misc/libphysfs/lzma/CPP/7zip/Compress/LZMA/LZMADecoder.h
author nemo
Mon, 10 Apr 2017 12:06:43 -0400
changeset 12213 bb5522e88ab2
permissions -rw-r--r--
bulk copy of latest physfs to our misc/libphysfs since this seems to fix an off-by-1 error reliably hit in readln read of 1 byte probably introduced in the addition of the buffered read. Whether this is excessive or whether libphysfs should even be maintained by us is another matter. But at least we shouldn't crash

// LZMA/Decoder.h

#ifndef __LZMA_DECODER_H
#define __LZMA_DECODER_H

#include "../../../Common/MyCom.h"
#include "../../ICoder.h"
#include "../LZ/LZOutWindow.h"
#include "../RangeCoder/RangeCoderBitTree.h"

extern "C"
{
  #include "../../../../C/Alloc.h"
}

#include "LZMA.h"

namespace NCompress {
namespace NLZMA {

typedef NRangeCoder::CBitDecoder<kNumMoveBits> CMyBitDecoder;

class CLiteralDecoder2
{
  CMyBitDecoder _decoders[0x300];
public:
  void Init()
  {
    for (int i = 0; i < 0x300; i++)
      _decoders[i].Init();
  }
  Byte DecodeNormal(NRangeCoder::CDecoder *rangeDecoder)
  {
    UInt32 symbol = 1;
    RC_INIT_VAR
    do
    {
      // symbol = (symbol << 1) | _decoders[0][symbol].Decode(rangeDecoder);
      RC_GETBIT(kNumMoveBits, _decoders[symbol].Prob, symbol)
    }
    while (symbol < 0x100);
    RC_FLUSH_VAR
    return (Byte)symbol;
  }
  Byte DecodeWithMatchByte(NRangeCoder::CDecoder *rangeDecoder, Byte matchByte)
  {
    UInt32 symbol = 1;
    RC_INIT_VAR
    do
    {
      UInt32 matchBit = (matchByte >> 7) & 1;
      matchByte <<= 1;
      // UInt32 bit = _decoders[1 + matchBit][symbol].Decode(rangeDecoder);
      // symbol = (symbol << 1) | bit;
      UInt32 bit;
      RC_GETBIT2(kNumMoveBits, _decoders[0x100 + (matchBit << 8) + symbol].Prob, symbol, 
          bit = 0, bit = 1)
      if (matchBit != bit)
      {
        while (symbol < 0x100)
        {
          // symbol = (symbol << 1) | _decoders[0][symbol].Decode(rangeDecoder);
          RC_GETBIT(kNumMoveBits, _decoders[symbol].Prob, symbol)
        }
        break;
      }
    }
    while (symbol < 0x100);
    RC_FLUSH_VAR
    return (Byte)symbol;
  }
};

class CLiteralDecoder
{
  CLiteralDecoder2 *_coders;
  int _numPrevBits;
  int _numPosBits;
  UInt32 _posMask;
public:
  CLiteralDecoder(): _coders(0) {}
  ~CLiteralDecoder()  { Free(); }
  void Free()
  { 
    MyFree(_coders);
    _coders = 0;
  }
  bool Create(int numPosBits, int numPrevBits)
  {
    if (_coders == 0 || (numPosBits + numPrevBits) != 
        (_numPrevBits + _numPosBits) )
    {
      Free();
      UInt32 numStates = 1 << (numPosBits + numPrevBits);
      _coders = (CLiteralDecoder2 *)MyAlloc(numStates * sizeof(CLiteralDecoder2));
    }
    _numPosBits = numPosBits;
    _posMask = (1 << numPosBits) - 1;
    _numPrevBits = numPrevBits;
    return (_coders != 0);
  }
  void Init()
  {
    UInt32 numStates = 1 << (_numPrevBits + _numPosBits);
    for (UInt32 i = 0; i < numStates; i++)
      _coders[i].Init();
  }
  UInt32 GetState(UInt32 pos, Byte prevByte) const
    { return ((pos & _posMask) << _numPrevBits) + (prevByte >> (8 - _numPrevBits)); }
  Byte DecodeNormal(NRangeCoder::CDecoder *rangeDecoder, UInt32 pos, Byte prevByte)
    { return _coders[GetState(pos, prevByte)].DecodeNormal(rangeDecoder); }
  Byte DecodeWithMatchByte(NRangeCoder::CDecoder *rangeDecoder, UInt32 pos, Byte prevByte, Byte matchByte)
    { return _coders[GetState(pos, prevByte)].DecodeWithMatchByte(rangeDecoder, matchByte); }
};

namespace NLength {

class CDecoder
{
  CMyBitDecoder _choice;
  CMyBitDecoder _choice2;
  NRangeCoder::CBitTreeDecoder<kNumMoveBits, kNumLowBits>  _lowCoder[kNumPosStatesMax];
  NRangeCoder::CBitTreeDecoder<kNumMoveBits, kNumMidBits>  _midCoder[kNumPosStatesMax];
  NRangeCoder::CBitTreeDecoder<kNumMoveBits, kNumHighBits> _highCoder; 
public:
  void Init(UInt32 numPosStates)
  {
    _choice.Init();
    _choice2.Init();
    for (UInt32 posState = 0; posState < numPosStates; posState++)
    {
      _lowCoder[posState].Init();
      _midCoder[posState].Init();
    }
    _highCoder.Init();
  }
  UInt32 Decode(NRangeCoder::CDecoder *rangeDecoder, UInt32 posState)
  {
    if(_choice.Decode(rangeDecoder) == 0)
      return _lowCoder[posState].Decode(rangeDecoder);
    if(_choice2.Decode(rangeDecoder) == 0)
      return kNumLowSymbols + _midCoder[posState].Decode(rangeDecoder);
    return kNumLowSymbols + kNumMidSymbols + _highCoder.Decode(rangeDecoder);
  }
};

}

class CDecoder: 
  public ICompressCoder,
  public ICompressSetDecoderProperties2,
  public ICompressGetInStreamProcessedSize,
  #ifndef NO_READ_FROM_CODER
  public ICompressSetInStream,
  public ICompressSetOutStreamSize,
  public ISequentialInStream,
  #endif
  public CMyUnknownImp
{
  CLZOutWindow _outWindowStream;
  NRangeCoder::CDecoder _rangeDecoder;

  CMyBitDecoder _isMatch[kNumStates][NLength::kNumPosStatesMax];
  CMyBitDecoder _isRep[kNumStates];
  CMyBitDecoder _isRepG0[kNumStates];
  CMyBitDecoder _isRepG1[kNumStates];
  CMyBitDecoder _isRepG2[kNumStates];
  CMyBitDecoder _isRep0Long[kNumStates][NLength::kNumPosStatesMax];

  NRangeCoder::CBitTreeDecoder<kNumMoveBits, kNumPosSlotBits> _posSlotDecoder[kNumLenToPosStates];

  CMyBitDecoder _posDecoders[kNumFullDistances - kEndPosModelIndex];
  NRangeCoder::CBitTreeDecoder<kNumMoveBits, kNumAlignBits> _posAlignDecoder;
  
  NLength::CDecoder _lenDecoder;
  NLength::CDecoder _repMatchLenDecoder;

  CLiteralDecoder _literalDecoder;

  UInt32 _posStateMask;

  ///////////////////
  // State
  UInt32 _reps[4];
  CState _state;
  Int32 _remainLen; // -1 means end of stream. // -2 means need Init
  UInt64 _outSize;
  bool _outSizeDefined;

  void Init();
  HRESULT CodeSpec(UInt32 size);
public:

  #ifndef NO_READ_FROM_CODER
  MY_UNKNOWN_IMP5(
      ICompressSetDecoderProperties2, 
      ICompressGetInStreamProcessedSize,
      ICompressSetInStream, 
      ICompressSetOutStreamSize, 
      ISequentialInStream)
  #else
  MY_UNKNOWN_IMP2(
      ICompressSetDecoderProperties2,
      ICompressGetInStreamProcessedSize)
  #endif

  void ReleaseStreams()
  {
    _outWindowStream.ReleaseStream();
    ReleaseInStream();
  }

  class CDecoderFlusher
  {
    CDecoder *_decoder;
  public:
    bool NeedFlush;
    CDecoderFlusher(CDecoder *decoder): _decoder(decoder), NeedFlush(true) {}
    ~CDecoderFlusher() 
    { 
      if (NeedFlush)
        _decoder->Flush();
      _decoder->ReleaseStreams(); 
    }
  };

  HRESULT Flush() {  return _outWindowStream.Flush(); }  

  STDMETHOD(CodeReal)(ISequentialInStream *inStream,
      ISequentialOutStream *outStream, const UInt64 *inSize, const UInt64 *outSize,
      ICompressProgressInfo *progress);
  
  STDMETHOD(Code)(ISequentialInStream *inStream,
      ISequentialOutStream *outStream, const UInt64 *inSize, const UInt64 *outSize,
      ICompressProgressInfo *progress);

  STDMETHOD(SetDecoderProperties2)(const Byte *data, UInt32 size);

  STDMETHOD(GetInStreamProcessedSize)(UInt64 *value);

  STDMETHOD(SetInStream)(ISequentialInStream *inStream);
  STDMETHOD(ReleaseInStream)();
  STDMETHOD(SetOutStreamSize)(const UInt64 *outSize);

  #ifndef NO_READ_FROM_CODER
  STDMETHOD(Read)(void *data, UInt32 size, UInt32 *processedSize);
  #endif

  CDecoder(): _outSizeDefined(false) {}
  virtual ~CDecoder() {}
};

}}

#endif