Adding AssociatedObject to NSObject

NSObject+AssociatedObject.h

#import <Foundation/Foundation.h>

@interface NSObject (AssociatedObject)

- (id)associatedObjectForKey:(void*)key;
- (void)setAssociatedObject:(id)object forKey:(void*)key;

@end

NSObject+AssociatedObject.m

#import "NSObject+AssociatedObject.h"
#import <objc/runtime.h>

@implementation NSObject (AssociatedObject)

- (id)associatedObjectForKey:(void*)key
{
    return objc_getAssociatedObject(self, key);
}

- (void)setAssociatedObject:(id)obj forKey:(void*)key
{
    objc_setAssociatedObject(self, key, obj, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

@end