How to implement a queue in Objective-C

Introduction

Last time, I posted a tip abort stacking with Objective-C. This time, I will implement a queue.

@interface HsuQueue : NSObject {
    NSMutableArray* m_array;
}
 
- (void)enqueue:(id)anObject;
- (id)dequeue;
- (void)clear;
 
@property (nonatomic, readonly) int count;
 
@end

@implementation HsuQueue

@synthesize count;
 
- (id)init
{
    if( self=[super init] )
    {
        m_array = [[NSMutableArray alloc] init];
        count = 0;
    }
    return self;
}
 
- (void)dealloc {
    [m_array release];
    [self dealloc];
    [super dealloc];
}
 
- (void)enqueue:(id)anObject
{
    [m_array addObject:anObject];
    count = m_array.count;
}
- (id)dequeue
{
    id obj = nil;
    if(m_array.count > 0)
    {
        obj = [[[m_array objectAtIndex:0]retain]autorelease];
        [m_array removeObjectAtIndex:0];
        count = m_array.count;
    }
    return obj;
}
 
- (void)clear
{
    [m_array removeAllObjects];
    count = 0;
}
 
@end