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77 lines
2.7 KiB
77 lines
2.7 KiB
// LzmaBase.cs
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namespace SevenZip.Compression.LZMA
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{
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internal abstract class Base
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{
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public const uint kNumRepDistances = 4;
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public const uint kNumStates = 12;
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// static byte []kLiteralNextStates = {0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5};
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// static byte []kMatchNextStates = {7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10};
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// static byte []kRepNextStates = {8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11};
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// static byte []kShortRepNextStates = {9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11};
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public struct State
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{
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public uint Index;
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public void Init() { Index = 0; }
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public void UpdateChar()
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{
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if (Index < 4) Index = 0;
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else if (Index < 10) Index -= 3;
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else Index -= 6;
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}
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public void UpdateMatch() { Index = (uint)(Index < 7 ? 7 : 10); }
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public void UpdateRep() { Index = (uint)(Index < 7 ? 8 : 11); }
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public void UpdateShortRep() { Index = (uint)(Index < 7 ? 9 : 11); }
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public bool IsCharState() { return Index < 7; }
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}
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public const int kNumPosSlotBits = 6;
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public const int kDicLogSizeMin = 0;
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// public const int kDicLogSizeMax = 30;
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// public const uint kDistTableSizeMax = kDicLogSizeMax * 2;
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public const int kNumLenToPosStatesBits = 2; // it's for speed optimization
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public const uint kNumLenToPosStates = 1 << kNumLenToPosStatesBits;
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public const uint kMatchMinLen = 2;
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public static uint GetLenToPosState(uint len)
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{
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len -= kMatchMinLen;
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if (len < kNumLenToPosStates)
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return len;
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return (uint)(kNumLenToPosStates - 1);
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}
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public const int kNumAlignBits = 4;
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public const uint kAlignTableSize = 1 << kNumAlignBits;
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public const uint kAlignMask = (kAlignTableSize - 1);
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public const uint kStartPosModelIndex = 4;
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public const uint kEndPosModelIndex = 14;
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public const uint kNumPosModels = kEndPosModelIndex - kStartPosModelIndex;
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public const uint kNumFullDistances = 1 << ((int)kEndPosModelIndex / 2);
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public const uint kNumLitPosStatesBitsEncodingMax = 4;
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public const uint kNumLitContextBitsMax = 8;
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public const int kNumPosStatesBitsMax = 4;
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public const uint kNumPosStatesMax = (1 << kNumPosStatesBitsMax);
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public const int kNumPosStatesBitsEncodingMax = 4;
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public const uint kNumPosStatesEncodingMax = (1 << kNumPosStatesBitsEncodingMax);
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public const int kNumLowLenBits = 3;
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public const int kNumMidLenBits = 3;
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public const int kNumHighLenBits = 8;
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public const uint kNumLowLenSymbols = 1 << kNumLowLenBits;
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public const uint kNumMidLenSymbols = 1 << kNumMidLenBits;
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public const uint kNumLenSymbols = kNumLowLenSymbols + kNumMidLenSymbols +
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(1 << kNumHighLenBits);
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public const uint kMatchMaxLen = kMatchMinLen + kNumLenSymbols - 1;
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}
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}
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