state machine

void update() {
    if(!initialize()) {
        return;
    }
    if(!use_interrupt) {
        process_change(this);
    }
    if(m_pressed==1) {
        return;
    }
    if(m_last_change_ms!=0 && !m_events.empty() && millis()-m_last_change_ms>= double_click_ms) {
        event_entry_t ev;
        event_entry_t ev_next;
        uint32_t press_ms=0;
        int state = 0;
        int clicks = 0;
        int longp = 0;
        int done = 0;
        while(!done) {
            switch(state) {
            case 0:
                if(!m_events.get(&ev)) {
                    done = true;
                    break;
                }
                if(ev.state==1) {
                    // pressed
                    state = 1;
                    break;
                } else {
                    // released
                    if(m_on_boot_click!=nullptr) {
                        m_on_boot_click(m_on_boot_click_state);
                    }
                    m_events.get(&ev);
                    // pressed
                    state = 1;
                    break;
                }
            case 1: // press state
                ++clicks;
                press_ms = ev.ms;
                if(!m_events.get(&ev)) {
                    done = true;
                    break;
                }
                state = 2;
                break;
            case 2: // release state
                longp = !!(m_on_long_click && ev.ms-press_ms>=long_click_ms);
                if(!m_events.get(&ev)) {
                    // flush the clicks
                    if(m_on_click) {
                        if(clicks>longp) {
                            m_on_click(clicks-longp,m_on_click_state);
                        }
                    }
                    if(longp) {
                        m_on_long_click(m_on_long_click_state);
                    }
                    done = true;
                    break;
                }
                state = 1;
                break;
            }
        }
    }
}