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
124
125
126
127
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "ultima/ultima4/filesys/rle.h"
namespace Ultima {
namespace Ultima4 {
/**
* Decompress an RLE encoded file.
*/
long rleDecompressFile(Common::ReadStream *in, long inlen, void **out) {
void *indata;
long outlen;
/* input file should be longer than 0 bytes */
if (inlen <= 0)
return -1;
/* load compressed file into memory */
indata = malloc(inlen);
in->read(indata, inlen);
outlen = rleDecompressMemory(indata, inlen, out);
free(indata);
return outlen;
}
long rleDecompressMemory(void *in, long inlen, void **out) {
byte *indata, *outdata;
long outlen;
/* input should be longer than 0 bytes */
if (inlen <= 0)
return -1;
indata = (byte *)in;
/* determine decompressed file size */
outlen = rleGetDecompressedSize(indata, inlen);
if (outlen <= 0)
return -1;
/* decompress file from inlen to outlen */
outdata = (byte *) malloc(outlen);
rleDecompress(indata, inlen, outdata, outlen);
*out = outdata;
return outlen;
}
/**
* Determine the uncompressed size of RLE compressed data.
*/
long rleGetDecompressedSize(byte *indata, long inlen) {
byte *p;
byte ch, count;
long len = 0;
p = indata;
while ((p - indata) < inlen) {
ch = *p++;
if (ch == RLE_RUNSTART) {
count = *p++;
p++;
len += count;
} else
len++;
}
return len;
}
/**
* Decompress a block of RLE encoded memory.
*/
long rleDecompress(byte *indata, long inlen, byte *outdata, long outlen) {
int i;
byte *p, *q;
byte ch, count, val;
p = indata;
q = outdata;
while ((p - indata) < inlen) {
ch = *p++;
if (ch == RLE_RUNSTART) {
count = *p++;
val = *p++;
for (i = 0; i < count; i++) {
*q++ = val;
if ((q - outdata) >= outlen)
break;
}
} else {
*q++ = ch;
if ((q - outdata) >= outlen)
break;
}
}
return q - outdata;
}
} // End of namespace Ultima4
} // End of namespace Ultima
|
