示例#1
0
            public async Task DecodeStream()
            {
                // Reset position to use same buffer
                zlibMemoryStream.Position = 0;

                // Get compressed stream length to read
                var buff = new byte[4];

                if (await BaseStream.ReadAsync(buff, 0, 4).ConfigureAwait(false) != 4)
                {
                    throw new Exception("ZRLE decoder: Invalid compressed stream size");
                }

                // BigEndian to LittleEndian conversion
                var compressedBufferSize = buff[3] | buff[2] << 8 | buff[1] << 16 | buff[0] << 24;

                if (compressedBufferSize > 64 * 1024 * 1024)
                {
                    throw new Exception("ZRLE decoder: Invalid compressed data size");
                }

                #region Decode stream
                // Decode stream
                // int pos = 0;
                // while (pos++ < compressedBufferSize)
                //  zlibDecompressedStream.WriteByte(this.BaseStream.ReadByte());
                #endregion

                #region Decode stream in blocks
                // Decode stream in blocks
                var       bytesNeeded   = compressedBufferSize;
                const int maxBufferSize = 64 * 1024;                 // 64k buffer
                var       receiveBuffer = new byte[maxBufferSize];
                var       netStream     = (NetworkStream)BaseStream;
                netStream.ReadTimeout = 15000;                 // Set timeout to 15s
                do
                {
                    // TODO remove sleep
                    if (netStream.DataAvailable)
                    {
                        var bytesToRead = bytesNeeded;

                        // the byteToRead should never exceed the maxBufferSize
                        if (bytesToRead > maxBufferSize)
                        {
                            bytesToRead = maxBufferSize;
                        }

                        // try reading bytes (read in 1024 byte chunks) - improvement for slow connections
                        int toRead    = (bytesToRead > 1024) ? 1024 : bytesToRead;
                        int bytesRead = 0;
                        try
                        {
                            bytesRead = await netStream.ReadAsync(receiveBuffer, bytesRead, toRead).ConfigureAwait(false);
                        }
                        catch { }

                        // lower the bytesNeeded with the bytesRead.
                        bytesNeeded -= bytesRead;

                        // write the readed bytes to the decompression stream.
                        await zlibDecompressedStream.WriteAsync(receiveBuffer, 0, bytesRead).ConfigureAwait(false);
                    }
                    else
                    {
                        // there isn't any data atm. let's give the processor some time.
                        Thread.Sleep(100);                         // increased to 100ms for slow connections
                    }
                } while (bytesNeeded > 0);
                #endregion

                zlibMemoryStream.Position = 0;
            }