chmhandler.cpp

著名的7zip的压缩算法,压缩比最高,但是压缩时间也比较长!

      if (fileOffset > m_PosInSection)
      {
        UInt32 numBytesToWrite = (UInt32)MyMin(fileOffset - m_PosInSection, UInt64(size));
        realProcessed += numBytesToWrite;
        if (processedSize != NULL)
          *processedSize = realProcessed;
        data = (const void *)((const Byte *)data + numBytesToWrite);
        size -= numBytesToWrite;
        m_PosInSection += numBytesToWrite;
        m_PosInFolder += numBytesToWrite;
      }
      if (fileOffset == m_PosInSection)
      {
        RINOK(OpenFile());
        m_FileIsOpen = true;
        m_CurrentIndex++;
        m_IsOk = true;
      }
    }
  }
  return WriteEmptyFiles();
}

STDMETHODIMP CChmFolderOutStream::Write(const void *data, UInt32 size, UInt32 *processedSize)
{
  return Write2(data, size, processedSize, true);
}

HRESULT CChmFolderOutStream::FlushCorrupted()
{
  const UInt32 kBufferSize = (1 << 10);
  Byte buffer[kBufferSize];
  for (int i = 0; i < kBufferSize; i++)
    buffer[i] = 0;
  while(m_PosInFolder < m_FolderSize)
  {
    UInt32 size = (UInt32)MyMin(m_FolderSize - m_PosInFolder, (UInt64)kBufferSize);
    UInt32 processedSizeLocal = 0;
    RINOK(Write2(buffer, size, &processedSizeLocal, false));
  }
  return S_OK;
}


STDMETHODIMP CHandler::Extract(const UInt32* indices, UInt32 numItems,
    Int32 _aTestMode, IArchiveExtractCallback *extractCallback)
{
  COM_TRY_BEGIN
  bool allFilesMode = (numItems == UInt32(-1));

  if (allFilesMode)
    numItems = m_Database.NewFormat ? 1:
      (m_Database.LowLevel ?
      m_Database.Items.Size():
      m_Database.Indices.Size());
  if(numItems == 0)
    return S_OK;
  bool testMode = (_aTestMode != 0);

  UInt64 currentTotalSize = 0;

  CMyComPtr<ICompressCoder> copyCoder;
  UInt32 i;

  CLimitedSequentialInStream *streamSpec = new CLimitedSequentialInStream;
  CMyComPtr<ISequentialInStream> inStream(streamSpec);

  if (m_Database.LowLevel)
  {
    UInt64 currentItemSize = 0;
    UInt64 totalSize = 0;
    if (m_Database.NewFormat)
      totalSize = m_Database.NewFormatString.Length();
    else
      for(i = 0; i < numItems; i++)
        totalSize += m_Database.Items[allFilesMode ? i : indices[i]].Size;
    extractCallback->SetTotal(totalSize);
    
    for(i = 0; i < numItems; i++, currentTotalSize += currentItemSize)
    {
      RINOK(extractCallback->SetCompleted(&currentTotalSize));
      CMyComPtr<ISequentialOutStream> realOutStream;
      Int32 askMode;
      askMode = testMode ? NArchive::NExtract::NAskMode::kTest :
      NArchive::NExtract::NAskMode::kExtract;
      Int32 index = allFilesMode ? i : indices[i];
      RINOK(extractCallback->GetStream(index, &realOutStream, askMode));

      if (m_Database.NewFormat)
      {
        if (index != 0)
          return E_FAIL;
        if(!testMode && (!realOutStream))
          continue;
        if (!testMode)
        {
          UInt32 size = m_Database.NewFormatString.Length();
          RINOK(WriteStream(realOutStream, (const char *)m_Database.NewFormatString, size, 0));
        }
        RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kOK));
        continue;
      }
      const CItem &item = m_Database.Items[index];
      
      currentItemSize = item.Size;
      
      if(!testMode && (!realOutStream))
        continue;
      RINOK(extractCallback->PrepareOperation(askMode));
      if (item.Section != 0)
      {
        RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kUnSupportedMethod));
        continue;
      }

      if (testMode)
      {
        RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kOK));
        continue;
      }
      
      RINOK(m_Stream->Seek(m_Database.ContentOffset + item.Offset, STREAM_SEEK_SET, NULL));
      streamSpec->Init(m_Stream, item.Size);
      
      CLocalProgress *localProgressSpec = new CLocalProgress;
      CMyComPtr<ICompressProgressInfo> progress = localProgressSpec;
      localProgressSpec->Init(extractCallback, false);
      
      CLocalCompressProgressInfo *localCompressProgressSpec = new CLocalCompressProgressInfo;
      CMyComPtr<ICompressProgressInfo> compressProgress = localCompressProgressSpec;
      localCompressProgressSpec->Init(progress, &currentTotalSize, &currentTotalSize);
      
      if(!copyCoder)
        copyCoder = new NCompress::CCopyCoder;
      RINOK(copyCoder->Code(inStream, realOutStream, NULL, NULL, compressProgress));
      realOutStream.Release();
      RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kOK));
    }
    return S_OK;
  }
  
  UInt64 lastFolderIndex = ((UInt64)0 - 1);
  for(i = 0; i < numItems; i++)
  {
    UInt32 index = allFilesMode ? i : indices[i];
    int entryIndex = m_Database.Indices[index];
    const CItem &item = m_Database.Items[entryIndex];
    UInt64 sectionIndex = item.Section;
    if (item.IsDirectory() || item.Size == 0)
      continue;
    if (sectionIndex == 0)
    {
      currentTotalSize += item.Size;
      continue;
    }
    const CSectionInfo &section = m_Database.Sections[(size_t)item.Section];
    if (section.IsLzx())
    {
      const CLzxInfo &lzxInfo = section.Methods[0].LzxInfo;
      UInt64 folderIndex = m_Database.GetFolder(index);
      if (lastFolderIndex == folderIndex)
        folderIndex++;
      lastFolderIndex = m_Database.GetLastFolder(index);
      for (; folderIndex <= lastFolderIndex; folderIndex++)
        currentTotalSize += lzxInfo.GetFolderSize();
    }
  }

  RINOK(extractCallback->SetTotal(currentTotalSize));

  NCompress::NLzx::CDecoder *lzxDecoderSpec = 0;
  CMyComPtr<ICompressCoder> lzxDecoder;
  CChmFolderOutStream *chmFolderOutStream = 0;
  CMyComPtr<ISequentialOutStream> outStream;

  currentTotalSize = 0;

  CRecordVector<bool> extractStatuses;
  for(i = 0; i < numItems;)
  {
    RINOK(extractCallback->SetCompleted(&currentTotalSize));
    UInt32 index = allFilesMode ? i : indices[i];
    i++;
    int entryIndex = m_Database.Indices[index];
    const CItem &item = m_Database.Items[entryIndex];
    UInt64 sectionIndex = item.Section;
    Int32 askMode= testMode ? 
        NArchive::NExtract::NAskMode::kTest :
        NArchive::NExtract::NAskMode::kExtract;
    if (item.IsDirectory())
    {
      CMyComPtr<ISequentialOutStream> realOutStream;
      RINOK(extractCallback->GetStream(index, &realOutStream, askMode));
      RINOK(extractCallback->PrepareOperation(askMode));
      realOutStream.Release();
      RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kOK));
      continue;
    }

    CLocalProgress *localProgressSpec = new CLocalProgress;
    CMyComPtr<ICompressProgressInfo> progress = localProgressSpec;
    localProgressSpec->Init(extractCallback, false);
    
    CLocalCompressProgressInfo *localCompressProgressSpec = new CLocalCompressProgressInfo;
    CMyComPtr<ICompressProgressInfo> compressProgress = localCompressProgressSpec;
    localCompressProgressSpec->Init(progress, NULL, &currentTotalSize);

    if (item.Size == 0 || sectionIndex == 0)
    {
      CMyComPtr<ISequentialOutStream> realOutStream;
      RINOK(extractCallback->GetStream(index, &realOutStream, askMode));
      if(!testMode && (!realOutStream))
        continue;
      RINOK(extractCallback->PrepareOperation(askMode));
      if (!testMode && item.Size != 0)
      {
        RINOK(m_Stream->Seek(m_Database.ContentOffset + item.Offset, STREAM_SEEK_SET, NULL));
        streamSpec->Init(m_Stream, item.Size);
        if(!copyCoder)
          copyCoder = new NCompress::CCopyCoder;
        RINOK(copyCoder->Code(inStream, realOutStream, NULL, NULL, compressProgress));
      }
      realOutStream.Release();
      RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kOK));
      currentTotalSize += item.Size;
      continue;
    }
  
    const CSectionInfo &section = m_Database.Sections[(size_t)sectionIndex];

    if (!section.IsLzx())
    {
      CMyComPtr<ISequentialOutStream> realOutStream;
      RINOK(extractCallback->GetStream(index, &realOutStream, askMode));
      if(!testMode && (!realOutStream))
        continue;
      RINOK(extractCallback->PrepareOperation(askMode));
      RINOK(extractCallback->SetOperationResult(NArchive::NExtract::NOperationResult::kUnSupportedMethod));
      continue;
    }

    const CLzxInfo &lzxInfo = section.Methods[0].LzxInfo;

    if (chmFolderOutStream == 0)
    {
      chmFolderOutStream = new CChmFolderOutStream;
      outStream = chmFolderOutStream;
    }

    chmFolderOutStream->Init(&m_Database, extractCallback, testMode);

    if(lzxDecoderSpec == NULL)
    {
      lzxDecoderSpec = new NCompress::NLzx::CDecoder;
      lzxDecoder = lzxDecoderSpec;
    }

    UInt64 folderIndex = m_Database.GetFolder(index);

    UInt64 compressedPos = m_Database.ContentOffset + section.Offset;
    UInt32 numDictBits = lzxInfo.GetNumDictBits();
    RINOK(lzxDecoderSpec->SetParams(numDictBits));

    const CItem *lastItem = &item;
    extractStatuses.Clear();
    extractStatuses.Add(true);

    for (;true; folderIndex++)
    {
      RINOK(extractCallback->SetCompleted(&currentTotalSize));

      UInt64 startPos = lzxInfo.GetFolderPos(folderIndex);
      UInt64 finishPos = lastItem->Offset + lastItem->Size;
      UInt64 limitFolderIndex = lzxInfo.GetFolder(finishPos);

      lastFolderIndex = m_Database.GetLastFolder(index);
      UInt64 folderSize = lzxInfo.GetFolderSize();
      UInt64 unPackSize = folderSize;
      if (extractStatuses.IsEmpty())
        chmFolderOutStream->m_StartIndex = index + 1;
      else
        chmFolderOutStream->m_StartIndex = index;
      if (limitFolderIndex == folderIndex)
      {
        for(; i < numItems; i++)
        {
          UInt32 nextIndex = allFilesMode ? i : indices[i];
          int entryIndex = m_Database.Indices[nextIndex];
          const CItem &nextItem = m_Database.Items[entryIndex];
          if (nextItem.Section != sectionIndex)
            break;
          UInt64 nextFolderIndex = m_Database.GetFolder(nextIndex);
          if (nextFolderIndex != folderIndex)
            break;
          for (index++; index < nextIndex; index++)
            extractStatuses.Add(false);
          extractStatuses.Add(true);
          index = nextIndex;
          lastItem = &nextItem;
          if (nextItem.Size != 0)
            finishPos = nextItem.Offset + nextItem.Size;
          lastFolderIndex = m_Database.GetLastFolder(index);
        }
      }
      unPackSize = MyMin(finishPos - startPos, unPackSize);

      chmFolderOutStream->m_FolderSize = folderSize;
      chmFolderOutStream->m_PosInFolder = 0;
      chmFolderOutStream->m_PosInSection = startPos;
      chmFolderOutStream->m_ExtractStatuses = &extractStatuses;
      chmFolderOutStream->m_NumFiles = extractStatuses.Size();
      chmFolderOutStream->m_CurrentIndex = 0;
      try
      {
        UInt64 startBlock = lzxInfo.GetBlockIndexFromFolderIndex(folderIndex);
        const CResetTable &rt = lzxInfo.ResetTable;
        UInt32 numBlocks = (UInt32)rt.GetNumBlocks(unPackSize);
        for (UInt32 b = 0; b < numBlocks; b++)
        {
          UInt64 completedSize = currentTotalSize + chmFolderOutStream->m_PosInSection - startPos;
          RINOK(extractCallback->SetCompleted(&completedSize));
          UInt64 bCur = startBlock + b;
          if (bCur >= rt.ResetOffsets.Size())
            return E_FAIL;
          UInt64 startOffset = rt.ResetOffsets[(int)startBlock];
          UInt64 offset = rt.ResetOffsets[(int)bCur];
          UInt64 compressedSize;
          rt.GetCompressedSizeOfBlock(bCur, compressedSize);
          UInt64 rem = finishPos - chmFolderOutStream->m_PosInSection;
          if (rem > rt.BlockSize)
            rem = rt.BlockSize;
          const UInt64 *offsets = (const UInt64 *)&rt.ResetOffsets.Front();
          RINOK(m_Stream->Seek(compressedPos + offset, STREAM_SEEK_SET, NULL));
          streamSpec->Init(m_Stream, compressedSize);
          lzxDecoderSpec->SetKeepHistory(b > 0, (int)((offset - startOffset) & 1));
          RINOK(lzxDecoder->Code(inStream, outStream, NULL, &rem, NULL));
        }
      }
      catch(...)
      {
        RINOK(chmFolderOutStream->FlushCorrupted());
      }
      currentTotalSize += folderSize;
      if (folderIndex == lastFolderIndex)
        break;
      extractStatuses.Clear();
    }
  }
  return S_OK;
  COM_TRY_END
}

STDMETHODIMP CHandler::GetNumberOfItems(UInt32 *numItems)
{
  COM_TRY_BEGIN
    *numItems = m_Database.NewFormat ? 1:
      (m_Database.LowLevel ?
      m_Database.Items.Size():
      m_Database.Indices.Size());
  return S_OK;
  COM_TRY_END
}

}}