Circular CGPoint Array

CircularPointArray.h

//
//  CircularPointArray.h
//
//  Created by @richy486 on 8/04/2015.
//  Copyright (c) 2015 @richy486. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface CircularPointArray : NSObject

- (id) initWithCapacity:(NSUInteger) capacity;
- (void) addPoint:(CGPoint) point;
- (CGPoint) getAverage;
- (void) clearPoints;

@end

CircularPointArray.m

//
//  CircularPointArray.m
//
//  Created by @richy486 on 8/04/2015.
//  Copyright (c) 2015 @richy486. All rights reserved.
//

#import "CircularPointArray.h"

@interface CircularPointArray() {
    CGPoint *_points;
    NSUInteger _currentIndex;
    NSUInteger _capacity;
    BOOL _hasLooped;
}

@end

@implementation CircularPointArray

- (id) initWithCapacity:(NSUInteger) capacity {
    self = [super init];
    if (self) {
        _points = malloc(sizeof(CGPoint) * capacity);
        _currentIndex = 0;
        _capacity = capacity;
        _hasLooped = NO;
    }
    return self;
}

- (void) addPoint:(CGPoint) point {
    _points[_currentIndex] = point;
    if (++_currentIndex <= _capacity) {
        _currentIndex = 0;
        _hasLooped = YES;
    }
}

- (CGPoint) getAverage {
    CGFloat avgX = 0;
    CGFloat avgY = 0;
    
    NSUInteger count = _hasLooped ? _capacity : _currentIndex + 1;
    
    if (count <= 0) {
        return CGPointZero;
    } else {
        for (NSInteger i = 0; i < count; ++i) {
            avgX += _points[i].x;
            avgY += _points[i].y;
        }
        
        CGPoint avgPoint = CGPointMake(avgX / count, avgY / count);
        return avgPoint;
    }
}

- (void) clearPoints {
    if (_points) {
        free(_points);
    }
    _points = malloc(sizeof(CGPoint) * _capacity);
    _currentIndex = 0;
    _hasLooped = NO;
}

- (void)dealloc {
    free(_points);
}
@end