Add ModbusDevice as preparation for server implementations.

AMWD.Protocols.Modbus.Common/Extensions/ArrayExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 
 namespace AMWD.Protocols.Modbus.Common
 {
@@ -10,5 +11,19 @@ namespace AMWD.Protocols.Modbus.Common
 			if (BitConverter.IsLittleEndian)
 				Array.Reverse(bytes);
 		}
+
+		public static ushort NetworkUInt16(this byte[] bytes, int offset = 0)
+		{
+			byte[] b = bytes.Skip(offset).Take(2).ToArray();
+			b.SwapNetworkOrder();
+			return BitConverter.ToUInt16(b, 0);
+		}
+
+		public static byte[] ToNetworkBytes(this ushort value)
+		{
+			byte[] b = BitConverter.GetBytes(value);
+			b.SwapNetworkOrder();
+			return b;
+		}
 	}
 }

AMWD.Protocols.Modbus.Common/Extensions/EnumExtensions.cs

@@ -5,7 +5,7 @@ using System.Linq;
 namespace System
 {
 	// ================================================================================================================================== //
-	// Source: https://git.am-wd.de/am.wd/common/-/blob/d4b390ad911ce302cc371bb2121fa9c31db1674a/AMWD.Common/Extensions/EnumExtensions.cs //
+	// Source: https://git.am-wd.de/am-wd/common/-/blob/d4b390ad911ce302cc371bb2121fa9c31db1674a/AMWD.Common/Extensions/EnumExtensions.cs //
 	// ================================================================================================================================== //
 	[Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
 	internal static class EnumExtensions

AMWD.Protocols.Modbus.Common/Extensions/ReaderWriterLockSlimExtensions.cs

@@ -0,0 +1,92 @@
+namespace System.Threading
+{
+	// ================================================================================================================================================== //
+	// Source: https://git.am-wd.de/am-wd/common/-/blob/d4b390ad911ce302cc371bb2121fa9c31db1674a/AMWD.Common/Extensions/ReaderWriterLockSlimExtensions.cs //
+	// ================================================================================================================================================== //
+	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+	internal static class ReaderWriterLockSlimExtensions
+	{
+		/// <summary>
+		/// Acquires a read lock on a lock object that can be released with an
+		/// <see cref="IDisposable"/> instance.
+		/// </summary>
+		/// <param name="rwLock">The lock object.</param>
+		/// <param name="timeoutMilliseconds">The number of milliseconds to wait, or -1
+		///   (<see cref="Timeout.Infinite"/>) to wait indefinitely.</param>
+		/// <returns>An <see cref="IDisposable"/> instance to release the lock.</returns>
+		public static IDisposable GetReadLock(this ReaderWriterLockSlim rwLock, int timeoutMilliseconds = -1)
+		{
+			if (!rwLock.TryEnterReadLock(timeoutMilliseconds))
+				throw new TimeoutException("The read lock could not be acquired.");
+
+			return new DisposableReadWriteLock(rwLock, LockMode.Read);
+		}
+
+		/// <summary>
+		/// Acquires a upgradeable read lock on a lock object that can be released with an
+		/// <see cref="IDisposable"/> instance. The lock can be upgraded to a write lock temporarily
+		/// with <see cref="GetWriteLock"/> or until the lock is released with
+		/// <see cref="ReaderWriterLockSlim.EnterWriteLock"/> alone.
+		/// </summary>
+		/// <param name="rwLock">The lock object.</param>
+		/// <param name="timeoutMilliseconds">The number of milliseconds to wait, or -1
+		///   (<see cref="Timeout.Infinite"/>) to wait indefinitely.</param>
+		/// <returns>An <see cref="IDisposable"/> instance to release the lock. If the lock was
+		///   upgraded to a write lock, that will be released as well.</returns>
+		public static IDisposable GetUpgradeableReadLock(this ReaderWriterLockSlim rwLock, int timeoutMilliseconds = -1)
+		{
+			if (!rwLock.TryEnterUpgradeableReadLock(timeoutMilliseconds))
+				throw new TimeoutException("The upgradeable read lock could not be acquired.");
+
+			return new DisposableReadWriteLock(rwLock, LockMode.Upgradable);
+		}
+
+		/// <summary>
+		/// Acquires a write lock on a lock object that can be released with an
+		/// <see cref="IDisposable"/> instance.
+		/// </summary>
+		/// <param name="rwLock">The lock object.</param>
+		/// <param name="timeoutMilliseconds">The number of milliseconds to wait, or -1
+		///   (<see cref="Timeout.Infinite"/>) to wait indefinitely.</param>
+		/// <returns>An <see cref="IDisposable"/> instance to release the lock.</returns>
+		public static IDisposable GetWriteLock(this ReaderWriterLockSlim rwLock, int timeoutMilliseconds = -1)
+		{
+			if (!rwLock.TryEnterWriteLock(timeoutMilliseconds))
+				throw new TimeoutException("The write lock could not be acquired.");
+
+			return new DisposableReadWriteLock(rwLock, LockMode.Write);
+		}
+
+		private struct DisposableReadWriteLock(ReaderWriterLockSlim rwLock, LockMode lockMode)
+			: IDisposable
+		{
+			private readonly ReaderWriterLockSlim _rwLock = rwLock;
+			private LockMode _lockMode = lockMode;
+
+			public void Dispose()
+			{
+				if (_lockMode == LockMode.Read)
+					_rwLock.ExitReadLock();
+
+				if (_lockMode == LockMode.Upgradable && _rwLock.IsWriteLockHeld)   // Upgraded with EnterWriteLock alone
+					_rwLock.ExitWriteLock();
+
+				if (_lockMode == LockMode.Upgradable)
+					_rwLock.ExitUpgradeableReadLock();
+
+				if (_lockMode == LockMode.Write)
+					_rwLock.ExitWriteLock();
+
+				_lockMode = LockMode.None;
+			}
+		}
+
+		private enum LockMode
+		{
+			None = 0,
+			Read = 1,
+			Upgradable = 2,
+			Write = 3,
+		}
+	}
+}

AMWD.Protocols.Modbus.Common/Models/ModbusDevice.cs

@@ -0,0 +1,220 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace AMWD.Protocols.Modbus.Common.Models
+{
+	/// <summary>
+	/// Represents a Modbus device used in a Modbus server implementation.
+	/// </summary>
+	/// <remarks>
+	/// Initializes a new instance of the <see cref="ModbusDevice"/> class.
+	/// </remarks>
+	/// <param name="id">The <see cref="ModbusDevice"/> ID.</param>
+	public class ModbusDevice(byte id) : IDisposable
+	{
+		private readonly ReaderWriterLockSlim _rwLockCoils = new();
+		private readonly ReaderWriterLockSlim _rwLockDiscreteInputs = new();
+		private readonly ReaderWriterLockSlim _rwLockHoldingRegisters = new();
+		private readonly ReaderWriterLockSlim _rwLockInputRegisters = new();
+
+		private readonly HashSet<ushort> _coils = [];
+		private readonly HashSet<ushort> _discreteInputs = [];
+		private readonly Dictionary<ushort, ushort> _holdingRegisters = [];
+		private readonly Dictionary<ushort, ushort> _inputRegisters = [];
+
+		private bool _isDisposed;
+
+		/// <summary>
+		/// Gets the ID of the <see cref="ModbusDevice"/>.
+		/// </summary>
+		public byte Id { get; } = id;
+
+		/// <summary>
+		/// Releases the unmanaged resources used by the <see cref="ModbusDevice"/>
+		/// and optionally also discards the managed resources.
+		/// </summary>
+		public void Dispose()
+		{
+			if (_isDisposed)
+				return;
+
+			_isDisposed = true;
+
+			_rwLockCoils.Dispose();
+			_rwLockDiscreteInputs.Dispose();
+			_rwLockHoldingRegisters.Dispose();
+			_rwLockInputRegisters.Dispose();
+
+			_coils.Clear();
+			_discreteInputs.Clear();
+			_holdingRegisters.Clear();
+			_inputRegisters.Clear();
+		}
+
+		/// <summary>
+		/// Gets a <see cref="Coil"/> from the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="address">The address of the <see cref="Coil"/>.</param>
+		public Coil GetCoil(ushort address)
+		{
+			Assertions();
+			using (_rwLockCoils.GetReadLock())
+			{
+				return new Coil
+				{
+					Address = address,
+					HighByte = (byte)(_coils.Contains(address) ? 0xFF : 0x00)
+				};
+			}
+		}
+
+		/// <summary>
+		/// Sets a <see cref="Coil"/> to the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="coil">The <see cref="Coil"/> to set.</param>
+		public void SetCoil(Coil coil)
+		{
+			Assertions();
+			using (_rwLockCoils.GetWriteLock())
+			{
+				if (coil.Value)
+					_coils.Add(coil.Address);
+				else
+					_coils.Remove(coil.Address);
+			}
+		}
+
+		/// <summary>
+		/// Gets a <see cref="DiscreteInput"/> from the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="address">The address of the <see cref="DiscreteInput"/>.</param>
+		public DiscreteInput GetDiscreteInput(ushort address)
+		{
+			Assertions();
+			using (_rwLockDiscreteInputs.GetReadLock())
+			{
+				return new DiscreteInput
+				{
+					Address = address,
+					HighByte = (byte)(_discreteInputs.Contains(address) ? 0xFF : 0x00)
+				};
+			}
+		}
+
+		/// <summary>
+		/// Sets a <see cref="DiscreteInput"/> to the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="input">The <see cref="DiscreteInput"/> to set.</param>
+		public void SetDiscreteInput(DiscreteInput input)
+		{
+			using (_rwLockDiscreteInputs.GetWriteLock())
+			{
+				if (input.Value)
+					_discreteInputs.Add(input.Address);
+				else
+					_discreteInputs.Remove(input.Address);
+			}
+		}
+
+		/// <summary>
+		/// Gets a <see cref="HoldingRegister"/> from the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="address">The address of the <see cref="HoldingRegister"/>.</param>
+		public HoldingRegister GetHoldingRegister(ushort address)
+		{
+			Assertions();
+			using (_rwLockHoldingRegisters.GetReadLock())
+			{
+				if (!_holdingRegisters.TryGetValue(address, out ushort value))
+					value = 0x0000;
+
+				byte[] blob = BitConverter.GetBytes(value);
+				blob.SwapNetworkOrder();
+
+				return new HoldingRegister
+				{
+					Address = address,
+					HighByte = blob[0],
+					LowByte = blob[1]
+				};
+			}
+		}
+
+		/// <summary>
+		/// Sets a <see cref="HoldingRegister"/> to the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="register">The <see cref="HoldingRegister"/> to set.</param>
+		public void SetHoldingRegister(HoldingRegister register)
+		{
+			Assertions();
+			using (_rwLockHoldingRegisters.GetWriteLock())
+			{
+				if (register.Value == 0)
+				{
+					_holdingRegisters.Remove(register.Address);
+					return;
+				}
+
+				byte[] blob = [register.HighByte, register.LowByte];
+				blob.SwapNetworkOrder();
+				_holdingRegisters[register.Address] = BitConverter.ToUInt16(blob, 0);
+			}
+		}
+
+		/// <summary>
+		/// Gets a <see cref="InputRegister"/> from the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="address">The address of the <see cref="InputRegister"/>.</param>
+		public InputRegister GetInputRegister(ushort address)
+		{
+			Assertions();
+			using (_rwLockInputRegisters.GetReadLock())
+			{
+				if (!_inputRegisters.TryGetValue(address, out ushort value))
+					value = 0x0000;
+
+				byte[] blob = BitConverter.GetBytes(value);
+				blob.SwapNetworkOrder();
+
+				return new InputRegister
+				{
+					Address = address,
+					HighByte = blob[0],
+					LowByte = blob[1]
+				};
+			}
+		}
+
+		/// <summary>
+		/// Sets a <see cref="InputRegister"/> to the <see cref="ModbusDevice"/>.
+		/// </summary>
+		/// <param name="register">The <see cref="InputRegister"/> to set.</param>
+		public void SetInputRegister(InputRegister register)
+		{
+			Assertions();
+			using (_rwLockInputRegisters.GetWriteLock())
+			{
+				if (register.Value == 0)
+				{
+					_inputRegisters.Remove(register.Address);
+					return;
+				}
+
+				byte[] blob = [register.HighByte, register.LowByte];
+				blob.SwapNetworkOrder();
+				_inputRegisters[register.Address] = BitConverter.ToUInt16(blob, 0);
+			}
+		}
+
+		private void Assertions()
+		{
+#if NET8_0_OR_GREATER
+			ObjectDisposedException.ThrowIf(_isDisposed, this);
+#else
+			if (_isDisposed)
+				throw new ObjectDisposedException(GetType().FullName);
+#endif
+		}
+	}
+}

AMWD.Protocols.Modbus.Common/Protocols/TcpProtocol.cs

@@ -89,12 +89,12 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			request[7] = (byte)ModbusFunctionCode.ReadCoils;
 
 			// Starting address
-			byte[] addrBytes = ToNetworkBytes(startAddress);
+			byte[] addrBytes = startAddress.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
 			// Quantity
-			byte[] countBytes = ToNetworkBytes(count);
+			byte[] countBytes = count.ToNetworkBytes();
 			request[10] = countBytes[0];
 			request[11] = countBytes[1];
 
@@ -144,12 +144,12 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			request[7] = (byte)ModbusFunctionCode.ReadDiscreteInputs;
 
 			// Starting address
-			byte[] addrBytes = ToNetworkBytes(startAddress);
+			byte[] addrBytes = startAddress.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
 			// Quantity
-			byte[] countBytes = ToNetworkBytes(count);
+			byte[] countBytes = count.ToNetworkBytes();
 			request[10] = countBytes[0];
 			request[11] = countBytes[1];
 
@@ -199,12 +199,12 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			request[7] = (byte)ModbusFunctionCode.ReadHoldingRegisters;
 
 			// Starting address
-			byte[] addrBytes = ToNetworkBytes(startAddress);
+			byte[] addrBytes = startAddress.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
 			// Quantity
-			byte[] countBytes = ToNetworkBytes(count);
+			byte[] countBytes = count.ToNetworkBytes();
 			request[10] = countBytes[0];
 			request[11] = countBytes[1];
 
@@ -251,12 +251,12 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			request[7] = (byte)ModbusFunctionCode.ReadInputRegisters;
 
 			// Starting address
-			byte[] addrBytes = ToNetworkBytes(startAddress);
+			byte[] addrBytes = startAddress.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
 			// Quantity
-			byte[] countBytes = ToNetworkBytes(count);
+			byte[] countBytes = count.ToNetworkBytes();
 			request[10] = countBytes[0];
 			request[11] = countBytes[1];
 
@@ -362,7 +362,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			// Function code
 			request[7] = (byte)ModbusFunctionCode.WriteSingleCoil;
 
-			byte[] addrBytes = ToNetworkBytes(coil.Address);
+			byte[] addrBytes = coil.Address.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
@@ -377,7 +377,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 		{
 			return new Coil
 			{
-				Address = ToNetworkUInt16(response.Skip(8).Take(2).ToArray()),
+				Address = response.ToArray().NetworkUInt16(8),
 				HighByte = response[10],
 				LowByte = response[11]
 			};
@@ -401,7 +401,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			// Function code
 			request[7] = (byte)ModbusFunctionCode.WriteSingleRegister;
 
-			byte[] addrBytes = ToNetworkBytes(register.Address);
+			byte[] addrBytes = register.Address.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
@@ -416,7 +416,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 		{
 			return new HoldingRegister
 			{
-				Address = ToNetworkUInt16(response.Skip(8).Take(2).ToArray()),
+				Address = response.ToArray().NetworkUInt16(8),
 				HighByte = response[10],
 				LowByte = response[11]
 			};
@@ -454,11 +454,11 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 
 			request[7] = (byte)ModbusFunctionCode.WriteMultipleCoils;
 
-			byte[] addrBytes = ToNetworkBytes(firstAddress);
+			byte[] addrBytes = firstAddress.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
-			byte[] countBytes = ToNetworkBytes((ushort)orderedList.Count);
+			byte[] countBytes = ((ushort)orderedList.Count).ToNetworkBytes();
 			request[10] = countBytes[0];
 			request[11] = countBytes[1];
 
@@ -483,8 +483,8 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 		/// <inheritdoc/>
 		public (ushort FirstAddress, ushort NumberOfCoils) DeserializeWriteMultipleCoils(IReadOnlyList<byte> response)
 		{
-			ushort firstAddress = ToNetworkUInt16(response.Skip(8).Take(2).ToArray());
-			ushort numberOfCoils = ToNetworkUInt16(response.Skip(10).Take(2).ToArray());
+			ushort firstAddress = response.ToArray().NetworkUInt16(8);
+			ushort numberOfCoils = response.ToArray().NetworkUInt16(10);
 
 			return (firstAddress, numberOfCoils);
 		}
@@ -521,11 +521,11 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 
 			request[7] = (byte)ModbusFunctionCode.WriteMultipleRegisters;
 
-			byte[] addrBytes = ToNetworkBytes(firstAddress);
+			byte[] addrBytes = firstAddress.ToNetworkBytes();
 			request[8] = addrBytes[0];
 			request[9] = addrBytes[1];
 
-			byte[] countBytes = ToNetworkBytes((ushort)orderedList.Count);
+			byte[] countBytes = ((ushort)orderedList.Count).ToNetworkBytes();
 			request[10] = countBytes[0];
 			request[11] = countBytes[1];
 
@@ -544,8 +544,8 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 		/// <inheritdoc/>
 		public (ushort FirstAddress, ushort NumberOfRegisters) DeserializeWriteMultipleHoldingRegisters(IReadOnlyList<byte> response)
 		{
-			ushort firstAddress = ToNetworkUInt16(response.Skip(8).Take(2).ToArray());
-			ushort numberOfRegisters = ToNetworkUInt16(response.Skip(10).Take(2).ToArray());
+			ushort firstAddress = response.ToArray().NetworkUInt16(8);
+			ushort numberOfRegisters = response.ToArray().NetworkUInt16(10);
 
 			return (firstAddress, numberOfRegisters);
 		}
@@ -563,7 +563,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			if (responseBytes.Count < 6)
 				return false;
 
-			ushort followingBytes = ToNetworkUInt16(responseBytes.Skip(4).Take(2).ToArray());
+			ushort followingBytes = responseBytes.ToArray().NetworkUInt16(4);
 			if (responseBytes.Count < followingBytes + 6)
 				return false;
 
@@ -582,7 +582,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			if (request[2] != response[2] || request[3] != response[3])
 				throw new ModbusException("Protocol Identifier does not match.");
 
-			ushort count = ToNetworkUInt16(response.Skip(4).Take(2).ToArray());
+			ushort count = response.ToArray().NetworkUInt16(4);
 			if (count != response.Count - 6)
 				throw new ModbusException("Number of following bytes does not match.");
 
@@ -636,7 +636,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 
 			// Transaction id
 			ushort txId = GetNextTransacitonId();
-			byte[] txBytes = ToNetworkBytes(txId);
+			byte[] txBytes = txId.ToNetworkBytes();
 			header[0] = txBytes[0];
 			header[1] = txBytes[1];
 
@@ -645,7 +645,7 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			header[3] = 0x00;
 
 			// Number of following bytes
-			byte[] countBytes = ToNetworkBytes((ushort)followingBytes);
+			byte[] countBytes = ((ushort)followingBytes).ToNetworkBytes();
 			header[4] = countBytes[0];
 			header[5] = countBytes[1];
 
@@ -655,24 +655,6 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 			return header;
 		}
 
-		private static byte[] ToNetworkBytes(ushort value)
-		{
-			byte[] bytes = BitConverter.GetBytes(value);
-
-			if (BitConverter.IsLittleEndian)
-				Array.Reverse(bytes);
-
-			return bytes;
-		}
-
-		private static ushort ToNetworkUInt16(byte[] bytes)
-		{
-			if (BitConverter.IsLittleEndian)
-				Array.Reverse(bytes);
-
-			return BitConverter.ToUInt16(bytes, 0);
-		}
-
 		#endregion Private helpers
 	}
 }