74 lines
1.4 KiB
C#
74 lines
1.4 KiB
C#
using System;
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using System.Runtime.InteropServices;
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namespace Martin.Collections.Generic {
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[Serializable]
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public abstract class EqualityComparer <T> : IEqualityComparer <T> {
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static EqualityComparer ()
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{
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if (typeof (IEquatable <T>).IsAssignableFrom (typeof (T)))
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_default = (EqualityComparer <T>) Activator.CreateInstance (typeof (IEquatableOfTEqualityComparer<>).MakeGenericType (typeof (T)));
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else
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_default = new DefaultComparer ();
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}
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public abstract int GetHashCode (T obj);
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public abstract bool Equals (T x, T y);
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static readonly EqualityComparer <T> _default;
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public static EqualityComparer <T> Default {
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get {
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return _default;
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}
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}
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[Serializable]
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class DefaultComparer : EqualityComparer<T> {
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public override int GetHashCode (T obj)
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{
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return obj.GetHashCode ();
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}
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public override bool Equals (T x, T y)
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{
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if (x == null)
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return y == null;
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return x.Equals (y);
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}
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}
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}
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[Serializable]
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class IEquatableOfTEqualityComparer <T> : EqualityComparer <T> where T : IEquatable <T> {
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public override int GetHashCode (T obj)
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{
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return obj.GetHashCode ();
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}
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public override bool Equals (T x, T y)
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{
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if (x == null)
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return y == null;
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return x.Equals (y);
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}
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}
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public interface IEqualityComparer<T> {
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bool Equals (T x, T y);
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int GetHashCode (T obj);
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}
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class X
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{
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public static void Main ()
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{ }
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}
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}
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