timer.hpp

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//-------------------------------------------------------------------------------------------------
/*

Fix8 is released under the GNU LESSER GENERAL PUBLIC LICENSE Version 3.

Fix8 Open Source FIX Engine.
Copyright (C) 2010-16 David L. Dight <fix@fix8.org>

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*/
//-------------------------------------------------------------------------------------------------
#ifndef FIX8_TIMER_HPP_
#define FIX8_TIMER_HPP_

//-------------------------------------------------------------------------------------------------
#include <iomanip>
#include <queue>
#ifdef _MSC_VER
#include <time.h>
#else
#include <sys/time.h>
#endif

//-------------------------------------------------------------------------------------------------
namespace FIX8
{

//-------------------------------------------------------------------------------------------------
template<typename T>
class Timer;


template<typename T>
class TimerEvent
{
   bool (T::*_callback)();
   Tickval _t {};
   unsigned _intervalMS = 0;
   bool _repeat;

public:
   explicit TimerEvent(bool (T::*callback)(), bool repeat=false) : _callback(callback), _repeat(repeat) {}

   ~TimerEvent() {}

   void set(const Tickval& t) { _t = t; }

   bool operator<(const TimerEvent<T>& right) const { return _t > right._t; };

   friend class Timer<T>;
};

//-------------------------------------------------------------------------------------------------

template<typename T>
class Timer
{
   T& _monitor;
   f8_thread<Timer> _thread;
   f8_spin_lock _spin_lock;
   unsigned _granularity;

   std::priority_queue<TimerEvent<T>> _event_queue;
   f8_thread_cancellation_token _cancellation_token;

public:
   explicit Timer(T& monitor, int granularity=10) : _monitor(monitor), _thread(std::ref(*this)), _granularity(granularity) {}

   virtual ~Timer()
   {
      stop();
      join();
   }

   bool schedule(TimerEvent<T> what, unsigned timeToWaitMS);

   size_t clear();

   void join() { _thread.join(); }

   void start() { _thread.start(); }

   void stop() { _thread.request_stop(); }

   int operator()();

   f8_thread_cancellation_token& cancellation_token() { return _cancellation_token;}
};

//-------------------------------------------------------------------------------------------------
template<typename T>
int Timer<T>::operator()()
{
   unsigned elapsed(0);

   while(!_cancellation_token)
   {
      bool shouldsleep(false);
      {
         f8_scoped_spin_lock guard(_spin_lock);

         if (_event_queue.size())
         {
            TimerEvent<T> op(_event_queue.top());
            if (!op._t) // ignore empty timeval
            {
               _event_queue.pop(); // remove from queue
               continue;
            }

            const Tickval now(Tickval::get_tickval());
            if (op._t <= now)  // has elapsed
            {
               TimerEvent<T> rop(_event_queue.top()); // take a copy
               _event_queue.pop(); // remove from queue
               ++elapsed;
               const bool result((_monitor.*rop._callback)());
               if (result && op._repeat) // don't repeat if callback returned false
               {
                  op._t = now.get_ticks() + op._intervalMS * Tickval::million;
                  _event_queue.push(std::move(op)); // push back on queue
               }
            }
            else
               shouldsleep = true;
         }
         else
            shouldsleep = true;
      }  // we want the lock to go out of scope before we sleep

      if (shouldsleep)
         hypersleep<h_milliseconds>(_granularity);
   }

   glout_info << "Terminating Timer thread (" << elapsed << " elapsed, " << _event_queue.size() << " queued).";
   return 0;
}

//-------------------------------------------------------------------------------------------------
template<typename T>
size_t Timer<T>::clear()
{
   size_t result(0);
   f8_scoped_spin_lock guard(_spin_lock);

   while (_event_queue.size())
   {
      ++result;
      _event_queue.pop(); // remove from queue
   }

   return result;
}

//-------------------------------------------------------------------------------------------------
template<typename T>
bool Timer<T>::schedule(TimerEvent<T> what, unsigned timeToWait)
{
   Tickval tofire;

   if (timeToWait)
   {
      // Calculate time to fire
      Tickval::get_tickval(tofire);
      tofire += timeToWait * Tickval::million;
      what._intervalMS = timeToWait;
   }

   what.set(tofire);
   f8_scoped_spin_lock guard(_spin_lock);
   _event_queue.push(std::move(what));

   return true;
}

//---------------------------------------------------------------------------------------------------
#if defined __x86_64__ && (defined(__linux__) || defined(__FreeBSD__) || defined(__APPLE__))
#define HAVE_RDTSC
inline Tickval::ticks rdtsc()
{
    uint32_t high, low;
    __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high));
    return (static_cast<Tickval::ticks>(high) << 32) + static_cast<Tickval::ticks>(low);
}
#endif

//---------------------------------------------------------------------------------------------------
class IntervalTimer
{
#if defined FIX8_USE_RDTSC && defined FIX8_HAVE_RDTSC
   Tickval::ticks startTime_, delta_;
#else
   Tickval startTime_, delta_;
#endif

public:
#if defined FIX8_USE_RDTSC && defined FIX8_HAVE_RDTSC
   IntervalTimer() : startTime_(rdtsc()) {}
#else
   IntervalTimer() : startTime_(true) {}
#endif

   virtual ~IntervalTimer() {}

   const IntervalTimer& Calculate()
   {
#if defined FIX8_USE_RDTSC && defined FIX8_HAVE_RDTSC
      Tickval::ticks now(rdtsc());
#else
      Tickval now(true);
#endif
      delta_ = now - startTime_;
      return *this;
   }

#if defined FIX8_USE_RDTSC && defined FIX8_HAVE_RDTSC
   double AsDouble() const { return delta_; }
#else
   double AsDouble() const { return delta_.todouble(); }
#endif

   double Reset()
   {
#if defined FIX8_USE_RDTSC && defined FIX8_HAVE_RDTSC
      const Tickval::ticks curr(delta_);
      startTime_ = rdtsc();
#else
      const double curr(AsDouble());
      startTime_.now();
#endif
      return curr;
   }

   friend std::ostream& operator<<(std::ostream& os, const IntervalTimer& what)
   {
      std::ostringstream ostr;
      ostr.setf(std::ios::showpoint);
      ostr.setf(std::ios::fixed);
#if defined FIX8_USE_RDTSC && defined FIX8_HAVE_RDTSC
      ostr << std::setprecision(9) << what;
#else
      ostr << std::setprecision(9) << what.AsDouble();
#endif
      return os << ostr.str();
   }
};

} // FIX8

#endif // FIX8_TIMER_HPP_