123 lines
3.4 KiB
C++
123 lines
3.4 KiB
C++
/*
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Copyright (C) 2002 Andrea Mazzoleni ( http://advancemame.sf.net )
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Copyright (C) 2001-4 Igor Pavlov ( http://www.7-zip.org )
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License version 2.1 as published by the Free Software Foundation.
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This library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __LITERALCODER_H
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#define __LITERALCODER_H
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#include "aribitcd.h"
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#include "rcdefs.h"
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namespace NLiteral {
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const int kNumMoveBits = 5;
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class CDecoder2
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{
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CMyBitDecoder<kNumMoveBits> m_Decoders[3][1 << 8];
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public:
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void Init()
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{
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for (int i = 0; i < 3; i++)
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for (int j = 1; j < (1 << 8); j++)
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m_Decoders[i][j].Init();
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}
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BYTE DecodeNormal(CMyRangeDecoder *aRangeDecoder)
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{
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UINT32 aSymbol = 1;
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RC_INIT_VAR
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do
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{
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// aSymbol = (aSymbol << 1) | m_Decoders[0][aSymbol].Decode(aRangeDecoder);
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RC_GETBIT(kNumMoveBits, m_Decoders[0][aSymbol].m_Probability, aSymbol)
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}
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while (aSymbol < 0x100);
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RC_FLUSH_VAR
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return aSymbol;
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}
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BYTE DecodeWithMatchByte(CMyRangeDecoder *aRangeDecoder, BYTE aMatchByte)
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{
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UINT32 aSymbol = 1;
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RC_INIT_VAR
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do
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{
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UINT32 aMatchBit = (aMatchByte >> 7) & 1;
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aMatchByte <<= 1;
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// UINT32 aBit = m_Decoders[1 + aMatchBit][aSymbol].Decode(aRangeDecoder);
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// aSymbol = (aSymbol << 1) | aBit;
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UINT32 aBit;
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RC_GETBIT2(kNumMoveBits, m_Decoders[1 + aMatchBit][aSymbol].m_Probability, aSymbol,
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aBit = 0, aBit = 1)
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if (aMatchBit != aBit)
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{
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while (aSymbol < 0x100)
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{
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// aSymbol = (aSymbol << 1) | m_Decoders[0][aSymbol].Decode(aRangeDecoder);
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RC_GETBIT(kNumMoveBits, m_Decoders[0][aSymbol].m_Probability, aSymbol)
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}
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break;
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}
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}
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while (aSymbol < 0x100);
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RC_FLUSH_VAR
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return aSymbol;
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}
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};
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class CDecoder
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{
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CDecoder2 *m_Coders;
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UINT32 m_NumPrevBits;
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UINT32 m_NumPosBits;
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UINT32 m_PosMask;
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public:
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CDecoder(): m_Coders(0) {}
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~CDecoder() { Free(); }
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void Free()
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{
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delete []m_Coders;
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m_Coders = 0;
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}
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void Create(UINT32 aNumPosBits, UINT32 aNumPrevBits)
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{
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Free();
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m_NumPosBits = aNumPosBits;
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m_PosMask = (1 << aNumPosBits) - 1;
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m_NumPrevBits = aNumPrevBits;
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UINT32 aNumStates = 1 << (m_NumPrevBits + m_NumPosBits);
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m_Coders = new CDecoder2[aNumStates];
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}
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void Init()
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{
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UINT32 aNumStates = 1 << (m_NumPrevBits + m_NumPosBits);
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for (UINT32 i = 0; i < aNumStates; i++)
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m_Coders[i].Init();
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}
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UINT32 GetState(UINT32 aPos, BYTE aPrevByte) const
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{ return ((aPos & m_PosMask) << m_NumPrevBits) + (aPrevByte >> (8 - m_NumPrevBits)); }
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BYTE DecodeNormal(CMyRangeDecoder *aRangeDecoder, UINT32 aPos, BYTE aPrevByte)
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{ return m_Coders[GetState(aPos, aPrevByte)].DecodeNormal(aRangeDecoder); }
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BYTE DecodeWithMatchByte(CMyRangeDecoder *aRangeDecoder, UINT32 aPos, BYTE aPrevByte, BYTE aMatchByte)
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{ return m_Coders[GetState(aPos, aPrevByte)].DecodeWithMatchByte(aRangeDecoder, aMatchByte); }
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};
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}
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#endif
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