rtorrent/src/timer.h

#ifndef LIBTORRENT_TIMER_H
#define LIBTORRENT_TIMER_H

#include <inttypes.h>
#include <sys/time.h>

// Don't convert negative Timer to timeval.
class Timer {
 public:
  Timer() : m_time(0) {}
  Timer(int64_t usec) : m_time(usec) {}
  Timer(timeval tv) : m_time((int64_t)(uint32_t)tv.tv_sec * 1000000 + (int64_t)(uint32_t)tv.tv_usec % 1000000) {}

  int64_t   usec() const                  { return m_time; }

  timeval tval() const                    { return (timeval) { m_time / 1000000, m_time % 1000000}; }

  Timer operator - (const Timer& t) const { return Timer(m_time - t.m_time); }
  Timer operator + (const Timer& t) const { return Timer(m_time + t.m_time); }

  Timer operator -= (int64_t t)           { m_time -= t; return *this; }
  Timer operator -= (const Timer& t)      { m_time -= t.m_time; return *this; }

  Timer operator += (int64_t t)           { m_time += t; return *this; }
  Timer operator += (const Timer& t)      { m_time += t.m_time; return *this; }

  static Timer current() {
    timeval t;
    gettimeofday(&t, 0);

    return Timer(t);
  }

  // Cached time, updated in the beginning of torrent::work call.
  // Don't use outside socket_base read/write/except or Service::service.
  
  // TODO: Find out if it's worth it. The kernel is supposed to cache the
  // time. Though system calls would be more expensive than we can afford.
  static Timer cache()                    { return Timer(m_cache); }

  static void update()                    { m_cache = Timer::current().usec(); }

  bool operator <  (const Timer& t) const { return m_time < t.m_time; }
  bool operator >  (const Timer& t) const { return m_time > t.m_time; }
  bool operator <= (const Timer& t) const { return m_time <= t.m_time; }
  bool operator >= (const Timer& t) const { return m_time >= t.m_time; }
  bool operator == (const Timer& t) const { return m_time == t.m_time; }

 private:
  int64_t m_time;

  // Instantiated in torrent.cc
  static int64_t m_cache;
};

#endif // LIBTORRENT_TIMER_H