7zout.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。

    switch(type)
    {
      case NID::kCreationTime:
        defined = item.IsCreationTimeDefined;
        break;
      case NID::kLastWriteTime:
        defined = item.IsLastWriteTimeDefined;
        break;
      case NID::kLastAccessTime:
        defined = item.IsLastAccessTimeDefined;
        break;
      default:
        throw 1;
    }
    boolVector.Add(defined);
    thereAreDefined = (thereAreDefined || defined);
    allDefined = (allDefined && defined);
  }
  if (!thereAreDefined)
    return S_OK;
  RINOK(WriteByte(type));
  size_t dataSize = 1 + 1;
    dataSize += files.Size() * 8;
  if (allDefined)
  {
    RINOK(WriteNumber(dataSize));
    WriteByte(1);
  }
  else
  {
    RINOK(WriteNumber(1 + (boolVector.Size() + 7) / 8 + dataSize));
    WriteByte(0);
    RINOK(WriteBoolVector(boolVector));
  }
  RINOK(WriteByte(0));
  for(i = 0; i < files.Size(); i++)
  {
    if (boolVector[i])
    {
      const CFileItem &item = files[i];
      CArchiveFileTime timeValue;
      timeValue.dwLowDateTime = 0;
      timeValue.dwHighDateTime = 0;
      switch(type)
      {
        case NID::kCreationTime:
          timeValue = item.CreationTime;
          break;
        case NID::kLastWriteTime:
          timeValue = item.LastWriteTime;
          break;
        case NID::kLastAccessTime:
          timeValue = item.LastAccessTime;
          break;
      }
      RINOK(WriteUInt32(timeValue.dwLowDateTime));
      RINOK(WriteUInt32(timeValue.dwHighDateTime));
    }
  }
  return S_OK;
}

HRESULT COutArchive::EncodeStream(
    DECL_EXTERNAL_CODECS_LOC_VARS
    CEncoder &encoder, const Byte *data, size_t dataSize,
    CRecordVector<UInt64> &packSizes, CObjectVector<CFolder> &folders)
{
  CSequentialInStreamImp *streamSpec = new CSequentialInStreamImp;
  CMyComPtr<ISequentialInStream> stream = streamSpec;
  streamSpec->Init(data, dataSize);
  CFolder folderItem;
  folderItem.UnPackCRCDefined = true;
  folderItem.UnPackCRC = CrcCalc(data, dataSize);
  UInt64 dataSize64 = dataSize;
  RINOK(encoder.Encode(
      EXTERNAL_CODECS_LOC_VARS
      stream, NULL, &dataSize64, folderItem, SeqStream, packSizes, NULL))
  folders.Add(folderItem);
  return S_OK;
}

HRESULT COutArchive::EncodeStream(
    DECL_EXTERNAL_CODECS_LOC_VARS
    CEncoder &encoder, const CByteBuffer &data, 
    CRecordVector<UInt64> &packSizes, CObjectVector<CFolder> &folders)
{
  return EncodeStream(
      EXTERNAL_CODECS_LOC_VARS
      encoder, data, data.GetCapacity(), packSizes, folders);
}

static void WriteUInt32ToBuffer(Byte *data, UInt32 value)
{
  for (int i = 0; i < 4; i++)
  {
    *data++ = (Byte)value;
    value >>= 8;
  }
}

static void WriteUInt64ToBuffer(Byte *data, UInt64 value)
{
  for (int i = 0; i < 8; i++)
  {
    *data++ = (Byte)value;
    value >>= 8;
  }
}


HRESULT COutArchive::WriteHeader(
    const CArchiveDatabase &database,
    const CHeaderOptions &headerOptions,
    UInt64 &headerOffset)
{
  int i;
  
  /////////////////////////////////
  // Names

  CNum numDefinedNames = 0;
  size_t namesDataSize = 0;
  for(i = 0; i < database.Files.Size(); i++)
  {
    const UString &name = database.Files[i].Name;
    if (!name.IsEmpty())
      numDefinedNames++;
    namesDataSize += (name.Length() + 1) * 2;
  }

  CByteBuffer namesData;
  if (numDefinedNames > 0)
  {
    namesData.SetCapacity((size_t)namesDataSize);
    size_t pos = 0;
    for(int i = 0; i < database.Files.Size(); i++)
    {
      const UString &name = database.Files[i].Name;
      for (int t = 0; t < name.Length(); t++)
      {
        wchar_t c = name[t];
        namesData[pos++] = Byte(c);
        namesData[pos++] = Byte(c >> 8);
      }
      namesData[pos++] = 0;
      namesData[pos++] = 0;
    }
  }

  /////////////////////////////////
  // Write Attributes
  CBoolVector attributesBoolVector;
  attributesBoolVector.Reserve(database.Files.Size());
  int numDefinedAttributes = 0;
  for(i = 0; i < database.Files.Size(); i++)
  {
    bool defined = database.Files[i].AreAttributesDefined;
    attributesBoolVector.Add(defined);
    if (defined)
      numDefinedAttributes++;
  }

  CByteBuffer attributesData;
  if (numDefinedAttributes > 0)
  {
    attributesData.SetCapacity(numDefinedAttributes * 4);
    size_t pos = 0;
    for(i = 0; i < database.Files.Size(); i++)
    {
      const CFileItem &file = database.Files[i];
      if (file.AreAttributesDefined)
      {
        WriteUInt32ToBuffer(attributesData + pos, file.Attributes);
        pos += 4;
      }
    }
  }

  /////////////////////////////////
  // Write StartPos
  CBoolVector startsBoolVector;
  startsBoolVector.Reserve(database.Files.Size());
  int numDefinedStarts = 0;
  for(i = 0; i < database.Files.Size(); i++)
  {
    bool defined = database.Files[i].IsStartPosDefined;
    startsBoolVector.Add(defined);
    if (defined)
      numDefinedStarts++;
  }

  CByteBuffer startsData;
  if (numDefinedStarts > 0)
  {
    startsData.SetCapacity(numDefinedStarts * 8);
    size_t pos = 0;
    for(i = 0; i < database.Files.Size(); i++)
    {
      const CFileItem &file = database.Files[i];
      if (file.IsStartPosDefined)
      {
        WriteUInt64ToBuffer(startsData + pos, file.StartPos);
        pos += 8;
      }
    }
  }
  
  /////////////////////////////////
  // Write Last Write Time
  // /*
  CNum numDefinedLastWriteTimes = 0;
  for(i = 0; i < database.Files.Size(); i++)
    if (database.Files[i].IsLastWriteTimeDefined)
      numDefinedLastWriteTimes++;

  if (numDefinedLastWriteTimes > 0)
  {
    CByteBuffer lastWriteTimeData;
    lastWriteTimeData.SetCapacity(numDefinedLastWriteTimes * 8);
    size_t pos = 0;
    for(i = 0; i < database.Files.Size(); i++)
    {
      const CFileItem &file = database.Files[i];
      if (file.IsLastWriteTimeDefined)
      {
        WriteUInt32ToBuffer(lastWriteTimeData + pos, file.LastWriteTime.dwLowDateTime);
        pos += 4;
        WriteUInt32ToBuffer(lastWriteTimeData + pos, file.LastWriteTime.dwHighDateTime);
        pos += 4;
      }
    }
  }
  // */
  

  UInt64 packedSize = 0;
  for(i = 0; i < database.PackSizes.Size(); i++)
    packedSize += database.PackSizes[i];

  headerOffset = packedSize;

  _mainMode = true;

  _outByte.SetStream(SeqStream);
  _outByte.Init();
  _crc = CRC_INIT_VAL;


  RINOK(WriteByte(NID::kHeader));

  // Archive Properties

  if (database.Folders.Size() > 0)
  {
    RINOK(WriteByte(NID::kMainStreamsInfo));
    RINOK(WritePackInfo(0, database.PackSizes, 
        database.PackCRCsDefined,
        database.PackCRCs));

    RINOK(WriteUnPackInfo(database.Folders));

    CRecordVector<UInt64> unPackSizes;
    CRecordVector<bool> digestsDefined;
    CRecordVector<UInt32> digests;
    for (i = 0; i < database.Files.Size(); i++)
    {
      const CFileItem &file = database.Files[i];
      if (!file.HasStream)
        continue;
      unPackSizes.Add(file.UnPackSize);
      digestsDefined.Add(file.IsFileCRCDefined);
      digests.Add(file.FileCRC);
    }

    RINOK(WriteSubStreamsInfo(
        database.Folders,
        database.NumUnPackStreamsVector,
        unPackSizes,
        digestsDefined,
        digests));
    RINOK(WriteByte(NID::kEnd));
  }

  if (database.Files.IsEmpty())
  {
    RINOK(WriteByte(NID::kEnd));
    return _outByte.Flush();
  }

  RINOK(WriteByte(NID::kFilesInfo));
  RINOK(WriteNumber(database.Files.Size()));

  CBoolVector emptyStreamVector;
  emptyStreamVector.Reserve(database.Files.Size());
  int numEmptyStreams = 0;
  for(i = 0; i < database.Files.Size(); i++)
    if (database.Files[i].HasStream)
      emptyStreamVector.Add(false);
    else
    {
      emptyStreamVector.Add(true);
      numEmptyStreams++;
    }
  if (numEmptyStreams > 0)
  {
    RINOK(WriteByte(NID::kEmptyStream));
    RINOK(WriteNumber((emptyStreamVector.Size() + 7) / 8));
    RINOK(WriteBoolVector(emptyStreamVector));

    CBoolVector emptyFileVector, antiVector;
    emptyFileVector.Reserve(numEmptyStreams);
    antiVector.Reserve(numEmptyStreams);
    CNum numEmptyFiles = 0, numAntiItems = 0;
    for(i = 0; i < database.Files.Size(); i++)
    {
      const CFileItem &file = database.Files[i];
      if (!file.HasStream)
      {
        emptyFileVector.Add(!file.IsDirectory);
        if (!file.IsDirectory)
          numEmptyFiles++;
        antiVector.Add(file.IsAnti);
        if (file.IsAnti)
          numAntiItems++;
      }
    }

    if (numEmptyFiles > 0)
    {
      RINOK(WriteByte(NID::kEmptyFile));
      RINOK(WriteNumber((emptyFileVector.Size() + 7) / 8));
      RINOK(WriteBoolVector(emptyFileVector));
    }

    if (numAntiItems > 0)
    {
      RINOK(WriteByte(NID::kAnti));
      RINOK(WriteNumber((antiVector.Size() + 7) / 8));
      RINOK(WriteBoolVector(antiVector));
    }
  }

  if (numDefinedNames > 0)
  {
    /////////////////////////////////////////////////
    RINOK(WriteByte(NID::kName));
    {
      RINOK(WriteNumber(1 + namesData.GetCapacity()));
      RINOK(WriteByte(0));
      RINOK(WriteBytes(namesData));
    }

  }

  if (headerOptions.WriteCreated)
  {
    RINOK(WriteTime(database.Files, NID::kCreationTime));
  }
  if (headerOptions.WriteModified)
  {
    RINOK(WriteTime(database.Files, NID::kLastWriteTime));
  }
  if (headerOptions.WriteAccessed)
  {
    RINOK(WriteTime(database.Files, NID::kLastAccessTime));
  }

  if (numDefinedAttributes > 0)
  {
    RINOK(WriteByte(NID::kWinAttributes));
    size_t size = 2;
    if (numDefinedAttributes != database.Files.Size())
      size += (attributesBoolVector.Size() + 7) / 8 + 1;
      size += attributesData.GetCapacity();

    RINOK(WriteNumber(size));
    if (numDefinedAttributes == database.Files.Size())
    {
      RINOK(WriteByte(1));
    }
    else
    {
      RINOK(WriteByte(0));
      RINOK(WriteBoolVector(attributesBoolVector));
    }

    {
      RINOK(WriteByte(0));
      RINOK(WriteBytes(attributesData));
    }
  }

  if (numDefinedStarts > 0)
  {
    RINOK(WriteByte(NID::kStartPos));
    size_t size = 2;
    if (numDefinedStarts != database.Files.Size())
      size += (startsBoolVector.Size() + 7) / 8 + 1;
      size += startsData.GetCapacity();

    RINOK(WriteNumber(size));
    if (numDefinedStarts == database.Files.Size())
    {
      RINOK(WriteByte(1));
    }
    else
    {
      RINOK(WriteByte(0));
      RINOK(WriteBoolVector(startsBoolVector));
    }

    {
      RINOK(WriteByte(0));
      RINOK(WriteBytes(startsData));
    }
  }

  RINOK(WriteByte(NID::kEnd)); // for files
  RINOK(WriteByte(NID::kEnd)); // for headers

  return _outByte.Flush();
}

HRESULT COutArchive::WriteDatabase(
    DECL_EXTERNAL_CODECS_LOC_VARS
    const CArchiveDatabase &database,
    const CCompressionMethodMode *options, 
    const CHeaderOptions &headerOptions)
{
  UInt64 headerOffset;
  UInt32 headerCRC;
  UInt64 headerSize;
  if (database.IsEmpty())
  {
    headerSize = 0;
    headerOffset = 0;
    headerCRC = CrcCalc(0, 0);
  }
  else
  {
    _dynamicBuffer.Init();
    _dynamicMode = false;

    if (options != 0)
      if (options->IsEmpty())
        options = 0;
    if (options != 0)
      if (options->PasswordIsDefined || headerOptions.CompressMainHeader)
        _dynamicMode = true;
    RINOK(WriteHeader(database, headerOptions, headerOffset));

    if (_dynamicMode)
    {
      CCompressionMethodMode encryptOptions;
      encryptOptions.PasswordIsDefined = options->PasswordIsDefined;
      encryptOptions.Password = options->Password;
      CEncoder encoder(headerOptions.CompressMainHeader ? *options : encryptOptions);
      CRecordVector<UInt64> packSizes;
      CObjectVector<CFolder> folders;
      RINOK(EncodeStream(
          EXTERNAL_CODECS_LOC_VARS
          encoder, _dynamicBuffer, 
          _dynamicBuffer.GetSize(), packSizes, folders));
      _dynamicMode = false;
      _mainMode = true;
      
      _outByte.SetStream(SeqStream);
      _outByte.Init();
      _crc = CRC_INIT_VAL;
      
      if (folders.Size() == 0)
        throw 1;

      RINOK(WriteID(NID::kEncodedHeader));
      RINOK(WritePackInfo(headerOffset, packSizes, 
        CRecordVector<bool>(), CRecordVector<UInt32>()));
      RINOK(WriteUnPackInfo(folders));
      RINOK(WriteByte(NID::kEnd));
      for (int i = 0; i < packSizes.Size(); i++)
        headerOffset += packSizes[i];
      RINOK(_outByte.Flush());
    }
    headerCRC = CRC_GET_DIGEST(_crc);
    headerSize = _outByte.GetProcessedSize();
  }
  #ifdef _7Z_VOL
  if (_endMarker)
  {
    CFinishHeader h;
    h.NextHeaderSize = headerSize;
    h.NextHeaderCRC = headerCRC;
    h.NextHeaderOffset = 
        UInt64(0) - (headerSize + 
        4 + kFinishHeaderSize);
    h.ArchiveStartOffset = h.NextHeaderOffset - headerOffset;
    h.AdditionalStartBlockSize = 0;
    RINOK(WriteFinishHeader(h));
    return WriteFinishSignature();
  }
  else
  #endif
  {
    CStartHeader h;
    h.NextHeaderSize = headerSize;
    h.NextHeaderCRC = headerCRC;
    h.NextHeaderOffset = headerOffset;
    RINOK(Stream->Seek(_prefixHeaderPos, STREAM_SEEK_SET, NULL));
    return WriteStartHeader(h);
  }
}

}}