NSString vs. NSData Text File Parsing

FileParse.m

- (NSArray *)stringsFromFile:(NSString *)name
{
    NSDate *start = [NSDate date];
    NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@"yaml"];
    NSString *fileString = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    NSTimeInterval fileTime = [start timeIntervalSinceNow];
    NSArray *lines = [fileString componentsSeparatedByString:@"\n"];
    NSTimeInterval end = [start timeIntervalSinceNow];
    NSLog(@"end count:%.9f %.9f, %zd", fileTime, end, offsets.count);
    return lines;
}

- (void)bytesFromFile:(NSString *)name
{
    NSDate *start = [NSDate date];
    NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@"yaml"];
    offsets = [NSMutableArray new];
    words = [[NSData alloc] initWithContentsOfFile:path options:NSDataReadingMappedAlways error:nil];
    NSTimeInterval fileTime = [start timeIntervalSinceNow];
    const char *bytes = [words bytes];
    const char *cur = bytes;
    const char *end = bytes + [words length];
    [offsets addObject:@(0)];
    while (cur < end) {
        if (*cur++ == '\n') {
            [offsets addObject:@((int)(cur - bytes))];
        }
    }
    [offsets addObject:@((int)(end - bytes))];
    NSTimeInterval stop = [start timeIntervalSinceNow];
    NSLog(@"end count:%.9f %.9f, %zd", fileTime, stop, offsets.count);
}