Imported Upstream version 4.8.0.309

Former-commit-id: 5f9c6ae75f295e057a7d2971f3a6df4656fa8850

external/cecil-legacy/Mono.Cecil.PE/ByteBufferEqualityComparer.cs

@@ -0,0 +1,78 @@
+//
+// ByteBufferEqualityComparer.cs
+//
+// Author:
+//   Jb Evain (jbevain@gmail.com)
+//
+// Copyright (c) 2008 - 2011 Jb Evain
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+
+namespace Mono.Cecil.PE {
+
+	sealed class ByteBufferEqualityComparer : IEqualityComparer<ByteBuffer> {
+
+		public bool Equals (ByteBuffer x, ByteBuffer y)
+		{
+			if (x.length != y.length)
+				return false;
+
+			var x_buffer = x.buffer;
+			var y_buffer = y.buffer;
+
+			for (int i = 0; i < x.length; i++)
+				if (x_buffer [i] != y_buffer [i])
+					return false;
+
+			return true;
+		}
+
+		public int GetHashCode (ByteBuffer buffer)
+		{
+#if !BYTE_BUFFER_WELL_DISTRIBUTED_HASH
+			var hash = 0;
+			var bytes = buffer.buffer;
+			for (int i = 0; i < buffer.length; i++)
+				hash = (hash * 37) ^ bytes [i];
+
+			return hash;
+#else
+			const uint p = 16777619;
+			uint hash = 2166136261;
+
+			var bytes = buffer.buffer;
+			for (int i = 0; i < buffer.length; i++)
+			    hash = (hash ^ bytes [i]) * p;
+
+			hash += hash << 13;
+			hash ^= hash >> 7;
+			hash += hash << 3;
+			hash ^= hash >> 17;
+			hash += hash << 5;
+
+			return (int) hash;
+#endif
+		}
+	}
+}