BVB Source Codes

mars Show microsec_time_clock.hpp Source code

Return Download mars: download microsec_time_clock.hpp Source code - Download mars Source code - Type:.hpp
  1. #ifndef DATE_TIME_HIGHRES_TIME_CLOCK_HPP___
  2. #define DATE_TIME_HIGHRES_TIME_CLOCK_HPP___
  3.  
  4. /* Copyright (c) 2002,2003,2005 CrystalClear Software, Inc.
  5.  * Use, modification and distribution is subject to the
  6.  * Boost Software License, Version 1.0. (See accompanying
  7.  * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
  8.  * Author: Jeff Garland, Bart Garst
  9.  * $Date$
  10.  */
  11.  
  12.  
  13. /*! @file microsec_time_clock.hpp
  14.   This file contains a high resolution time clock implementation.
  15. */
  16.  
  17. #include <boost/cstdint.hpp>
  18. #include <boost/shared_ptr.hpp>
  19. #include <boost/detail/workaround.hpp>
  20. #include <boost/date_time/compiler_config.hpp>
  21. #include <boost/date_time/c_time.hpp>
  22. #include <boost/date_time/time_clock.hpp>
  23. #include <boost/date_time/filetime_functions.hpp>
  24.  
  25. #ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK
  26.  
  27. namespace mars_boost {} namespace boost = mars_boost; namespace mars_boost {
  28. namespace date_time {
  29.  
  30.   //! A clock providing microsecond level resolution
  31.   /*! A high precision clock that measures the local time
  32.    *  at a resolution up to microseconds and adjusts to the
  33.    *  resolution of the time system.  For example, for the
  34.    *  a library configuration with nano second resolution,
  35.    *  the last 3 places of the fractional seconds will always
  36.    *  be 000 since there are 1000 nano-seconds in a micro second.
  37.    */
  38.   template<class time_type>
  39.   class microsec_clock
  40.   {
  41.   private:
  42.     //! Type for the function used to convert time_t to tm
  43.     typedef std::tm* (*time_converter)(const std::time_t*, std::tm*);
  44.  
  45.   public:
  46.     typedef typename time_type::date_type date_type;
  47.     typedef typename time_type::time_duration_type time_duration_type;
  48.     typedef typename time_duration_type::rep_type resolution_traits_type;
  49.  
  50.     //! return a local time object for the given zone, based on computer clock
  51.     //JKG -- looks like we could rewrite this against universal_time
  52.     template<class time_zone_type>
  53.     static time_type local_time(shared_ptr<time_zone_type> tz_ptr)
  54.     {
  55.       typedef typename time_type::utc_time_type utc_time_type;
  56.       typedef second_clock<utc_time_type> second_clock;
  57.       // we'll need to know the utc_offset this machine has
  58.       // in order to get a utc_time_type set to utc
  59.       utc_time_type utc_time = second_clock::universal_time();
  60.       time_duration_type utc_offset = second_clock::local_time() - utc_time;
  61.       // use micro clock to get a local time with sub seconds
  62.       // and adjust it to get a true utc time reading with sub seconds
  63.       utc_time = microsec_clock<utc_time_type>::local_time() - utc_offset;
  64.       return time_type(utc_time, tz_ptr);
  65.     }
  66.  
  67.     //! Returns the local time based on computer clock settings
  68.     static time_type local_time()
  69.     {
  70.       return create_time(&c_time::localtime);
  71.     }
  72.  
  73.     //! Returns the UTC time based on computer settings
  74.     static time_type universal_time()
  75.     {
  76.       return create_time(&c_time::gmtime);
  77.     }
  78.  
  79.   private:
  80.     static time_type create_time(time_converter converter)
  81.     {
  82. #ifdef BOOST_HAS_GETTIMEOFDAY
  83.       timeval tv;
  84.       gettimeofday(&tv, 0); //gettimeofday does not support TZ adjust on Linux.
  85.       std::time_t t = tv.tv_sec;
  86.       mars_boost::uint32_t sub_sec = tv.tv_usec;
  87. #elif defined(BOOST_HAS_FTIME)
  88.       winapi::file_time ft;
  89.       winapi::get_system_time_as_file_time(ft);
  90.       uint64_t micros = winapi::file_time_to_microseconds(ft); // it will not wrap, since ft is the current time
  91.                                                                // and cannot be before 1970-Jan-01
  92.       std::time_t t = static_cast<std::time_t>(micros / 1000000UL); // seconds since epoch
  93.       // microseconds -- static casts suppress warnings
  94.       mars_boost::uint32_t sub_sec = static_cast<mars_boost::uint32_t>(micros % 1000000UL);
  95. #else
  96. #error Internal Boost.DateTime error: BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK is defined, however neither gettimeofday nor FILETIME support is detected.
  97. #endif
  98.  
  99.       std::tm curr;
  100.       std::tm* curr_ptr = converter(&t, &curr);
  101.       date_type d(static_cast< typename date_type::year_type::value_type >(curr_ptr->tm_year + 1900),
  102.                   static_cast< typename date_type::month_type::value_type >(curr_ptr->tm_mon + 1),
  103.                   static_cast< typename date_type::day_type::value_type >(curr_ptr->tm_mday));
  104.  
  105.       //The following line will adjust the fractional second tick in terms
  106.       //of the current time system.  For example, if the time system
  107.       //doesn't support fractional seconds then res_adjust returns 0
  108.       //and all the fractional seconds return 0.
  109.       int adjust = static_cast< int >(resolution_traits_type::res_adjust() / 1000000);
  110.  
  111.       time_duration_type td(static_cast< typename time_duration_type::hour_type >(curr_ptr->tm_hour),
  112.                             static_cast< typename time_duration_type::min_type >(curr_ptr->tm_min),
  113.                             static_cast< typename time_duration_type::sec_type >(curr_ptr->tm_sec),
  114.                             sub_sec * adjust);
  115.  
  116.       return time_type(d,td);
  117.     }
  118.   };
  119.  
  120.  
  121. } } //namespace date_time
  122.  
  123. #endif //BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK
  124.  
  125.  
  126. #endif
  127.  
  128.  
downloadmicrosec_time_clock.hpp Source code - Download mars Source code
Related Source Codes/Software:
Hero - Elegant transition library for iOS & tvOS 2017-06-09
deep-photo-styletransfer - Code and data for paper "Deep Photo Style Transfer... 2017-06-09
mastodon - A GNU Social-compatible microblogging server ... 2017-06-09
plyr - A simple HTML5, YouTube and Vimeo player ... 2017-06-08
prepack - Prepack is a partial evaluator for JavaScript. Pre... 2017-06-08
Public-APIs - 2017-06-09
lottie-ios - An iOS library to natively render After Effects ve... 2017-06-09
Awesome-Hacking - A collection of various awesome lists for hackers,... 2017-06-09
algorithms - Minimal examples of data structures and algorithms... 2017-06-10
lectures - Oxford Deep NLP 2017 course 2017-06-10
CRYENGINE - CRYENGINE is a powerful real-time game development... 2017-06-11
postal - 2017-06-11
reactide - Reactide is the first dedicated IDE for React web ... 2017-06-11
rkt - rkt is a pod-native container engine for Linux. It... 2017-06-11
uWebSockets - Tiny WebSockets https://for... 2017-06-11
realworld - TodoMVC for the RealWorld - Exemplary fullstack Me... 2017-06-11
goreplay - GoReplay is an open-source tool for capturing and ... 2017-06-10
pyenv - Simple Python version management 2017-06-10
redux-saga - An alternative side effect model for Redux apps ... 2017-06-10
angular-starter - 2017-06-10

 Back to top