From baef1afac1c88a85d17a2468e164f22bd5185ab3 Mon Sep 17 00:00:00 2001
From: Peter Butzhammer <peter.butzhammer@evopro-ag.de>
Date: Tue, 6 Feb 2024 17:47:00 +0100
Subject: [PATCH] Use BinaryPrimitives

---
 Sharp7.Rx/S7ValueConverter.cs | 40 ++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/Sharp7.Rx/S7ValueConverter.cs b/Sharp7.Rx/S7ValueConverter.cs
index 9533809..04d8965 100644
--- a/Sharp7.Rx/S7ValueConverter.cs
+++ b/Sharp7.Rx/S7ValueConverter.cs
@@ -1,5 +1,6 @@
 using System;
-using System.Linq;
+using System.Buffers.Binary;
+using System.Runtime.InteropServices;
 using System.Text;
 using Sharp7.Rx.Enums;
 
@@ -10,18 +11,15 @@ namespace Sharp7.Rx
         public static TValue ConvertToType<TValue>(byte[] buffer, S7VariableAddress address)
         {
             if (typeof(TValue) == typeof(bool))
-            {
-                return (TValue) (object) Convert.ToBoolean(buffer[0] & (1 << address.Bit));
-            }
+                return (TValue) (object) (((buffer[0] >> address.Bit) & 1) > 0);
 
             if (typeof(TValue) == typeof(int))
             {
                 if (address.Length == 2)
-                    return (TValue)(object)((buffer[0] << 8) + buffer[1]);
+                    return (TValue) (object) BinaryPrimitives.ReadInt16BigEndian(buffer);
                 if (address.Length == 4)
                 {
-                    Array.Reverse(buffer);
-                    return (TValue)(object)BitConverter.ToInt32(buffer,0);
+                    return (TValue) (object) BinaryPrimitives.ReadInt32BigEndian(buffer);
                 }
 
                 throw new InvalidOperationException($"length must be 2 or 4 but is {address.Length}");
@@ -29,35 +27,36 @@ namespace Sharp7.Rx
 
             if (typeof(TValue) == typeof(long))
             {
-                Array.Reverse(buffer);
-                return (TValue)(object)BitConverter.ToInt64(buffer,0);
+                return (TValue) (object) BinaryPrimitives.ReadInt64BigEndian(buffer);
             }
 
             if (typeof(TValue) == typeof(ulong))
             {
-                Array.Reverse(buffer);
-                return (TValue)(object)BitConverter.ToUInt64(buffer, 0);
+                return (TValue) (object) BinaryPrimitives.ReadUInt64BigEndian(buffer);
             }
 
             if (typeof(TValue) == typeof(short))
             {
-                return (TValue)(object)(short)((buffer[0] << 8) + buffer[1]);
+                return (TValue) (object) BinaryPrimitives.ReadInt16BigEndian(buffer);
             }
 
             if (typeof(TValue) == typeof(byte) || typeof(TValue) == typeof(char))
             {
-                return (TValue)(object)buffer[0];
+                return (TValue) (object) buffer[0];
             }
 
             if (typeof(TValue) == typeof(byte[]))
             {
-                return (TValue)(object)buffer;
+                return (TValue) (object) buffer;
             }
 
             if (typeof(TValue) == typeof(double) || typeof(TValue) == typeof(float))
             {
-                var d = BitConverter.ToSingle(buffer.Reverse().ToArray(),0);
-                return (TValue)(object)d;
+                var d = new UInt32SingleMap
+                {
+                    UInt32 = BinaryPrimitives.ReadUInt32BigEndian(buffer)
+                };
+                return (TValue) (object) d.Single;
             }
 
             if (typeof(TValue) == typeof(string))
@@ -68,7 +67,7 @@ namespace Sharp7.Rx
                     // https://cache.industry.siemens.com/dl/files/480/22506480/att_105176/v1/s7_scl_string_parameterzuweisung_e.pdf
 
                     var length = Math.Min(address.Length, buffer[1]);
-                    
+
                     return (TValue) (object) Encoding.ASCII.GetString(buffer, 2, length);
                 }
                 else
@@ -78,5 +77,12 @@ namespace Sharp7.Rx
 
             throw new InvalidOperationException(string.Format("type '{0}' not supported.", typeof(TValue)));
         }
+
+        [StructLayout(LayoutKind.Explicit)]
+        private struct UInt32SingleMap
+        {
+            [FieldOffset(0)] public uint UInt32;
+            [FieldOffset(0)] public float Single;
+        }
     }
 }
\ No newline at end of file