Merge pull request #501 from Himmelt/add_set_bit

Add SetBit method to modify one bit of a byte
S7NetPlus · Aug 18, 2023 · 22451bc · 22451bc
2 parents a8ef47b + e98ce00
commit 22451bc
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Showing 2 changed files with 62 additions and 6 deletions.
diff --git a/S7.Net.UnitTest/ConvertersUnitTest.cs b/S7.Net.UnitTest/ConvertersUnitTest.cs
@@ -24,5 +24,21 @@ public void T00_TestSelectBit()
             Assert.IsFalse(dummyByte.SelectBit(7));
 
         }
+
+        [TestMethod]
+        public void T01_TestSetBit()
+        {
+            byte dummyByte = 0xAA; // 1010 1010
+            dummyByte.SetBit(0, true);
+            dummyByte.SetBit(1, false);
+            dummyByte.SetBit(2, true);
+            dummyByte.SetBit(3, false);
+            Assert.AreEqual<byte>(dummyByte, 0xA5);// 1010 0101
+            dummyByte.SetBit(4, true);
+            dummyByte.SetBit(5, true);
+            dummyByte.SetBit(6, true);
+            dummyByte.SetBit(7, true);
+            Assert.AreEqual<byte>(dummyByte, 0xF5);// 1111 0101
+        }
     }
 }
diff --git a/S7.Net/Conversion.cs b/S7.Net/Conversion.cs
@@ -138,19 +138,59 @@ public static string ValToBinString(this object value)
 
         /// <summary>
         /// Helper to get a bit value given a byte and the bit index.
-        /// Example: DB1.DBX0.5 -> var bytes = ReadBytes(DB1.DBW0); bool bit = bytes[0].SelectBit(5); 
+        /// <br/>
+        /// <example>
+        ///   Get the bit at DB1.DBX0.5:
+        ///   <code>
+        ///     byte data = ReadByte("DB1.DBB0");
+        ///     bool bit = data.SelectBit(5);
+        ///   </code>
+        /// </example>
         /// </summary>
-        /// <param name="data"></param>
-        /// <param name="bitPosition"></param>
-        /// <returns></returns>
-        public static bool SelectBit(this byte data, int bitPosition)
+        /// <param name="data">The data to get from.</param>
+        /// <param name="index">The zero-based index of the bit to get.</param>
+        /// <returns>The Boolean value will get.</returns>
+        public static bool SelectBit(this byte data, int index)
         {
-            int mask = 1 << bitPosition;
+            int mask = 1 << index;
             int result = data & mask;
 
             return (result != 0);
         }
 
+        /// <summary>
+        /// Helper to set a bit value to the given byte at the bit index.
+        /// <br/>
+        /// <example>
+        ///   Set the bit at index 4:
+        ///   <code>
+        ///     byte data = 0;
+        ///     data.SetBit(4, true);
+        ///   </code>
+        /// </example>
+        /// </summary>
+        /// <param name="data">The data to be modified.</param>
+        /// <param name="index">The zero-based index of the bit to set.</param>
+        /// <param name="value">The Boolean value to assign to the bit.</param>
+        public static void SetBit(this ref byte data, int index, bool value)
+        {
+            if ((uint)index > 7)
+            {
+                return;
+            }
+
+            if (value)
+            {
+                byte mask = (byte)(1 << index);
+                data |= mask;
+            }
+            else
+            {
+                byte mask = (byte)~(1 << index);
+                data &= mask;
+            }
+        }
+
         /// <summary>
         /// Converts from ushort value to short value; it's used to retrieve negative values from words
         /// </summary>