Fix IBufferWriterExtensions Write for unmanaged types

CommunityToolkit · Aug 20, 2024 · 8de7190 · 8de7190
1 parent b7ad78e
commit 8de7190
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Showing 2 changed files with 21 additions and 4 deletions.
diff --git a/src/CommunityToolkit.HighPerformance/Extensions/IBufferWriterExtensions.cs b/src/CommunityToolkit.HighPerformance/Extensions/IBufferWriterExtensions.cs
@@ -48,10 +48,9 @@ public static Stream AsStream(this IBufferWriter<byte> writer)
  public static unsafe void Write<T>(this IBufferWriter<byte> writer, T value)
  where T : unmanaged
  {
- int length = sizeof(T);
- Span<byte> span = writer.GetSpan(1);
+ Span<byte> span = writer.GetSpan(sizeof(T));
 
- if (span.Length < length)
+ if (span.Length < sizeof(T))
  {
  ThrowArgumentExceptionForEndOfBuffer();
  }
@@ -60,7 +59,7 @@ public static unsafe void Write<T>(this IBufferWriter<byte> writer, T value)
 
  Unsafe.WriteUnaligned(ref r0, value);
 
- writer.Advance(length);
+ writer.Advance(sizeof(T));
  }
 
  /// <summary>

diff --git a/tests/CommunityToolkit.HighPerformance.UnitTests/Extensions/Test_IBufferWriterExtensions.cs b/tests/CommunityToolkit.HighPerformance.UnitTests/Extensions/Test_IBufferWriterExtensions.cs
@@ -118,4 +118,22 @@ public void Test_IBufferWriterExtensions_WriteReadOverItems_ReadOnlySpan()
 
  Assert.IsTrue(span.SequenceEqual(buffer.AsSpan()));
  }
+
+ // See https://github.com/CommunityToolkit/dotnet/issues/798
+ [TestMethod]
+ public void Test_IBufferWriterExtensions_WriteExceedingFreeCapacity()
+ {
+ ArrayPoolBufferWriter<byte> writer = new();
+
+ // Leave only one byte of free capacity
+ int count = writer.Capacity - 1;
+
+ for (int i = 0; i < count; i++)
+ {
+ writer.Write<byte>(0);
+ }
+
+ // Write 4 bytes
+ writer.Write(1);
+ }
 }