Merge pull request #199 from SceneGate/feature/189-compare-itself

🐛  Comparing stream to itself returns false

src/Yarhl.UnitTests/IO/DataStreamTests.cs

@@ -1606,6 +1606,18 @@ public void WriteSegmentToGuards()
                 Throws.InstanceOf<ObjectDisposedException>());
         }
 
+        [Test]
+        public void CompareSameStreams()
+        {
+            using var stream1 = new DataStream();
+            stream1.WriteByte(0xCA);
+            stream1.WriteByte(0xFE);
+            stream1.WriteByte(0x00);
+            stream1.WriteByte(0xFF);
+            DataStream stream2 = stream1;
+            Assert.IsTrue(stream1.Compare(stream2));
+        }
+
         [Test]
         public void CompareTwoEqualStreams()
         {

src/Yarhl/IO/DataStream.cs

@@ -674,13 +674,19 @@ public void WriteSegmentTo(long start, long length, Stream stream)
         /// <param name="otherStream">Stream to compare with.</param>
         public bool Compare(Stream otherStream)
         {
-            if (otherStream == null)
+            if (otherStream == null) {
                 throw new ArgumentNullException(nameof(otherStream));
+            }
 
             // We can't check if the other stream is disposed because Stream
             // doesn't provide the property, so we delay it to the Seek method.
-            if (Disposed)
+            if (Disposed) {
                 throw new ObjectDisposedException(nameof(DataStream));
+            }
+
+            if (this == otherStream) {
+                return true;
+            }
 
             long startPosition = Position;
             long otherStreamStartPosition = otherStream.Position;