private int CompressAndWriteClusters(long focusVcn, int count, byte[] buffer, int offset)
{
BlockCompressor compressor = _context.Options.Compressor;
compressor.BlockSize = _bytesPerCluster;
int totalAllocated = 0;
int compressedLength = _ioBuffer.Length;
CompressionResult result = compressor.Compress(buffer, offset, _attr.CompressionUnitSize * _bytesPerCluster, _ioBuffer, 0,
ref compressedLength);
if (result == CompressionResult.AllZeros)
{
totalAllocated -= _rawStream.ReleaseClusters(focusVcn, count);
}
else if (result == CompressionResult.Compressed &&
_attr.CompressionUnitSize * _bytesPerCluster - compressedLength > _bytesPerCluster)
{
int compClusters = Utilities.Ceil(compressedLength, _bytesPerCluster);
totalAllocated += _rawStream.AllocateClusters(focusVcn, compClusters);
totalAllocated += _rawStream.WriteClusters(focusVcn, compClusters, _ioBuffer, 0);
totalAllocated -= _rawStream.ReleaseClusters(focusVcn + compClusters,
_attr.CompressionUnitSize - compClusters);
}
else
{
totalAllocated += _rawStream.AllocateClusters(focusVcn, _attr.CompressionUnitSize);
totalAllocated += _rawStream.WriteClusters(focusVcn, _attr.CompressionUnitSize, buffer, offset);
}
return(totalAllocated);
}
public override int WriteClusters(long startVcn, int count, byte[] buffer, int offset)
{
int clustersAllocated = 0;
clustersAllocated += _rawStream.AllocateClusters(startVcn, count);
clustersAllocated += _rawStream.WriteClusters(startVcn, count, buffer, offset);
return(clustersAllocated);
}