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
|
// Compress/RangeCoder.h
// 2009-05-30 : Igor Pavlov : Public domain
#ifndef __COMPRESS_RANGE_CODER_H
#define __COMPRESS_RANGE_CODER_H
#include "../Common/InBuffer.h"
#include "../Common/OutBuffer.h"
namespace NCompress {
namespace NRangeCoder {
const int kNumTopBits = 24;
const UInt32 kTopValue = (1 << kNumTopBits);
class CEncoder
{
UInt32 _cacheSize;
Byte _cache;
public:
UInt64 Low;
UInt32 Range;
COutBuffer Stream;
bool Create(UInt32 bufferSize) { return Stream.Create(bufferSize); }
void SetStream(ISequentialOutStream *stream) { Stream.SetStream(stream); }
void Init()
{
Stream.Init();
Low = 0;
Range = 0xFFFFFFFF;
_cacheSize = 1;
_cache = 0;
}
void FlushData()
{
// Low += 1;
for(int i = 0; i < 5; i++)
ShiftLow();
}
HRESULT FlushStream() { return Stream.Flush(); }
void ReleaseStream() { Stream.ReleaseStream(); }
void Encode(UInt32 start, UInt32 size, UInt32 total)
{
Low += start * (Range /= total);
Range *= size;
while (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
void ShiftLow()
{
if ((UInt32)Low < (UInt32)0xFF000000 || (int)(Low >> 32) != 0)
{
Byte temp = _cache;
do
{
Stream.WriteByte((Byte)(temp + (Byte)(Low >> 32)));
temp = 0xFF;
}
while(--_cacheSize != 0);
_cache = (Byte)((UInt32)Low >> 24);
}
_cacheSize++;
Low = (UInt32)Low << 8;
}
void EncodeDirectBits(UInt32 value, int numBits)
{
for (numBits--; numBits >= 0; numBits--)
{
Range >>= 1;
Low += Range & (0 - ((value >> numBits) & 1));
if (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
}
void EncodeBit(UInt32 size0, UInt32 numTotalBits, UInt32 symbol)
{
UInt32 newBound = (Range >> numTotalBits) * size0;
if (symbol == 0)
Range = newBound;
else
{
Low += newBound;
Range -= newBound;
}
while (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
UInt64 GetProcessedSize() { return Stream.GetProcessedSize() + _cacheSize + 4; }
};
class CDecoder
{
public:
CInBuffer Stream;
UInt32 Range;
UInt32 Code;
bool Create(UInt32 bufferSize) { return Stream.Create(bufferSize); }
void Normalize()
{
while (Range < kTopValue)
{
Code = (Code << 8) | Stream.ReadByte();
Range <<= 8;
}
}
void SetStream(ISequentialInStream *stream) { Stream.SetStream(stream); }
void Init()
{
Stream.Init();
Code = 0;
Range = 0xFFFFFFFF;
for(int i = 0; i < 5; i++)
Code = (Code << 8) | Stream.ReadByte();
}
void ReleaseStream() { Stream.ReleaseStream(); }
UInt32 GetThreshold(UInt32 total)
{
return (Code) / ( Range /= total);
}
void Decode(UInt32 start, UInt32 size)
{
Code -= start * Range;
Range *= size;
Normalize();
}
UInt32 DecodeDirectBits(int numTotalBits)
{
UInt32 range = Range;
UInt32 code = Code;
UInt32 result = 0;
for (int i = numTotalBits; i != 0; i--)
{
range >>= 1;
/*
result <<= 1;
if (code >= range)
{
code -= range;
result |= 1;
}
*/
UInt32 t = (code - range) >> 31;
code -= range & (t - 1);
result = (result << 1) | (1 - t);
if (range < kTopValue)
{
code = (code << 8) | Stream.ReadByte();
range <<= 8;
}
}
Range = range;
Code = code;
return result;
}
UInt32 DecodeBit(UInt32 size0, UInt32 numTotalBits)
{
UInt32 newBound = (Range >> numTotalBits) * size0;
UInt32 symbol;
if (Code < newBound)
{
symbol = 0;
Range = newBound;
}
else
{
symbol = 1;
Code -= newBound;
Range -= newBound;
}
Normalize();
return symbol;
}
UInt64 GetProcessedSize() {return Stream.GetProcessedSize(); }
};
}}
#endif
|
