libavcodec/xiph.c

   1 /*
   2  * Copyright (C) 2007 The 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 <limits.h>
  22 #include "libavutil/error.h"
  23 #include "libavutil/intreadwrite.h"
  24 #include "xiph.h"
  25
  26 int avpriv_split_xiph_headers(const uint8_t *extradata, int extradata_size,
  27                           int first_header_size, const uint8_t *header_start[3],
  28                           int header_len[3])
  29 {
  30     int i;
  31
  32     if (extradata_size >= 6 && AV_RB16(extradata) == first_header_size) {
  33         int overall_len = 6;
  34         for (i=0; i<3; i++) {
  35             header_len[i] = AV_RB16(extradata);
  36             extradata += 2;
  37             header_start[i] = extradata;
  38             extradata += header_len[i];
  39             if (overall_len > extradata_size - header_len[i])
  40                 return AVERROR_INVALIDDATA;
  41             overall_len += header_len[i];
  42         }
  43     } else if (extradata_size >= 3 && extradata_size < INT_MAX - 0x1ff && extradata[0] == 2) {
  44         int overall_len = 3;
  45         extradata++;
  46         for (i=0; i<2; i++, extradata++) {
  47             header_len[i] = 0;
  48             for (; overall_len < extradata_size && *extradata==0xff; extradata++) {
  49                 header_len[i] += 0xff;
  50                 overall_len   += 0xff + 1;
  51             }
  52             header_len[i] += *extradata;
  53             overall_len   += *extradata;
  54             if (overall_len > extradata_size)
  55                 return AVERROR_INVALIDDATA;
  56         }
  57         header_len[2] = extradata_size - overall_len;
  58         header_start[0] = extradata;
  59         header_start[1] = header_start[0] + header_len[0];
  60         header_start[2] = header_start[1] + header_len[1];
  61     } else {
  62         return -1;
  63     }
  64     return 0;
  65 }