1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
/*
* Copyright (C) 2003-2009 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "riff.h"
#include <glib.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "riff"
struct riff_header {
char id[4];
uint32_t size;
char format[4];
};
struct riff_chunk_header {
char id[4];
uint32_t size;
};
size_t
riff_seek_id3(FILE *file)
{
int ret;
struct stat st;
struct riff_header header;
struct riff_chunk_header chunk;
size_t size;
/* determine the file size */
ret = fstat(fileno(file), &st);
if (ret < 0) {
g_warning("Failed to stat file descriptor: %s",
strerror(errno));
return 0;
}
/* seek to the beginning and read the RIFF header */
ret = fseek(file, 0, SEEK_SET);
if (ret != 0) {
g_warning("Failed to seek: %s", g_strerror(errno));
return 0;
}
size = fread(&header, sizeof(header), 1, file);
if (size != 1 ||
memcmp(header.id, "RIFF", 4) != 0 ||
GUINT32_FROM_LE(header.size) > st.st_size)
/* not a RIFF file */
return 0;
while (true) {
/* read the chunk header */
size = fread(&chunk, sizeof(chunk), 1, file);
if (size != 1)
return 0;
size = GUINT32_FROM_LE(chunk.size);
if (size % 2 != 0)
/* pad byte */
++size;
g_debug("chunk='%.4s' size=%zu\n", chunk.id, size);
if (memcmp(chunk.id, "id3 ", 4) == 0)
/* found it! */
return size;
if ((off_t)size < 0)
/* integer underflow after cast to signed
type */
return 0;
ret = fseek(file, size, SEEK_CUR);
if (ret != 0)
return 0;
}
}
|
