Detect device type of iPhone

detectDeviceType.m

#define IS_HEIGHT_GTE_568 [[UIScreen mainScreen ] bounds].size.height >= 568.0f

typedef NS_ENUM(NSInteger, DeviceType) {
    DeviceType_iPhone3Gs,
    DeviceType_iPhone4_4s,
    DeviceType_iPhone5,
};

- (DeviceType)getTypeOfDevice {
    if ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] &&
        ([UIScreen mainScreen].scale == 2.0)) {
        return (IS_HEIGHT_GTE_568)?DeviceType_iPhone5:DeviceType_iPhone4_4s;
    } else {
        return DeviceType_iPhone3Gs;
    }
}