hysteresis.h

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/**
 * @file hysteresis.h
 *
 * Hysteresis of a boolean value.
 *
 * @author Julian Oes <julian@oes.ch>
 */

#pragma once

#include <drivers/drv_hrt.h>

namespace systemlib
{

class Hysteresis
{
public:
    explicit Hysteresis(bool init_state) :
        _state(init_state),
        _requested_state(init_state)
    {}
    Hysteresis() = delete; // no default constructor

    ~Hysteresis() = default;

    bool get_state() const { return _state; }

    void set_hysteresis_time_from(const bool from_state, const hrt_abstime new_hysteresis_time_us);

    void set_state_and_update(const bool new_state, const hrt_abstime &now_us);

    void update(const hrt_abstime &now_us);

private:

    hrt_abstime _last_time_to_change_state{0};

    hrt_abstime _time_from_true_us{0};
    hrt_abstime _time_from_false_us{0};

    bool _state;
    bool _requested_state;
};

} // namespace systemlib