New test.

[mono.git] / mcs / class / corlib / System.Collections.Generic / Comparer.cs

diff --git a/mcs/class/corlib/System.Collections.Generic/Comparer.cs b/mcs/class/corlib/System.Collections.Generic/Comparer.cs
index b13697f167d2de3d7935fcdd38f5fa9fe52ab5e1..8604443a45d9444094268d758e69140c77720c42 100644 (file)
--- a/mcs/class/corlib/System.Collections.Generic/Comparer.cs
+++ b/mcs/class/corlib/System.Collections.Generic/Comparer.cs
@@ -31,31 +31,25 @@ using System;
 using System.Runtime.InteropServices;
 
 namespace System.Collections.Generic {
-       [CLSCompliant(false)]
-       public abstract class Comparer<T> : IComparer<T>, System.Collections.IKeyComparer,
-               System.Collections.IComparer, System.Collections.IHashCodeProvider {
-       
-               public Comparer () {} /* workaround 60438 by not having a protected ctor */
-               public abstract int Compare (T x, T y);
-               public virtual bool Equals (T x, T y)
-               {
-                       return Compare (x, y) == 0;
-               }
-               public virtual int GetHashCode (T obj)
+       [Serializable]
+       public abstract class Comparer<T> : IComparer<T>, System.Collections.IComparer {
+               
+               static Comparer ()
                {
-                       if (obj == null)
-                               throw new ArgumentNullException ();
-                       return obj.GetHashCode ();
+                       if (typeof (IComparable<T>).IsAssignableFrom (typeof (T)))
+                               _default = (Comparer<T>) Activator.CreateInstance (typeof (IComparableOfTComparer <>).MakeGenericType (typeof (T)));
+                       else
+                               _default = new DefaultComparer ();
                }
+               
+               
+               public abstract int Compare (T x, T y);
        
-               static DefaultComparer <T> _default;
+               static readonly Comparer <T> _default;
                
-               [MonoTODO ("This is going to make a really slow comparer. We need to speed this up if T : ICompareable<T> create a class with a where clause of T : ICompareable <T>")]
-               public static Comparer<T> Default {
+               public static Comparer <T> Default {
                        get {
-                               if (_default != null)
-                                       return _default;
-                               return _default = new DefaultComparer<T> ();
+                               return _default;
                        }
                }
        
@@ -73,31 +67,7 @@ namespace System.Collections.Generic {
                        throw new ArgumentException ();
                }
        
-               bool System.Collections.IKeyComparer.Equals (object x, object y)
-               {
-                       if (x == y)
-                               return true;
-                       
-                       if (x == null || y == null)
-                               return false;
-                       
-                       if (x is T && y is T)
-                               return Equals ((T) x, (T) y);
-                       
-                       throw new ArgumentException ();
-               }
-       
-               int System.Collections.IHashCodeProvider.GetHashCode (object obj)
-               {
-                       if (obj == null)
-                               throw new ArgumentNullException ();
-                       if (obj is T)
-                               return GetHashCode ((T) obj);
-                       
-                       throw new ArgumentException ();
-               }
-       
-               class DefaultComparer<T> : Comparer<T> {
+               class DefaultComparer : Comparer<T> {
        
                        public override int Compare (T x, T y)
                        {
@@ -114,11 +84,19 @@ namespace System.Collections.Generic {
                                else
                                        throw new ArgumentException ("does not implement right interface");
                        }
+               }
+       }
        
-                       public override bool Equals (T x, T y)
-                       {
-                               return Object.Equals (x, y);
-                       }
+       class IComparableOfTComparer <T> : Comparer <T> where T : IComparable<T> {
+               public override int Compare (T x, T y)
+               {
+                       // `null' is less than any other ref type
+                       if (x == null)
+                               return y == null ? 0 : -1;
+                       else if (y == null)
+                               return 1;
+                       
+                       return x.CompareTo (y);
                }
        }