RateLimiter.hpp

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// ====================================================================== 
// \title  RateLimiter.hpp
// \author vwong
// \brief  hpp file for a rate limiter utility class
//
// \copyright
// Copyright (C) 2009-2020 California Institute of Technology.
//
// ALL RIGHTS RESERVED. United States Government Sponsorship
// acknowledged.
// ====================================================================== 
 
#ifndef RateLimiter_HPP
#define RateLimiter_HPP
 
#include <Fw/Types/BasicTypes.hpp>
#include <Fw/Time/Time.hpp>
 
namespace Utils {
 
  class RateLimiter
  {
 
    public:
 
      // Construct with defined cycles
      RateLimiter(U32 counterCycle, U32 timeCycle);
 
      // Construct with cycles set to 0
      RateLimiter();
 
    public:
 
      // Adjust cycles at run-time
      void setCounterCycle(U32 counterCycle);
      void setTimeCycle(U32 timeCycle);
 
      // Main point of entry
      //
      // It will only factor in counter or time, whichever one has a cycle defined
      //
      // If both are defined, then satisfying _either_ one will work
      // e.g. I want to trigger only once every X times or once every Y
      // seconds, whichever comes first
      //
      // The argument-less version is a shorthand for counter-only RateLimiters
      // If a time cycle is defined but the argument-less version is called,
      // RateLimiter assumes the client forgot to supply a time, and asserts
      //
      bool trigger(Fw::Time time);
      bool trigger();
 
      // Manual state adjustments, if necessary
      void reset();
      void resetCounter();
      void resetTime();
      void setCounter(U32);
      void setTime(Fw::Time time);
 
    private:
 
      // Helper functions to update each independently
      bool shouldCounterTrigger();
      bool shouldTimeTrigger(Fw::Time time);
      void updateCounter(bool triggered);
      void updateTime(bool triggered, Fw::Time time);
 
    private:
 
      // parameters
      U32 m_counterCycle;
      U32 m_timeCycle;
 
      // state
      U32 m_counter;
      Fw::Time m_time;
      bool m_timeAtNegativeInfinity;
  };
 
} // end namespace Utils
 
#endif