gistfile1.m

typedef NS_ENUM(NSUInteger, MeasurementsType) {
    MeasurementsTypeUnknown,
    MeasurementsTypePhone,
    MeasurementsTypePhoneTall,
    MeasurementsTypePadPortrait,
    MeasurementsTypePadLandscape
};

struct Measurements {
public:
    Measurements() {
    }

    void initialize(MeasurementsType measurementsType) {
        NSCAssert(!_initialized, @"Already initialized");
        switch (measurementsType) {
            case MeasurementsTypePhone:
                base();
                basePhone();
                phone();
                break;
            case MeasurementsTypePhoneTall:
                base();
                basePhone();
                phoneTall();
                break;
            case MeasurementsTypePadPortrait:
                base();
                basePad();
                padPortrait();
                break;
            case MeasurementsTypePadLandscape:
                base();
                basePad();
                padLandscape();
                break;
            case MeasurementsTypeUnknown:
            default:
                NSCAssert(NO, @"Unknown device");
                break;
        }

        _initialized = YES;
    }

    static MeasurementsType _getMeasurementsType(BOOL portrait) {
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
            return portrait ? MeasurementsTypePadPortrait : MeasurementsTypePadLandscape;
        } else if (/* logic goes here */) {
            return MeasurementsTypePhoneTall;
        } else if (/* logic goes here */) {
            return MeasurementsTypePhone;
        } else {
            return MeasurementsTypeUnknown
        }
    }

private:
    BOOL _initialized;

protected:
    virtual void base() {}
    virtual void basePhone() {}
    virtual void basePad() {}
    virtual void phone () {}
    virtual void phoneTall() {}
    virtual void padPortrait() {}
    virtual void padLandscape() {}
};

template <typename T> static T GetMeasurements(BOOL isPortrait) {
    T *measurements = new T();
    measurements->initialize(Measurements::_getMeasurementsType(isPortrait));
    const T constMeasurements = *measurements;
    delete measurements;
    return constMeasurements;
}