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// LzxDecoder.h
#ifndef __LZX_DECODER_H
#define __LZX_DECODER_H
#include "../../../C/CpuArch.h"
#include "../../Common/MyCom.h"
#include "HuffmanDecoder.h"
#include "Lzx.h"
namespace NCompress {
namespace NLzx {
class CBitDecoder
{
unsigned _bitPos;
UInt32 _value;
const Byte *_buf;
const Byte *_bufLim;
UInt32 _extraSize;
public:
void Init(const Byte *data, size_t size)
{
_buf = data;
_bufLim = data + size - 1;
_bitPos = 0;
_extraSize = 0;
}
size_t GetRem() const { return _bufLim + 1 - _buf; }
bool WasExtraReadError_Fast() const { return _extraSize > 4; }
bool WasFinishedOK() const
{
if (_buf != _bufLim + 1)
return false;
if ((_bitPos >> 4) * 2 != _extraSize)
return false;
unsigned numBits = _bitPos & 15;
return (((_value >> (_bitPos - numBits)) & (((UInt32)1 << numBits) - 1)) == 0);
}
void NormalizeSmall()
{
if (_bitPos <= 16)
{
UInt32 val;
if (_buf >= _bufLim)
{
val = 0xFFFF;
_extraSize += 2;
}
else
{
val = GetUi16(_buf);
_buf += 2;
}
_value = (_value << 16) | val;
_bitPos += 16;
}
}
void NormalizeBig()
{
if (_bitPos <= 16)
{
{
UInt32 val;
if (_buf >= _bufLim)
{
val = 0xFFFF;
_extraSize += 2;
}
else
{
val = GetUi16(_buf);
_buf += 2;
}
_value = (_value << 16) | val;
_bitPos += 16;
}
if (_bitPos <= 16)
{
UInt32 val;
if (_buf >= _bufLim)
{
val = 0xFFFF;
_extraSize += 2;
}
else
{
val = GetUi16(_buf);
_buf += 2;
}
_value = (_value << 16) | val;
_bitPos += 16;
}
}
}
UInt32 GetValue(unsigned numBits) const
{
return (_value >> (_bitPos - numBits)) & (((UInt32)1 << numBits) - 1);
}
void MovePos(unsigned numBits)
{
_bitPos -= numBits;
NormalizeSmall();
}
UInt32 ReadBitsSmall(unsigned numBits)
{
_bitPos -= numBits;
UInt32 val = (_value >> _bitPos) & (((UInt32)1 << numBits) - 1);
NormalizeSmall();
return val;
}
UInt32 ReadBitsBig(unsigned numBits)
{
_bitPos -= numBits;
UInt32 val = (_value >> _bitPos) & (((UInt32)1 << numBits) - 1);
NormalizeBig();
return val;
}
bool PrepareUncompressed()
{
if (_extraSize != 0)
return false;
unsigned numBits = _bitPos - 16;
if (((_value >> 16) & (((UInt32)1 << numBits) - 1)) != 0)
return false;
_buf -= 2;
_bitPos = 0;
return true;
}
UInt32 ReadUInt32()
{
UInt32 v = GetUi32(_buf);
_buf += 4;
return v;
}
void CopyTo(Byte *dest, size_t size)
{
memcpy(dest, _buf, size);
_buf += size;
}
bool IsOneDirectByteLeft() const { return _buf == _bufLim && _extraSize == 0; }
Byte DirectReadByte()
{
if (_buf > _bufLim)
{
_extraSize++;
return 0xFF;
}
return *_buf++;
}
};
class CDecoder:
public IUnknown,
public CMyUnknownImp
{
CBitDecoder _bitStream;
Byte *_win;
UInt32 _pos;
UInt32 _winSize;
bool _overDict;
bool _isUncompressedBlock;
bool _skipByte;
unsigned _numAlignBits;
UInt32 _reps[kNumReps];
UInt32 _numPosLenSlots;
UInt32 _unpackBlockSize;
public:
bool KeepHistoryForNext;
bool NeedAlloc;
private:
bool _keepHistory;
bool _wimMode;
unsigned _numDictBits;
UInt32 _writePos;
Byte *_x86_buf;
UInt32 _x86_translationSize;
UInt32 _x86_processedSize;
Byte *_unpackedData;
NHuffman::CDecoder<kNumHuffmanBits, kMainTableSize> _mainDecoder;
NHuffman::CDecoder<kNumHuffmanBits, kNumLenSymbols> _lenDecoder;
NHuffman::CDecoder7b<kAlignTableSize> _alignDecoder;
NHuffman::CDecoder<kNumHuffmanBits, kLevelTableSize, 7> _levelDecoder;
Byte _mainLevels[kMainTableSize];
Byte _lenLevels[kNumLenSymbols];
HRESULT Flush();
UInt32 ReadBits(unsigned numBits);
bool ReadTable(Byte *levels, unsigned numSymbols);
bool ReadTables();
HRESULT CodeSpec(UInt32 size);
HRESULT SetParams2(unsigned numDictBits);
public:
CDecoder(bool wimMode = false);
~CDecoder();
MY_UNKNOWN_IMP
HRESULT SetExternalWindow(Byte *win, unsigned numDictBits)
{
NeedAlloc = false;
_win = win;
_winSize = (UInt32)1 << numDictBits;
return SetParams2(numDictBits);
}
void SetKeepHistory(bool keepHistory) { _keepHistory = keepHistory; }
HRESULT SetParams_and_Alloc(unsigned numDictBits);
HRESULT Code(const Byte *inData, size_t inSize, UInt32 outSize);
bool WasBlockFinished() const { return _unpackBlockSize == 0; }
const Byte *GetUnpackData() const { return _unpackedData; }
const UInt32 GetUnpackSize() const { return _pos - _writePos; }
};
}}
#endif
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