Add missing set filtering functionality

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@27833 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,11 @@
+2009-02-09  Xavier Glattard <xavier.glattard@online.fr>
+
+	* Headers/Foundation/NSPredicate.h: 
+	* Source/NSPredicate.m: Declare and implement two new methods for
+	filtering NSSet: 
+	  * [-filterUsingPredicate:]
+	  * [+filteredSetUsingPredicate:]
+
 2009-02-09  Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/win32/NSMessagePortNameServer.m: Fix GC error on windows

Headers/Foundation/NSPredicate.h

@@ -30,6 +30,7 @@
 
 #import	<Foundation/NSObject.h>
 #import	<Foundation/NSArray.h>
+#import	<Foundation/NSSet.h>
 
 #if	defined(__cplusplus)
 extern "C" {
@@ -64,6 +65,20 @@ extern "C" {
 - (void) filterUsingPredicate: (NSPredicate *)predicate;
 @end
 
+@interface NSSet (NSPredicate)
+/** Evaluate each object in the set using the specified predicate and
+ * return an set containing all the objects which evaluate to YES.
+ */
+- (NSSet *) filteredSetUsingPredicate: (NSPredicate *)predicate;
+@end
+
+@interface NSMutableSet (NSPredicate)
+/** Evaluate each object in the set using the specified predicate and
+ * remove each objects which evaluates to NO.
+ */
+- (void) filterUsingPredicate: (NSPredicate *)predicate;
+@end
+
 #if	defined(__cplusplus)
 }
 #endif

Source/NSPredicate.m

@@ -1534,6 +1534,48 @@
 
 @end
 
+@implementation NSSet (NSPredicate)
+
+- (NSSet *) filteredSetUsingPredicate: (NSPredicate *)predicate
+{
+  NSMutableSet	*result;
+  NSEnumerator	*e = [self objectEnumerator];
+  id		object;
+
+  result = [NSMutableSet setWithCapacity: [self count]];
+  while ((object = [e nextObject]) != nil)
+    {
+      if ([predicate evaluateWithObject: object] == YES)
+        {
+          [result addObject: object];  // passes filter
+        }
+    }
+  return [result makeImmutableCopyOnFail: NO];
+}
+
+@end
+
+@implementation NSMutableSet (NSPredicate)
+
+- (void) filterUsingPredicate: (NSPredicate *)predicate
+{
+  NSMutableSet	*rejected;
+  NSEnumerator	*e = [self objectEnumerator];
+  id		object;
+
+  rejected = [NSMutableSet setWithCapacity: [self count]];
+  while ((object = [e nextObject]) != nil)
+    {
+      if ([predicate evaluateWithObject: object] == NO)
+        {
+          [rejected addObject: object];
+        }
+    }
+  [self minusSet: rejected];
+}
+
+@end
+
 
 
 @implementation GSPredicateScanner