tablution/NSIndexSet+SetOperations.m at master · valrus/tablution · GitHub

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//
//  NSIndexSet+SetOperations.m
//  tablution
//
//  Created by Ian Mccowan on 6/24/12.
//  Copyright (c) 2012 Nuance, Inc. All rights reserved.
//

#import "NSIndexSet+SetOperations.h"

@implementation NSIndexSet (SetOperations)

- (NSMutableIndexSet *)indexSetByAddingIndexes:(NSIndexSet *)indexes
{
    NSMutableIndexSet *newIndexSet = [[NSMutableIndexSet alloc] initWithIndexSet:self];
    [newIndexSet addIndexes:indexes];
    return newIndexSet;
}

- (NSMutableIndexSet *)indexSetByRemovingIndexes:(NSIndexSet *)indexes
{
    NSMutableIndexSet *newIndexSet = [[NSMutableIndexSet alloc] initWithIndexSet:self];
    [newIndexSet removeIndexes:indexes];
    return newIndexSet;
}

- (BOOL)intersectsIndexes:(NSIndexSet *)otherIndexes
{
    // Could maybe make more efficient using technique described here:
    // http://www.cocoabuilder.com/archive/cocoa/82348-nsindexset.html
    NSUInteger intersectIndex = [self indexPassingTest:^BOOL(NSUInteger idx, BOOL *stop) {
        if ([otherIndexes containsIndex:idx]) {
            *stop = YES;
            return YES;
        }
        return NO;
    }];
    if (intersectIndex == NSNotFound) {
        return NO;
    }
    return YES;
}

@end