sync/posix/timepoint_to_timespec.hpp

0001 //////////////////////////////////////////////////////////////////////////////
0002 //
0003 // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
0004 // Software License, Version 1.0. (See accompanying file
0005 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // See http://www.boost.org/libs/interprocess for documentation.
0008 //
0009 //////////////////////////////////////////////////////////////////////////////
0010
0011 #ifndef BOOST_INTERPROCESS_DETAIL_TIMEPOINT_TO_TIMESPEC_HPP
0012 #define BOOST_INTERPROCESS_DETAIL_TIMEPOINT_TO_TIMESPEC_HPP
0013
0014 #ifndef BOOST_CONFIG_HPP
0015 #  include <boost/config.hpp>
0016 #endif
0017 0018 ">#
0019 #if defined(BOOST_HAS_PRAGMA_ONCE)
0020 #  pragma once
0021 #endif
0022
0023 #include <boost/interprocess/detail/mpl.hpp>
0024 #include <boost/interprocess/detail/type_traits.hpp>
0025 #include <boost/interprocess/timed_utils.hpp>
0026
0027 namespace boost {
0028
0029 namespace interprocess {
0030
0031 namespace ipcdetail {
0032
0033 template<class TimePoint>
0034 inline timespec timepoint_to_timespec ( const TimePoint &tm
0035                                       , typename enable_if_ptime<TimePoint>::type * = 0)
0036 {
0037    typedef typename TimePoint::date_type            date_type;
0038    typedef typename TimePoint::time_duration_type   time_duration_type;
0039
0040    const TimePoint epoch(date_type(1970,1,1));
0041
0042    //Avoid negative absolute times
0043    time_duration_type duration  = (tm <= epoch) ? time_duration_type(epoch - epoch)
0044                                                 : time_duration_type(tm - epoch);
0045    timespec ts;
0046    ts.tv_sec  = static_cast<time_t>(duration.total_seconds());
0047    ts.tv_nsec = static_cast<long>(duration.total_nanoseconds() % 1000000000);
0048    return ts;
0049 }
0050
0051 inline timespec timepoint_to_timespec (const ustime &tm)
0052 {
0053    timespec ts;
0054    const boost::uint64_t micros = tm.get_microsecs();
0055    ts.tv_sec  = static_cast<time_t>(micros /1000000u);
0056    ts.tv_nsec = static_cast<long>((micros%1000000u)*1000u);
0057    return ts;
0058 }
0059
0060 template<class TimePoint>
0061 inline timespec timepoint_to_timespec ( const TimePoint &tm
0062                                       , typename enable_if_time_point<TimePoint>::type * = 0)
0063 {
0064    typedef typename TimePoint::duration duration_t;
0065    duration_t d(tm.time_since_epoch());
0066
0067    timespec ts;
0068    const typename duration_t::rep cnt = d.count();
0069
0070    BOOST_IF_CONSTEXPR(duration_t::period::num == 1 && duration_t::period::den == 1000000000)
0071    {
0072
0073       ts.tv_sec  = static_cast<time_t>(cnt /duration_t::period::den);
0074       ts.tv_nsec = static_cast<long>(cnt%duration_t::period::den);
0075    }
0076    else
0077    {
0078       const double factor = double(duration_t::period::num)/double(duration_t::period::den);
0079       const double res = double(cnt)*factor;
0080       ts.tv_sec  = static_cast<time_t>(res);
0081       ts.tv_nsec = static_cast<long>(1000000000.0*(res - double(ts.tv_sec)));
0082    }
0083    return ts;
0084 }
0085
0086 }  //namespace ipcdetail {
0087
0088 }  //namespace interprocess {
0089
0090 }  //namespace boost {
0091
0092 #endif   //ifndef BOOST_INTERPROCESS_DETAIL_TIMEPOINT_TO_TIMESPEC_HPP