NSMutableArray+QueueAdditions.m

/*!
 Class modified by Ricardo Ruiz López.
 */

#import "NSMutableArray+QueueAdditions.h"

@implementation NSMutableArray (QueueAdditions) 

// Add to the tail of the queue (no one likes it when people cut in line!)
-(void) enqueue:(id)anObject {
    [self addObject:anObject];
    //this method automatically adds to the end of the array
}

-(id) dequeue {
    if ([self count] == 0) {
        return nil;
    }
    id queueObject = [[[self objectAtIndex:0] retain] autorelease];
    [self removeObjectAtIndex:0];       // beginning of the array is the back of the queue
    return queueObject;
}

-(id) peek:(int)index {
	if (self.count==0 || index<0) {
        return nil;
    }
	return [[self objectAtIndex:index] retain];
}

// if there aren't any objects in the queue
// peek returns nil, and we will too
-(id) peekHead
{
	return [self peek:0];
}

// if 0 objects, we call peek:-1 which returns nil
-(id) peekTail
{
	return [self peek:self.count-1];
}

-(BOOL) empty {
    return self.count==0;
}

@end