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
|
/*
* CCompressedStream.cpp, part of VCMI engine
*
* Authors: listed in file AUTHORS in main folder
*
* License: GNU General Public License v2.0 or later
* Full text of license available in license.txt file, in main folder
*
*/
#include "StdInc.h"
#include "CCompressedStream.h"
#include <zlib.h>
VCMI_LIB_NAMESPACE_BEGIN
static const int inflateBlockSize = 10000;
CBufferedStream::CBufferedStream():
position(0),
endOfFileReached(false)
{
}
si64 CBufferedStream::read(ui8 * data, si64 size)
{
ensureSize(position + size);
auto * start = buffer.data() + position;
si64 toRead = std::min<si64>(size, buffer.size() - position);
std::copy(start, start + toRead, data);
position += toRead;
return size;
}
si64 CBufferedStream::seek(si64 position)
{
ensureSize(position);
this->position = std::min<si64>(position, buffer.size());
return this->position;
}
si64 CBufferedStream::tell()
{
return position;
}
si64 CBufferedStream::skip(si64 delta)
{
return seek(position + delta) - delta;
}
si64 CBufferedStream::getSize()
{
si64 prevPos = tell();
seek(std::numeric_limits<si64>::max());
si64 size = tell();
seek(prevPos);
return size;
}
void CBufferedStream::ensureSize(si64 size)
{
while(static_cast<si64>(buffer.size()) < size && !endOfFileReached)
{
si64 initialSize = buffer.size();
si64 currentStep = std::min<si64>(size, buffer.size());
// to avoid large number of calls at start
// this is often used to load h3m map headers, most of which are ~300 bytes in size
vstd::amax(currentStep, 512);
buffer.resize(initialSize + currentStep);
si64 readSize = readMore(buffer.data() + initialSize, currentStep);
if (readSize != currentStep)
{
endOfFileReached = true;
buffer.resize(initialSize + readSize);
buffer.shrink_to_fit();
return;
}
}
}
void CBufferedStream::reset()
{
buffer.clear();
position = 0;
endOfFileReached = false;
}
CCompressedStream::CCompressedStream(std::unique_ptr<CInputStream> stream, bool gzip, size_t decompressedSize):
gzipStream(std::move(stream)),
compressedBuffer(inflateBlockSize)
{
assert(gzipStream);
// Allocate inflate state
inflateState = new z_stream();
inflateState->zalloc = Z_NULL;
inflateState->zfree = Z_NULL;
inflateState->opaque = Z_NULL;
inflateState->avail_in = 0;
inflateState->next_in = Z_NULL;
int wbits = 15;
if (gzip)
wbits += 16;
int ret = inflateInit2(inflateState, wbits);
if (ret != Z_OK)
throw std::runtime_error("Failed to initialize inflate!\n");
}
CCompressedStream::~CCompressedStream()
{
inflateEnd(inflateState);
vstd::clear_pointer(inflateState);
}
si64 CCompressedStream::readMore(ui8 *data, si64 size)
{
if (inflateState == nullptr)
return 0; //file already decompressed
bool fileEnded = false; //end of file reached
bool endLoop = false;
int decompressed = inflateState->total_out;
inflateState->avail_out = static_cast<uInt>(size);
inflateState->next_out = data;
do
{
if (inflateState->avail_in == 0)
{
if (gzipStream == nullptr)
throw std::runtime_error("Potentially truncated gzip file");
//inflate ran out of available data or was not initialized yet
// get new input data and update state accordingly
si64 availSize = gzipStream->read(compressedBuffer.data(), compressedBuffer.size());
if (availSize != compressedBuffer.size())
gzipStream.reset();
inflateState->avail_in = static_cast<uInt>(availSize);
inflateState->next_in = compressedBuffer.data();
}
int ret = inflate(inflateState, Z_NO_FLUSH);
if (inflateState->avail_in == 0 && gzipStream == nullptr)
fileEnded = true;
switch (ret)
{
case Z_OK: //input data ended/ output buffer full
endLoop = false;
break;
case Z_STREAM_END: // stream ended. Note that campaign files consist from multiple such streams
endLoop = true;
break;
case Z_BUF_ERROR: // output buffer full. Can be triggered?
endLoop = true;
break;
default:
if (inflateState->msg == nullptr)
throw DecompressionException("Error code " + std::to_string(ret));
else
throw DecompressionException(inflateState->msg);
}
}
while (!endLoop && inflateState->avail_out != 0 );
decompressed = inflateState->total_out - decompressed;
// Clean up and return
if (fileEnded)
{
inflateEnd(inflateState);
vstd::clear_pointer(inflateState);
}
return decompressed;
}
bool CCompressedStream::getNextBlock()
{
if (!inflateState)
return false;
if (inflateReset(inflateState) < 0)
return false;
reset();
return true;
}
VCMI_LIB_NAMESPACE_END
|
