Fixed size calculation issues when reading and writing arrays

S7.Net.UnitTest/Helpers/TestClassUnevenSize.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace S7.Net.UnitTest.Helpers
+{
+    public class TestClassUnevenSize
+    {
+        public bool Bool { get; set; }
+        public byte[] Bytes { get; set; }
+        public bool[] Bools { get; set; }
+
+        public TestClassUnevenSize(int byteCount, int bitCount)
+        {
+            Bytes = new byte[byteCount];
+            Bools = new bool[bitCount];
+        }
+    }
+}

S7.Net.UnitTest/S7.Net.UnitTest.csproj

@@ -62,6 +62,7 @@
   <ItemGroup>
     <Compile Include="ConnectionRequestTest.cs" />
     <Compile Include="ConvertersUnitTest.cs" />
+    <Compile Include="Helpers\TestClassUnevenSize.cs" />
     <Compile Include="Helpers\TestClassWithNestedClass.cs" />
     <Compile Include="ProtocolTests.cs" />
     <Compile Include="Helpers\ConsoleManager.cs" />
@@ -79,6 +80,7 @@
     <Compile Include="S7NetTestsSync.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Helpers\TestLongStruct.cs" />
+    <Compile Include="TypeTests\ClassTests.cs" />
     <Compile Include="TypeTests\StringExTests.cs" />
     <Compile Include="TypeTests\StringTests.cs" />
   </ItemGroup>

S7.Net.UnitTest/TypeTests/ClassTests.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using S7.Net.Types;
+using S7.Net.UnitTest.Helpers;
+
+namespace S7.Net.UnitTest.TypeTests
+{
+    [TestClass]
+    public class ClassTests
+    {
+        [TestMethod]
+        public void GetClassSizeTest()
+        {
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(1, 1)), 6);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(2, 15)), 6);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(2, 16)), 6);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(2, 17)), 8);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(3, 15)), 8);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(3, 17)), 10);
+        }
+    }
+}

S7.Net/Types/Class.cs

@@ -85,6 +85,8 @@ public static double GetClassSize(object instance, double numBytes = 0.0, bool i
                         throw new Exception("Cannot determine size of class, because an array is defined which has no fixed size greater than zero.");
                     }
 
+                    // Array starts at even byte adress
+                    numBytes = IncreaseToEvenNumber(numBytes);
                     for (int i = 0; i < array.Length; i++)
                     {
                         numBytes = GetIncreasedNumberOfBytes(numBytes, elementType);
@@ -95,14 +97,9 @@ public static double GetClassSize(object instance, double numBytes = 0.0, bool i
                     numBytes = GetIncreasedNumberOfBytes(numBytes, property.PropertyType);
                 }
             }
-            if (false == isInnerProperty)
-            {
-                // enlarge numBytes to next even number because S7-Structs in a DB always will be resized to an even byte count
-                numBytes = Math.Ceiling(numBytes);
-                if ((numBytes / 2 - Math.Floor(numBytes / 2.0)) > 0)
-                    numBytes++;
-            }
-            return numBytes;
+            // enlarge numBytes to next even number because S7-Structs in a DB always will be resized to an even byte count
+            numBytes = IncreaseToEvenNumber(numBytes);
+            return (int)numBytes;
         }
 
         private static object GetPropertyValue(Type propertyType, byte[] bytes, ref double numBytes)
@@ -219,6 +216,7 @@ public static double FromBytes(object sourceClass, byte[] bytes, double numBytes
                 if (property.PropertyType.IsArray)
                 {
                     Array array = (Array)property.GetValue(sourceClass, null);
+                    numBytes = IncreaseToEvenNumber(numBytes);
                     Type elementType = property.PropertyType.GetElementType();
                     for (int i = 0; i < array.Length && numBytes < bytes.Length; i++)
                     {
@@ -313,6 +311,7 @@ public static double ToBytes(object sourceClass, byte[] bytes, double numBytes =
             {
                 if (property.PropertyType.IsArray)
                 {
+                    numBytes = IncreaseToEvenNumber(numBytes);
                     Array array = (Array)property.GetValue(sourceClass, null);
                     Type elementType = property.PropertyType.GetElementType();
                     for (int i = 0; i < array.Length && numBytes < bytes.Length; i++)
@@ -327,5 +326,13 @@ public static double ToBytes(object sourceClass, byte[] bytes, double numBytes =
             }
             return numBytes;
         }
+
+        private static double IncreaseToEvenNumber(double numBytes)
+        {
+            var numBytesInt = (int)Math.Ceiling(numBytes);
+            if (numBytesInt % 2 > 0)
+                numBytesInt++;
+            return numBytesInt;
+        }
     }
 }