ceph/src/boost/boost/chrono/round.hpp

   1 //  boost/chrono/round.hpp  ------------------------------------------------------------//
   2
   3 //  (C) Copyright Howard Hinnant
   4 //  Copyright 2011 Vicente J. Botet Escriba
   5
   6 //  Distributed under the Boost Software License, Version 1.0. (See accompanying
   7 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8
   9 //  See http://www.boost.org/libs/chrono for documentation.
  10
  11 #ifndef BOOST_CHRONO_ROUND_HPP
  12 #define BOOST_CHRONO_ROUND_HPP
  13
  14 #include <boost/chrono/duration.hpp>
  15 #include <boost/chrono/duration.hpp>
  16 //#include <boost/chrono/typeof/boost/chrono/chrono.hpp>
  17
  18 namespace boost
  19 {
  20   namespace chrono
  21   {
  22
  23     /**
  24      * rounds to nearest, to even on tie
  25      */
  26     template <class To, class Rep, class Period>
  27     To round(const duration<Rep, Period>& d)
  28     {
  29         typedef typename common_type<To, duration<Rep, Period> >::type  result_type;
  30         result_type diff0;
  31         result_type diff1;
  32
  33         To t0 = duration_cast<To>(d);
  34         To t1 = t0;
  35         if (t0>d) {
  36           --t1;
  37           diff0 = t0 - d;
  38           diff1 = d - t1;
  39         } else {
  40           ++t1;
  41           diff0 = d - t0;
  42           diff1 = t1 - d;
  43         }
  44
  45         if (diff0 == diff1)
  46         {
  47             if (t0.count() & 1)
  48                 return t1;
  49             return t0;
  50         }
  51         else if (diff0 < diff1)
  52             return t0;
  53         return t1;
  54     }
  55
  56   } // namespace chrono
  57 } // namespace boost
  58
  59 #endif