Function Calling Comparison

// Code in this article:
// https://it.toolbox.com/blogs/hohlecow/bypassing-objective-cs-message-passing-mechanism-for-speed-052708

#import <Cocoa/Cocoa.h>
@interface Fib : NSObject {
}
- (long long) messageFib: (NSUInteger) number;
- (long long) impFib: (NSUInteger) number;
- (long long) cFib: (NSUInteger) number;
@end

@implementation Fib

// message passing implementation of fib
- (long long) messageFib: (NSUInteger) number {
    return (number < 3) ? 1 : [self messageFib: number - 1] + [self messageFib: number - 2];
}

// imp implementation of fib
- (long long) impFib: (NSUInteger) number {
    static long long (*impFibIMP)(id, SEL, NSUInteger) = nil;
    if (!impFibIMP) {
        impFibIMP = (long long (*)(id, SEL, NSUInteger)) [self methodForSelector: _cmd];
    }
    return (number < 3) ? 1 : impFibIMP(self, _cmd, number - 1) + impFibIMP(self, _cmd, number - 2);
}

// c implementation of fib
long long cFib(NSUInteger number) {
    return (number < 3) ? 1 : cFib(number - 1) + cFib(number - 2);
}

// method wrapper for c implementation of fib
- (long long) cFib: (NSUInteger) number {
    return cFib(number);
}

@end