Random comparisons of isEqual:, isEqualToString:, and compare:

equaltime.m

#import <Foundation/Foundation.h>
#import <mach/mach_time.h>  // for mach_absolute_time() and friends

// clang -g -Wall -framework Foundation -o equaltime equaltime.m
// clang -g -arch i386 -Wall -framework Foundation -o equaltime equaltime.m

CGFloat BNRTimeBlock (void (^block)(void)) {
    mach_timebase_info_data_t info;
    if (mach_timebase_info(&info) != KERN_SUCCESS) return -1.0;

    uint64_t start = mach_absolute_time ();
    block ();
    uint64_t end = mach_absolute_time ();
    uint64_t elapsed = end - start;

    uint64_t nanos = elapsed * info.numer / info.denom;
    return (CGFloat)nanos / NSEC_PER_SEC;

} // BNRTimeBlock


#define LOOPAGE 10000000
void CompareStrings (NSString *thing1, NSString *thing2) {
    CGFloat equalTime = BNRTimeBlock (^{
            for (NSInteger i = 0; i < LOOPAGE; i++) {
                (void) [thing1 isEqual: thing2];
            }
        });

    CGFloat equalToStringTime = BNRTimeBlock (^{
            for (NSInteger i = 0; i < LOOPAGE; i++) {
                (void) [thing1 isEqualToString: thing2];
            }
        });
    
    CGFloat compareTime = BNRTimeBlock (^{
            for (NSInteger i = 0; i < LOOPAGE; i++) {
                (void) [thing1 compare: thing2];
            }
        });

    NSLog (@"Time for         isEqual: %f", equalTime);
    NSLog (@"Time for isEqualToString: %f", equalToStringTime);
    NSLog (@"Time for         compare: %f", compareTime);

} // CompareStrings

// Replace the zero with a one for the chunk fo test code you want to run
#define RUN_TIMINGS 0
#define STATIC_ERROR_CHECKING 0
#define RUNTIME_TYPE_CHECKING 0
#define LITERAL_COMPARISON 0
#define NILS_ARE_ALIVE 0


int main (void) {
    @autoreleasepool {

#if RUN_TIMINGS
        // Different strings, so literal NSString 
        NSString *thing1 = @"Hello there, how are you doing today?";
        NSString *thing2 = @"Hello there, how are you doing today!";

        CompareStrings (thing1, thing2);
#endif

#if STATIC_TYPE_CHECKING
        NSString *string = @"I seem to be a verb.";
        NSNumber *number = [NSNumber numberWithInt: 42];
        [number isEqualToString: string];
        [string isEqualToString: number];
#endif

#if RUNTIME_TYPE_CHECKING
        NSString *string = @"i can haz cheezburger?";
        NSArray *stringArray = [NSArray arrayWithObject: string];
        NSNumber *number = [NSNumber numberWithInt: 42];
        NSArray *numberArray = [NSArray arrayWithObject: number];

        [[stringArray lastObject] isEqualToString: [numberArray lastObject]];
        // [[numberArray lastObject] isEqualToString: [stringArray lastObject]];
#endif

#if LITERAL_COMPARISON
        NSString *oUmlaut = @"\u00f6"; // o-umlaut
        NSString *oPlusUmlaut = @"o\u0308";  // o + combining diaeresis
        
        NSLog (@"%@ and %@: equal %d vs compare: %d",
               oUmlaut, oPlusUmlaut,
               [oUmlaut isEqualToString: oPlusUmlaut],
               [oUmlaut compare: oPlusUmlaut] == NSOrderedSame);
#endif

#if NILS_ARE_ALIVE
        NSString *nil1 = nil;
        NSString *nil2 = nil;

        NSLog (@"nil and nil: equal %d vs compare: %d",
               [nil1 isEqualToString: nil2],
               [nil1 compare: nil2] == NSOrderedSame);

        NSString *notNil = @"greeble bork";
        NSLog (@"nil and non-nil: equal %d vs compare: %d",
               [nil1 isEqualToString: notNil],
               [nil1 compare: notNil] == NSOrderedSame);

        NSLog (@"non-nil and nil: equal %d vs compare: %d",
               [notNil isEqualToString: nil1],
               [notNil compare: nil1] == NSOrderedSame);
#endif

    }

    
    return 0;

} // main