Microsoft.Protocols.TestSuites.Common.Common.CompressStream C# (CSharp) Method

        public static byte[] CompressStream(byte[] inputStream)
        {
            #region Consts
            // Size of Version field in RPC_HEADER_EXT
            const int RpcHeaderExtVersionByteSize = 2;

            // Size of Flags field in RPC_HEADER_EXT
            const int RpcHeaderExtFlagsByteSize = 2;

            // Size of Size field in RPC_HEADER_EXT
            const int RpcHeaderExtSizeByteSize = 2;

            // The length of RPC_HEADER_EXT.
            const int RPCHeaderExtLength = 8;
            #endregion

            if (inputStream == null)
            {
                throw new ArgumentNullException("inputStream");
            }

            if (inputStream.Length < RPCHeaderExtLength)
            {
                throw new ArgumentException("Input must contain valid RPC_HEADER_EXT.", "inputStream");
            }

            // The third and fourth byte represents Flags field in RPC_HEADER_EXT
            RpcHeaderExtFlags flag = (RpcHeaderExtFlags)BitConverter.ToInt16(inputStream, RpcHeaderExtVersionByteSize);
            if ((flag & RpcHeaderExtFlags.Compressed) == RpcHeaderExtFlags.Compressed)
            {
                // Data stream is already compressed.
                return inputStream;
            }

            ushort originalPayloadSize = BitConverter.ToUInt16(inputStream, RpcHeaderExtVersionByteSize + RpcHeaderExtFlagsByteSize);

            // Compress payload
            byte[] originalPayload = new byte[originalPayloadSize];
            Array.Copy(inputStream, RPCHeaderExtLength, originalPayload, 0, originalPayloadSize);
            byte[] compressedPayload = LZ77Compress(originalPayload);

            // Output the original stream if compressed payload is bigger.
            if (originalPayloadSize <= compressedPayload.Length)
            {
                return inputStream;
            }

            byte[] outStream = new byte[RPCHeaderExtLength + compressedPayload.Length];
            Array.Copy(inputStream, 0, outStream, 0, RPCHeaderExtLength);

            // Update Compressed flag.
            flag |= RpcHeaderExtFlags.Compressed;
            Array.Copy(BitConverter.GetBytes((short)flag), 0, outStream, RpcHeaderExtVersionByteSize, RpcHeaderExtFlagsByteSize);

            // Update Size field.
            Array.Copy(BitConverter.GetBytes((ushort)compressedPayload.Length), 0, outStream, RpcHeaderExtVersionByteSize + RpcHeaderExtFlagsByteSize, RpcHeaderExtSizeByteSize);

            // Fill compressed payload.
            Array.Copy(compressedPayload, 0, outStream, RPCHeaderExtLength, compressedPayload.Length);

            return outStream;
        }