108 lines
3.8 KiB
C#
108 lines
3.8 KiB
C#
/* This file is part of SevenZipSharp.
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SevenZipSharp is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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SevenZipSharp is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with SevenZipSharp. If not, see <http://www.gnu.org/licenses/>.
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*/
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namespace SevenZip.Sdk.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 kAlignMask = (kAlignTableSize - 1);
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public const uint kAlignTableSize = 1 << kNumAlignBits;
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public const int kDicLogSizeMin = 0;
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public const uint kEndPosModelIndex = 14;
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public const uint kMatchMaxLen = kMatchMinLen + kNumLenSymbols - 1;
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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 uint kMatchMinLen = 2;
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public const int kNumAlignBits = 4;
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public const uint kNumFullDistances = 1 << ((int) kEndPosModelIndex/2);
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public const int kNumHighLenBits = 8;
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public const uint kNumLenSymbols = kNumLowLenSymbols + kNumMidLenSymbols +
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(1 << kNumHighLenBits);
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public const uint kNumLenToPosStates = 1 << kNumLenToPosStatesBits;
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public const int kNumLenToPosStatesBits = 2; // it's for speed optimization
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public const uint kNumLitContextBitsMax = 8;
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public const uint kNumLitPosStatesBitsEncodingMax = 4;
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public const int kNumLowLenBits = 3;
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public const uint kNumLowLenSymbols = 1 << kNumLowLenBits;
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public const int kNumMidLenBits = 3;
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public const uint kNumMidLenSymbols = 1 << kNumMidLenBits;
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public const uint kNumPosModels = kEndPosModelIndex - kStartPosModelIndex;
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public const int kNumPosSlotBits = 6;
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public const int kNumPosStatesBitsEncodingMax = 4;
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public const int kNumPosStatesBitsMax = 4;
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public const uint kNumPosStatesEncodingMax = (1 << kNumPosStatesBitsEncodingMax);
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public const uint kNumPosStatesMax = (1 << kNumPosStatesBitsMax);
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public const uint kNumRepDistances = 4;
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public const uint kNumStates = 12;
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public const uint kStartPosModelIndex = 4;
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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 (kNumLenToPosStates - 1);
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}
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#region Nested type: State
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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()
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{
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Index = 0;
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}
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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()
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{
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Index = (uint) (Index < 7 ? 7 : 10);
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}
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public void UpdateRep()
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{
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Index = (uint) (Index < 7 ? 8 : 11);
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}
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public void UpdateShortRep()
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{
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Index = (uint) (Index < 7 ? 9 : 11);
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}
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public bool IsCharState()
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{
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return Index < 7;
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}
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}
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#endregion
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}
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} |