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author | 2015-01-11 08:10:25 +0100 | |
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committer | 2015-01-11 08:10:25 +0100 | |
commit | 6a23c2f3b766cf4fc7028628f76b5ff9396383f0 (patch) | |
tree | a01e16637118ae0c80f337119898bdf18f081e24 /3rdparty/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBit.cs | |
parent | 45ac9b351e0076c371de4c7453f59567b27b1cb6 (diff) |
Added full lzma sdk source (nw)
Diffstat (limited to '3rdparty/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBit.cs')
-rw-r--r-- | 3rdparty/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBit.cs | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/3rdparty/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBit.cs b/3rdparty/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBit.cs new file mode 100644 index 00000000000..4f0346d179a --- /dev/null +++ b/3rdparty/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBit.cs @@ -0,0 +1,117 @@ +using System; + +namespace SevenZip.Compression.RangeCoder +{ + struct BitEncoder + { + public const int kNumBitModelTotalBits = 11; + public const uint kBitModelTotal = (1 << kNumBitModelTotalBits); + const int kNumMoveBits = 5; + const int kNumMoveReducingBits = 2; + public const int kNumBitPriceShiftBits = 6; + + uint Prob; + + public void Init() { Prob = kBitModelTotal >> 1; } + + public void UpdateModel(uint symbol) + { + if (symbol == 0) + Prob += (kBitModelTotal - Prob) >> kNumMoveBits; + else + Prob -= (Prob) >> kNumMoveBits; + } + + public void Encode(Encoder encoder, uint symbol) + { + // encoder.EncodeBit(Prob, kNumBitModelTotalBits, symbol); + // UpdateModel(symbol); + uint newBound = (encoder.Range >> kNumBitModelTotalBits) * Prob; + if (symbol == 0) + { + encoder.Range = newBound; + Prob += (kBitModelTotal - Prob) >> kNumMoveBits; + } + else + { + encoder.Low += newBound; + encoder.Range -= newBound; + Prob -= (Prob) >> kNumMoveBits; + } + if (encoder.Range < Encoder.kTopValue) + { + encoder.Range <<= 8; + encoder.ShiftLow(); + } + } + + private static UInt32[] ProbPrices = new UInt32[kBitModelTotal >> kNumMoveReducingBits]; + + static BitEncoder() + { + const int kNumBits = (kNumBitModelTotalBits - kNumMoveReducingBits); + for (int i = kNumBits - 1; i >= 0; i--) + { + UInt32 start = (UInt32)1 << (kNumBits - i - 1); + UInt32 end = (UInt32)1 << (kNumBits - i); + for (UInt32 j = start; j < end; j++) + ProbPrices[j] = ((UInt32)i << kNumBitPriceShiftBits) + + (((end - j) << kNumBitPriceShiftBits) >> (kNumBits - i - 1)); + } + } + + public uint GetPrice(uint symbol) + { + return ProbPrices[(((Prob - symbol) ^ ((-(int)symbol))) & (kBitModelTotal - 1)) >> kNumMoveReducingBits]; + } + public uint GetPrice0() { return ProbPrices[Prob >> kNumMoveReducingBits]; } + public uint GetPrice1() { return ProbPrices[(kBitModelTotal - Prob) >> kNumMoveReducingBits]; } + } + + struct BitDecoder + { + public const int kNumBitModelTotalBits = 11; + public const uint kBitModelTotal = (1 << kNumBitModelTotalBits); + const int kNumMoveBits = 5; + + uint Prob; + + public void UpdateModel(int numMoveBits, uint symbol) + { + if (symbol == 0) + Prob += (kBitModelTotal - Prob) >> numMoveBits; + else + Prob -= (Prob) >> numMoveBits; + } + + public void Init() { Prob = kBitModelTotal >> 1; } + + public uint Decode(RangeCoder.Decoder rangeDecoder) + { + uint newBound = (uint)(rangeDecoder.Range >> kNumBitModelTotalBits) * (uint)Prob; + if (rangeDecoder.Code < newBound) + { + rangeDecoder.Range = newBound; + Prob += (kBitModelTotal - Prob) >> kNumMoveBits; + if (rangeDecoder.Range < Decoder.kTopValue) + { + rangeDecoder.Code = (rangeDecoder.Code << 8) | (byte)rangeDecoder.Stream.ReadByte(); + rangeDecoder.Range <<= 8; + } + return 0; + } + else + { + rangeDecoder.Range -= newBound; + rangeDecoder.Code -= newBound; + Prob -= (Prob) >> kNumMoveBits; + if (rangeDecoder.Range < Decoder.kTopValue) + { + rangeDecoder.Code = (rangeDecoder.Code << 8) | (byte)rangeDecoder.Stream.ReadByte(); + rangeDecoder.Range <<= 8; + } + return 1; + } + } + } +} |