fsfw/src/fsfw/timemanager/Countdown.h

#ifndef FSFW_TIMEMANAGER_COUNTDOWN_H_
#define FSFW_TIMEMANAGER_COUNTDOWN_H_

#include "Clock.h"

/**
 *
 * Countdown keeps track of a timespan.
 * This class uses the system clock internally to achieve
 * a high resolution. This means that the API is only partially
 * resistant against time jumps. The user must take care to account
 * for time jumps in some from if this relevant.
 *
 * Countdown::resetTimer restarts the timer.
 * Countdown::setTimeout sets a new countdown duration and resets.
 *
 * Can be checked with Countdown::hasTimedOut or
 * Countdown::isBusy.
 *
 * Countdown::timeOut will force the timer to time out.
 *
 */
class Countdown {
 public:
  /**
   * Constructor which sets the countdown duration in milliseconds
   *
   * It does not start the countdown!
   * Call resetTimer or setTimeout before usage!
   * Otherwise a call to hasTimedOut might return True.
   *
   * @param initialTimeout Countdown duration in milliseconds
   * @param startImmediately  Set to false if countdown should not be started immediately
   */
  Countdown(uint32_t initialTimeout = 0, bool startImmediately = true);
  ~Countdown();
  /**
   * Call to set a new countdown duration.
   *
   * Resets the countdown!
   *
   * @param milliseconds new countdown duration in milliseconds
   * @return Returnvalue from Clock::getUptime
   */
  ReturnValue_t setTimeout(uint32_t milliseconds);
  ReturnValue_t setTimeoutTv(timeval tv);

  /**
   * Returns true if the countdown duration has passed.
   *
   * @return True if the countdown has passed
   * 		   False if it is still running
   */
  bool hasTimedOut() const;
  /**
   * Complementary to hasTimedOut.
   *
   * @return True if the countdown is till running
   * 		   False if it is still running
   */
  bool isBusy() const;
  /**
   *  Uses last set timeout value and restarts timer.
   */
  ReturnValue_t resetTimer();
  /**
   * Returns the remaining milliseconds (0 if timeout)
   */
  uint32_t getRemainingMillis() const;

  uint32_t getTimeoutMs() const;

  timeval getTimeout() const;

  /**
   * Makes hasTimedOut() return true
   */
  void timeOut();

  static inline uint32_t timevalToMs(timeval& tv);

 private:
  /**
   * Start time of the countdown.
   */
  timeval startTime{};

  /**
   * Timeout as timeval type. The countdown has timed out when the
   * current time exceeds the start time plus the timeout.
   */
  timeval timeout{};

  timeval getCurrentTime() const;
};

#endif /* FSFW_TIMEMANAGER_COUNTDOWN_H_ */