Added unit test that can be used to reproduce the issue reported in #…

…1387.
dlemstra · May 15, 2023 · 8613068 · 8613068
1 parent 7d84716
commit 8613068
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diff --git a/src/Magick.NET/Helpers/ByteArrayWrapper.cs b/src/Magick.NET/Helpers/ByteArrayWrapper.cs
@@ -10,7 +10,7 @@ namespace ImageMagick;
 
 internal sealed unsafe class ByteArrayWrapper : IDisposable
 {
-    private const int BufferSize = 81920;
+    internal const int BufferSize = 81920;
 
     private readonly byte[] _buffer;
     private readonly byte* _bufferStart;

diff --git a/tests/Magick.NET.Tests/Helpers/ByteArrayWrapperTests/TheWriteMethod.cs b/tests/Magick.NET.Tests/Helpers/ByteArrayWrapperTests/TheWriteMethod.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.IO;
+using System.Linq;
 using ImageMagick;
 using Xunit;
 
@@ -53,5 +54,23 @@ public unsafe void ShouldReturnTheNumberOfBytesThatCouldBeWritten()
                 Assert.Equal(19, wrapper.GetBytes().Length);
             }
         }
+
+        [Fact]
+        public unsafe void ShouldCalculateRemainingBytesInBytesCorrectly()
+        {
+            using var wrapper = new ByteArrayWrapper();
+            wrapper.Seek(ByteArrayWrapper.BufferSize + 2, (IntPtr)SeekOrigin.Begin, IntPtr.Zero);
+            wrapper.Seek(ByteArrayWrapper.BufferSize + 1, (IntPtr)SeekOrigin.Begin, IntPtr.Zero);
+
+            var buffer = new byte[5] { 1, 2, 3, 4, 5 };
+            fixed (byte* p = buffer)
+            {
+                var count = wrapper.Write((IntPtr)p, (UIntPtr)buffer.Length, IntPtr.Zero);
+                Assert.Equal(5, count);
+
+                var bytes = wrapper.GetBytes().Reverse().Take(5).Reverse();
+                Assert.Equal(buffer, bytes);
+            }
+        }
     }
 }