mirror of https://github.com/snes9xgit/snes9x.git
94 lines
2.6 KiB
C
94 lines
2.6 KiB
C
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/*
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Copyright (C) 2005-2006 NSRT Team ( http://nsrt.edgeemu.com )
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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 __LENCODER_H
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#define __LENCODER_H
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#include "btreecd.h"
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namespace NLength {
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const UINT32 kNumPosStatesBitsMax = 4;
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const int kNumPosStatesMax = (1 << kNumPosStatesBitsMax);
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const int kNumPosStatesBitsEncodingMax = 4;
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const int kNumPosStatesEncodingMax = (1 << kNumPosStatesBitsEncodingMax);
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const int kNumMoveBits = 5;
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const int kNumLenBits = 3;
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const int kNumLowSymbols = 1 << kNumLenBits;
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const int kNumMidBits = 3;
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const int kNumMidSymbols = 1 << kNumMidBits;
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const int kNumHighBits = 8;
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const int kNumSymbolsTotal = kNumLowSymbols + kNumMidSymbols + (1 << kNumHighBits);
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const int kNumSpecSymbols = kNumLowSymbols + kNumMidSymbols;
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class CDecoder
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{
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CMyBitDecoder<kNumMoveBits> m_Choice;
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CBitTreeDecoder<kNumMoveBits, kNumLenBits> m_LowCoder[kNumPosStatesMax];
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CMyBitDecoder<kNumMoveBits> m_Choice2;
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CBitTreeDecoder<kNumMoveBits, kNumMidBits> m_MidCoder[kNumPosStatesMax];
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CBitTreeDecoder<kNumMoveBits, kNumHighBits> m_HighCoder;
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UINT32 m_NumPosStates;
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public:
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void Create(UINT32 aNumPosStates)
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{ m_NumPosStates = aNumPosStates; }
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void Init()
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{
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m_Choice.Init();
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for (UINT32 aPosState = 0; aPosState < m_NumPosStates; aPosState++)
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{
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m_LowCoder[aPosState].Init();
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m_MidCoder[aPosState].Init();
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}
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m_Choice2.Init();
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m_HighCoder.Init();
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}
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UINT32 Decode(CMyRangeDecoder *aRangeDecoder, UINT32 aPosState)
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{
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if(m_Choice.Decode(aRangeDecoder) == 0)
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return m_LowCoder[aPosState].Decode(aRangeDecoder);
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else
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{
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UINT32 aSymbol = kNumLowSymbols;
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if(m_Choice2.Decode(aRangeDecoder) == 0)
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aSymbol += m_MidCoder[aPosState].Decode(aRangeDecoder);
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else
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{
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aSymbol += kNumMidSymbols;
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aSymbol += m_HighCoder.Decode(aRangeDecoder);
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}
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return aSymbol;
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}
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}
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};
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}
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#endif
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