Use BlockCopy

Author: linkdotnet

CHANGELOG.md

@@ -6,6 +6,10 @@ All notable changes to **ValueStringBuilder** will be documented in this file. T
 
 ## [Unreleased]
 
+### Changed
+
+- Optimized `Append(scoped ReadOnlySpan<char>)` to be roughly 5% faster.
+
 ## [1.18.3] - 2023-09-22
 
 ### Changed

src/LinkDotNet.StringBuilder/ValueStringBuilder.Append.cs

@@ -1,4 +1,5 @@
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace LinkDotNet.StringBuilder;
 
@@ -51,7 +52,13 @@ public void Append(scoped ReadOnlySpan<char> str)
             Grow(newSize);
         }
 
-        str.CopyTo(buffer[bufferPosition..]);
+        ref var strRef = ref MemoryMarshal.GetReference(str);
+        ref var bufferRef = ref MemoryMarshal.GetReference(buffer[bufferPosition..]);
+        Unsafe.CopyBlock(
+            ref Unsafe.As<char, byte>(ref bufferRef),
+            ref Unsafe.As<char, byte>(ref strRef),
+            (uint)(str.Length * sizeof(char)));
+
         bufferPosition += str.Length;
     }