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RangeCoder /
RangeCoder.h
Revision
1.1.1.1 (vendor branch):
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Tue May 14 09:04:51 2013 UTC (11 years, 3 months ago) by
misho
Branches:
misho,
elwix1_9_mips,
MAIN
CVS tags:
start,
elwix2_8,
elwix2_7,
elwix2_6,
elwix2_3,
elwix2_2,
HEAD,
ELWIX2_7,
ELWIX2_6,
ELWIX2_5,
ELWIX2_2p0
oldlzma needs for uboot
// Compress/RangeCoder/RangeCoder.h
#ifndef __COMPRESS_RANGECODER_H
#define __COMPRESS_RANGECODER_H
#include "../../Common/InBuffer.h"
#include "../../Common/OutBuffer.h"
namespace NCompress {
namespace NRangeCoder {
const int kNumTopBits = 24;
const UInt32 kTopValue = (1 << kNumTopBits);
class CEncoder
{
UInt32 _ffNum;
Byte _cache;
public:
UInt64 Low;
UInt32 Range;
COutBuffer Stream;
bool Create(UInt32 bufferSize) { return Stream.Create(bufferSize); }
void SetStream(ISequentialOutStream *stream) { Stream.SetStream(stream); }
void Init()
{
Stream.Init();
Low = 0;
Range = 0xFFFFFFFF;
_ffNum = 0;
_cache = 0;
}
void FlushData()
{
// Low += 1;
for(int i = 0; i < 5; i++)
ShiftLow();
}
HRESULT FlushStream() { return Stream.Flush(); }
void ReleaseStream() { Stream.ReleaseStream(); }
void Encode(UInt32 start, UInt32 size, UInt32 total)
{
Low += start * (Range /= total);
Range *= size;
while (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
/*
void EncodeDirectBitsDiv(UInt32 value, UInt32 numTotalBits)
{
Low += value * (Range >>= numTotalBits);
Normalize();
}
void EncodeDirectBitsDiv2(UInt32 value, UInt32 numTotalBits)
{
if (numTotalBits <= kNumBottomBits)
EncodeDirectBitsDiv(value, numTotalBits);
else
{
EncodeDirectBitsDiv(value >> kNumBottomBits, (numTotalBits - kNumBottomBits));
EncodeDirectBitsDiv(value & ((1 << kBottomValueBits) - 1), kNumBottomBits);
}
}
*/
void ShiftLow()
{
if (Low < (UInt32)0xFF000000 || UInt32(Low >> 32) == 1)
{
Stream.WriteByte(Byte(_cache + Byte(Low >> 32)));
for (;_ffNum != 0; _ffNum--)
Stream.WriteByte(Byte(0xFF + Byte(Low >> 32)));
_cache = Byte(UInt32(Low) >> 24);
}
else
_ffNum++;
Low = UInt32(Low) << 8;
}
void EncodeDirectBits(UInt32 value, int numTotalBits)
{
for (int i = numTotalBits - 1; i >= 0; i--)
{
Range >>= 1;
if (((value >> i) & 1) == 1)
Low += Range;
if (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
}
void EncodeBit(UInt32 size0, UInt32 numTotalBits, UInt32 symbol)
{
UInt32 newBound = (Range >> numTotalBits) * size0;
if (symbol == 0)
Range = newBound;
else
{
Low += newBound;
Range -= newBound;
}
while (Range < kTopValue)
{
Range <<= 8;
ShiftLow();
}
}
UInt64 GetProcessedSize() { return Stream.GetProcessedSize() + _ffNum; }
};
class CDecoder
{
public:
CInBuffer Stream;
UInt32 Range;
UInt32 Code;
bool Create(UInt32 bufferSize) { return Stream.Create(bufferSize); }
void Normalize()
{
while (Range < kTopValue)
{
Code = (Code << 8) | Stream.ReadByte();
Range <<= 8;
}
}
void SetStream(ISequentialInStream *stream) { Stream.SetStream(stream); }
void Init()
{
Stream.Init();
Code = 0;
Range = 0xFFFFFFFF;
for(int i = 0; i < 5; i++)
Code = (Code << 8) | Stream.ReadByte();
}
void ReleaseStream() { Stream.ReleaseStream(); }
UInt32 GetThreshold(UInt32 total)
{
return (Code) / ( Range /= total);
}
void Decode(UInt32 start, UInt32 size)
{
Code -= start * Range;
Range *= size;
Normalize();
}
/*
UInt32 DecodeDirectBitsDiv(UInt32 numTotalBits)
{
Range >>= numTotalBits;
UInt32 threshold = Code / Range;
Code -= threshold * Range;
Normalize();
return threshold;
}
UInt32 DecodeDirectBitsDiv2(UInt32 numTotalBits)
{
if (numTotalBits <= kNumBottomBits)
return DecodeDirectBitsDiv(numTotalBits);
UInt32 result = DecodeDirectBitsDiv(numTotalBits - kNumBottomBits) << kNumBottomBits;
return (result | DecodeDirectBitsDiv(kNumBottomBits));
}
*/
UInt32 DecodeDirectBits(int numTotalBits)
{
UInt32 range = Range;
UInt32 code = Code;
UInt32 result = 0;
for (int i = numTotalBits; i != 0; i--)
{
range >>= 1;
/*
result <<= 1;
if (code >= range)
{
code -= range;
result |= 1;
}
*/
UInt32 t = (code - range) >> 31;
code -= range & (t - 1);
result = (result << 1) | (1 - t);
if (range < kTopValue)
{
code = (code << 8) | Stream.ReadByte();
range <<= 8;
}
}
Range = range;
Code = code;
return result;
}
UInt32 DecodeBit(UInt32 size0, UInt32 numTotalBits)
{
UInt32 newBound = (Range >> numTotalBits) * size0;
UInt32 symbol;
if (Code < newBound)
{
symbol = 0;
Range = newBound;
}
else
{
symbol = 1;
Code -= newBound;
Range -= newBound;
}
Normalize();
return symbol;
}
UInt64 GetProcessedSize() {return Stream.GetProcessedSize(); }
};
}}
#endif
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