/// <summary>
/// Read from the stream
/// </summary>
/// <param name="buffer">the buffer to read</param>
/// <param name="offset">the offset at which to start</param>
/// <param name="count">the number of bytes to read</param>
/// <returns>the number of bytes actually read</returns>
public override int Read(byte[] buffer, int offset, int count)
{
int bytesToRead = count;
// Need to limit the # of bytes returned, if the stream is intended to have
// a definite length. This is especially useful when returning a stream for
// the uncompressed data directly to the application. The app won't
// necessarily read only the UncompressedSize number of bytes. For example
// wrapping the stream returned from OpenReader() into a StreadReader() and
// calling ReadToEnd() on it, We can "over-read" the zip data and get a
// corrupt string. The length limits that, prevents that problem.
if (_lengthLimit != CrcCalculatorStream.UnsetLengthLimit)
{
if (_Crc32.TotalBytesRead >= _lengthLimit)
{
return(0); // EOF
}
Int64 bytesRemaining = _lengthLimit - _Crc32.TotalBytesRead;
if (bytesRemaining < count)
{
bytesToRead = (int)bytesRemaining;
}
}
int n = _innerStream.Read(buffer, offset, bytesToRead);
if (n > 0)
{
_Crc32.SlurpBlock(buffer, offset, n);
}
return(n);
}
private void _DeflateOne(Object wi)
{
WorkItem workitem = (WorkItem)wi;
try
{
// compress one buffer
int myItem = workitem.index;
lock (workitem)
{
if (workitem.status != (int)WorkItem.Status.Filled)
{
throw new InvalidOperationException();
}
PMDCP.Compression.Zlib.CRC32 crc = new CRC32();
// use the workitem:
// calc CRC on the buffer
crc.SlurpBlock(workitem.buffer, 0, workitem.inputBytesAvailable);
// deflate it
DeflateOneSegment(workitem);
// update status
workitem.status = (int)WorkItem.Status.Compressed;
workitem.crc = crc.Crc32Result;
TraceOutput(TraceBits.Compress,
"Compress wi({0}) stat({1}) len({2})",
workitem.index,
workitem.status,
workitem.compressedBytesAvailable
);
// release the item
Monitor.Pulse(workitem);
}
}
catch (System.Exception exc1)
{
lock (_eLock)
{
// expose the exception to the main thread
if (_pendingException != null)
{
_pendingException = exc1;
}
}
}
}
private void _DeflateOne(Object wi)
{
WorkItem workitem = (WorkItem) wi;
try
{
// compress one buffer
int myItem = workitem.index;
lock(workitem)
{
if (workitem.status != (int)WorkItem.Status.Filled)
throw new InvalidOperationException();
PMDCP.Compression.Zlib.CRC32 crc = new CRC32();
// use the workitem:
// calc CRC on the buffer
crc.SlurpBlock(workitem.buffer, 0, workitem.inputBytesAvailable);
// deflate it
DeflateOneSegment(workitem);
// update status
workitem.status = (int)WorkItem.Status.Compressed;
workitem.crc = crc.Crc32Result;
TraceOutput(TraceBits.Compress,
"Compress wi({0}) stat({1}) len({2})",
workitem.index,
workitem.status,
workitem.compressedBytesAvailable
);
// release the item
Monitor.Pulse(workitem);
}
}
catch (System.Exception exc1)
{
lock(_eLock)
{
// expose the exception to the main thread
if (_pendingException!=null)
_pendingException = exc1;
}
}
}