Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.Entity/System/Data/Common/Utils/Pair.cs

@@ -0,0 +1,106 @@
+//---------------------------------------------------------------------
+// <copyright file="Pair.cs" company="Microsoft">
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//
+// @owner [....]
+// @backupOwner [....]
+//---------------------------------------------------------------------
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Text;
+using System.Diagnostics;
+using System.Linq;
+
+
+namespace System.Data.Common.Utils
+{
+    internal class Pair<TFirst, TSecond> : InternalBase
+    {
+        #region Fields
+        private readonly TFirst first;
+        private readonly TSecond second;
+
+        #endregion
+
+        #region Constructor
+        internal Pair(TFirst first, TSecond second)
+        {
+            this.first = first;
+            this.second = second;
+        }
+        #endregion
+
+        #region Properties
+        internal TFirst First
+        {
+            get
+            {
+                return first;
+            }
+        }
+
+        internal TSecond Second
+        {
+            get
+            {
+                return second;
+            }
+        }
+        #endregion 
+
+        #region Methods
+        public override int GetHashCode()
+        {
+            return (first.GetHashCode()<<5) ^ second.GetHashCode();
+        }
+
+        public bool Equals(Pair<TFirst, TSecond> other)
+        {
+            return first.Equals(other.first) && second.Equals(other.second);
+        }
+
+        public override bool Equals(object other)
+        {
+            Pair<TFirst, TSecond> otherPair = other as Pair<TFirst, TSecond>;
+
+            return (otherPair != null && Equals(otherPair));
+        }
+        #endregion
+
+        #region InternalBase
+        internal override void ToCompactString(StringBuilder builder)
+        {
+            builder.Append("<");
+            builder.Append(first.ToString());
+            builder.Append(", "+second.ToString());
+            builder.Append(">");
+        }
+        #endregion
+
+
+        internal class PairComparer : IEqualityComparer<Pair<TFirst, TSecond>>
+        {
+            private PairComparer() { }
+
+            internal static readonly PairComparer Instance = new PairComparer();
+            private static readonly EqualityComparer<TFirst> firstComparer = EqualityComparer<TFirst>.Default;
+            private static readonly EqualityComparer<TSecond> secondComparer = EqualityComparer<TSecond>.Default;
+
+            public bool Equals(Pair<TFirst, TSecond> x, Pair<TFirst, TSecond> y)
+            {
+                return firstComparer.Equals(x.First, y.First) && secondComparer.Equals(x.Second, y.Second);
+            }
+
+            public int GetHashCode(Pair<TFirst, TSecond> source)
+            {
+                return source.GetHashCode();
+            }
+        }
+    }
+
+    
+
+}