Merge pull request #435 from ismdiego/develop

Allow changing the default Encoding used in S7String

S7.Net/Types/S7String.cs

@@ -8,7 +8,19 @@ namespace S7.Net.Types
     /// An S7 String has a preceeding 2 byte header containing its capacity and length
     /// </summary>
     public static class S7String
-    {
+    {
+        private static Encoding stringEncoding = Encoding.ASCII;
+
+        /// <summary>
+        /// The Encoding used when serializing and deserializing S7String (Encoding.ASCII by default)
+        /// </summary>
+        /// <exception cref="ArgumentNullException">StringEncoding must not be null</exception>
+        public static Encoding StringEncoding
+        {
+            get => stringEncoding;
+            set => stringEncoding = value ?? throw new ArgumentNullException(nameof(StringEncoding));
+        }
+
         /// <summary>
         /// Converts S7 bytes to a string
         /// </summary>
@@ -30,15 +42,14 @@ public static string FromByteArray(byte[] bytes)
 
             try
             {
-                return Encoding.ASCII.GetString(bytes, 2, length);
+                return StringEncoding.GetString(bytes, 2, length);
             }
             catch (Exception e)
             {
                 throw new PlcException(ErrorCode.ReadData,
                     $"Failed to parse {VarType.S7String} from data. Following fields were read: size: '{size}', actual length: '{length}', total number of bytes (including header): '{bytes.Length}'.",
                     e);
             }
-
         }
 
         /// <summary>
@@ -56,7 +67,7 @@ public static byte[] ToByteArray(string value, int reservedLength)
 
             if (reservedLength > 254) throw new ArgumentException($"The maximum string length supported is 254.");
 
-            var bytes = Encoding.ASCII.GetBytes(value);
+            var bytes = StringEncoding.GetBytes(value);
             if (bytes.Length > reservedLength) throw new ArgumentException($"The provided string length ({bytes.Length} is larger than the specified reserved length ({reservedLength}).");
 
             var buffer = new byte[2 + reservedLength];