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
|
#ifndef __COMPRESSION_RANGECODER_H
#define __COMPRESSION_RANGECODER_H
#include "InByte.h"
#include "OutByte.h"
namespace NCompression {
namespace NArithmetic {
const UINT32 kNumTopBits = 24;
const UINT32 kTopValue = (1 << kNumTopBits);
class CRangeEncoder
{
NStream::COutByte m_Stream;
UINT64 m_Low;
UINT32 m_Range;
UINT32 m_FFNum;
BYTE m_Cache;
public:
void Init(ISequentialOutStream *aStream)
{
m_Stream.Init(aStream);
m_Low = 0;
m_Range = UINT32(-1);
m_FFNum = 0;
m_Cache = 0;
}
void FlushData()
{
// m_Low += 1;
for(int i = 0; i < 5; i++)
ShiftLow();
}
HRESULT FlushStream()
{ return m_Stream.Flush(); }
void Encode(UINT32 aStart, UINT32 aSize, UINT32 aTotal)
{
m_Low += aStart * (m_Range /= aTotal);
m_Range *= aSize;
while (m_Range < kTopValue)
{
m_Range <<= 8;
ShiftLow();
}
}
void ShiftLow()
{
if (m_Low < (UINT32)0xFF000000 || UINT32(m_Low >> 32) == 1)
{
m_Stream.WriteByte(m_Cache + BYTE(m_Low >> 32));
for (;m_FFNum != 0; m_FFNum--)
m_Stream.WriteByte(0xFF + BYTE(m_Low >> 32));
m_Cache = BYTE(UINT32(m_Low) >> 24);
}
else
m_FFNum++;
m_Low = UINT32(m_Low) << 8;
}
void EncodeDirectBits(UINT32 aValue, UINT32 aNumTotalBits)
{
for (int i = aNumTotalBits - 1; i >= 0; i--)
{
m_Range >>= 1;
if (((aValue >> i) & 1) == 1)
m_Low += m_Range;
if (m_Range < kTopValue)
{
m_Range <<= 8;
ShiftLow();
}
}
}
void EncodeBit(UINT32 aSize0, UINT32 aNumTotalBits, UINT32 aSymbol)
{
UINT32 aNewBound = (m_Range >> aNumTotalBits) * aSize0;
if (aSymbol == 0)
m_Range = aNewBound;
else
{
m_Low += aNewBound;
m_Range -= aNewBound;
}
while (m_Range < kTopValue)
{
m_Range <<= 8;
ShiftLow();
}
}
UINT64 GetProcessedSize() { return m_Stream.GetProcessedSize() + m_FFNum; }
};
class CRangeDecoder
{
public:
NStream::CInByte m_Stream;
UINT32 m_Range;
UINT32 m_Code;
UINT32 m_Word;
void Normalize()
{
while (m_Range < kTopValue)
{
m_Code = (m_Code << 8) | m_Stream.ReadByte();
m_Range <<= 8;
}
}
void Init(ISequentialInStream *aStream)
{
m_Stream.Init(aStream);
m_Code = 0;
m_Range = UINT32(-1);
for(int i = 0; i < 5; i++)
m_Code = (m_Code << 8) | m_Stream.ReadByte();
}
UINT32 GetThreshold(UINT32 aTotal)
{
return (m_Code) / ( m_Range /= aTotal);
}
void Decode(UINT32 aStart, UINT32 aSize, UINT32 aTotal)
{
m_Code -= aStart * m_Range;
m_Range *= aSize;
Normalize();
}
UINT32 DecodeDirectBits(UINT32 aNumTotalBits)
{
UINT32 aRange = m_Range;
UINT32 aCode = m_Code;
UINT32 aResult = 0;
for (UINT32 i = aNumTotalBits; i > 0; i--)
{
aRange >>= 1;
/*
aResult <<= 1;
if (aCode >= aRange)
{
aCode -= aRange;
aResult |= 1;
}
*/
UINT32 t = (aCode - aRange) >> 31;
aCode -= aRange & (t - 1);
// aRange = aRangeTmp + ((aRange & 1) & (1 - t));
aResult = (aResult << 1) | (1 - t);
if (aRange < kTopValue)
{
aCode = (aCode << 8) | m_Stream.ReadByte();
aRange <<= 8;
}
}
m_Range = aRange;
m_Code = aCode;
return aResult;
}
UINT32 DecodeBit(UINT32 aSize0, UINT32 aNumTotalBits)
{
UINT32 aNewBound = (m_Range >> aNumTotalBits) * aSize0;
UINT32 aSymbol;
if (m_Code < aNewBound)
{
aSymbol = 0;
m_Range = aNewBound;
}
else
{
aSymbol = 1;
m_Code -= aNewBound;
m_Range -= aNewBound;
}
Normalize();
return aSymbol;
}
UINT64 GetProcessedSize() {return m_Stream.GetProcessedSize(); }
};
}}
#endif
|
