Heavily improved the overall performance and async handling

- added a queuing manager for all messages
- tcp now keeps the connection after the first handshake
- async tasks are now run by the time order they were added
- minor bugfixes

Examples/Program.cs

@@ -40,18 +40,30 @@ namespace Examples {
 
                             await Task.Delay(2000);
 
-                            Console.WriteLine("Testregister was toggled");
+                            await interf.SetRegisterAsync(nameof(registers.TestInt32), 100);
+
+                            _ = Task.Factory.StartNew(async () => {
+                                while(true) {
+                                    for (int i = 0; i < 5; i++) {
+                                        var bytes = await interf.ReadByteRange(1020, 20);
+                                        await interf.SetRegisterAsync(nameof(registers.TestBool1), !registers.TestBool1);
+                                        await interf.SetRegisterAsync(nameof(registers.TestInt32), registers.TestInt32 + 100);
+                                        await Task.Delay(1333);
+                                    }
+                                    await Task.Delay(10000);
+                                }
+                            });
 
                             //adds 10 each time the plc connects to the PLCs INT regíster
-                            interf.SetRegister(nameof(registers.TestInt16), (short)(registers.TestInt16 + 10));
+                            //interf.SetRegister(nameof(registers.TestInt16), (short)(registers.TestInt16 + 10));
                             //adds 1 each time the plc connects to the PLCs DINT regíster
-                            interf.SetRegister(nameof(registers.TestInt32), (registers.TestInt32 + 1));
+                            //interf.SetRegister(nameof(registers.TestInt32), (registers.TestInt32 + 1));
                             //adds 11.11 each time the plc connects to the PLCs REAL regíster
-                            interf.SetRegister(nameof(registers.TestFloat32), (float)(registers.TestFloat32 + 11.11));
+                            //interf.SetRegister(nameof(registers.TestFloat32), (float)(registers.TestFloat32 + 11.11));
                             //writes 'Hello' to the PLCs string register
-                            interf.SetRegister(nameof(registers.TestString2), "Hello");
+                            //interf.SetRegister(nameof(registers.TestString2), "Hello");
                             //set the current second to the PLCs TIME register
-                            interf.SetRegister(nameof(registers.TestTime), TimeSpan.FromSeconds(DateTime.Now.Second));
+                            //interf.SetRegister(nameof(registers.TestTime), TimeSpan.FromSeconds(DateTime.Now.Second));
 
                         });
 

Examples/TestRegisters.cs

@@ -18,11 +18,11 @@ namespace Examples {
         public bool TestBoolInputXD { get; private set; } 
 
         //corresponds to a DT1101 - DT1104 string register in the PLC with (STRING[4])
-        [Register(1101, 4)]
+        //[Register(1101, 4)]
-        public string TestString1 { get; private set; }
+        //public string TestString1 { get; private set; }
 
         //corresponds to a DT7000 16 bit int register in the PLC
-        [Register(7000)]
+        [Register(899)]
         public short TestInt16 { get; private set; }
 
         //corresponds to a DTD7001 - DTD7002 32 bit int register in the PLC

MewtocolNet/Mewtocol/DynamicInterface.cs

@@ -33,134 +33,90 @@ namespace MewtocolNet {
         /// </summary>
         internal void AttachPoller () {
 
-            if (ContinousReaderRunning) return;
+            if (ContinousReaderRunning)
+                return;
 
-            cTokenAutoUpdater = new CancellationTokenSource();
+            Task.Factory.StartNew(async () => {
 
-            Logger.Log("Poller is attaching", LogLevel.Info, this);
+                cTokenAutoUpdater = new CancellationTokenSource();
 
-            try {
+                Logger.Log("Poller is attaching", LogLevel.Info, this);
 
-                Task.Factory.StartNew(async () => {
+                int it = 0;
 
-                    var plcinf = await GetPLCInfoAsync();
+                while (it < Registers.Count + 1) {
-                    if (plcinf == null) {
-                        Logger.Log("PLC not reachable, stopping logger", LogLevel.Info, this);
-                        return;
-                    }
-
-                    PolledCycle += MewtocolInterface_PolledCycle;
-                    void MewtocolInterface_PolledCycle () {
-
-                        StringBuilder stringBuilder = new StringBuilder();
-                        foreach (var reg in GetAllRegisters()) {
-                            string address = $"{reg.GetRegisterString()}{reg.GetStartingMemoryArea()}".PadRight(8, (char)32);
-                            stringBuilder.AppendLine($"{address}{(reg.Name != null ? $" ({reg.Name})" : "")}: {reg.GetValueString()}");
-                        }
-
-                        Logger.Log($"Registers loaded are: \n" +
-                                   $"--------------------\n" +
-                                   $"{stringBuilder.ToString()}" +
-                                   $"--------------------",
-                                   LogLevel.Verbose, this);
-
-                        Logger.Log("Logger did its first cycle successfully", LogLevel.Info, this);
-
-                        PolledCycle -= MewtocolInterface_PolledCycle;
-                    }
-
-                    ContinousReaderRunning = true;
-
-                    int getPLCinfoCycleCount = 0;
-
-                    while (ContinousReaderRunning) {
-
-                        //do priority tasks first
-                        if (PriorityTasks != null && PriorityTasks.Count > 0) {
-
-                            try {
-                                await PriorityTasks?.FirstOrDefault(x => !x.IsCompleted);
-                            } catch (NullReferenceException) { }
-
-                        } else if (getPLCinfoCycleCount > 25) {
-
-                            await GetPLCInfoAsync();
-                            getPLCinfoCycleCount = 0;
-
-                        }
-
-                        foreach (var reg in Registers) {
-
-                            if (reg is NRegister<short> shortReg) {
-                                var lastVal = shortReg.Value;
-                                var readout = (await ReadNumRegister(shortReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(shortReg);
-                                }
-                            }
-                            if (reg is NRegister<ushort> ushortReg) {
-                                var lastVal = ushortReg.Value;
-                                var readout = (await ReadNumRegister(ushortReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(ushortReg);
-                                }
-                            }
-                            if (reg is NRegister<int> intReg) {
-                                var lastVal = intReg.Value;
-                                var readout = (await ReadNumRegister(intReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(intReg);
-                                }
-                            }
-                            if (reg is NRegister<uint> uintReg) {
-                                var lastVal = uintReg.Value;
-                                var readout = (await ReadNumRegister(uintReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(uintReg);
-                                }
-                            }
-                            if (reg is NRegister<float> floatReg) {
-                                var lastVal = floatReg.Value;
-                                var readout = (await ReadNumRegister(floatReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(floatReg);
-                                }
-                            }
-                            if (reg is NRegister<TimeSpan> tsReg) {
-                                var lastVal = tsReg.Value;
-                                var readout = (await ReadNumRegister(tsReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(tsReg);
-                                }
-                            }
-                            if (reg is BRegister boolReg) {
-                                var lastVal = boolReg.Value;
-                                var readout = (await ReadBoolRegister(boolReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(boolReg);
-                                }
-                            }
-                            if (reg is SRegister stringReg) {
-                                var lastVal = stringReg.Value;
-                                var readout = (await ReadStringRegister(stringReg)).Register.Value;
-                                if (lastVal != readout) {
-                                    InvokeRegisterChanged(stringReg);
-                                }
-
-                            }
-
-                        }
-
-                        getPLCinfoCycleCount++;
 
+                    if (it >= Registers.Count) {
+                        it = 0;
                         //invoke cycle polled event
                         InvokePolledCycleDone();
-
+                        continue;
                     }
 
-                }, cTokenAutoUpdater.Token);
+                    var reg = Registers[it];
 
-            } catch (TaskCanceledException) { }  
+                    if (reg is NRegister<short> shortReg) {
+                        var lastVal = shortReg.Value;
+                        var readout = (await ReadNumRegister(shortReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(shortReg);
+                        }
+                    }
+                    if (reg is NRegister<ushort> ushortReg) {
+                        var lastVal = ushortReg.Value;
+                        var readout = (await ReadNumRegister(ushortReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(ushortReg);
+                        }
+                    }
+                    if (reg is NRegister<int> intReg) {
+                        var lastVal = intReg.Value;
+                        var readout = (await ReadNumRegister(intReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(intReg);
+                        }
+                    }
+                    if (reg is NRegister<uint> uintReg) {
+                        var lastVal = uintReg.Value;
+                        var readout = (await ReadNumRegister(uintReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(uintReg);
+                        }
+                    }
+                    if (reg is NRegister<float> floatReg) {
+                        var lastVal = floatReg.Value;
+                        var readout = (await ReadNumRegister(floatReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(floatReg);
+                        }
+                    }
+                    if (reg is NRegister<TimeSpan> tsReg) {
+                        var lastVal = tsReg.Value;
+                        var readout = (await ReadNumRegister(tsReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(tsReg);
+                        }
+                    }
+                    if (reg is BRegister boolReg) {
+                        var lastVal = boolReg.Value;
+                        var readout = (await ReadBoolRegister(boolReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(boolReg);
+                        }
+                    }
+                    if (reg is SRegister stringReg) {
+                        var lastVal = stringReg.Value;
+                        var readout = (await ReadStringRegister(stringReg)).Register.Value;
+                        if (lastVal != readout) {
+                            InvokeRegisterChanged(stringReg);
+                        }
+                    }
+
+                    it++;
+
+                }
+
+            });
 
         }
 

MewtocolNet/Mewtocol/MewtocolHelpers.cs

@@ -75,7 +75,7 @@ namespace MewtocolNet {
             var res = new Regex(@"\%([0-9]{2})\$RD.{8}(.*)...").Match(_onString);
             if(res.Success) {
                 string val = res.Groups[2].Value;
-                return val.GetStringFromAsciiHex().Trim();
+                return val.GetStringFromAsciiHex()?.Trim();
             }
             return null;
         }
@@ -143,7 +143,7 @@ namespace MewtocolNet {
 
         internal static string GetStringFromAsciiHex (this string input) {
             if (input.Length % 2 != 0)
-                throw new ArgumentException("input not a hex string");
+                return null;
             byte[] bytes = new byte[input.Length / 2];
             for (int i = 0; i < input.Length; i += 2) {
                 String hex = input.Substring(i, 2);
@@ -158,6 +158,8 @@ namespace MewtocolNet {
         }
 
         internal static byte[] HexStringToByteArray(this string hex) {
+            if (hex == null)
+                return null;
             return Enumerable.Range(0, hex.Length)
                              .Where(x => x % 2 == 0)
                              .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))

MewtocolNet/Mewtocol/MewtocolInterface.cs

@@ -12,6 +12,9 @@ using MewtocolNet.Logging;
 using System.Collections;
 using System.Diagnostics;
 using System.ComponentModel;
+using System.Net;
+using System.Threading;
+using MewtocolNet.Queue;
 
 namespace MewtocolNet {
 
@@ -86,7 +89,7 @@ namespace MewtocolNet {
         /// </summary>
         public int StationNumber => stationNumber;
 
-        private int cycleTimeMs;
+        private int cycleTimeMs = 25;
         /// <summary>
         /// The duration of the last message cycle
         /// </summary>
@@ -98,9 +101,10 @@ namespace MewtocolNet {
             }
         }
 
-
+        internal NetworkStream stream;
-        internal List<Task> PriorityTasks { get; set; } = new List<Task>();
+        internal TcpClient client;
-
+        internal readonly SerialQueue queue = new SerialQueue();
+        private int RecBufferSize = 64;
         internal int SendExceptionsInRow = 0;
 
         #region Initialization
@@ -205,8 +209,6 @@ namespace MewtocolNet {
 
             OnMajorSocketException();
 
-            PriorityTasks.Clear();
-
         }
 
         /// <summary>
@@ -335,9 +337,12 @@ namespace MewtocolNet {
 
                             var bytes = BitConverter.GetBytes(reg16.Value);
                             BitArray bitAr = new BitArray(bytes);
-                            prop.SetValue(collection, bitAr[bitIndex]);
-                            collection.TriggerPropertyChanged(prop.Name);
 
+                            if (bitIndex < bitAr.Length && bitIndex >= 0) {
+                                prop.SetValue(collection, bitAr[bitIndex]);
+                                collection.TriggerPropertyChanged(prop.Name);
+                            }
+                                
                         } else if (bitWiseFound != null && reg is NRegister<int> reg32) {
                             var casted = (RegisterAttribute)bitWiseFound;
                             var bitIndex = casted.AssignedBitIndex;
@@ -542,6 +547,25 @@ namespace MewtocolNet {
 
         #region Low level command handling
 
+        private async Task ConnectTCP () {
+
+            var targetIP = IPAddress.Parse(ip);
+
+            client = new TcpClient() {
+                ReceiveBufferSize = RecBufferSize,
+                NoDelay = false,
+                ExclusiveAddressUse = true
+            };
+
+            await client.ConnectAsync(targetIP, port);
+
+            stream = client.GetStream();
+            stream.ReadTimeout = 1000;
+
+            Console.WriteLine($"Connected {client.Connected}");
+
+        }
+
         /// <summary>
         /// Calculates checksum and sends a command to the PLC then awaits results
         /// </summary>
@@ -553,29 +577,42 @@ namespace MewtocolNet {
             _msg += "\r";
 
             //send request
+            try {
 
-            string response = null;
+                var response = await queue.Enqueue(() => SendSingleBlock(_msg));
 
-            if (ContinousReaderRunning) {
+                if (response == null) {
+                    return new CommandResult {
+                        Success = false,
+                        Error = "0000",
+                        ErrorDescription = "null result"
+                    };
+                }
 
-                //if the poller is active then add all messages to a qeueue
+                //error catching
+                Regex errorcheck = new Regex(@"\%[0-9]{2}\!([0-9]{2})", RegexOptions.IgnoreCase);
+                Match m = errorcheck.Match(response.ToString());
+                if (m.Success) {
+                    string eCode = m.Groups[1].Value;
+                    string eDes = Links.LinkedData.ErrorCodes[Convert.ToInt32(eCode)];
+                    Console.ForegroundColor = ConsoleColor.Red;
+                    Console.WriteLine($"Response is: {response}");
+                    Logger.Log($"Error on command {_msg.Replace("\r", "")} the PLC returned error code: {eCode}, {eDes}", LogLevel.Error);
+                    Console.ResetColor();
+                    return new CommandResult {
+                        Success = false,
+                        Error = eCode,
+                        ErrorDescription = eDes
+                    };
+                }
 
-                var awaittask = SendSingleBlock(_msg);
+                return new CommandResult {
-                PriorityTasks.Add(awaittask);
+                    Success = true,
-                await awaittask;
+                    Error = "0000",
+                    Response = response.ToString()
+                };
 
-                PriorityTasks.Remove(awaittask);
+            } catch {
-                response = awaittask.Result;
-
-            } else {
-
-                //poller not active let the user manage message timing
-
-                response = await SendSingleBlock(_msg);
-
-            }
-
-            if (response == null) {
                 return new CommandResult {
                     Success = false,
                     Error = "0000",
@@ -583,97 +620,63 @@ namespace MewtocolNet {
                 };
             }
 
-            //error catching
-            Regex errorcheck = new Regex(@"\%[0-9]{2}\!([0-9]{2})", RegexOptions.IgnoreCase);
-            Match m = errorcheck.Match(response.ToString());
-            if (m.Success) {
-                string eCode = m.Groups[1].Value;
-                string eDes = Links.LinkedData.ErrorCodes[Convert.ToInt32(eCode)];
-                Console.ForegroundColor = ConsoleColor.Red;
-                Console.WriteLine($"Response is: {response}");
-                Console.WriteLine($"Error on command {_msg.Replace("\r", "")} the PLC returned error code: {eCode}, {eDes}");
-                Console.ResetColor();
-                return new CommandResult {
-                    Success = false,
-                    Error = eCode,
-                    ErrorDescription = eDes
-                };
-            }
-
-            return new CommandResult {
-                Success = true,
-                Error = "0000",
-                Response = response.ToString()
-            };
-
         }
 
         private async Task<string> SendSingleBlock (string _blockString) {
 
-            Stopwatch sw = Stopwatch.StartNew();
+            if (client == null || !client.Connected ) {
-
+                await ConnectTCP();
-            using (TcpClient client = new TcpClient() { ReceiveBufferSize = 64, NoDelay = true, ExclusiveAddressUse = true }) {
+                if (!client.Connected)
-
-                try {
-
-                    await client.ConnectAsync(ip, port);
-
-                    using (NetworkStream stream = client.GetStream()) {
-
-                        var message = _blockString.ToHexASCIIBytes();
-                        var messageAscii = BitConverter.ToString(message).Replace("-", " ");
-
-                        //send request
-                        try {
-                            using (var sendStream = new MemoryStream(message)) {
-                                await sendStream.CopyToAsync(stream);
-                                Logger.Log($"OUT MSG: {_blockString}", LogLevel.Critical, this);
-                                //log message sent
-                                ASCIIEncoding enc = new ASCIIEncoding();
-                                string characters = enc.GetString(message);
-                            }
-                        } catch (IOException) {
-                            Logger.Log($"Critical IO exception on send", LogLevel.Critical, this);
-                            return null;
-                        } catch (SocketException) {
-                            OnMajorSocketException();
-                            return null;
-                        }
-
-                        //await result
-                        StringBuilder response = new StringBuilder();
-                        try {
-                            byte[] responseBuffer = new byte[256];
-                            do {
-                                int bytes = stream.Read(responseBuffer, 0, responseBuffer.Length);
-                                response.Append(Encoding.UTF8.GetString(responseBuffer, 0, bytes));
-                            }
-                            while (stream.DataAvailable);
-                        } catch (IOException) {
-                            Logger.Log($"Critical IO exception on receive", LogLevel.Critical, this);
-                            return null;
-                        } catch (SocketException) {
-                            OnMajorSocketException();
-                            return null;
-                        }
-
-                        sw.Stop();
-                        var curCycle = (int)sw.ElapsedMilliseconds;
-                        if (Math.Abs(CycleTimeMs - curCycle) > 2) {
-                            CycleTimeMs = curCycle;
-                        }
-
-                        Logger.Log($"IN MSG ({(int)sw.Elapsed.TotalMilliseconds}ms): {response}", LogLevel.Critical, this);
-                        return response.ToString();
-                    }
-
-                } catch (SocketException) {
-
-                    OnMajorSocketException();
                     return null;
+            }
+
+            var message = _blockString.ToHexASCIIBytes();
+
+            //send request
+            using (var sendStream = new MemoryStream(message)) {
+                await sendStream.CopyToAsync(stream);
+                Logger.Log($"[--------------------------------]", LogLevel.Critical, this);
+                Logger.Log($"--> OUT MSG: {_blockString}", LogLevel.Critical, this);
+            }
+
+            //await result
+            StringBuilder response = new StringBuilder();
+            try {
+
+                byte[] responseBuffer = new byte[128 * 16];
+
+                bool endLineCode = false;
+                bool startMsgCode = false;
+
+                while (!endLineCode && !startMsgCode) {
+
+                    do {
+                        int bytes = await stream.ReadAsync(responseBuffer, 0, responseBuffer.Length);
+
+                        endLineCode = responseBuffer.Any(x => x == 0x0D);
+                        startMsgCode = responseBuffer.Count(x => x == 0x25) > 1;
+
+                        if (!endLineCode && !startMsgCode) break;
+
+                        response.Append(Encoding.UTF8.GetString(responseBuffer, 0, bytes));
+                    }
+                    while (stream.DataAvailable);
 
                 }
 
+            } catch (IOException) {
+                Logger.Log($"Critical IO exception on receive", LogLevel.Critical, this);
+                return null;
+            } catch (SocketException) {
+                OnMajorSocketException();
+                return null;
+            }
+
+            if(!string.IsNullOrEmpty(response.ToString())) {
+                Logger.Log($"<-- IN MSG (TXT): {response} ({response.Length} bytes)", LogLevel.Critical, this);
+                return response.ToString();
+            } else {
+                return null;
             }
 
         }
@@ -709,4 +712,5 @@ namespace MewtocolNet {
 
     }
 
+
 }

MewtocolNet/Mewtocol/MewtocolInterfaceRequests.cs

@@ -117,7 +117,6 @@ namespace MewtocolNet {
 
             string startStr = start.ToString().PadLeft(5, '0');
             var wordLength = count / 2;
-            bool wasOdd = false;
             if (count % 2 != 0) 
                 wordLength++;
 
@@ -128,8 +127,13 @@ namespace MewtocolNet {
 
             if(result.Success && !string.IsNullOrEmpty(result.Response)) {
 
+                var res = result;
+
                 var bytes = result.Response.ParseDTByteString(wordLength * 4).HexStringToByteArray();
 
+                if (bytes == null)
+                    return null;
+
                 return bytes.BigToMixedEndian().Take(count).ToArray();
 
             }
@@ -196,7 +200,6 @@ namespace MewtocolNet {
         /// </summary>
         /// <typeparam name="T">Type of number (short, ushort, int, uint, float)</typeparam>
         /// <param name="_toRead">The register to read</param>
-        /// <param name="_stationNumber">Station number to access</param>
         /// <returns>A result with the given NumberRegister containing the readback value and a result struct</returns>
         public async Task<NRegisterResult<T>> ReadNumRegister<T> (NRegister<T> _toRead) {
 
@@ -205,40 +208,47 @@ namespace MewtocolNet {
             string requeststring = $"%{GetStationNumber()}#RD{_toRead.BuildMewtocolIdent()}";
             var result = await SendCommandAsync(requeststring);
 
-            if(!result.Success || string.IsNullOrEmpty(result.Response)) {
+            var failedResult = new NRegisterResult<T> {
-                return new NRegisterResult<T> {
+                Result = result,
-                    Result = result,
+                Register = _toRead
-                    Register = _toRead
+            };
-                };
+
+            if (!result.Success || string.IsNullOrEmpty(result.Response)) {
+                return failedResult;
             }
                 
             if (numType == typeof(short)) {
 
                 var resultBytes = result.Response.ParseDTByteString(4).ReverseByteOrder();
+                if (resultBytes == null) return failedResult;
                 var val = short.Parse(resultBytes, NumberStyles.HexNumber);
                 _toRead.SetValueFromPLC(val);
 
             } else if (numType == typeof(ushort)) {
 
                 var resultBytes = result.Response.ParseDTByteString(4).ReverseByteOrder();
+                if (resultBytes == null) return failedResult;
                 var val = ushort.Parse(resultBytes, NumberStyles.HexNumber);
                 _toRead.SetValueFromPLC(val);
 
             } else if (numType == typeof(int)) {
 
                 var resultBytes = result.Response.ParseDTByteString(8).ReverseByteOrder();
+                if (resultBytes == null) return failedResult;
                 var val = int.Parse(resultBytes, NumberStyles.HexNumber);
                 _toRead.SetValueFromPLC(val);
 
             } else if (numType == typeof(uint)) {
 
                 var resultBytes = result.Response.ParseDTByteString(8).ReverseByteOrder();
+                if (resultBytes == null) return failedResult;
                 var val = uint.Parse(resultBytes, NumberStyles.HexNumber);
                 _toRead.SetValueFromPLC(val);
 
             } else if (numType == typeof(float)) {
 
                 var resultBytes = result.Response.ParseDTByteString(8).ReverseByteOrder();
+                if (resultBytes == null) return failedResult;
                 //convert to unsigned int first
                 var val = uint.Parse(resultBytes, NumberStyles.HexNumber);
 
@@ -250,6 +260,7 @@ namespace MewtocolNet {
             } else if (numType == typeof(TimeSpan)) {
 
                 var resultBytes = result.Response.ParseDTByteString(8).ReverseByteOrder();
+                if (resultBytes == null) return failedResult;
                 //convert to unsigned int first
                 var vallong = long.Parse(resultBytes, NumberStyles.HexNumber);
                 var valMillis = vallong * 10;

MewtocolNet/Mewtocol/Subregisters/Register.cs

@@ -145,7 +145,7 @@ namespace MewtocolNet.Registers {
                 return boolReg.Value.ToString();
             }
             if (this is SRegister stringReg) {
-                return stringReg.Value.ToString();
+                return stringReg.Value ?? "";
             }
 
             return "Type of the register is not supported.";

MewtocolNet/MewtocolNet.csproj

@@ -2,7 +2,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <PackageId>MewtocolNet</PackageId>
-    <Version>0.4.3</Version>
+    <Version>0.5.0</Version>
     <Authors>Felix Weiss</Authors>
     <Company>Womed</Company>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>

MewtocolNet/Queue/SerialQueue.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Threading.Tasks;
+
+namespace MewtocolNet.Queue {
+
+    internal class SerialQueue {
+
+        readonly object _locker = new object();
+        readonly WeakReference<Task> _lastTask = new WeakReference<Task>(null);
+
+        internal Task Enqueue (Action action) {
+            return Enqueue<bool>(() => {
+                action();
+                return true;
+            });
+        }
+
+        internal Task<T> Enqueue<T> (Func<T> function) {
+            lock (_locker) {
+                Task lastTask;
+                Task<T> resultTask;
+
+                if (_lastTask.TryGetTarget(out lastTask)) {
+                    resultTask = lastTask.ContinueWith(_ => function(), TaskContinuationOptions.ExecuteSynchronously);
+                } else {
+                    resultTask = Task.Run(function);
+                }
+
+                _lastTask.SetTarget(resultTask);
+
+                return resultTask;
+            }
+        }
+
+        internal Task Enqueue (Func<Task> asyncAction) {
+            lock (_locker) {
+                Task lastTask;
+                Task resultTask;
+
+                if (_lastTask.TryGetTarget(out lastTask)) {
+                    resultTask = lastTask.ContinueWith(_ => asyncAction(), TaskContinuationOptions.ExecuteSynchronously).Unwrap();
+                } else {
+                    resultTask = Task.Run(asyncAction);
+                }
+
+                _lastTask.SetTarget(resultTask);
+
+                return resultTask;
+            }
+        }
+
+        internal Task<T> Enqueue<T> (Func<Task<T>> asyncFunction) {
+            lock (_locker) {
+                Task lastTask;
+                Task<T> resultTask;
+
+                if (_lastTask.TryGetTarget(out lastTask)) {
+                    resultTask = lastTask.ContinueWith(_ => asyncFunction(), TaskContinuationOptions.ExecuteSynchronously).Unwrap();
+                } else {
+                    resultTask = Task.Run(asyncFunction);
+                }
+
+                _lastTask.SetTarget(resultTask);
+
+                return resultTask;
+            }
+        }
+
+    }
+
+}