Air-Craft

    
    dispatch_source_t _timer;
    
    _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0));
    dispatch_source_set_timer(_timer,
                              dispatch_walltime(NULL, <#timeout#> * NSEC_PER_SEC),
                              1 * NSEC_PER_SEC, // this doenst really matter
                              <# 0.01 (tolerance) #> * NSEC_PER_SEC); 
    dispatch_source_set_event_handler(_timer, ^{
        dispatch_source_cancel(_timer);  // cancel the repeat

Air-Craft

+ (NSArray *)arrayOfClassNamesFilteredByPredicate:(NSPredicate *)predicate
{
    int numClasses;
    Class *classes = NULL;
    
    classes = NULL;
    numClasses = objc_getClassList(NULL, 0);
    
    if (numClasses < 1 ) return nil;
    

Air-Craft

+ (NSArray *)arrayOfClassObjectsFilteredByPredicate:(NSPredicate *)predicate
{
    int numClasses;
    Class *classes = NULL;
    
    classes = NULL;
    numClasses = objc_getClassList(NULL, 0);
    
    if (numClasses < 1 ) return nil;
    

Air-Craft

+ (NSArray *)subclassesOfClass:(Class)parentClass
{
    int numClasses = objc_getClassList(NULL, 0);
    Class *classes = NULL;
    
    classes = (__unsafe_unretained Class *)malloc(sizeof(Class) * numClasses);
    numClasses = objc_getClassList(classes, numClasses);
    
    NSMutableArray *result = [NSMutableArray array];
    for (NSInteger i = 0; i < numClasses; i++)

Air-Craft

NSDate *birthday = value;
        
NSDate *now = [NSDate date];
NSDateComponents *ageComponents = [[NSCalendar currentCalendar]
                                           components:NSYearCalendarUnit
                                           fromDate:birthday
                                           toDate:now
                                           options:0];
NSInteger age = [ageComponents year];

Air-Craft

// Native...
NSCharacterSet* illegalFileNameCharacters = [NSCharacterSet characterSetWithCharactersInString:@"/\\?%*|\"<>"];
NSString *sanitized = [[fileName componentsSeparatedByCharactersInSet:illegalFileNameCharacters] componentsJoinedByString:@""];

// With Overline (negative matching)
NSString *sanitized = [fileName stringByReplacingOccurrencesOfRegExpPattern:@"[^a-zA-Z0-9_\\+\\-]+" withString:@"_"

Air-Craft

+ (NSArray *)classPropertyList
{
    // Get array of all property names
    unsigned int count;
    objc_property_t *props = class_copyPropertyList(self, &count);
    NSMutableArray *propNames = [NSMutableArray array];
    for (int i=0; i<count; i++)
    {
        NSString *p = [NSString stringWithUTF8String:property_getName(props[i])];
        [propNames addObject:p];

Air-Craft

// FOR CATEGORIES (From same class into same class)
// `swizzle()` allows replacing methods in a Category while still leaving access 
//  to the original akin to `super` for subclasses

// INJECT/REPLACE (loses original)
void (^inject)(Class, SEL, SEL) = ^(Class c, SEL orig, SEL new){
    Method newMethod = class_getInstanceMethod(c, new);
    class_replaceMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod));
};

Air-Craft

+ (UIImage *)imageOfRibbonBGWithFrame:(CGRect)frame
{
    CGImageRef bgSolid = [super imageOfRibbonBGWithFrame:frame].CGImage;
    CGImageRef holes = [super imageOfRibbonDotsWithFrame:frame].CGImage;
    
    CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(holes),
                                        CGImageGetHeight(holes),
                                        CGImageGetBitsPerComponent(holes),
                                        CGImageGetBitsPerPixel(holes),
                                        CGImageGetBytesPerRow(holes),

Air-Craft

// iOS >=8
NSOperatingSystemVersion ios8_0_0 = (NSOperatingSystemVersion){8, 0, 0};
if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion:ios8_0_0]) {
  // iOS 8 logic
} else {
  // iOS 7 and below logic
}
   
   
// iOS <=7