{
                //throw new IOException(reply.Substring(4));
            }

        }

        ///
        /// Upload a file.
        ///
        ///
        public void upload(string fileName)
        {
            upload(fileName, false);
        }

        ///
        /// Upload a file and set the resume flag.
        ///
        ///
        ///
        public void upload(string fileName, Boolean resume)
        {

            if (!logined)
            {
                login();
            }

            Socket cSocket = createDataSocket();
            long offset = 0;

            if (resume)
            {

                try
                {

                    setBinaryMode(true);
                    offset = getFileSize(fileName);

                }
                catch (Exception)
                {
                    offset = 0;
                }
            }

            if (offset > 0)
            {
                sendCommand("REST " + offset);
                if (retValue != 350)
                {
                    //throw new IOException(reply.Substring(4));
                    //Remote server may not support resuming.
                    offset = 0;
                }
            }

            sendCommand("STOR " + Path.GetFileName(fileName));

            if (!(retValue == 125 || retValue == 150))
            {
                throw new IOException(reply.Substring(4));
            }

            // open input stream to read source file
            FileStream input = new
                FileStream(fileName, FileMode.Open);

            if (offset != 0)
            {

                if (debug)
                {
                    Console.WriteLine("seeking to " + offset);
                }
                input.Seek(offset, SeekOrigin.Begin);
            }

            Console.WriteLine("Uploading file " + fileName + " to " + remotePath);

            while ((bytes = input.Read(buffer, 0, buffer.Length)) > 0)
            {

                cSocket.Send(buffer, bytes, 0);

            }
            input.Close();

            Console.WriteLine("");

            if (cSocket.Connected)
            {
                cSocket.Close();
            }

            readReply();
            if (!(retValue == 226 || retValue == 250))
            {
                throw new IOException(reply.Substring(4));
            }
        }

        ///
        /// Delete a file from the remote FTP server.
        ///
        ///
        public void deleteRemoteFile(string fileName)
        {

            if (!logined)
            {
                login();
            }

            sendCommand("DELE " + fileName);

            if (retValue != 250)
            {
                throw new IOException(reply.Substring(4));
            }

        }

        ///
        /// Rename a file on the remote FTP server.
        ///
        ///
        ///
        public void renameRemoteFile(string oldFileName, string
            newFileName)
        {

            if (!logined)
            {
                login();
            }

            sendCommand("RNFR " + oldFileName);

            if (retValue != 350)
            {
                throw new IOException(reply.Substring(4));
            }

            //  known problem
            //  rnto will not take care of existing file.
            //  i.e. It will overwrite if newFileName exist
            sendCommand("RNTO " + newFileName);
            if (retValue != 250)
            {
                throw new IOException(reply.Substring(4));
            }

        }
///
        /// Create a directory on the remote FTP server.
        ///
        ///
        public void mkdir(string dirName)
        {

            if (!logined)
            {
                login();
            }

            sendCommand("MKD " + dirName);

            if (retValue != 250)
            {
                throw new IOException(reply.Substring(4));
            }

        }

        ///
        /// Delete a directory on the remote FTP server.
        ///
        ///
        public void rmdir(string dirName)
        {

            if (!logined)
            {
                login();
            }

            sendCommand("RMD " + dirName);

            if (retValue != 250)
            {
                throw new IOException(reply.Substring(4));
            }

        }

        ///
        /// Change the current working directory on the remote FTP server.
        ///
        ///
        public void chdir(string dirName)
        {

            if (dirName.Equals("."))
            {
                return;
            }

            if (!logined)
            {
                login();
            }

            sendCommand("CWD " + dirName);

            if (retValue != 250)
            {
                throw new IOException(reply.Substring(4));
            }

            this.remotePath = dirName;

            Console.WriteLine("Current directory is " + remotePath);

        }

        ///
        /// Close the FTP connection.
        ///
        public void close()
        {

            if (clientSocket != null)
            {
                sendCommand("QUIT");
            }

            cleanup();
            Console.WriteLine("Closing...");
        }

        ///
        /// Set debug mode.
        ///
        ///
        public void setDebug(Boolean debug)
        {
            this.debug = debug;
        }

        private void readReply()
        {
            mes = "";
            reply = readLine();
            retValue = Int32.Parse(reply.Substring(0, 3));
        }

        private void cleanup()
        {
            if (clientSocket != null)
            {
                clientSocket.Close();
                clientSocket = null;
            }
            logined = false;
        }

        private string readLine()
        {

            while (true)
            {
                bytes = clientSocket.Receive(buffer, buffer.Length, 0);
                mes += ASCII.GetString(buffer, 0, bytes);
                if (bytes < buffer.Length)
                {
                    break;
                }
            }

            char[] seperator = { '\n' };
            string[] mess = mes.Split(seperator);

            if (mes.Length > 2)
            {
                mes = mess[mess.Length - 2];
            }
            else
            {
                mes = mess[0];
            }

            if (!mes.Substring(3, 1).Equals(" "))
            {
                return readLine();
            }

            if (debug)
            {
                for (int k = 0; k < mess.Length - 1; k++)
                {
                    Console.WriteLine(mess[k]);
                }
            }
            return mes;
        }

        private void sendCommand(String command)
        {

            Byte[] cmdBytes = Encoding.ASCII.GetBytes((command + "\r\n").ToCharArray());
            clientSocket.Send(cmdBytes, cmdBytes.Length, 0);
            readReply();
        }

        private Socket createDataSocket()
        {
            sendCommand("PASV");
            if (retValue != 227)
            {
                throw new IOException(reply.Substring(4));
            }

            int index1 = reply.IndexOf('(');
            int index2 = reply.IndexOf(')');
            string ipData =
                reply.Substring(index1 + 1, index2 - index1 - 1);
            int[] parts = new int[6];

            int len = ipData.Length;
            int partCount = 0;
            string buf = "";

            for (int i = 0; i < len && partCount <= 6; i++)
            {

                char ch = Char.Parse(ipData.Substring(i, 1));
                if (Char.IsDigit(ch))
                    buf += ch;
                else if (ch != ',')
                {
                    throw new IOException("Malformed PASV reply: " +
                        reply);
                }

                if (ch == ',' || i + 1 == len)
                {

                    try
                    {
                        parts[partCount++] = Int32.Parse(buf);
                        buf = "";
                    }
                    catch (Exception)
                    {
                        throw new IOException("Malformed PASV reply: " +
                            reply);
                    }
                }
            }

            string ipAddress = parts[0] + "." + parts[1] + "." +
                parts[2] + "." + parts[3];

            int port = (parts[4] << 8) + parts[5];

            Socket s = new
                Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPEndPoint ep = new
                IPEndPoint(Dns.Resolve(ipAddress).AddressList[0], port);

            try
            {
                s.Connect(ep);
            }
            catch (Exception)
            {
                throw new IOException("Can't connect to remote server");
            }

            return s;
        }

    }