CPArray sorting: improve performance by 40% (JSC) replacing native js sort() with the merge-sort algorithm.

Test with ojunit CPArrayPerformance.j

Foundation/CPArray.j

@@ -1316,19 +1316,7 @@ CPEnumerationReverse    = 1 << 1;
 
 - (CPArray)sortUsingDescriptors:(CPArray)descriptors
 {
-    var count = [descriptors count];
-
-    sort(function(lhs, rhs)
-    {
-        var i = 0,
-            result = CPOrderedSame;
-
-        while (i < count)
-            if ((result = [descriptors[i++] compareObject:lhs withObject:rhs]) != CPOrderedSame)
-                return result;
-
-        return result;
-    });
+    [self sortUsingFunction:compareObjectsUsingDescriptors context:descriptors];
 }
 
 /*!
@@ -1338,7 +1326,36 @@ CPEnumerationReverse    = 1 << 1;
 */
 - (void)sortUsingFunction:(Function)aFunction context:(id)aContext
 {
-    sort(function(lhs, rhs) { return aFunction(lhs, rhs, aContext); });
+    var h, i, j, k, l, m, n = [self count];
+    var A, B = [];
+     
+    for (h = 1; h < n; h += h)
+    {
+        for (m = n - 1 - h; m >= 0; m -= h + h)
+        {
+            l = m - h + 1;
+            if (l < 0)
+                l = 0;
+            
+            for (i = 0, j = l; j <= m; i++, j++)
+                B[i] = self[j];
+            
+            for (i = 0, k = l; k < j && j <= m + h; k++)
+            {
+                A = self[j];
+                if (aFunction(A, B[i], aContext) == CPOrderedDescending)
+                    self[k] = B[i++];
+                else
+                {
+                    self[k] = A;
+                    j++;
+                }
+            }
+            
+            while (k < j)
+                self[k++] = B[i++];
+        }
+    }
 }
 
 /*!
@@ -1347,11 +1364,29 @@ CPEnumerationReverse    = 1 << 1;
 */
 - (void)sortUsingSelector:(SEL)aSelector
 {
-    sort(function(lhs, rhs) { return objj_msgSend(lhs, aSelector, rhs); });
+    [self sortUsingFunction:selectorCompare context:aSelector];
 }
 
 @end
 
+var selectorCompare = function selectorCompare(object1, object2, selector)
+{
+    return [object1 performSelector:selector withObject:object2];
+}
+
+// sort using sort descriptors
+var compareObjectsUsingDescriptors= function compareObjectsUsingDescriptors(lhs, rhs, descriptors)
+{ 
+    var result,
+        i = 0,  
+        n = [descriptors count];
+        
+    while (i < n && result == CPOrderedSame);
+       result = [descriptors[i++] compareObject:lhs withObject:rhs];
+    
+    return result;
+}
+
 @implementation CPArray (CPCoding)
 
 - (id)initWithCoder:(CPCoder)aCoder