lzmaalone.cpp

一个7ZIP的解压源码。比较详细。里面含有四种语言的实现代码。

  CMyComPtr<ISequentialOutStream> outStream;
  COutFileStream *outStreamSpec = NULL;
  if (stdOutMode)
  {
    outStream = new CStdOutFileStream;
    MY_SET_BINARY_MODE(stdout);
  }
  else
  {
    if (paramIndex >= nonSwitchStrings.Size())
      IncorrectCommand();
    const UString &outputName = nonSwitchStrings[paramIndex++]; 
    outStreamSpec = new COutFileStream;
    outStream = outStreamSpec;
    if (!outStreamSpec->Create(GetSystemString(outputName), true))
    {
      fprintf(stderr, "\nError: can not open output file %s\n", 
        (const char *)GetOemString(outputName));
      return 1;
    }
  }

  if (parser[NKey::kFilter86].ThereIs)
  {
    // -f86 switch is for x86 filtered mode: BCJ + LZMA.
    if (parser[NKey::kEOS].ThereIs || stdInMode)
      throw "Can not use stdin in this mode";
    UInt64 fileSize;
    inStreamSpec->File.GetLength(fileSize);
    if (fileSize > 0xF0000000)
      throw "File is too big";
    UInt32 inSize = (UInt32)fileSize;
    Byte *inBuffer = 0;
    if (inSize != 0)
    {
      inBuffer = (Byte *)MyAlloc((size_t)inSize); 
      if (inBuffer == 0)
        throw kCantAllocate;
    }
    
    UInt32 processedSize;
    if (ReadStream(inStream, inBuffer, (UInt32)inSize, &processedSize) != S_OK)
      throw "Can not read";
    if ((UInt32)inSize != processedSize)
      throw "Read size error";

    Byte *outBuffer = 0;
    size_t outSizeProcessed;
    if (encodeMode)
    {
      // we allocate 105% of original size for output buffer
      size_t outSize = (size_t)fileSize / 20 * 21 + (1 << 16);
      if (outSize != 0)
      {
        outBuffer = (Byte *)MyAlloc((size_t)outSize); 
        if (outBuffer == 0)
          throw kCantAllocate;
      }
      if (!dictionaryIsDefined)
        dictionary = 1 << 23;
      int res = LzmaRamEncode(inBuffer, inSize, outBuffer, outSize, &outSizeProcessed, 
          dictionary, parser[NKey::kFilter86].PostCharIndex == 0 ? SZ_FILTER_YES : SZ_FILTER_AUTO);
      if (res != 0)
      {
        fprintf(stderr, "\nEncoder error = %d\n", (int)res);
        return 1;
      }
    }
    else
    {
      size_t outSize;
      if (LzmaRamGetUncompressedSize(inBuffer, inSize, &outSize) != 0)
        throw "data error";
      if (outSize != 0)
      {
        outBuffer = (Byte *)MyAlloc(outSize); 
        if (outBuffer == 0)
          throw kCantAllocate;
      }
      int res = LzmaRamDecompress(inBuffer, inSize, outBuffer, outSize, &outSizeProcessed, malloc, free);
      if (res != 0)
        throw "LzmaDecoder error";
    }
    if (WriteStream(outStream, outBuffer, (UInt32)outSizeProcessed, &processedSize) != S_OK)
      throw kWriteError;
    MyFree(outBuffer);
    MyFree(inBuffer);
    return 0;
  }


  UInt64 fileSize;
  if (encodeMode)
  {
    NCompress::NLZMA::CEncoder *encoderSpec = new NCompress::NLZMA::CEncoder;
    CMyComPtr<ICompressCoder> encoder = encoderSpec;

    if (!dictionaryIsDefined)
      dictionary = 1 << 23;

    UInt32 posStateBits = 2;
    UInt32 litContextBits = 3; // for normal files
    // UInt32 litContextBits = 0; // for 32-bit data
    UInt32 litPosBits = 0;
    // UInt32 litPosBits = 2; // for 32-bit data
    UInt32 algorithm = 1;
    UInt32 numFastBytes = 128;
    UInt32 matchFinderCycles = 16 + numFastBytes / 2;
    bool matchFinderCyclesDefined = false;

    bool eos = parser[NKey::kEOS].ThereIs || stdInMode;
 
    if(parser[NKey::kMode].ThereIs)
      if (!GetNumber(parser[NKey::kMode].PostStrings[0], algorithm))
        IncorrectCommand();

    if(parser[NKey::kFastBytes].ThereIs)
      if (!GetNumber(parser[NKey::kFastBytes].PostStrings[0], numFastBytes))
        IncorrectCommand();
    matchFinderCyclesDefined = parser[NKey::kMatchFinderCycles].ThereIs;
    if (matchFinderCyclesDefined)
      if (!GetNumber(parser[NKey::kMatchFinderCycles].PostStrings[0], matchFinderCycles))
        IncorrectCommand();
    if(parser[NKey::kLitContext].ThereIs)
      if (!GetNumber(parser[NKey::kLitContext].PostStrings[0], litContextBits))
        IncorrectCommand();
    if(parser[NKey::kLitPos].ThereIs)
      if (!GetNumber(parser[NKey::kLitPos].PostStrings[0], litPosBits))
        IncorrectCommand();
    if(parser[NKey::kPosBits].ThereIs)
      if (!GetNumber(parser[NKey::kPosBits].PostStrings[0], posStateBits))
        IncorrectCommand();

    PROPID propIDs[] = 
    {
      NCoderPropID::kDictionarySize,
      NCoderPropID::kPosStateBits,
      NCoderPropID::kLitContextBits,
      NCoderPropID::kLitPosBits,
      NCoderPropID::kAlgorithm,
      NCoderPropID::kNumFastBytes,
      NCoderPropID::kMatchFinder,
      NCoderPropID::kEndMarker,
      NCoderPropID::kNumThreads,
      NCoderPropID::kMatchFinderCycles,
    };
    const int kNumPropsMax = sizeof(propIDs) / sizeof(propIDs[0]);

    PROPVARIANT properties[kNumPropsMax];
    for (int p = 0; p < 6; p++)
      properties[p].vt = VT_UI4;

    properties[0].ulVal = (UInt32)dictionary;
    properties[1].ulVal = (UInt32)posStateBits;
    properties[2].ulVal = (UInt32)litContextBits;
    properties[3].ulVal = (UInt32)litPosBits;
    properties[4].ulVal = (UInt32)algorithm;
    properties[5].ulVal = (UInt32)numFastBytes;

    properties[6].vt = VT_BSTR;
    properties[6].bstrVal = (BSTR)(const wchar_t *)mf;

    properties[7].vt = VT_BOOL;
    properties[7].boolVal = eos ? VARIANT_TRUE : VARIANT_FALSE;

    properties[8].vt = VT_UI4;
    properties[8].ulVal = (UInt32)numThreads;

    // it must be last in property list
    properties[9].vt = VT_UI4;
    properties[9].ulVal = (UInt32)matchFinderCycles;

    int numProps = kNumPropsMax;
    if (!matchFinderCyclesDefined)
      numProps--;

    if (encoderSpec->SetCoderProperties(propIDs, properties, numProps) != S_OK)
      IncorrectCommand();
    encoderSpec->WriteCoderProperties(outStream);

    if (eos || stdInMode)
      fileSize = (UInt64)(Int64)-1;
    else
      inStreamSpec->File.GetLength(fileSize);

    for (int i = 0; i < 8; i++)
    {
      Byte b = Byte(fileSize >> (8 * i));
      if (outStream->Write(&b, 1, 0) != S_OK)
      {
        fprintf(stderr, kWriteError);
        return 1;
      }
    }
    HRESULT result = encoder->Code(inStream, outStream, 0, 0, 0);
    if (result == E_OUTOFMEMORY)
    {
      fprintf(stderr, "\nError: Can not allocate memory\n");
      return 1;
    }   
    else if (result != S_OK)
    {
      fprintf(stderr, "\nEncoder error = %X\n", (unsigned int)result);
      return 1;
    }   
  }
  else
  {
    NCompress::NLZMA::CDecoder *decoderSpec = new NCompress::NLZMA::CDecoder;
    CMyComPtr<ICompressCoder> decoder = decoderSpec;
    const UInt32 kPropertiesSize = 5;
    Byte properties[kPropertiesSize];
    UInt32 processedSize;
    if (ReadStream(inStream, properties, kPropertiesSize, &processedSize) != S_OK)
    {
      fprintf(stderr, kReadError);
      return 1;
    }
    if (processedSize != kPropertiesSize)
    {
      fprintf(stderr, kReadError);
      return 1;
    }
    if (decoderSpec->SetDecoderProperties2(properties, kPropertiesSize) != S_OK)
    {
      fprintf(stderr, "SetDecoderProperties error");
      return 1;
    }
    fileSize = 0;
    for (int i = 0; i < 8; i++)
    {
      Byte b;
      if (inStream->Read(&b, 1, &processedSize) != S_OK)
      {
        fprintf(stderr, kReadError);
        return 1;
      }
      if (processedSize != 1)
      {
        fprintf(stderr, kReadError);
        return 1;
      }
      fileSize |= ((UInt64)b) << (8 * i);
    }
    if (decoder->Code(inStream, outStream, 0, &fileSize, 0) != S_OK)
    {
      fprintf(stderr, "Decoder error");
      return 1;
    }   
  }
  if (outStreamSpec != NULL)
  {
    if (outStreamSpec->Close() != S_OK)
    {
      fprintf(stderr, "File closing error");
      return 1;
    }
  }
  return 0;
}

int main(int n, const char *args[])
{
  try { return main2(n, args); }
  catch(const char *s) 
  { 
    fprintf(stderr, "\nError: %s\n", s);
    return 1; 
  }
  catch(...) 
  { 
    fprintf(stderr, "\nError\n");
    return 1; 
  }
}