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#ifndef __COMPRESSION_RANGECODER_H
#define __COMPRESSION_RANGECODER_H
#include "InByte.h"
#include "OutByte.h"
namespace NCompression {
namespace NArithmetic {
const UINT32 kNumTopBits = 24;
const UINT32 kTopValue = (1 << kNumTopBits);
class CRangeEncoder
{
NStream::COutByte m_Stream;
UINT64 m_Low;
UINT32 m_Range;
UINT32 m_FFNum;
BYTE m_Cache;
public:
void Init(ISequentialOutStream *aStream)
{
m_Stream.Init(aStream);
m_Low = 0;
m_Range = UINT32(-1);
m_FFNum = 0;
m_Cache = 0;
}
void FlushData()
{
// m_Low += 1;
for(int i = 0; i < 5; i++)
ShiftLow();
}
HRESULT FlushStream()
{ return m_Stream.Flush(); }
void Encode(UINT32 aStart, UINT32 aSize, UINT32 aTotal)
{
m_Low += aStart * (m_Range /= aTotal);
m_Range *= aSize;
while (m_Range < kTopValue)
{
m_Range <<= 8;
ShiftLow();
}
}
/*
void EncodeDirectBitsDiv(UINT32 aValue, UINT32 aNumTotalBits)
{
m_Low += aValue * (m_Range >>= aNumTotalBits);
Normalize();
}
void EncodeDirectBitsDiv2(UINT32 aValue, UINT32 aNumTotalBits)
{
if (aNumTotalBits <= kNumBottomBits)
EncodeDirectBitsDiv(aValue, aNumTotalBits);
else
{
EncodeDirectBitsDiv(aValue >> kNumBottomBits, (aNumTotalBits - kNumBottomBits));
EncodeDirectBitsDiv(aValue & ((1 << kBottomValueBits) - 1), kNumBottomBits);
}
}
*/
void ShiftLow()
{
if (m_Low < (UINT32)0xFF000000 || UINT32(m_Low >> 32) == 1)
{
m_Stream.WriteByte(m_Cache + BYTE(m_Low >> 32));
for (;m_FFNum != 0; m_FFNum--)
m_Stream.WriteByte(0xFF + BYTE(m_Low >> 32));
m_Cache = BYTE(UINT32(m_Low) >> 24);
}
else
m_FFNum++;
m_Low = UINT32(m_Low) << 8;
}
void EncodeDirectBits(UINT32 aValue, UINT32 aNumTotalBits)
{
for (int i = aNumTotalBits - 1; i >= 0; i--)
{
m_Range >>= 1;
if (((aValue >> i) & 1) == 1)
m_Low += m_Range;
if (m_Range < kTopValue)
{
m_Range <<= 8;
ShiftLow();
}
}
}
void EncodeBit(UINT32 aSize0, UINT32 aNumTotalBits, UINT32 aSymbol)
{
UINT32 aNewBound = (m_Range >> aNumTotalBits) * aSize0;
if (aSymbol == 0)
m_Range = aNewBound;
else
{
m_Low += aNewBound;
m_Range -= aNewBound;
}
while (m_Range < kTopValue)
{
m_Range <<= 8;
ShiftLow();
}
}
UINT64 GetProcessedSize() { return m_Stream.GetProcessedSize() + m_FFNum; }
};
class CRangeDecoder
{
public:
NStream::CInByte m_Stream;
UINT32 m_Range;
UINT32 m_Code;
UINT32 m_Word;
void Normalize()
{
while (m_Range < kTopValue)
{
m_Code = (m_Code << 8) | m_Stream.ReadByte();
m_Range <<= 8;
}
}
void Init(ISequentialInStream *aStream)
{
m_Stream.Init(aStream);
m_Code = 0;
m_Range = UINT32(-1);
for(int i = 0; i < 5; i++)
m_Code = (m_Code << 8) | m_Stream.ReadByte();
}
UINT32 GetThreshold(UINT32 aTotal)
{
return (m_Code) / ( m_Range /= aTotal);
}
void Decode(UINT32 aStart, UINT32 aSize, UINT32 aTotal)
{
m_Code -= aStart * m_Range;
m_Range *= aSize;
Normalize();
}
/*
UINT32 DecodeDirectBitsDiv(UINT32 aNumTotalBits)
{
m_Range >>= aNumTotalBits;
UINT32 aThreshold = m_Code / m_Range;
m_Code -= aThreshold * m_Range;
Normalize();
return aThreshold;
}
UINT32 DecodeDirectBitsDiv2(UINT32 aNumTotalBits)
{
if (aNumTotalBits <= kNumBottomBits)
return DecodeDirectBitsDiv(aNumTotalBits);
UINT32 aResult = DecodeDirectBitsDiv(aNumTotalBits - kNumBottomBits) << kNumBottomBits;
return (aResult | DecodeDirectBitsDiv(kNumBottomBits));
}
*/
UINT32 DecodeDirectBits(UINT32 aNumTotalBits)
{
UINT32 aRange = m_Range;
UINT32 aCode = m_Code;
UINT32 aResult = 0;
for (UINT32 i = aNumTotalBits; i > 0; i--)
{
aRange >>= 1;
/*
aResult <<= 1;
if (aCode >= aRange)
{
aCode -= aRange;
aResult |= 1;
}
*/
UINT32 t = (aCode - aRange) >> 31;
aCode -= aRange & (t - 1);
// aRange = aRangeTmp + ((aRange & 1) & (1 - t));
aResult = (aResult << 1) | (1 - t);
if (aRange < kTopValue)
{
aCode = (aCode << 8) | m_Stream.ReadByte();
aRange <<= 8;
}
}
m_Range = aRange;
m_Code = aCode;
return aResult;
}
UINT32 DecodeBit(UINT32 aSize0, UINT32 aNumTotalBits)
{
UINT32 aNewBound = (m_Range >> aNumTotalBits) * aSize0;
UINT32 aSymbol;
if (m_Code < aNewBound)
{
aSymbol = 0;
m_Range = aNewBound;
}
else
{
aSymbol = 1;
m_Code -= aNewBound;
m_Range -= aNewBound;
}
Normalize();
return aSymbol;
}
UINT64 GetProcessedSize() {return m_Stream.GetProcessedSize(); }
};
}}
#endif
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