frequencyGoverner.h

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#ifndef _DLRUTILITIES_FREQUENCYGOVERNER_H_
#define _DLRUTILITIES_FREQUENCYGOVERNER_H_

#include <dlrUtilities/timeUtilities.h>

namespace dlr {

  namespace utilities {
    
    class FrequencyGoverner {
    public:

      explicit
      FrequencyGoverner(double frequency, double duration = 0.0)
        : m_count(0), m_duration(duration), m_period(1.0 / frequency),
          m_startTime(getCurrentTime()) {}


      ~FrequencyGoverner() {}


      double
      getActualFrequency() {
        if(m_count == 0) {return 0.0;}
        return (getCurrentTime() - m_startTime) / m_count;
      }

      
      unsigned int 
      getCount() {return static_cast<unsigned int>(m_count);}


      double
      getSlack() {return m_startTime + m_count * m_period - getCurrentTime();}
      
      
      inline bool
      isFinished() {
        return ((m_duration != 0.0)
                && ((getCurrentTime() - m_startTime) > m_duration));
      }


      inline void
      sleepIfNecessary() {
        // Function portableSleep is smart enough to return
        // immediately for negative arguments.
        portableSleep(this->getSlack());
        ++m_count;
      }
      
    private:

      int m_count;
      double m_duration;
      double m_period;
      double m_startTime;

    }; // class FrequencyGoverner

  } // namespace utilities
  
} // namespace dlr


/* ======= Declarations to maintain compatibility with legacy code. ======= */

namespace dlr {

  using utilities::FrequencyGoverner;
  
} // namespace dlr

#endif // #ifndef _DLRUTILITES_FREQUENCYGOVERNER_H_