// LzmaBase.cs

namespace SevenZip.Compression.LZMA

{

internal abstract class Base

{

public const uint kNumRepDistances = 4;

public const uint kNumStates = 12;

// static byte []kLiteralNextStates = {0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5};

// static byte []kMatchNextStates = {7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10};

// static byte []kRepNextStates = {8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11};

// static byte []kShortRepNextStates = {9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11};

public struct State

{

public uint Index;

public void Init() { Index = 0; }

public void UpdateChar()

{

if (Index < 4) Index = 0;

else if (Index < 10) Index -= 3;

else Index -= 6;

}

public void UpdateMatch() { Index = (uint)(Index < 7 ? 7 : 10); }

public void UpdateRep() { Index = (uint)(Index < 7 ? 8 : 11); }

public void UpdateShortRep() { Index = (uint)(Index < 7 ? 9 : 11); }

public bool IsCharState() { return Index < 7; }

}

public const int kNumPosSlotBits = 6;

public const int kDicLogSizeMin = 0;

// public const int kDicLogSizeMax = 30;

// public const uint kDistTableSizeMax = kDicLogSizeMax * 2;

public const int kNumLenToPosStatesBits = 2; // it's for speed optimization

public const uint kNumLenToPosStates = 1 << kNumLenToPosStatesBits;

public const uint kMatchMinLen = 2;

public static uint GetLenToPosState(uint len)

{

len -= kMatchMinLen;

if (len < kNumLenToPosStates)

return len;

return (uint)(kNumLenToPosStates - 1);

}

public const int kNumAlignBits = 4;

public const uint kAlignTableSize = 1 << kNumAlignBits;

public const uint kAlignMask = (kAlignTableSize - 1);

public const uint kStartPosModelIndex = 4;

public const uint kEndPosModelIndex = 14;

public const uint kNumPosModels = kEndPosModelIndex - kStartPosModelIndex;

public const uint kNumFullDistances = 1 << ((int)kEndPosModelIndex / 2);

public const uint kNumLitPosStatesBitsEncodingMax = 4;

public const uint kNumLitContextBitsMax = 8;

public const int kNumPosStatesBitsMax = 4;

public const uint kNumPosStatesMax = (1 << kNumPosStatesBitsMax);

public const int kNumPosStatesBitsEncodingMax = 4;

public const uint kNumPosStatesEncodingMax = (1 << kNumPosStatesBitsEncodingMax);

public const int kNumLowLenBits = 3;

public const int kNumMidLenBits = 3;

public const int kNumHighLenBits = 8;

public const uint kNumLowLenSymbols = 1 << kNumLowLenBits;

public const uint kNumMidLenSymbols = 1 << kNumMidLenBits;

public const uint kNumLenSymbols = kNumLowLenSymbols + kNumMidLenSymbols +

(1 << kNumHighLenBits);

public const uint kMatchMaxLen = kMatchMinLen + kNumLenSymbols - 1;

}

}