Implement buffer copy using different policies (#1599)

use Memory-Copy

Co-authored-by: Christian <6939810+chkr1011@users.noreply.github.com>

Source/MQTTnet.Benchmarks/MQTTnet.Benchmarks.csproj

@@ -1,6 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
         <OutputType>Exe</OutputType>
         <DebugType>Full</DebugType>
         <TargetFrameworks>net6.0</TargetFrameworks>

Source/MQTTnet.Benchmarks/MemoryCopyBenchmark.cs

@@ -0,0 +1,40 @@
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Jobs;
+using System;
+
+
+namespace MQTTnet.Benchmarks
+{
+    [SimpleJob(RuntimeMoniker.Net60)]
+    [RPlotExporter, RankColumn]
+    [MemoryDiagnoser]
+    public class MemoryCopyBenchmark
+    {
+        const int max_length = 1024 * 8;
+        private byte[] source;
+        private byte[] target;
+
+        [Params(64 - 1, 128 - 1, 256 - 1, 512 - 1, 1024 - 1, 2048 - 1, 5096 - 1)]
+        public int Length { get; set; }
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            source = new byte[max_length];
+            target = new byte[max_length];
+        }
+
+        [Benchmark(Baseline = true)]
+        public void Array_Copy()
+        {
+            Array.Copy(source, 0, target, 0, Length);
+        }
+
+        [Benchmark]
+        public void Memory_Copy()
+        {
+            MQTTnet.Internal.Memory.Copy(source, 0, target, 0, Length);
+        }
+
+    }
+}

Source/MQTTnet/Formatter/MqttBufferReader.cs

@@ -36,7 +36,7 @@ namespace MQTTnet.Formatter
             ValidateReceiveBuffer(length);
 
             var result = new byte[length];
-            Array.Copy(_buffer, _position, result, 0, length);
+            Memory.Copy(_buffer, _position, result, 0, length);
             _position += length;
 
             return result;
@@ -80,8 +80,7 @@ namespace MQTTnet.Formatter
             }
 
             var buffer = new byte[bufferLength];
-            Array.Copy(_buffer, _position, buffer, 0, bufferLength);
+            Memory.Copy(_buffer, _position, buffer, 0, bufferLength);
-
             _position += bufferLength;
 
             return buffer;

Source/MQTTnet/Formatter/MqttBufferWriter.cs

@@ -6,6 +6,7 @@ using System;
 using System.Runtime.CompilerServices;
 using System.Text;
 using MQTTnet.Exceptions;
+using MQTTnet.Internal;
 using MQTTnet.Protocol;
 
 namespace MQTTnet.Formatter
@@ -125,7 +126,7 @@ namespace MQTTnet.Formatter
 
             EnsureAdditionalCapacity(count);
 
-            Array.Copy(buffer, offset, _buffer, _position, count);
+            Memory.Copy(buffer, offset, _buffer, _position, count);
             IncreasePosition(count);
         }
 
@@ -149,7 +150,7 @@ namespace MQTTnet.Formatter
                 _buffer[_position] = (byte)(valueLength >> 8);
                 _buffer[_position + 1] = (byte)valueLength;
 
-                Array.Copy(value, 0, _buffer, _position + 2, valueLength);
+                Memory.Copy(value, 0, _buffer, _position + 2, valueLength);
                 IncreasePosition(valueLength + 2);
             }
         }

Source/MQTTnet/Formatter/MqttPacketBuffer.cs

@@ -43,8 +43,8 @@ namespace MQTTnet.Formatter
             }
 
             var buffer = new byte[Length];
-            Array.Copy(Packet.Array, Packet.Offset, buffer, 0, Packet.Count);
+            Memory.Copy(Packet.Array, Packet.Offset, buffer, 0, Packet.Count);
-            Array.Copy(Payload.Array, Payload.Offset, buffer, Packet.Count, Payload.Count);
+            Memory.Copy(Payload.Array, Payload.Offset, buffer, Packet.Count, Payload.Count);
 
             return buffer;
         }
@@ -57,8 +57,8 @@ namespace MQTTnet.Formatter
             }
 
             var buffer = new byte[Length];
-            Array.Copy(Packet.Array, Packet.Offset, buffer, 0, Packet.Count);
+            Memory.Copy(Packet.Array, Packet.Offset, buffer, 0, Packet.Count);
-            Array.Copy(Payload.Array, Payload.Offset, buffer, Packet.Count, Payload.Count);
+            Memory.Copy(Payload.Array, Payload.Offset, buffer, Packet.Count, Payload.Count);
 
             return new ArraySegment<byte>(buffer);
         }

Source/MQTTnet/Internal/Memory.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Runtime.CompilerServices;
+
+namespace MQTTnet.Internal
+{
+    public static class Memory
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void Copy(byte[] source, int sourceIndex, byte[] destination, int destinationIndex, int length)
+        {
+#if NETCOREAPP3_1_OR_GREATER || NETSTANDARD2_1
+            source.AsSpan(sourceIndex, length).CopyTo(destination.AsSpan(destinationIndex, length));
+#elif NET461_OR_GREATER || NETSTANDARD1_3_OR_GREATER
+            unsafe
+            {
+                fixed (byte* pSoure = &source[sourceIndex])
+                {
+                    fixed (byte* pDestination = &destination[destinationIndex])
+                    {
+                        System.Buffer.MemoryCopy(pSoure, pDestination, length, length);
+                    }
+                }
+            }
+#else
+            Array.Copy(source, sourceIndex, destination, destinationIndex, length);
+#endif
+        }
+    }
+}

Source/MQTTnet/MQTTnet.csproj

@@ -42,6 +42,7 @@
         <PackageLicenseExpression>MIT</PackageLicenseExpression>
         <DisableImplicitAspNetCoreAnalyzers>true</DisableImplicitAspNetCoreAnalyzers>
         <NoWarn>1591</NoWarn>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     </PropertyGroup>
 
     <PropertyGroup Condition="'$(TargetFramework)'=='uap10.0'">