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
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
/* ScummVM - Scumm Interpreter
* Copyright (C) 2003-2005 The ScummVM project
*
* 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.
*
* $Header$
*
*/
#include "stdafx.h"
#include "common/scummsys.h"
#include "sky/rnc_deco.h"
namespace Sky {
//return codes
#define NOT_PACKED 0
#define PACKED_CRC -1
#define UNPACKED_CRC -2
//other defines
#define TABLE_SIZE (16 * 8)
#define MIN_LENGTH 2
#define HEADER_LEN 18
RncDecoder::RncDecoder() {
initCrc();
}
RncDecoder::~RncDecoder() { }
void RncDecoder::initCrc() {
uint16 cnt = 0;
uint16 tmp1 = 0;
uint16 tmp2 = 0;
for (tmp2 = 0; tmp2 < 0x100; tmp2++) {
tmp1 = tmp2;
for (cnt = 8; cnt > 0; cnt--) {
if (tmp1 % 2) {
tmp1 >>= 1;
tmp1 ^= 0x0a001;
} else
tmp1 >>= 1;
}
_crcTable[tmp2] = tmp1;
}
}
//calculate 16 bit crc of a block of memory
uint16 RncDecoder::crcBlock(const uint8 *block, uint32 size) {
uint16 crc = 0;
uint8 *crcTable8 = (uint8 *)_crcTable; //make a uint8* to crc_table
uint8 tmp;
uint32 i;
for (i = 0; i < size; i++) {
tmp = *block++;
crc ^= tmp;
tmp = (uint8)((crc >> 8) & 0x00FF);
crc &= 0x00FF;
crc = *(uint16 *)&crcTable8[crc << 1];
crc ^= tmp;
}
return crc;
}
uint16 RncDecoder::inputBits(uint8 amount) {
uint16 newBitBuffh = _bitBuffh;
uint16 newBitBuffl = _bitBuffl;
int16 newBitCount = _bitCount;
uint16 remBits, returnVal;
returnVal = ((1 << amount) - 1) & newBitBuffl;
newBitCount -= amount;
if (newBitCount < 0) {
newBitCount += amount;
remBits = (newBitBuffh << (16 - newBitCount));
newBitBuffh >>= newBitCount;
newBitBuffl >>= newBitCount;
newBitBuffl |= remBits;
_srcPtr += 2;
newBitBuffh = READ_LE_UINT16(_srcPtr);
amount -= newBitCount;
newBitCount = 16 - amount;
}
remBits = (newBitBuffh << (16 - amount));
_bitBuffh = newBitBuffh >> amount;
_bitBuffl = (newBitBuffl >> amount) | remBits;
_bitCount = (uint8)newBitCount;
return returnVal;
}
void RncDecoder::makeHufftable(uint16 *table) {
uint16 bitLength, i, j;
uint16 numCodes = inputBits(5);
if (!numCodes)
return;
uint8 huffLength[16];
for (i = 0; i < numCodes; i++)
huffLength[i] = (uint8)(inputBits(4) & 0x00FF);
uint16 huffCode = 0;
for (bitLength = 1; bitLength < 17; bitLength++) {
for (i = 0; i < numCodes; i++) {
if (huffLength[i] == bitLength) {
*table++ = (1 << bitLength) - 1;
uint16 b = huffCode >> (16 - bitLength);
uint16 a = 0;
for (j = 0; j < bitLength; j++)
a |= ((b >> j) & 1) << (bitLength - j - 1);
*table++ = a;
*(table + 0x1e) = (huffLength[i] << 8) | (i & 0x00FF);
huffCode += 1 << (16 - bitLength);
}
}
}
}
uint16 RncDecoder::inputValue(uint16 *table) {
uint16 valOne, valTwo, value = _bitBuffl;
do {
valTwo = (*table++) & value;
valOne = *table++;
} while (valOne != valTwo);
value = *(table + 0x1e);
inputBits((uint8)((value>>8) & 0x00FF));
value &= 0x00FF;
if (value >= 2) {
value--;
valOne = inputBits((uint8)value & 0x00FF);
valOne |= (1 << value);
value = valOne;
}
return value;
}
int32 RncDecoder::unpackM1(const void *input, void *output, uint16 key) {
uint8 *outputLow, *outputHigh;
const uint8 *inputHigh, *inputptr = (const uint8 *)input;
uint32 unpackLen = 0;
uint32 packLen = 0;
uint16 counts = 0;
uint16 crcUnpacked = 0;
uint16 crcPacked = 0;
_bitBuffl = 0;
_bitBuffh = 0;
_bitCount = 0;
//Check for "RNC "
if (READ_BE_UINT32(inputptr) != RNC_SIGNATURE)
return NOT_PACKED;
inputptr += 4;
// read unpacked/packed file length
unpackLen = READ_BE_UINT32(inputptr); inputptr += 4;
packLen = READ_BE_UINT32(inputptr); inputptr += 4;
uint8 blocks = *(inputptr + 5);
//read CRC's
crcUnpacked = READ_BE_UINT16(inputptr); inputptr += 2;
crcPacked = READ_BE_UINT16(inputptr); inputptr += 2;
inputptr = (inputptr + HEADER_LEN - 16);
if (crcBlock(inputptr, packLen) != crcPacked)
return PACKED_CRC;
inputptr = (((const uint8 *)input) + HEADER_LEN);
_srcPtr = inputptr;
inputHigh = ((const uint8 *)input) + packLen + HEADER_LEN;;
outputLow = (uint8 *)output;
outputHigh = *(((const uint8 *)input) + 16) + unpackLen + outputLow;
if (! ((inputHigh <= outputLow) || (outputHigh <= inputHigh)) ) {
_srcPtr = inputHigh;
_dstPtr = outputHigh;
memcpy((_dstPtr-packLen), (_srcPtr-packLen), packLen);
_srcPtr = (_dstPtr-packLen);
}
_dstPtr = (uint8 *)output;
_bitCount = 0;
_bitBuffl = READ_LE_UINT16(_srcPtr);
inputBits(2);
do {
makeHufftable(_rawTable);
makeHufftable(_posTable);
makeHufftable(_lenTable);
counts = inputBits(16);
do {
uint32 inputLength = inputValue(_rawTable);
uint32 inputOffset;
if (inputLength) {
memcpy(_dstPtr, _srcPtr, inputLength); //memcpy is allowed here
_dstPtr += inputLength;
_srcPtr += inputLength;
uint16 a = READ_LE_UINT16(_srcPtr);
uint16 b = READ_LE_UINT16(_srcPtr + 2);
_bitBuffl &= ((1 << _bitCount) - 1);
_bitBuffl |= (a << _bitCount);
_bitBuffh = (a >> (16 - _bitCount)) | (b << _bitCount);
}
if (counts > 1) {
inputOffset = inputValue(_posTable) + 1;
inputLength = inputValue(_lenTable) + MIN_LENGTH;
// Don't use memcpy here! because input and output overlap.
uint8 *tmpPtr = (_dstPtr-inputOffset);
while (inputLength--)
*_dstPtr++ = *tmpPtr++;
}
} while (--counts);
} while (--blocks);
if (crcBlock((uint8 *)output, unpackLen) != crcUnpacked)
return UNPACKED_CRC;
// all is done..return the amount of unpacked bytes
return unpackLen;
}
} // End of namespace Sky
|
