NSArray+UniqueObjects.h: get unique objects from an NSArray, whilst maintaining sort ordering

NSArray+UniqueObjects.h

#import <Foundation/Foundation.h>


@interface NSArray (UniqueObjects)

-(NSArray*) uniqueObjects;

-(NSArray*) uniqueObjectsSortedUsingSelector: (SEL)comparator;

-(NSArray*) uniqueObjectsSortedUsingFunction: (NSInteger (*)(id, id, void *)) comparator  
                                     context: (id)context 
                                        hint: (id)hint;

-(NSArray*) uniqueObjectsSortedUsingFunction: (NSInteger (*)(id, id, void *)) comparator 
                                     context: (id)context;

-(NSArray*) uniqueObjectsSortedUsingSortDescriptors: (NSArray*) sortDescs;

@end

// The implementation

#import "NSArray+UniqueObjects.h"
 
@implementation NSArray (UniqueObjects)
 
-(NSArray*) uniqueObjects {
    NSSet *set = [[NSSet alloc] initWithArray: self];
    NSArray *vals = [set allObjects];
    [set release];
    return vals;
}
 
 
-(NSArray*) uniqueObjectsSortedUsingSelector: (SEL)comparator {
    NSSet *set = 
        [[NSSet alloc] initWithArray: self];
    NSArray *vals = 
        [[set allObjects] sortedArrayUsingSelector: comparator];
    [set release];
    return vals;
}
 
 
-(NSArray*) 
uniqueObjectsSortedUsingFunction: 
(NSInteger (*)(id, id, void *)) comparator 
context: (id)context 
 
hint: (id)hint {
    NSSet *set = [[NSSet alloc] initWithArray: self];
    NSArray *vals = 
        [[set allObjects] sortedArrayUsingFunction: comparator
                                           context: context 
                                              hint: hint];
    [set release];
    return vals;
}
 
 
-(NSArray*) 
uniqueObjectsSortedUsingFunction: 
(NSInteger (*)(id, id, void *)) comparator 
context: (id)context {
    NSSet *set = [[NSSet alloc] initWithArray: self];
 
    NSArray *vals = [[set allObjects] 
    sortedArrayUsingFunction:comparator context:context];
    [set release];
    return vals;
}
 
 
-(NSArray*) 
uniqueObjectsSortedUsingSortDescriptors: (NSArray*) sortDescs 
{
    NSSet *set = [[NSSet alloc] initWithArray: self];
    NSArray *vals = 
        [[set allObjects] sortedArrayUsingDescriptors:sortDescs];
    [set release];
    return vals;
}
 
 
@end