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
|
/*++
Copyright (c) Alex Ionescu. All rights reserved.
Module Name:
lzma2dec.c
Abstract:
This module implements the LZMA2 decoding logic responsible for parsing the
LZMA2 Control Byte, the Information Bytes (Compressed & Uncompressed Stream
Size), and the Property Byte during the initial Dictionary Reset. Note that
this module only implements support for a single such reset (i.e.: archives
in "solid" mode).
Author:
Alex Ionescu (@aionescu) 15-Apr-2020 - Initial version
Environment:
Windows & Linux, user mode and kernel mode.
--*/
#include "minlzlib.h"
#include "lzma2dec.h"
bool
Lz2DecodeChunk (
uint32_t* BytesProcessed,
uint32_t RawSize,
uint16_t CompressedSize
)
{
uint32_t bytesProcessed;
//
// Go and decode this chunk, sequence by sequence
//
if (!LzDecode())
{
return false;
}
//
// In a correctly formatted stream, the last arithmetic-coded sequence must
// be zero once we finished with the last chunk. Make sure the stream ended
// exactly where we expected it to.
//
if (!RcIsComplete(&bytesProcessed) || (bytesProcessed != CompressedSize))
{
return false;
}
//
// The entire output stream must have been written to, and the dictionary
// must be full now.
//
if (!DtIsComplete(&bytesProcessed) || (bytesProcessed != RawSize))
{
return false;
}
*BytesProcessed += bytesProcessed;
return true;
}
bool
Lz2DecodeStream (
uint32_t* BytesProcessed,
bool GetSizeOnly
)
{
uint8_t* inBytes;
LZMA2_CONTROL_BYTE controlByte;
uint8_t propertyByte;
uint32_t rawSize;
uint16_t compressedSize;
//
// Read the first control byte
//
*BytesProcessed = 0;
while (BfRead(&controlByte.Value))
{
//
// When the LZMA2 control byte is 0, the entire stream is decoded. This
// is the only success path out of this function.
//
if (controlByte.Value == 0)
{
return true;
}
//
// Read the appropriate number of info bytes based on the stream type.
//
if (!BfSeek((controlByte.u.Common.IsLzma == 1 ) ? 4 : 2, &inBytes))
{
break;
}
//
// For LZMA streams calculate both the uncompressed and compressed size
// from the info bytes. Uncompressed streams only have the former.
//
if (controlByte.u.Common.IsLzma == 1)
{
rawSize = controlByte.u.Lzma.RawSize << 16;
compressedSize = inBytes[2] << 8;
compressedSize += inBytes[3] + 1;
}
else
{
rawSize = 0;
compressedSize = 0;
}
//
// Make sure that the output buffer that was supplied is big enough to
// fit the uncompressed chunk, unless we're just calculating the size.
//
rawSize += inBytes[0] << 8;
rawSize += inBytes[1] + 1;
if (!GetSizeOnly && !DtSetLimit(rawSize))
{
break;
}
//
// Check if the full LZMA state needs to be reset, which must happen at
// the start of stream. Also check for a property reset, which occurs
// when an LZMA stream follows an uncompressed stream. Separately,
// check for a state reset without a property byte (happens rarely,
// but does happen in a few compressed streams).
//
if ((controlByte.u.Lzma.ResetState == Lzma2FullReset) ||
(controlByte.u.Lzma.ResetState == Lzma2PropertyReset))
{
//
// Read the LZMA properties and then initialize the decoder.
//
if (!BfRead(&propertyByte) || !LzInitialize(propertyByte))
{
break;
}
}
else if (controlByte.u.Lzma.ResetState == Lzma2SimpleReset)
{
LzResetState();
}
//
// else controlByte.u.Lzma.ResetState == Lzma2NoReset, since a two-bit
// field only has four possible values
//
//
// Don't do any decompression if the caller only wants to know the size
//
if (GetSizeOnly)
{
*BytesProcessed += rawSize;
BfSeek((controlByte.u.Common.IsLzma == 1) ? compressedSize : rawSize,
&inBytes);
continue;
}
else if (controlByte.u.Common.IsLzma == 0)
{
//
// Seek to the requested size in the input buffer
//
if (!BfSeek(rawSize, &inBytes))
{
return false;
}
//
// Copy the data into the dictionary as-is
//
for (uint32_t i = 0; i < rawSize; i++)
{
DtPutSymbol(inBytes[i]);
}
//
// Update bytes and keep going to the next chunk
//
*BytesProcessed += rawSize;
continue;
}
//
// Record how many bytes are left in this sequence as our SoftLimit for
// the other operations. This allows us to omit most range checking
// logic in rangedec.c. This soft limit lasts until reset below.
//
if (!BfSetSoftLimit(compressedSize))
{
break;
}
//
// Read the initial range and code bytes to initialize the arithmetic
// coding decoder, and let it know how much input data exists. We've
// already validated that this much space exists in the input buffer.
//
if (!RcInitialize(&compressedSize))
{
break;
}
//
// Start decoding the LZMA sequences in this chunk
//
if (!Lz2DecodeChunk(BytesProcessed, rawSize, compressedSize))
{
break;
}
//
// Having decoded that chunk, reset our soft limit (to the full
// input stream) so we can read the next chunk.
//
BfResetSoftLimit();
}
return false;
}
|
