2007-11-08 Jb Evain <[email protected]>

	* Enumerable.cs: correctly implement Intersect.


svn path=/trunk/mcs/; revision=89188

mcs/class/System.Core/System.Linq/ChangeLog

@@ -1,3 +1,7 @@
+2007-11-08  Jb Evain  <[email protected]>
+
+	* Enumerable.cs: correctly implement Intersect.
+
 2007-11-08  Jb Evain  <[email protected]>
 
 	* Enumerable.cs: code cleanup.

mcs/class/System.Core/System.Linq/Enumerable.cs

@@ -869,25 +869,23 @@ namespace System.Linq
 
 		#region Intersect
 
-
 		public static IEnumerable<TSource> Intersect<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second)
+		{
+			return Intersect (first, second, null);
+		}
+
+		public static IEnumerable<TSource> Intersect<TSource> (this IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource> comparer)
 		{
 			if (first == null || second == null)
 				throw new ArgumentNullException ();
 
-			List<TSource> items = new List<TSource> (Distinct (first));
-			bool [] marked = new bool [items.Count];
-			for (int i = 0; i < marked.Length; i++)
-				marked [i] = false;
+			if (comparer == null)
+				comparer = EqualityComparer<TSource>.Default;
 
+			List<TSource> items = new List<TSource> (Distinct (first));
 			foreach (TSource element in second) {
-				int index = IndexOf (items, element);
-				if (index != -1)
-					marked [index] = true;
-			}
-			for (int i = 0; i < marked.Length; i++) {
-				if (marked [i])
-					yield return items [i];
+				if (Contains (items, element, comparer))
+					yield return element;
 			}
 		}