mirror of https://github.com/snes9xgit/snes9x.git
123 lines
3.4 KiB
C++
123 lines
3.4 KiB
C++
/*
|
|
Copyright (C) 2002 Andrea Mazzoleni ( http://advancemame.sf.net )
|
|
Copyright (C) 2001-4 Igor Pavlov ( http://www.7-zip.org )
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License version 2.1 as published by the Free Software Foundation.
|
|
|
|
This library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with this library; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#ifndef __LITERALCODER_H
|
|
#define __LITERALCODER_H
|
|
|
|
#include "aribitcd.h"
|
|
#include "rcdefs.h"
|
|
|
|
namespace NLiteral {
|
|
|
|
const int kNumMoveBits = 5;
|
|
|
|
class CDecoder2
|
|
{
|
|
CMyBitDecoder<kNumMoveBits> m_Decoders[3][1 << 8];
|
|
public:
|
|
void Init()
|
|
{
|
|
for (int i = 0; i < 3; i++)
|
|
for (int j = 1; j < (1 << 8); j++)
|
|
m_Decoders[i][j].Init();
|
|
}
|
|
|
|
BYTE DecodeNormal(CMyRangeDecoder *aRangeDecoder)
|
|
{
|
|
UINT32 aSymbol = 1;
|
|
RC_INIT_VAR
|
|
do
|
|
{
|
|
// aSymbol = (aSymbol << 1) | m_Decoders[0][aSymbol].Decode(aRangeDecoder);
|
|
RC_GETBIT(kNumMoveBits, m_Decoders[0][aSymbol].m_Probability, aSymbol)
|
|
}
|
|
while (aSymbol < 0x100);
|
|
RC_FLUSH_VAR
|
|
return aSymbol;
|
|
}
|
|
|
|
BYTE DecodeWithMatchByte(CMyRangeDecoder *aRangeDecoder, BYTE aMatchByte)
|
|
{
|
|
UINT32 aSymbol = 1;
|
|
RC_INIT_VAR
|
|
do
|
|
{
|
|
UINT32 aMatchBit = (aMatchByte >> 7) & 1;
|
|
aMatchByte <<= 1;
|
|
// UINT32 aBit = m_Decoders[1 + aMatchBit][aSymbol].Decode(aRangeDecoder);
|
|
// aSymbol = (aSymbol << 1) | aBit;
|
|
UINT32 aBit;
|
|
RC_GETBIT2(kNumMoveBits, m_Decoders[1 + aMatchBit][aSymbol].m_Probability, aSymbol,
|
|
aBit = 0, aBit = 1)
|
|
if (aMatchBit != aBit)
|
|
{
|
|
while (aSymbol < 0x100)
|
|
{
|
|
// aSymbol = (aSymbol << 1) | m_Decoders[0][aSymbol].Decode(aRangeDecoder);
|
|
RC_GETBIT(kNumMoveBits, m_Decoders[0][aSymbol].m_Probability, aSymbol)
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
while (aSymbol < 0x100);
|
|
RC_FLUSH_VAR
|
|
return aSymbol;
|
|
}
|
|
};
|
|
|
|
class CDecoder
|
|
{
|
|
CDecoder2 *m_Coders;
|
|
UINT32 m_NumPrevBits;
|
|
UINT32 m_NumPosBits;
|
|
UINT32 m_PosMask;
|
|
public:
|
|
CDecoder(): m_Coders(0) {}
|
|
~CDecoder() { Free(); }
|
|
void Free()
|
|
{
|
|
delete []m_Coders;
|
|
m_Coders = 0;
|
|
}
|
|
void Create(UINT32 aNumPosBits, UINT32 aNumPrevBits)
|
|
{
|
|
Free();
|
|
m_NumPosBits = aNumPosBits;
|
|
m_PosMask = (1 << aNumPosBits) - 1;
|
|
m_NumPrevBits = aNumPrevBits;
|
|
UINT32 aNumStates = 1 << (m_NumPrevBits + m_NumPosBits);
|
|
m_Coders = new CDecoder2[aNumStates];
|
|
}
|
|
void Init()
|
|
{
|
|
UINT32 aNumStates = 1 << (m_NumPrevBits + m_NumPosBits);
|
|
for (UINT32 i = 0; i < aNumStates; i++)
|
|
m_Coders[i].Init();
|
|
}
|
|
UINT32 GetState(UINT32 aPos, BYTE aPrevByte) const
|
|
{ return ((aPos & m_PosMask) << m_NumPrevBits) + (aPrevByte >> (8 - m_NumPrevBits)); }
|
|
BYTE DecodeNormal(CMyRangeDecoder *aRangeDecoder, UINT32 aPos, BYTE aPrevByte)
|
|
{ return m_Coders[GetState(aPos, aPrevByte)].DecodeNormal(aRangeDecoder); }
|
|
BYTE DecodeWithMatchByte(CMyRangeDecoder *aRangeDecoder, UINT32 aPos, BYTE aPrevByte, BYTE aMatchByte)
|
|
{ return m_Coders[GetState(aPos, aPrevByte)].DecodeWithMatchByte(aRangeDecoder, aMatchByte); }
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|