other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBitTree.h@97036ab72558
other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBitTree.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
1 // Compress/RangeCoder/RangeCoderBitTree.h
3 #ifndef __COMPRESS_RANGECODER_BIT_TREE_H
4 #define __COMPRESS_RANGECODER_BIT_TREE_H
6 #include "RangeCoderBit.h"
7 #include "RangeCoderOpt.h"
9 namespace NCompress {
10 namespace NRangeCoder {
12 template <int numMoveBits, int NumBitLevels>
13 class CBitTreeEncoder
14 {
15 CBitEncoder<numMoveBits> Models[1 << NumBitLevels];
16 public:
17 void Init()
18 {
19 for(UInt32 i = 1; i < (1 << NumBitLevels); i++)
20 Models[i].Init();
21 }
22 void Encode(CEncoder *rangeEncoder, UInt32 symbol)
23 {
24 UInt32 modelIndex = 1;
25 for (int bitIndex = NumBitLevels; bitIndex != 0 ;)
26 {
27 bitIndex--;
28 UInt32 bit = (symbol >> bitIndex) & 1;
29 Models[modelIndex].Encode(rangeEncoder, bit);
30 modelIndex = (modelIndex << 1) | bit;
31 }
32 };
33 void ReverseEncode(CEncoder *rangeEncoder, UInt32 symbol)
34 {
35 UInt32 modelIndex = 1;
36 for (int i = 0; i < NumBitLevels; i++)
37 {
38 UInt32 bit = symbol & 1;
39 Models[modelIndex].Encode(rangeEncoder, bit);
40 modelIndex = (modelIndex << 1) | bit;
41 symbol >>= 1;
42 }
43 }
44 UInt32 GetPrice(UInt32 symbol) const
45 {
46 symbol |= (1 << NumBitLevels);
47 UInt32 price = 0;
48 while (symbol != 1)
49 {
50 price += Models[symbol >> 1].GetPrice(symbol & 1);
51 symbol >>= 1;
52 }
53 return price;
54 }
55 UInt32 ReverseGetPrice(UInt32 symbol) const
56 {
57 UInt32 price = 0;
58 UInt32 modelIndex = 1;
59 for (int i = NumBitLevels; i != 0; i--)
60 {
61 UInt32 bit = symbol & 1;
62 symbol >>= 1;
63 price += Models[modelIndex].GetPrice(bit);
64 modelIndex = (modelIndex << 1) | bit;
65 }
66 return price;
67 }
68 };
70 template <int numMoveBits, int NumBitLevels>
71 class CBitTreeDecoder
72 {
73 CBitDecoder<numMoveBits> Models[1 << NumBitLevels];
74 public:
75 void Init()
76 {
77 for(UInt32 i = 1; i < (1 << NumBitLevels); i++)
78 Models[i].Init();
79 }
80 UInt32 Decode(CDecoder *rangeDecoder)
81 {
82 UInt32 modelIndex = 1;
83 RC_INIT_VAR
84 for(int bitIndex = NumBitLevels; bitIndex != 0; bitIndex--)
85 {
86 // modelIndex = (modelIndex << 1) + Models[modelIndex].Decode(rangeDecoder);
87 RC_GETBIT(numMoveBits, Models[modelIndex].Prob, modelIndex)
88 }
89 RC_FLUSH_VAR
90 return modelIndex - (1 << NumBitLevels);
91 };
92 UInt32 ReverseDecode(CDecoder *rangeDecoder)
93 {
94 UInt32 modelIndex = 1;
95 UInt32 symbol = 0;
96 RC_INIT_VAR
97 for(int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
98 {
99 // UInt32 bit = Models[modelIndex].Decode(rangeDecoder);
100 // modelIndex <<= 1;
101 // modelIndex += bit;
102 // symbol |= (bit << bitIndex);
103 RC_GETBIT2(numMoveBits, Models[modelIndex].Prob, modelIndex, ; , symbol |= (1 << bitIndex))
104 }
105 RC_FLUSH_VAR
106 return symbol;
107 }
108 };
110 template <int numMoveBits>
111 void ReverseBitTreeEncode(CBitEncoder<numMoveBits> *Models,
112 CEncoder *rangeEncoder, int NumBitLevels, UInt32 symbol)
113 {
114 UInt32 modelIndex = 1;
115 for (int i = 0; i < NumBitLevels; i++)
116 {
117 UInt32 bit = symbol & 1;
118 Models[modelIndex].Encode(rangeEncoder, bit);
119 modelIndex = (modelIndex << 1) | bit;
120 symbol >>= 1;
121 }
122 }
124 template <int numMoveBits>
125 UInt32 ReverseBitTreeGetPrice(CBitEncoder<numMoveBits> *Models,
126 UInt32 NumBitLevels, UInt32 symbol)
127 {
128 UInt32 price = 0;
129 UInt32 modelIndex = 1;
130 for (int i = NumBitLevels; i != 0; i--)
131 {
132 UInt32 bit = symbol & 1;
133 symbol >>= 1;
134 price += Models[modelIndex].GetPrice(bit);
135 modelIndex = (modelIndex << 1) | bit;
136 }
137 return price;
138 }
140 template <int numMoveBits>
141 UInt32 ReverseBitTreeDecode(CBitDecoder<numMoveBits> *Models,
142 CDecoder *rangeDecoder, int NumBitLevels)
143 {
144 UInt32 modelIndex = 1;
145 UInt32 symbol = 0;
146 RC_INIT_VAR
147 for(int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
148 {
149 // UInt32 bit = Models[modelIndex].Decode(rangeDecoder);
150 // modelIndex <<= 1;
151 // modelIndex += bit;
152 // symbol |= (bit << bitIndex);
153 RC_GETBIT2(numMoveBits, Models[modelIndex].Prob, modelIndex, ; , symbol |= (1 << bitIndex))
154 }
155 RC_FLUSH_VAR
156 return symbol;
157 }
159 }}
161 #endif
