private void Compress(CompressionBlock block)
{
using (var memoryStream = new MemoryStream(_bufferSize))
{
using (var gzipStream = new GZipStream(memoryStream, _compressionMode))
{
gzipStream.Write(block.Data, 0, block.EffectiveSize);
}
byte[] data = memoryStream.ToArray();
GZipHeader gZipHeader = new GZipHeader(data);
int initialHeaderSize = gZipHeader.Header.Length;
int size = 0;
// Добавляем поле с размером.
gZipHeader.SetExtra(
CompressedBlocksProvider.VeeamArchiverSI1,
CompressedBlocksProvider.VeeamArchiverSI2,
BitConverter.GetBytes(size));
// Устанавливаем конечный размер блока.
size = (int)(gZipHeader.Header.Length + data.Length - initialHeaderSize);
gZipHeader.SetExtra(
CompressedBlocksProvider.VeeamArchiverSI1,
CompressedBlocksProvider.VeeamArchiverSI2,
BitConverter.GetBytes(size));
byte[] resultBlock = new byte[size];
Array.Copy(gZipHeader.Header, resultBlock, gZipHeader.Header.Length);
Array.Copy(data, initialHeaderSize, resultBlock, gZipHeader.Header.Length, data.Length - initialHeaderSize);
_processedIndex = block.BlockIndex;
WriteBlock(new CompressionBlock(_processedIndex, resultBlock));
}
}
private void CompressionWorker(Object stream)
{
while (_readerThread.IsAlive || _readBlocks.Count > 0)
{
if (_blocksToWrite.Count > _blockCacheSize)
{
_onWrittenEvent.WaitOne(SyncWaitMs);
continue;
}
CompressionBlock currentBlock = ReadBlock();
if (currentBlock == null)
{
if (_readerThread.IsAlive)
{
_onReadEvent.WaitOne(SyncWaitMs);
}
continue;
}
if (currentBlock.BlockIndex == 0)
{
int desiredThreadsCount = 1;
_parallelDecompression = false;
if (_compressionMode == CompressionMode.Compress)
{
desiredThreadsCount = Environment.ProcessorCount;
_parallelDecompression = true;
}
else
{
try
{
GZipHeader header = new GZipHeader(currentBlock.Data);
byte[] sizeData = header.GetExtra(
CompressedBlocksProvider.VeeamArchiverSI1,
CompressedBlocksProvider.VeeamArchiverSI2);
if (sizeData != null && BitConverter.ToInt32(sizeData, 0) > 0)
{
desiredThreadsCount = Environment.ProcessorCount;
_parallelDecompression = true;
}
}
catch (Exception ex)
{
RaiseErrorOccured(ex);
}
}
for (int i = 0; i < desiredThreadsCount - 1; i++)
{
var thread = new Thread(new ParameterizedThreadStart(CompressionWorker));
_compressionThreads.Add(thread);
thread.Start();
}
}
try
{
if (_compressionMode == CompressionMode.Compress)
{
Compress(currentBlock);
}
else
{
Decompress(currentBlock);
}
}
catch (Exception ex)
{
RaiseErrorOccured(ex);
}
}
if (_decompressionStream != null)
{
_decompressionStream.Dispose();
}
if (_memoryToDecompress != null)
{
_memoryToDecompress.Dispose();
}
}
/// <inheritdoc />
public CompressionBlock GetNextBlock()
{
lock (_streamLock)
{
int readSize = _internalBufferSize;
GZipHeader header = null;
_currentBlockIndex++;
byte[] resultBuffer;
int bytesRead = 0;
if (_gzippedStream.Position == _gzippedStream.Length)
{
return(null);
}
// Для первого буфера нужно вычитать заголовок, который гарантировано должен присутствовать.
// Дальше принимается решение о том, записан файл данной утилитой и можно вычитывать поблочно или
// блоки могут быть произвольными, поскольку границы блоков не выделить.
if (_currentBlockIndex == 0)
{
header = new GZipHeader(_gzippedStream);
byte[] sizeData = header.GetExtra(1, 4);
if (sizeData != null && BitConverter.ToInt32(sizeData, 0) > 0)
{
_isBlocksDelimited = true;
readSize = BitConverter.ToInt32(sizeData, 0);
resultBuffer = new byte[readSize];
Array.Copy(header.Header, resultBuffer, header.Header.Length);
_gzippedStream.Read(
resultBuffer,
header.Header.Length,
readSize - header.Header.Length);
_bytesProvided += resultBuffer.Length;
return(new CompressionBlock(_currentBlockIndex, resultBuffer));
}
else
{
resultBuffer = new byte[_internalBufferSize];
Array.Copy(header.Header, resultBuffer, header.Header.Length);
bytesRead = _gzippedStream.Read(
resultBuffer,
header.Header.Length,
_internalBufferSize - header.Header.Length);
_bytesProvided += bytesRead + header.Header.Length;
return(new CompressionBlock(
_currentBlockIndex, resultBuffer, bytesRead + header.Header.Length));
}
}
if (_isBlocksDelimited)
{
header = new GZipHeader(_gzippedStream);
byte[] sizeData = header.GetExtra(1, 4);
if (sizeData != null && BitConverter.ToInt32(sizeData, 0) > 0)
{
readSize = BitConverter.ToInt32(sizeData, 0);
}
resultBuffer = new byte[readSize];
Array.Copy(header.Header, resultBuffer, header.Header.Length);
_gzippedStream.Read(
resultBuffer,
header.Header.Length,
readSize - header.Header.Length);
bytesRead = readSize;
}
else
{
resultBuffer = new byte[_internalBufferSize];
bytesRead = _gzippedStream.Read(
resultBuffer,
0,
_internalBufferSize);
}
if (bytesRead == 0)
{
return(null);
}
_bytesProvided += bytesRead;
return(new CompressionBlock(_currentBlockIndex, resultBuffer, bytesRead));
}
}
