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
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
// The authors have released ID3Lib as Public Domain (PD) and claim no copyright,
// patent or other intellectual property protection in this work. This means that
// it may be modified, redistributed and used in commercial and non-commercial
// software and hardware without restrictions. ID3Lib is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
//
// The ID3Lib authors encourage improvements and optimisations to be sent to the
// ID3Lib coordinator, currently Dirk Mahoney (dirk@id3.org). Approved
// submissions may be altered, and will be included and released under these terms.
//
// Mon Nov 23 18:34:01 1998
#include "id3_tag.h"
// To be used when reading an ID3v2-tag
// Transforms all FF 00 sequences into FF
luint ID3_Tag::ReSync(uchar *binarySourceData, luint sourceSize)
{
uchar *source, *dest;
uchar temp;
luint destinationSize;
source = binarySourceData;
destinationSize = sourceSize;
while (source < binarySourceData + sourceSize)
{
temp = *source++;
if (temp == 0xFF && source < binarySourceData + sourceSize)
{
if ((temp = *source++) == 0x00)
destinationSize--;
}
}
dest = source = binarySourceData;
while ((source < binarySourceData + sourceSize) && (dest < binarySourceData + sourceSize))
{
*dest++ = temp = *source++;
if (temp == 0xFF && source < binarySourceData + sourceSize)
{
if ((temp = *source++) != 0x00 && dest < binarySourceData + sourceSize)
* dest++ = temp;
}
}
for (luint cl=destinationSize;cl<sourceSize;cl++)
binarySourceData[cl]=0;
return destinationSize;
}
// How big will the tag be after we unsync?
luint ID3_Tag::GetUnSyncSize(uchar *buffer, luint size)
{
luint extraSize = 0;
uchar *source = buffer;
// Determine the size needed for the destination data
while (source < buffer + size)
{
uchar temp = *source++;
if (temp == 0xFF)
{
// last byte?
if (source == (buffer + size))
extraSize++;
else
{
temp = *source;
if (((temp & 0xE0) == 0xE0) || (temp == 0))
extraSize++;
}
}
}
return extraSize + size;
}
// To be used when writing an ID3v2-tag
// Transforms:
// 11111111 111xxxxx -> 11111111 00000000 111xxxxx
// 11111111 00000000 -> 11111111 00000000 00000000
// 11111111 <EOF> -> 11111111 00000000 <EOF>
void ID3_Tag::UnSync(uchar *destData, luint destSize, uchar *sourceData, luint sourceSize)
{
uchar *source = sourceData;
uchar *dest = destData;
// Now do the real transformation
while (source < sourceData + sourceSize)
{
uchar temp = *dest++ = *source++;
if (temp == 0xFF)
{
// last byte?
if (source == (sourceData + sourceSize))
*dest++ = 0;
else
{
temp = *source;
if (((temp & 0xE0) == 0xE0) || (temp == 0))
*dest++ = 0;
}
}
}
return ;
}
|
