Lucene.Net.Index: Added IndexOptionsComparer to eliminate boxing when comparing IndexOptions enum values with System.Enum.CompareTo()
diff --git a/src/Lucene.Net/Support/Index/IndexOptionsComparer.cs b/src/Lucene.Net/Support/Index/IndexOptionsComparer.cs
new file mode 100644
index 0000000..de49ff3
--- /dev/null
+++ b/src/Lucene.Net/Support/Index/IndexOptionsComparer.cs
@@ -0,0 +1,67 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Lucene.Net.Index
+{
+ /*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ /// <summary>
+ /// Since in .NET the standard comparers will do boxing when comparing enum types,
+ /// this class was created as a more performant workaround than calling <c>CompareTo()</c> on <see cref="IndexOptions"/>.
+ /// </summary>
+ internal class IndexOptionsComparer : IComparer<IndexOptions>
+ {
+ private IndexOptionsComparer() { } // No instance
+
+ /// <summary>
+ /// Gets the default static singleton instance of <see cref="IndexOptionsComparer"/>.
+ /// </summary>
+ public static IComparer<IndexOptions> Default { get; } = new IndexOptionsComparer();
+
+ /// <summary>
+ /// Compares two <see cref="IndexOptions"/> enums and returns an indication of their relative sort order.
+ /// </summary>
+ /// <param name="x">An <see cref="IndexOptions"/> enum to compare to <paramref name="y"/>.</param>
+ /// <param name="y">An <see cref="IndexOptions"/> enum to compare to <paramref name="x"/>.</param>
+ /// <returns>
+ /// A signed integer that indicates the relative values of <paramref name="x"/> and <paramref name="y"/>, as shown in the following table.
+ /// <list type="table">
+ /// <listheader>
+ /// <term>Value</term>
+ /// <term>Meaning</term>
+ /// </listheader>
+ /// <item>
+ /// <term>Less than zero </term>
+ /// <term><paramref name="x"/> precedes y in the sort order.</term>
+ /// </item>
+ /// <item>
+ /// <term>Zero </term>
+ /// <term><paramref name="x"/> is equal to <paramref name="y"/>.</term>
+ /// </item>
+ /// <item>
+ /// <term>Greater than zero </term>
+ /// <term><paramref name="x"/> follows <paramref name="y"/> in the sort order.</term>
+ /// </item>
+ /// </list>
+ /// </returns>
+ public int Compare([DisallowNull] IndexOptions x, [DisallowNull] IndexOptions y)
+ {
+ return ((int)x).CompareTo((int)y);
+ }
+ }
+}
