third_party/lzma/v4_65/files/CS/7zip/Compress/RangeCoder/RangeCoder.cs - Issue 624713003: Keep only base/extractor.[cc|h].

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Issue 624713003: Keep only base/extractor.[cc|h]. (Closed) Base URL: https://chromium.googlesource.com/external/omaha.git@master

Patch Set: Created 6 years, 2 months ago

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1 using System;

2

3 namespace SevenZip.Compression.RangeCoder

4 {

5 class Encoder

6 {

7 public const uint kTopValue = (1 << 24);

8

9 System.IO.Stream Stream;

10

11 public UInt64 Low;

12 public uint Range;

13 uint _cacheSize;

14 byte _cache;

15

16 long StartPosition;

17

18 public void SetStream(System.IO.Stream stream)

19 {

20 Stream = stream;

21 }

22

23 public void ReleaseStream()

24 {

25 Stream = null;

26 }

27

28 public void Init()

29 {

30 StartPosition = Stream.Position;

31

32 Low = 0;

33 Range = 0xFFFFFFFF;

34 _cacheSize = 1;

35 _cache = 0;

36 }

37

38 public void FlushData()

39 {

40 for (int i = 0; i < 5; i++)

41 ShiftLow();

42 }

43

44 public void FlushStream()

45 {

46 Stream.Flush();

47 }

48

49 public void CloseStream()

50 {

51 Stream.Close();

52 }

53

54 public void Encode(uint start, uint size, uint total)

55 {

56 Low += start * (Range /= total);

57 Range *= size;

58 while (Range < kTopValue)

59 {

60 Range <<= 8;

61 ShiftLow();

62 }

63 }

64

65 public void ShiftLow()

66 {

67 if ((uint)Low < (uint)0xFF000000 \|\| (uint)(Low >> 32) == 1)

68 {

69 byte temp = _cache;

70 do

71 {

72 Stream.WriteByte((byte)(temp + (Low >> 3 2)));

73 temp = 0xFF;

74 }

75 while (--_cacheSize != 0);

76 _cache = (byte)(((uint)Low) >> 24);

77 }

78 _cacheSize++;

79 Low = ((uint)Low) << 8;

80 }

81

82 public void EncodeDirectBits(uint v, int numTotalBits)

83 {

84 for (int i = numTotalBits - 1; i >= 0; i--)

85 {

86 Range >>= 1;

87 if (((v >> i) & 1) == 1)

88 Low += Range;

89 if (Range < kTopValue)

90 {

91 Range <<= 8;

92 ShiftLow();

93 }

94 }

95 }

96

97 public void EncodeBit(uint size0, int numTotalBits, uint symbol)

98 {

99 uint newBound = (Range >> numTotalBits) * size0;

100 if (symbol == 0)

101 Range = newBound;

102 else

103 {

104 Low += newBound;

105 Range -= newBound;

106 }

107 while (Range < kTopValue)

108 {

109 Range <<= 8;

110 ShiftLow();

111 }

112 }

113

114 public long GetProcessedSizeAdd()

115 {

116 return _cacheSize +

117 Stream.Position - StartPosition + 4;

118 // (long)Stream.GetProcessedSize();

119 }

120 }

121

122 class Decoder

123 {

124 public const uint kTopValue = (1 << 24);

125 public uint Range;

126 public uint Code;

127 // public Buffer.InBuffer Stream = new Buffer.InBuffer(1 << 16);

128 public System.IO.Stream Stream;

129

130 public void Init(System.IO.Stream stream)

131 {

132 // Stream.Init(stream);

133 Stream = stream;

134

135 Code = 0;

136 Range = 0xFFFFFFFF;

137 for (int i = 0; i < 5; i++)

138 Code = (Code << 8) \| (byte)Stream.ReadByte();

139 }

140

141 public void ReleaseStream()

142 {

143 // Stream.ReleaseStream();

144 Stream = null;

145 }

146

147 public void CloseStream()

148 {

149 Stream.Close();

150 }

151

152 public void Normalize()

153 {

154 while (Range < kTopValue)

155 {

156 Code = (Code << 8) \| (byte)Stream.ReadByte();

157 Range <<= 8;

158 }

159 }

160

161 public void Normalize2()

162 {

163 if (Range < kTopValue)

164 {

165 Code = (Code << 8) \| (byte)Stream.ReadByte();

166 Range <<= 8;

167 }

168 }

169

170 public uint GetThreshold(uint total)

171 {

172 return Code / (Range /= total);

173 }

174

175 public void Decode(uint start, uint size, uint total)

176 {

177 Code -= start * Range;

178 Range *= size;

179 Normalize();

180 }

181

182 public uint DecodeDirectBits(int numTotalBits)

183 {

184 uint range = Range;

185 uint code = Code;

186 uint result = 0;

187 for (int i = numTotalBits; i > 0; i--)

188 {

189 range >>= 1;

190 /*

191 result <<= 1;

192 if (code >= range)

193 {

194 code -= range;

195 result \|= 1;

196 }

197 */

198 uint t = (code - range) >> 31;

199 code -= range & (t - 1);

200 result = (result << 1) \| (1 - t);

201

202 if (range < kTopValue)

203 {

204 code = (code << 8) \| (byte)Stream.ReadBy te();

205 range <<= 8;

206 }

207 }

208 Range = range;

209 Code = code;

210 return result;

211 }

212

213 public uint DecodeBit(uint size0, int numTotalBits)

214 {

215 uint newBound = (Range >> numTotalBits) * size0;

216 uint symbol;

217 if (Code < newBound)

218 {

219 symbol = 0;

220 Range = newBound;

221 }

222 else

223 {

224 symbol = 1;

225 Code -= newBound;

226 Range -= newBound;

227 }

228 Normalize();

229 return symbol;

230 }

231

232 // ulong GetProcessedSize() {return Stream.GetProcessedSize(); }

233 }

234 }

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