test.cc

#include <inttypes.h>
#include <avr/io.h>

class Port {
public:
    Port(volatile uint8_t* const ddr_address,
         volatile uint8_t* const port_address);

    bool get_pin(uint8_t pin_number) const;
    void set_pin(uint8_t pin_number) const;
private:
    volatile uint8_t* const ddr_address_;
    volatile uint8_t* const port_address_;
};

inline Port::Port(volatile uint8_t* const ddr_address,
                  volatile uint8_t* const port_address)
: ddr_address_(ddr_address),
  port_address_(port_address)
{
    // empty
    return;
}

inline bool Port::get_pin(uint8_t pin_number) const
{
    bool result = *port_address_ & (1 << pin_number);

    return result;
}

inline void Port::set_pin(uint8_t pin_number) const
{
    *port_address_ |= (1 << pin_number);

    return;
}

class Button
{
public:
    Button(Port* port, const uint8_t pin_number, bool active_high);

    bool is_active() const;
    bool has_changed() const;
    bool activated() const;
    bool deactivated() const;
    void Poll();

private:
    const Port* const port_;
    const uint8_t pin_number_;
    const bool active_high_;

    bool active_;
    bool has_changed_;
};


inline Button::Button(Port* port, uint8_t pin_number, bool active_high)
: port_(port),
  pin_number_(pin_number),
  active_high_(active_high),
  active_(false),
  has_changed_(false)
{
    //empty
    return;
}

inline bool Button::is_active() const
{
    return active_;
}

inline bool Button::has_changed() const
{
    return has_changed_;
}

inline bool Button::activated() const
{
    bool activated = (is_active() && has_changed());

    return activated;
}

inline bool Button::deactivated() const
{
    bool deactivated = ((!is_active()) && has_changed());

    return deactivated;
}

inline void Button::Poll()
{
    bool new_state = (port_->get_pin(3) == active_high_);

    has_changed_ = (new_state != active_);

    active_ = new_state;

    return;
}


int main(void)
{
    const uint8_t pin = 3;
    Port PortB = Port(&PORTB, &DDRB);
    Button ButtonB2 = Button(&PortB, pin, true);

    ButtonB2.Poll();
    bool active = ButtonB2.is_active();
    bool has_changed = ButtonB2.has_changed();
    bool activated = ButtonB2.activated();
    bool deactivated = ButtonB2.deactivated();

    bool x = (active && has_changed && activated);

    if (x) PortB.set_pin(2);

    while (true) { }

    return 0;
}