File size: 3,956 Bytes
fab29d7 |
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 |
using System;
namespace SevenZip.Compression.RangeCoder
{
class Encoder
{
public const uint kTopValue = (1 << 24);
System.IO.Stream Stream;
public UInt64 Low;
public uint Range;
uint _cacheSize;
byte _cache;
long StartPosition;
public void SetStream(System.IO.Stream stream)
{
Stream = stream;
}
public void ReleaseStream()
{
Stream = null;
}
public void Init()
{
StartPosition = Stream.Position;
Low = 0;
Range = 0xFFFFFFFF;
_cacheSize = 1;
_cache = 0;
}
public void FlushData()
{
for (int i = 0; i < 5; i++)
ShiftLow();
}
public void FlushStream()
{
Stream.Flush();
}
public void CloseStream()
{
Stream.Close();
}
public void Encode(uint start, uint size, uint total)
{
Low += start * (Range /= total);
Range *= size;
while (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
public void ShiftLow()
{
if ((uint)Low < (uint)0xFF000000 || (uint)(Low >> 32) == 1)
{
byte temp = _cache;
do
{
Stream.WriteByte((byte)(temp + (Low >> 32)));
temp = 0xFF;
}
while (--_cacheSize != 0);
_cache = (byte)(((uint)Low) >> 24);
}
_cacheSize++;
Low = ((uint)Low) << 8;
}
public void EncodeDirectBits(uint v, int numTotalBits)
{
for (int i = numTotalBits - 1; i >= 0; i--)
{
Range >>= 1;
if (((v >> i) & 1) == 1)
Low += Range;
if (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
}
public void EncodeBit(uint size0, int numTotalBits, uint symbol)
{
uint newBound = (Range >> numTotalBits) * size0;
if (symbol == 0)
Range = newBound;
else
{
Low += newBound;
Range -= newBound;
}
while (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
public long GetProcessedSizeAdd()
{
return _cacheSize +
Stream.Position - StartPosition + 4;
// (long)Stream.GetProcessedSize();
}
}
class Decoder
{
public const uint kTopValue = (1 << 24);
public uint Range;
public uint Code;
// public Buffer.InBuffer Stream = new Buffer.InBuffer(1 << 16);
public System.IO.Stream Stream;
public void Init(System.IO.Stream stream)
{
// Stream.Init(stream);
Stream = stream;
Code = 0;
Range = 0xFFFFFFFF;
for (int i = 0; i < 5; i++)
Code = (Code << 8) | (byte)Stream.ReadByte();
}
public void ReleaseStream()
{
// Stream.ReleaseStream();
Stream = null;
}
public void CloseStream()
{
Stream.Close();
}
public void Normalize()
{
while (Range < kTopValue)
{
Code = (Code << 8) | (byte)Stream.ReadByte();
Range <<= 8;
}
}
public void Normalize2()
{
if (Range < kTopValue)
{
Code = (Code << 8) | (byte)Stream.ReadByte();
Range <<= 8;
}
}
public uint GetThreshold(uint total)
{
return Code / (Range /= total);
}
public void Decode(uint start, uint size, uint total)
{
Code -= start * Range;
Range *= size;
Normalize();
}
public uint DecodeDirectBits(int numTotalBits)
{
uint range = Range;
uint code = Code;
uint result = 0;
for (int i = numTotalBits; i > 0; i--)
{
range >>= 1;
/*
result <<= 1;
if (code >= range)
{
code -= range;
result |= 1;
}
*/
uint t = (code - range) >> 31;
code -= range & (t - 1);
result = (result << 1) | (1 - t);
if (range < kTopValue)
{
code = (code << 8) | (byte)Stream.ReadByte();
range <<= 8;
}
}
Range = range;
Code = code;
return result;
}
public uint DecodeBit(uint size0, int numTotalBits)
{
uint newBound = (Range >> numTotalBits) * size0;
uint symbol;
if (Code < newBound)
{
symbol = 0;
Range = newBound;
}
else
{
symbol = 1;
Code -= newBound;
Range -= newBound;
}
Normalize();
return symbol;
}
// ulong GetProcessedSize() {return Stream.GetProcessedSize(); }
}
}
|