Boost C++ Libraries

boost/interprocess/sync/posix/timepoint_to_timespec.hpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_INTERPROCESS_DETAIL_TIMEPOINT_TO_TIMESPEC_HPP
#define BOOST_INTERPROCESS_DETAIL_TIMEPOINT_TO_TIMESPEC_HPP

#ifndef BOOST_CONFIG_HPP
#  include <boost/config.hpp>
#endif
#
#if defined(BOOST_HAS_PRAGMA_ONCE)
#  pragma once
#endif

#include <boost/interprocess/detail/mpl.hpp>
#include <boost/interprocess/detail/type_traits.hpp>
#include <boost/interprocess/timed_utils.hpp>

namespace boost {

namespace interprocess {

namespace ipcdetail {

template<class TimePoint>
inline timespec timepoint_to_timespec ( const TimePoint &tm
                                      , typename enable_if_ptime<TimePoint>::type * = 0)
{
   typedef typename TimePoint::date_type            date_type;
   typedef typename TimePoint::time_duration_type   time_duration_type;

   const TimePoint epoch(date_type(1970,1,1));

   //Avoid negative absolute times
   time_duration_type duration  = (tm <= epoch) ? time_duration_type(epoch - epoch)
                                                : time_duration_type(tm - epoch);
   timespec ts;
   ts.tv_sec  = static_cast<time_t>(duration.total_seconds());
   ts.tv_nsec = static_cast<long>(duration.total_nanoseconds() % 1000000000);
   return ts;
}

inline timespec timepoint_to_timespec (const ustime &tm)
{
   timespec ts;
   const boost::uint64_t micros = tm.get_microsecs();
   ts.tv_sec  = static_cast<time_t>(micros /1000000u);
   ts.tv_nsec = static_cast<long>((micros%1000000u)*1000u);
   return ts;
}

template<class TimePoint>
inline timespec timepoint_to_timespec ( const TimePoint &tm
                                      , typename enable_if_time_point<TimePoint>::type * = 0)
{
   typedef typename TimePoint::duration duration_t;
   duration_t d(tm.time_since_epoch());

   timespec ts;
   const typename duration_t::rep cnt = d.count();

   BOOST_IF_CONSTEXPR(duration_t::period::num == 1 && duration_t::period::den == 1000000000)
   {

      ts.tv_sec  = static_cast<time_t>(cnt /duration_t::period::den);
      ts.tv_nsec = static_cast<long>(cnt%duration_t::period::den);
   }
   else
   {
      const double factor = double(duration_t::period::num)/double(duration_t::period::den);
      const double res = double(cnt)*factor;
      ts.tv_sec  = static_cast<time_t>(res);
      ts.tv_nsec = static_cast<long>(1000000000.0*(res - double(ts.tv_sec)));
   }
   return ts;
}

}  //namespace ipcdetail {

}  //namespace interprocess {

}  //namespace boost {

#endif   //ifndef BOOST_INTERPROCESS_DETAIL_TIMEPOINT_TO_TIMESPEC_HPP