Add more conversion methos for application message payloads

Source/MQTTnet/MqttApplicationMessageExtensions.cs

@@ -5,13 +5,78 @@
 using System;
 using System.Text;
 
+// ReSharper disable MemberCanBePrivate.Global
+
 namespace MQTTnet
 {
     public static class MqttApplicationMessageExtensions
     {
+        public static short ConvertPayloadToByte(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            if (applicationMessage.Payload.Length != 1)
+            {
+                throw new ArgumentException("Payload requires to be 1 bytes long.");
+            }
+
+            return applicationMessage.Payload[0];
+        }
+
+        public static short ConvertPayloadToInt16(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            if (applicationMessage.Payload.Length != 2)
+            {
+                throw new ArgumentException("Payload requires to be 2 bytes long.");
+            }
+
+            return BitConverter.ToInt16(applicationMessage.Payload, 0);
+        }
+
+        public static int ConvertPayloadToInt32(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            if (applicationMessage.Payload?.Length != 4)
+            {
+                throw new ArgumentException("Payload requires to be 4 bytes long.");
+            }
+
+            return BitConverter.ToInt32(applicationMessage.Payload, 0);
+        }
+
+        public static long ConvertPayloadToInt64(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            if (applicationMessage.Payload.Length != 8)
+            {
+                throw new ArgumentException("Payload requires to be 8 bytes long.");
+            }
+
+            return BitConverter.ToInt64(applicationMessage.Payload, 0);
+        }
+
         public static string ConvertPayloadToString(this MqttApplicationMessage applicationMessage)
         {
-            if (applicationMessage == null) throw new ArgumentNullException(nameof(applicationMessage));
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
 
             if (applicationMessage.Payload == null)
             {
@@ -25,5 +90,65 @@ namespace MQTTnet
 
             return Encoding.UTF8.GetString(applicationMessage.Payload, 0, applicationMessage.Payload.Length);
         }
+
+        public static decimal ParsePayloadToDecimal(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return decimal.Parse(ConvertPayloadToString(applicationMessage));
+        }
+
+        public static double ParsePayloadToDouble(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return double.Parse(ConvertPayloadToString(applicationMessage));
+        }
+
+        public static short ParsePayloadToInt16(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return short.Parse(ConvertPayloadToString(applicationMessage));
+        }
+
+        public static int ParsePayloadToInt32(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return int.Parse(ConvertPayloadToString(applicationMessage));
+        }
+
+        public static long ParsePayloadToInt64(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return long.Parse(ConvertPayloadToString(applicationMessage));
+        }
+
+        public static float ParsePayloadToSingle(this MqttApplicationMessage applicationMessage)
+        {
+            if (applicationMessage == null)
+            {
+                throw new ArgumentNullException(nameof(applicationMessage));
+            }
+
+            return float.Parse(ConvertPayloadToString(applicationMessage));
+        }
     }
-}
+}