Only copy necessary entries

Author: linkdotnet

CHANGELOG.md

@@ -6,6 +6,10 @@ All notable changes to **ValueStringBuilder** will be documented in this file. T
 
 ## [Unreleased]
 
+### Changed
+
+- When growing only copy written content to the new buffer and safe some bytes
+
 ## [1.10.4] - 2022-12-27
 
 ### Fixed

src/LinkDotNet.StringBuilder/TypedSpanList.cs

@@ -46,7 +46,7 @@ private void Grow(int capacity = 0)
         var currentSize = buffer.Length;
         var newSize = capacity > 0 ? capacity : currentSize * 2;
         var rented = GC.AllocateUninitializedArray<T>(newSize);
-        buffer.CopyTo(rented);
+        buffer[..count].CopyTo(rented);
         buffer = rented;
     }
 }

src/LinkDotNet.StringBuilder/ValueStringBuilder.cs

@@ -294,7 +294,7 @@ private void Grow(int capacity = 0)
 
         var newSize = capacity > currentSize ? capacity : currentSize * 2;
         var rented = ArrayPool<char>.Shared.Rent(newSize);
-        buffer.CopyTo(rented);
+        buffer[..bufferPosition].CopyTo(rented);
         var oldBufferFromPool = arrayFromPool;
         buffer = arrayFromPool = rented;