Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.IdentityModel/System/IdentityModel/StringUtil.cs

@@ -0,0 +1,32 @@
+//-----------------------------------------------------------------------
+// <copyright file="StringUtil.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace System.IdentityModel
+{
+    internal static class StringUtil
+    {
+        /// <summary>
+        /// Returns an interned string equivaluent if found
+        /// </summary>
+        /// <param name="value">Input string.</param>
+        /// <returns>Optimized string.</returns>
+        public static string OptimizeString(string value)
+        {
+            if (value != null)
+            {
+                string interned = string.IsInterned(value);
+                if (interned != null)
+                {
+                    return interned;
+                }
+            }
+
+            // If the requested string isn't found in the CLR internal pool, don't
+            // intern it to avoid memory footprint ----up on the pool itself
+            return value;
+        }
+    }
+}