/// <summary>
/// Read the next <see cref="T:PacketBuffer"/> from the stream.
/// </summary>
/// <returns>The next packet extracted from the stream.</returns>
/// <param name="processedBytes">Incremented by the number of bytes read from the stream. See remarks.</param>
/// <remarks>
/// The next packet is returned first from the current <see cref="T:CollatedPacketDecoder"/> if possible.
/// Otherwise packet data are read from the stream and decoded as required. The <paramref name="processedBytes"/>
/// value is only adjusted when data are read from the stream, not when a packet is extracted from the
/// collation buffer.
/// </remarks>
public PacketBuffer NextPacket(ref long processedBytes)
{
PacketBuffer packet = null;
// If decoding, just pull from the decoder.
if (DecodingCollated)
{
packet = _decoder.Next();
if (packet != null)
{
return(packet);
}
}
// Check for transition from raw stream to GZip stream.
if (!_isGZipStream && GZipUtil.IsGZipStream(_activeStream))
{
_isGZipStream = true;
_activeStream = new GZipStream(_activeStream, CompressionMode.Decompress);
}
// Read next packet.
int bytesRead = 0;
_headerStream.Position = 0;
_headerStream.SetLength(PacketHeader.Size);
if (!_searchForHeader)
{
bytesRead = _activeStream.Read(_headerStream.GetBuffer(), 0, PacketHeader.Size);
}
else
{
_searchForHeader = false;
// Look for the marker bytes.
UInt32 marker = 0;
int markerSize = 4;
while (!EndOfStream && marker != PacketHeader.PacketMarker)
{
bytesRead = _activeStream.Read(_headerStream.GetBuffer(), 0, markerSize);
marker = Endian.FromNetwork(BitConverter.ToUInt32(_headerStream.GetBuffer(), 0));
}
if (marker != PacketHeader.PacketMarker)
{
// Failed.
EndOfStream = true;
return(null);
}
bytesRead += _activeStream.Read(_headerStream.GetBuffer(), markerSize, PacketHeader.Size - markerSize);
}
if (bytesRead < PacketHeader.Size)
{
EndOfStream = true;
return(null);
}
_headerStream.SetLength(bytesRead);
// Decode header.
if (!_header.Read(new NetworkReader(_headerStream)))
{
// TODO: Throw exception
_searchForHeader = true;
return(null);
}
// Extract packet.
int crcSize = ((_header.Flags & (byte)PacketFlag.NoCrc) == 0) ? Crc16.CrcSize : 0;
packet = new PacketBuffer(_header.PacketSize + crcSize);
packet.Emplace(_headerStream.GetBuffer(), bytesRead);
processedBytes += packet.Emplace(_activeStream, _header.PacketSize + crcSize - bytesRead);
if (packet.Status != PacketBufferStatus.Complete)
{
// TODO: throw exception
_searchForHeader = true;
return(packet);
}
// Decoder packet.
_decoder.SetPacket(packet);
packet = _decoder.Next();
return(packet);
}