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
|
// Mtf8.h
#ifndef __COMPRESS_MTF8_H
#define __COMPRESS_MTF8_H
#include "../../../C/CpuArch.h"
namespace NCompress {
struct CMtf8Encoder
{
Byte Buf[256];
unsigned FindAndMove(Byte v)
{
unsigned pos;
for (pos = 0; Buf[pos] != v; pos++);
unsigned resPos = pos;
for (; pos >= 8; pos -= 8)
{
Buf[pos] = Buf[pos - 1];
Buf[pos - 1] = Buf[pos - 2];
Buf[pos - 2] = Buf[pos - 3];
Buf[pos - 3] = Buf[pos - 4];
Buf[pos - 4] = Buf[pos - 5];
Buf[pos - 5] = Buf[pos - 6];
Buf[pos - 6] = Buf[pos - 7];
Buf[pos - 7] = Buf[pos - 8];
}
for (; pos != 0; pos--)
Buf[pos] = Buf[pos - 1];
Buf[0] = v;
return resPos;
}
};
/*
struct CMtf8Decoder
{
Byte Buf[256];
void Init(int) {};
Byte GetHead() const { return Buf[0]; }
Byte GetAndMove(int pos)
{
Byte res = Buf[pos];
for (; pos >= 8; pos -= 8)
{
Buf[pos] = Buf[pos - 1];
Buf[pos - 1] = Buf[pos - 2];
Buf[pos - 2] = Buf[pos - 3];
Buf[pos - 3] = Buf[pos - 4];
Buf[pos - 4] = Buf[pos - 5];
Buf[pos - 5] = Buf[pos - 6];
Buf[pos - 6] = Buf[pos - 7];
Buf[pos - 7] = Buf[pos - 8];
}
for (; pos > 0; pos--)
Buf[pos] = Buf[pos - 1];
Buf[0] = res;
return res;
}
};
*/
#ifdef MY_CPU_64BIT
typedef UInt64 CMtfVar;
#define MTF_MOVS 3
#else
typedef UInt32 CMtfVar;
#define MTF_MOVS 2
#endif
#define MTF_MASK ((1 << MTF_MOVS) - 1)
struct CMtf8Decoder
{
CMtfVar Buf[256 >> MTF_MOVS];
void StartInit() { memset(Buf, 0, sizeof(Buf)); }
void Add(unsigned pos, Byte val) { Buf[pos >> MTF_MOVS] |= ((CMtfVar)val << ((pos & MTF_MASK) << 3)); }
Byte GetHead() const { return (Byte)Buf[0]; }
Byte GetAndMove(unsigned pos)
{
UInt32 lim = ((UInt32)pos >> MTF_MOVS);
pos = (pos & MTF_MASK) << 3;
CMtfVar prev = (Buf[lim] >> pos) & 0xFF;
UInt32 i = 0;
if ((lim & 1) != 0)
{
CMtfVar next = Buf[0];
Buf[0] = (next << 8) | prev;
prev = (next >> (MTF_MASK << 3));
i = 1;
lim -= 1;
}
for (; i < lim; i += 2)
{
CMtfVar n0 = Buf[i];
CMtfVar n1 = Buf[i + 1];
Buf[i ] = (n0 << 8) | prev;
Buf[i + 1] = (n1 << 8) | (n0 >> (MTF_MASK << 3));
prev = (n1 >> (MTF_MASK << 3));
}
CMtfVar next = Buf[i];
CMtfVar mask = (((CMtfVar)0x100 << pos) - 1);
Buf[i] = (next & ~mask) | (((next << 8) | prev) & mask);
return (Byte)Buf[0];
}
};
/*
const int kSmallSize = 64;
class CMtf8Decoder
{
Byte SmallBuffer[kSmallSize];
int SmallSize;
Byte Counts[16];
int Size;
public:
Byte Buf[256];
Byte GetHead() const
{
if (SmallSize > 0)
return SmallBuffer[kSmallSize - SmallSize];
return Buf[0];
}
void Init(int size)
{
Size = size;
SmallSize = 0;
for (int i = 0; i < 16; i++)
{
Counts[i] = ((size >= 16) ? 16 : size);
size -= Counts[i];
}
}
Byte GetAndMove(int pos)
{
if (pos < SmallSize)
{
Byte *p = SmallBuffer + kSmallSize - SmallSize;
Byte res = p[pos];
for (; pos > 0; pos--)
p[pos] = p[pos - 1];
SmallBuffer[kSmallSize - SmallSize] = res;
return res;
}
if (SmallSize == kSmallSize)
{
int i = Size - 1;
int g = 16;
do
{
g--;
int offset = (g << 4);
for (int t = Counts[g] - 1; t >= 0; t--, i--)
Buf[i] = Buf[offset + t];
}
while (g != 0);
for (i = kSmallSize - 1; i >= 0; i--)
Buf[i] = SmallBuffer[i];
Init(Size);
}
pos -= SmallSize;
int g;
for (g = 0; pos >= Counts[g]; g++)
pos -= Counts[g];
int offset = (g << 4);
Byte res = Buf[offset + pos];
for (pos; pos < 16 - 1; pos++)
Buf[offset + pos] = Buf[offset + pos + 1];
SmallSize++;
SmallBuffer[kSmallSize - SmallSize] = res;
Counts[g]--;
return res;
}
};
*/
}
#endif
|
