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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
// <OWNER>Microsoft</OWNER>
//
using System;
namespace System.Collections {
public static class StructuralComparisons {
private static volatile IComparer s_StructuralComparer;
private static volatile IEqualityComparer s_StructuralEqualityComparer;
public static IComparer StructuralComparer {
get {
IComparer comparer = s_StructuralComparer;
if (comparer == null) {
comparer = new StructuralComparer();
s_StructuralComparer = comparer;
}
return comparer;
}
}
public static IEqualityComparer StructuralEqualityComparer {
get {
IEqualityComparer comparer = s_StructuralEqualityComparer;
if (comparer == null) {
comparer = new StructuralEqualityComparer();
s_StructuralEqualityComparer = comparer;
}
return comparer;
}
}
}
[Serializable]
internal class StructuralEqualityComparer : IEqualityComparer {
public new bool Equals(Object x, Object y) {
if (x != null) {
IStructuralEquatable seObj = x as IStructuralEquatable;
if (seObj != null){
return seObj.Equals(y, this);
}
if (y != null) {
return x.Equals(y);
} else {
return false;
}
}
if (y != null) return false;
return true;
}
public int GetHashCode(Object obj) {
if (obj == null) return 0;
IStructuralEquatable seObj = obj as IStructuralEquatable;
if (seObj != null) {
return seObj.GetHashCode(this);
}
return obj.GetHashCode();
}
}
[Serializable]
internal class StructuralComparer : IComparer {
public int Compare(Object x, Object y) {
if (x == null) return y == null ? 0 : -1;
if (y == null) return 1;
IStructuralComparable scX = x as IStructuralComparable;
if (scX != null) {
return scX.CompareTo(y, this);
}
return Comparer.Default.Compare(x, y);
}
}
}
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