FFmpeg
xiph.c
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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 "libavutil/intreadwrite.h"
22 #include "xiph.h"
23 
24 int avpriv_split_xiph_headers(const uint8_t *extradata, int extradata_size,
25  int first_header_size, const 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 }
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
uint8_t
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
int avpriv_split_xiph_headers(const uint8_t *extradata, int extradata_size, int first_header_size, const uint8_t *header_start[3], int header_len[3])
Split a single extradata buffer into the three headers that most Xiph codecs use. ...
Definition: xiph.c:24