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
|
// --------------------------------------------------------------------------
//
// File
// Name: Compress.h
// Purpose: Interface to zlib compression
// Created: 5/12/03
//
// --------------------------------------------------------------------------
#ifndef COMPRESSCONTEXT__H
#define COMPRESSCONTEXT__H
#include <zlib.h>
#include "CompressException.h"
// --------------------------------------------------------------------------
//
// Class
// Name: Compress
// Purpose: Interface to zlib compression, only very slight wrapper.
// (Use CompressStream for a more friendly interface.)
// Created: 5/12/03
//
// --------------------------------------------------------------------------
template<bool Compressing>
class Compress
{
public:
Compress()
: mFinished(false),
mFlush(Z_NO_FLUSH)
{
// initialise stream
mStream.zalloc = Z_NULL;
mStream.zfree = Z_NULL;
mStream.opaque = Z_NULL;
mStream.data_type = Z_BINARY;
if((Compressing)?(deflateInit(&mStream, Z_DEFAULT_COMPRESSION))
:(inflateInit(&mStream)) != Z_OK)
{
THROW_EXCEPTION(CompressException, InitFailed)
}
mStream.avail_in = 0;
}
~Compress()
{
int r = 0;
if((r = ((Compressing)?(deflateEnd(&mStream))
:(inflateEnd(&mStream)))) != Z_OK)
{
BOX_WARNING("zlib error code = " << r);
if(r == Z_DATA_ERROR)
{
BOX_WARNING("End of compress/decompress "
"without all input being consumed, "
"possible corruption?");
}
else
{
THROW_EXCEPTION(CompressException, EndFailed)
}
}
}
// --------------------------------------------------------------------------
//
// Function
// Name: Compress<Function>::InputRequired()
// Purpose: Input required yet?
// Created: 5/12/03
//
// --------------------------------------------------------------------------
bool InputRequired()
{
return mStream.avail_in <= 0;
}
// --------------------------------------------------------------------------
//
// Function
// Name: Compress<Function>::Input(const void *, int)
// Purpose: Set the input buffer ready for next output call.
// Created: 5/12/03
//
// --------------------------------------------------------------------------
void Input(const void *pInBuffer, int InLength)
{
// Check usage
if(mStream.avail_in != 0)
{
THROW_EXCEPTION(CompressException, BadUsageInputNotRequired)
}
// Store info
mStream.next_in = (unsigned char *)pInBuffer;
mStream.avail_in = InLength;
}
// --------------------------------------------------------------------------
//
// Function
// Name: Compress<Function>::FinishInput()
// Purpose: When compressing, no more input will be given.
// Created: 5/12/03
//
// --------------------------------------------------------------------------
void FinishInput()
{
mFlush = Z_FINISH;
}
// --------------------------------------------------------------------------
//
// Function
// Name: Compress<Function>::Output(void *, int)
// Purpose: Get some output data
// Created: 5/12/03
//
// --------------------------------------------------------------------------
int Output(void *pOutBuffer, int OutLength, bool SyncFlush = false)
{
// need more input?
if(mStream.avail_in == 0 && mFlush != Z_FINISH && !SyncFlush)
{
return 0;
}
// Buffers
mStream.next_out = (unsigned char *)pOutBuffer;
mStream.avail_out = OutLength;
// Call one of the functions
int flush = mFlush;
if(SyncFlush && mFlush != Z_FINISH)
{
flush = Z_SYNC_FLUSH;
}
int ret = (Compressing)?(deflate(&mStream, flush)):(inflate(&mStream, flush));
if(SyncFlush && ret == Z_BUF_ERROR)
{
// No progress possible. Just return 0.
return 0;
}
// Check errors
if(ret < 0)
{
BOX_WARNING("zlib error code = " << ret);
THROW_EXCEPTION(CompressException, TransformFailed)
}
// Parse result
if(ret == Z_STREAM_END)
{
mFinished = true;
}
// Return how much data was output
return OutLength - mStream.avail_out;
}
// --------------------------------------------------------------------------
//
// Function
// Name: Compress<Function>::OutputHasFinished()
// Purpose: No more output to be recieved
// Created: 5/12/03
//
// --------------------------------------------------------------------------
bool OutputHasFinished()
{
return mFinished;
}
private:
z_stream mStream;
bool mFinished;
int mFlush;
};
template<typename Integer>
Integer Compress_MaxSizeForCompressedData(Integer InLen)
{
// Conservative rendition of the info found here: http://www.gzip.org/zlib/zlib_tech.html
int blocks = (InLen + 32*1024 - 1) / (32*1024);
return InLen + (blocks * 6) + 8;
}
#endif // COMPRESSCONTEXT__H
|
