Merge pull request #391 from mycroes/set-bit-clear-bit

SetBit and ClearBit tests, fixes

S7.Net.UnitTest/TypeTests/BooleanTests.cs

@@ -0,0 +1,38 @@
+using System;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Boolean = S7.Net.Types.Boolean;
+
+namespace S7.Net.UnitTest.TypeTests
+{
+    [TestClass]
+    public class BooleanTests
+    {
+        [DataTestMethod]
+        [DataRow(0)]
+        [DataRow(1)]
+        [DataRow(2)]
+        [DataRow(3)]
+        [DataRow(4)]
+        [DataRow(5)]
+        [DataRow(6)]
+        [DataRow(7)]
+        public void TestValidSetBitValues(int index)
+        {
+            Assert.AreEqual(Math.Pow(2, index), Boolean.SetBit(0, index));
+        }
+
+        [DataTestMethod]
+        [DataRow(0)]
+        [DataRow(1)]
+        [DataRow(2)]
+        [DataRow(3)]
+        [DataRow(4)]
+        [DataRow(5)]
+        [DataRow(6)]
+        [DataRow(7)]
+        public void TestValidClearBitValues(int index)
+        {
+            Assert.AreEqual((byte) ((uint) Math.Pow(2, index) ^ uint.MaxValue), Boolean.ClearBit(byte.MaxValue, index));
+        }
+    }
+}

S7.Net/PLC.cs

@@ -14,7 +14,7 @@ namespace S7.Net
     public partial class Plc : IDisposable
     {
         private const int CONNECTION_TIMED_OUT_ERROR_CODE = 10060;
-        
+
         //TCP connection to device
         private TcpClient? tcpClient;
         private NetworkStream? _stream;

S7.Net/PLCHelpers.cs

@@ -30,8 +30,8 @@ namespace S7.Net
         }
 
         /// <summary>
-        /// Create the bytes-package to request data from the PLC. You have to specify the memory type (dataType), 
-        /// the address of the memory, the address of the byte and the bytes count. 
+        /// Create the bytes-package to request data from the PLC. You have to specify the memory type (dataType),
+        /// the address of the memory, the address of the byte and the bytes count.
         /// </summary>
         /// <param name="dataType">MemoryType (DB, Timer, Counter, etc.)</param>
         /// <param name="db">Address of the memory to be read</param>

S7.Net/Types/Boolean.cs

@@ -14,20 +14,51 @@
         }
 
         /// <summary>
-        /// Sets the value of a bit to 1 (true), given the address of the bit
+        /// Sets the value of a bit to 1 (true), given the address of the bit. Returns
+        /// a copy of the value with the bit set.
         /// </summary>
+        /// <param name="value">The input value to modify.</param>
+        /// <param name="bit">The index (zero based) of the bit to set.</param>
+        /// <returns>The modified value with the bit at index set.</returns>
         public static byte SetBit(byte value, int bit)
         {
-            return (byte)((value | (1 << bit)) & 0xFF);
+            SetBit(ref value, bit);
+
+            return value;
+        }
+
+        /// <summary>
+        /// Sets the value of a bit to 1 (true), given the address of the bit.
+        /// </summary>
+        /// <param name="value">The value to modify.</param>
+        /// <param name="bit">The index (zero based) of the bit to set.</param>
+        public static void SetBit(ref byte value, int bit)
+        {
+            value = (byte) ((value | (1 << bit)) & 0xFF);
+        }
+
+        /// <summary>
+        /// Resets the value of a bit to 0 (false), given the address of the bit. Returns
+        /// a copy of the value with the bit cleared.
+        /// </summary>
+        /// <param name="value">The input value to modify.</param>
+        /// <param name="bit">The index (zero based) of the bit to clear.</param>
+        /// <returns>The modified value with the bit at index cleared.</returns>
+        public static byte ClearBit(byte value, int bit)
+        {
+            ClearBit(ref value, bit);
+
+            return value;
         }
 
         /// <summary>
         /// Resets the value of a bit to 0 (false), given the address of the bit
         /// </summary>
-        public static byte ClearBit(byte value, int bit)
+        /// <param name="value">The input value to modify.</param>
+        /// <param name="bit">The index (zero based) of the bit to clear.</param>
+        public static void ClearBit(ref byte value, int bit)
         {
-            return (byte)((value | (~(1 << bit))) & 0xFF);
+            value = (byte) (value & ~(1 << bit) & 0xFF);
         }
-
     }
 }