Esempio n. 1
0
HRESULT CDecoder::CodeReal(ISequentialInStream *inStream, ISequentialOutStream *outStream,
    const UInt64 * /* inSize */, const UInt64 * /* outSize */, ICompressProgressInfo *progress)
{
  NBitl::CBaseDecoder<CInBuffer> inBuffer;
  COutBuffer outBuffer;

  if (!inBuffer.Create(kBufferSize))
    return E_OUTOFMEMORY;
  inBuffer.SetStream(inStream);
  inBuffer.Init();

  if (!outBuffer.Create(kBufferSize))
    return E_OUTOFMEMORY;
  outBuffer.SetStream(outStream);
  outBuffer.Init();

  {
    unsigned i;
    for (i = 0; i < 257; i++)
      _parents[i] = (UInt16)i;
    for (; i < kNumItems; i++)
      _parents[i] = kNumItems;
    for (i = 0; i < kNumItems; i++)
      _suffixes[i] = 0;
  }

  UInt64 prevPos = 0;
  unsigned numBits = kNumMinBits;
  unsigned head = 257;
  int lastSym = -1;
  Byte lastChar2 = 0;

  for (;;)
  {
    UInt32 sym = inBuffer.ReadBits(numBits);
    
    if (inBuffer.ExtraBitsWereRead())
      break;
    
    if (sym == 256)
    {
      sym = inBuffer.ReadBits(numBits);
      if (sym == 1)
      {
        if (numBits >= kNumMaxBits)
          return S_FALSE;
        numBits++;
        continue;
      }
      if (sym != 2)
        return S_FALSE;
      {
        unsigned i;
        for (i = 257; i < kNumItems; i++)
          _stack[i] = 0;
        for (i = 257; i < kNumItems; i++)
        {
          unsigned par = _parents[i];
          if (par != kNumItems)
            _stack[par] = 1;
        }
        for (i = 257; i < kNumItems; i++)
          if (_stack[i] == 0)
            _parents[i] = kNumItems;
       
        head = 257;
       
        continue;
      }
    }

    bool needPrev = false;
    if (head < kNumItems && lastSym >= 0)
    {
      while (head < kNumItems && _parents[head] != kNumItems)
        head++;
      if (head < kNumItems)
      {
        if (head == (unsigned)lastSym)
        {
          // we need to fix the code for that case
          // _parents[head] is not allowed to link to itself
          return E_NOTIMPL;
        }
        needPrev = true;
        _parents[head] = (UInt16)lastSym;
        _suffixes[head] = (Byte)lastChar2;
        head++;
      }
    }

    if (_parents[sym] == kNumItems)
      return S_FALSE;

    lastSym = sym;
    unsigned cur = sym;
    unsigned i = 0;
    
    while (cur >= 256)
    {
      _stack[i++] = _suffixes[cur];
      cur = _parents[cur];
    }
    
    _stack[i++] = (Byte)cur;
    lastChar2 = (Byte)cur;

    if (needPrev)
      _suffixes[head - 1] = (Byte)cur;

    do
      outBuffer.WriteByte(_stack[--i]);
    while (i);
    
    if (progress)
    {
      const UInt64 nowPos = outBuffer.GetProcessedSize();
      if (nowPos - prevPos >= (1 << 18))
      {
        prevPos = nowPos;
        const UInt64 packSize = inBuffer.GetProcessedSize();
        RINOK(progress->SetRatioInfo(&packSize, &nowPos));
      }
    }
  }
  
  return outBuffer.Flush();
}
Esempio n. 2
0
HRESULT CDecoder::CodeReal(ISequentialInStream *inStream, ISequentialOutStream *outStream,
    const UInt64 * /* inSize */, const UInt64 * /* outSize */, ICompressProgressInfo *progress)
{
  NBitl::CBaseDecoder<CInBuffer> inBuffer;
  COutBuffer outBuffer;

  if (!inBuffer.Create(kBufferSize))
    return E_OUTOFMEMORY;
  inBuffer.SetStream(inStream);
  inBuffer.Init();

  if (!outBuffer.Create(kBufferSize))
    return E_OUTOFMEMORY;
  outBuffer.SetStream(outStream);
  outBuffer.Init();

  UInt64 prevPos = 0;
  int numBits = kNumMinBits;
  UInt32 head = 257;
  bool needPrev = false;
  UInt32 lastSymbol = 0;

  int i;
  for (i = 0; i < kNumItems; i++)
    _parents[i] = 0;
  for (i = 0; i < kNumItems; i++)
    _suffixes[i] = 0;
  for (i = 0; i < 257; i++)
    _isFree[i] = false;
  for (; i < kNumItems; i++)
    _isFree[i] = true;

  for (;;)
  {
    UInt32 symbol = inBuffer.ReadBits(numBits);
    if (inBuffer.ExtraBitsWereRead())
      break;
    if (_isFree[symbol])
      return S_FALSE;
    if (symbol == 256)
    {
      UInt32 symbol = inBuffer.ReadBits(numBits);
      if (symbol == 1)
      {
        if (numBits < kNumMaxBits)
          numBits++;
      }
      else if (symbol == 2)
      {
        if (needPrev)
          _isFree[head - 1] = true;
        for (i = 257; i < kNumItems; i++)
          _isParent[i] = false;
        for (i = 257; i < kNumItems; i++)
          if (!_isFree[i])
            _isParent[_parents[i]] = true;
        for (i = 257; i < kNumItems; i++)
          if (!_isParent[i])
            _isFree[i] = true;
        head = 257;
        while (head < kNumItems && !_isFree[head])
          head++;
        if (head < kNumItems)
        {
          needPrev = true;
          _isFree[head] = false;
          _parents[head] = (UInt16)lastSymbol;
          head++;
        }
      }
      else
        return S_FALSE;
      continue;
    }
    UInt32 cur = symbol;
    i = 0;
    int corectionIndex = -1;
    while (cur >= 256)
    {
      if (cur == head - 1)
        corectionIndex = i;
      _stack[i++] = _suffixes[cur];
      cur = _parents[cur];
    }
    _stack[i++] = (Byte)cur;
    if (needPrev)
    {
      _suffixes[head - 1] = (Byte)cur;
      if (corectionIndex >= 0)
        _stack[corectionIndex] = (Byte)cur;
    }
    while (i > 0)
      outBuffer.WriteByte((_stack[--i]));
    while (head < kNumItems && !_isFree[head])
      head++;
    if (head < kNumItems)
    {
      needPrev = true;
      _isFree[head] = false;
      _parents[head] = (UInt16)symbol;
      head++;
    }
    else
      needPrev = false;
    lastSymbol = symbol;

    UInt64 nowPos = outBuffer.GetProcessedSize();
    if (progress != NULL && nowPos - prevPos > (1 << 18))
    {
      prevPos = nowPos;
      UInt64 packSize = inBuffer.GetProcessedSize();
      RINOK(progress->SetRatioInfo(&packSize, &nowPos));
    }
  }
  return outBuffer.Flush();
}