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// Implode/Decoder.cpp
#include "StdAfx.h"
#include "ImplodeDecoder.h"
#include "Common/Defs.h"
namespace NCompress {
namespace NImplode {
namespace NDecoder {
class CException
{
public:
enum ECauseType
{
kData
} m_Cause;
CException(ECauseType cause): m_Cause(cause) {}
};
static const int kNumDistanceLowDirectBitsForBigDict = 7;
static const int kNumDistanceLowDirectBitsForSmallDict = 6;
static const int kNumBitsInByte = 8;
// static const int kLevelStructuresNumberFieldSize = kNumBitsInByte;
static const int kLevelStructuresNumberAdditionalValue = 1;
static const int kNumLevelStructureLevelBits = 4;
static const int kLevelStructureLevelAdditionalValue = 1;
static const int kNumLevelStructureRepNumberBits = 4;
static const int kLevelStructureRepNumberAdditionalValue = 1;
static const int kLiteralTableSize = (1 << kNumBitsInByte);
static const int kDistanceTableSize = 64;
static const int kLengthTableSize = 64;
static const UInt32 kHistorySize =
(1 << MyMax(kNumDistanceLowDirectBitsForBigDict,
kNumDistanceLowDirectBitsForSmallDict)) *
kDistanceTableSize; // = 8 KB;
static const int kNumAdditionalLengthBits = 8;
static const UInt32 kMatchMinLenWhenLiteralsOn = 3;
static const UInt32 kMatchMinLenWhenLiteralsOff = 2;
static const UInt32 kMatchMinLenMax = MyMax(kMatchMinLenWhenLiteralsOn,
kMatchMinLenWhenLiteralsOff); // 3
// static const UInt32 kMatchMaxLenMax = kMatchMinLenMax + (kLengthTableSize - 1) + (1 << kNumAdditionalLengthBits) - 1; // or 2
enum
{
kMatchId = 0,
kLiteralId = 1
};
CCoder::CCoder():
m_LiteralDecoder(kLiteralTableSize),
m_LengthDecoder(kLengthTableSize),
m_DistanceDecoder(kDistanceTableSize)
{
}
void CCoder::ReleaseStreams()
{
m_OutWindowStream.ReleaseStream();
m_InBitStream.ReleaseStream();
}
bool CCoder::ReadLevelItems(NImplode::NHuffman::CDecoder &decoder,
Byte *levels, int numLevelItems)
{
int numCodedStructures = m_InBitStream.ReadBits(kNumBitsInByte) +
kLevelStructuresNumberAdditionalValue;
int currentIndex = 0;
for(int i = 0; i < numCodedStructures; i++)
{
int level = m_InBitStream.ReadBits(kNumLevelStructureLevelBits) +
kLevelStructureLevelAdditionalValue;
int rep = m_InBitStream.ReadBits(kNumLevelStructureRepNumberBits) +
kLevelStructureRepNumberAdditionalValue;
if (currentIndex + rep > numLevelItems)
throw CException(CException::kData);
for(int j = 0; j < rep; j++)
levels[currentIndex++] = (Byte)level;
}
if (currentIndex != numLevelItems)
return false;
return decoder.SetCodeLengths(levels);
}
bool CCoder::ReadTables(void)
{
if (m_LiteralsOn)
{
Byte literalLevels[kLiteralTableSize];
if (!ReadLevelItems(m_LiteralDecoder, literalLevels, kLiteralTableSize))
return false;
}
Byte lengthLevels[kLengthTableSize];
if (!ReadLevelItems(m_LengthDecoder, lengthLevels, kLengthTableSize))
return false;
Byte distanceLevels[kDistanceTableSize];
return ReadLevelItems(m_DistanceDecoder, distanceLevels, kDistanceTableSize);
}
class CCoderReleaser
{
CCoder *m_Coder;
public:
CCoderReleaser(CCoder *coder): m_Coder(coder) {}
~CCoderReleaser() { m_Coder->ReleaseStreams(); }
};
HRESULT CCoder::CodeReal(ISequentialInStream *inStream, ISequentialOutStream *outStream,
const UInt64 * /* inSize */, const UInt64 *outSize, ICompressProgressInfo *progress)
{
if (!m_InBitStream.Create(1 << 20))
return E_OUTOFMEMORY;
if (!m_OutWindowStream.Create(kHistorySize))
return E_OUTOFMEMORY;
if (outSize == NULL)
return E_INVALIDARG;
UInt64 pos = 0, unPackSize = *outSize;
m_OutWindowStream.SetStream(outStream);
m_OutWindowStream.Init(false);
m_InBitStream.SetStream(inStream);
m_InBitStream.Init();
CCoderReleaser coderReleaser(this);
if (!ReadTables())
return S_FALSE;
while(pos < unPackSize)
{
if (progress != NULL && pos % (1 << 16) == 0)
{
UInt64 packSize = m_InBitStream.GetProcessedSize();
RINOK(progress->SetRatioInfo(&packSize, &pos));
}
if(m_InBitStream.ReadBits(1) == kMatchId) // match
{
UInt32 lowDistBits = m_InBitStream.ReadBits(m_NumDistanceLowDirectBits);
UInt32 distance = m_DistanceDecoder.DecodeSymbol(&m_InBitStream);
if (distance >= kDistanceTableSize)
return S_FALSE;
distance = (distance << m_NumDistanceLowDirectBits) + lowDistBits;
UInt32 lengthSymbol = m_LengthDecoder.DecodeSymbol(&m_InBitStream);
if (lengthSymbol >= kLengthTableSize)
return S_FALSE;
UInt32 length = lengthSymbol + m_MinMatchLength;
if (lengthSymbol == kLengthTableSize - 1) // special symbol = 63
length += m_InBitStream.ReadBits(kNumAdditionalLengthBits);
while(distance >= pos && length > 0)
{
m_OutWindowStream.PutByte(0);
pos++;
length--;
}
if (length > 0)
m_OutWindowStream.CopyBlock(distance, length);
pos += length;
}
else
{
Byte b;
if (m_LiteralsOn)
{
UInt32 temp = m_LiteralDecoder.DecodeSymbol(&m_InBitStream);
if (temp >= kLiteralTableSize)
return S_FALSE;
b = (Byte)temp;
}
else
b = (Byte)m_InBitStream.ReadBits(kNumBitsInByte);
m_OutWindowStream.PutByte(b);
pos++;
}
}
if (pos > unPackSize)
return S_FALSE;
return m_OutWindowStream.Flush();
}
STDMETHODIMP CCoder::Code(ISequentialInStream *inStream, ISequentialOutStream *outStream,
const UInt64 *inSize, const UInt64 *outSize, ICompressProgressInfo *progress)
{
try { return CodeReal(inStream, outStream, inSize, outSize, progress); }
catch(const CLzOutWindowException &e) { return e.ErrorCode; }
catch(...) { return S_FALSE; }
}
STDMETHODIMP CCoder::SetDecoderProperties2(const Byte *data, UInt32 size)
{
if (size < 1)
return E_INVALIDARG;
Byte flag = data[0];
m_BigDictionaryOn = ((flag & 2) != 0);
m_NumDistanceLowDirectBits = m_BigDictionaryOn ?
kNumDistanceLowDirectBitsForBigDict:
kNumDistanceLowDirectBitsForSmallDict;
m_LiteralsOn = ((flag & 4) != 0);
m_MinMatchLength = m_LiteralsOn ?
kMatchMinLenWhenLiteralsOn :
kMatchMinLenWhenLiteralsOff;
return S_OK;
}
}}}
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