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
|
/*
Copyright (c) 2005, The Musepack Development Team
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.
* Neither the name of the The Musepack Development Team nor the
names of its contributors may be used to endorse or promote
products derived from this software without specific prior
written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/// \file idtag.c
/// Rudimentary id3tag handling routines, just enough to skip id3v2 tags,
/// if present.
#include "musepack.h"
#include "internal.h"
mpc_int32_t
JumpID3v2 (mpc_reader* r) {
unsigned char tmp [10];
mpc_uint32_t Unsynchronisation; // ID3v2.4-flag
mpc_uint32_t ExtHeaderPresent; // ID3v2.4-flag
mpc_uint32_t ExperimentalFlag; // ID3v2.4-flag
mpc_uint32_t FooterPresent; // ID3v2.4-flag
mpc_int32_t ret;
// seek to first byte of mpc data
if (!r->seek (r->data, 0)) {
return 0;
}
r->read(r->data, tmp, sizeof(tmp));
// check id3-tag
if ( 0 != memcmp ( tmp, "ID3", 3) )
return 0;
// read flags
Unsynchronisation = tmp[5] & 0x80;
ExtHeaderPresent = tmp[5] & 0x40;
ExperimentalFlag = tmp[5] & 0x20;
FooterPresent = tmp[5] & 0x10;
if ( tmp[5] & 0x0F )
return -1; // not (yet???) allowed
if ( (tmp[6] | tmp[7] | tmp[8] | tmp[9]) & 0x80 )
return -1; // not allowed
// read HeaderSize (syncsave: 4 * $0xxxxxxx = 28 significant bits)
ret = tmp[6] << 21;
ret += tmp[7] << 14;
ret += tmp[8] << 7;
ret += tmp[9] ;
ret += 10;
if ( FooterPresent )
ret += 10;
return ret;
}
|
