bittreecoder.h

经过项目量产验证的代码.开发环境是sparc+vxworks. 这个LZMA是专门为sparc做的优化压缩,性能是最好的.

// BitTreeCoder.h


#ifndef __BITTREECODER_H
#define __BITTREECODER_H

#include "AriBitCoder.h"
#include "RCDefs.h"

class CBitTreeDecoder3
{
  CBitDecoder m_Models[1 << 3];
public:
  void Init()
  {
    for(int i = 1; i < (1 << 3); i++)
      m_Models[i].Init();
  }
  int Decode(CRangeDecoder *rangeDecoder)
  {
    int modelIndex = 1;
    RC_INIT_VAR
    for(int bitIndex = 3; bitIndex > 0; bitIndex--)
    {
      // modelIndex = (modelIndex << 1) + m_Models[modelIndex].Decode(rangeDecoder);
      RC_GETBIT(m_Models[modelIndex].m_Probability, modelIndex)
    }
    RC_FLUSH_VAR
    return modelIndex - (1 << 3);
  };
};

class CBitTreeDecoder6
{
  CBitDecoder m_Models[1 << 6];
public:
  void Init()
  {
    for(int i = 1; i < (1 << 6); i++)
      m_Models[i].Init();
  }
  int Decode(CRangeDecoder *rangeDecoder)
  {
    int modelIndex = 1;
    RC_INIT_VAR
    for(int bitIndex = 6; bitIndex > 0; bitIndex--)
    {
      // modelIndex = (modelIndex << 1) + m_Models[modelIndex].Decode(rangeDecoder);
      RC_GETBIT(m_Models[modelIndex].m_Probability, modelIndex)
    }
    RC_FLUSH_VAR
    return modelIndex - (1 << 6);
  };
};

class CBitTreeDecoder8
{
  CBitDecoder m_Models[1 << 8];
public:
  void Init()
  {
    for(int i = 1; i < (1 << 8); i++)
      m_Models[i].Init();
  }
  int Decode(CRangeDecoder *rangeDecoder)
  {
    int modelIndex = 1;
    RC_INIT_VAR
    for(int bitIndex = 8; bitIndex > 0; bitIndex--)
    {
      // modelIndex = (modelIndex << 1) + m_Models[modelIndex].Decode(rangeDecoder);
      RC_GETBIT(m_Models[modelIndex].m_Probability, modelIndex)
    }
    RC_FLUSH_VAR
    return modelIndex - (1 << 8);
  };
};

class CReverseBitTreeDecoder2
{
  CBitDecoder *m_Models;
  int m_NumBitLevels;
public:
  CReverseBitTreeDecoder2(): m_Models(0) { }
  BYTE *Create(BYTE *memory, int numBitLevels)
  {
    m_NumBitLevels = numBitLevels;
    // m_Models = new CBitDecoder<aNumMoveBits>[1 << numBitLevels];
    // return (m_Models != 0);
    m_Models = (CBitDecoder *)memory;
    return memory + sizeof(CBitDecoder) * (1 << numBitLevels);
  }
  void Init()
  {
    int numModels = 1 << m_NumBitLevels;
    for(int i = 1; i < numModels; i++)
      m_Models[i].Init();
  }
  int Decode(CRangeDecoder *rangeDecoder)
  {
    int modelIndex = 1;
    int symbol = 0;
    RC_INIT_VAR
    for(int bitIndex = 0; bitIndex < m_NumBitLevels; bitIndex++)
    {
      // int bit = m_Models[modelIndex].Decode(rangeDecoder);
      // modelIndex <<= 1;
      // modelIndex += bit;
      // symbol |= (bit << bitIndex);
      RC_GETBIT2(m_Models[modelIndex].m_Probability, modelIndex, ; , symbol |= (1 << bitIndex))
    }
    RC_FLUSH_VAR
    return symbol;
  };
};

class CReverseBitTreeDecoder4
{
  CBitDecoder m_Models[1 << 4];
public:
  void Init()
  {
    for(int i = 1; i < (1 << 4); i++)
      m_Models[i].Init();
  }
  int Decode(CRangeDecoder *rangeDecoder)
  {
    int modelIndex = 1;
    int symbol = 0;
    RC_INIT_VAR
    for(int bitIndex = 0; bitIndex < 4; bitIndex++)
    {
      // int bit = m_Models[modelIndex].Decode(rangeDecoder);
      // modelIndex <<= 1;
      // modelIndex += bit;
      // symbol |= (bit << bitIndex);
      RC_GETBIT2(m_Models[modelIndex].m_Probability, modelIndex, ; , symbol |= (1 << bitIndex))
    }
    RC_FLUSH_VAR
    return symbol;
  }
};


#endif