//
// StructuralComparisons.cs
//
// Authors:
// Marek Safar (marek.safar@gmail.com)
//
// Copyright (C) 2009 Novell, Inc (http://www.novell.com)
//
// 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.
//
#if NET_4_0
namespace System.Collections{
public static class StructuralComparisons
{
sealed class ComparerImpl : IComparer, IEqualityComparer
{
int IComparer.Compare (object x, object y)
{
var comparer = x as IStructuralComparable;
if (comparer != null)
return comparer.CompareTo (y, this);
return Comparer.Default.Compare (x, y);
}
int IEqualityComparer.GetHashCode (object obj)
{
var comparer = obj as IEqualityComparer;
if (comparer != null)
return comparer.GetHashCode (this);
return Generic.EqualityComparer<object>.Default.GetHashCode (obj);
}
bool IEqualityComparer.Equals (object x, object y)
{
var comparer = x as IEqualityComparer;
if (comparer != null)
return comparer.Equals (y, this);
return Generic.EqualityComparer<object>.Default.Equals (x, y);
}
}
static readonly ComparerImpl comparer = new ComparerImpl ();
public static IComparer StructuralComparer {
get {
return comparer;
}
}
public static IEqualityComparer StructuralEqualityComparer {
get {
return comparer;
}
}
}
}
#endif
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