0xff;
  48                 overall_len   += 0xff + 1;
  49             }
  50             header_len[i] += *extradata;
  51             overall_len   += *extradata;
  52             if (overall_len > extradata_size)
  53                 return -1;
  54         }
  55         header_len[2] = extradata_size - overall_len;
  56         header_start[0] = extradata;
  57         header_start[1] = header_start[0] + header_len[0];
  58         header_start[2] = header_start[1] + header_len[1];
  59     } else {
  60         return -1;
  61     }
  62     return 0;
  63 }