| #ifndef DATE_TIME_HIGHRES_TIME_CLOCK_HPP___ |
| #define DATE_TIME_HIGHRES_TIME_CLOCK_HPP___ |
| |
| /* Copyright (c) 2002,2003,2005 CrystalClear Software, Inc. |
| * Use, modification and distribution is subject to the |
| * Boost Software License, Version 1.0. (See accompanying |
| * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
| * Author: Jeff Garland, Bart Garst |
| * $Date: 2010-05-10 05:15:48 -0400 (Mon, 10 May 2010) $ |
| */ |
| |
| |
| /*! @file microsec_time_clock.hpp |
| This file contains a high resolution time clock implementation. |
| */ |
| |
| #include <boost/cstdint.hpp> |
| #include <boost/shared_ptr.hpp> |
| #include <boost/detail/workaround.hpp> |
| #include <boost/date_time/compiler_config.hpp> |
| #include <boost/date_time/c_time.hpp> |
| #include <boost/date_time/time_clock.hpp> |
| #include <boost/date_time/filetime_functions.hpp> |
| |
| #ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK |
| |
| namespace boost { |
| namespace date_time { |
| |
| //! A clock providing microsecond level resolution |
| /*! A high precision clock that measures the local time |
| * at a resolution up to microseconds and adjusts to the |
| * resolution of the time system. For example, for the |
| * a library configuration with nano second resolution, |
| * the last 3 places of the fractional seconds will always |
| * be 000 since there are 1000 nano-seconds in a micro second. |
| */ |
| template<class time_type> |
| class microsec_clock |
| { |
| private: |
| //! Type for the function used to convert time_t to tm |
| typedef std::tm* (*time_converter)(const std::time_t*, std::tm*); |
| |
| public: |
| typedef typename time_type::date_type date_type; |
| typedef typename time_type::time_duration_type time_duration_type; |
| typedef typename time_duration_type::rep_type resolution_traits_type; |
| |
| //! return a local time object for the given zone, based on computer clock |
| //JKG -- looks like we could rewrite this against universal_time |
| template<class time_zone_type> |
| static time_type local_time(shared_ptr<time_zone_type> tz_ptr) |
| { |
| typedef typename time_type::utc_time_type utc_time_type; |
| typedef second_clock<utc_time_type> second_clock; |
| // we'll need to know the utc_offset this machine has |
| // in order to get a utc_time_type set to utc |
| utc_time_type utc_time = second_clock::universal_time(); |
| time_duration_type utc_offset = second_clock::local_time() - utc_time; |
| // use micro clock to get a local time with sub seconds |
| // and adjust it to get a true utc time reading with sub seconds |
| utc_time = microsec_clock<utc_time_type>::local_time() - utc_offset; |
| return time_type(utc_time, tz_ptr); |
| } |
| |
| //! Returns the local time based on computer clock settings |
| static time_type local_time() |
| { |
| return create_time(&c_time::localtime); |
| } |
| |
| //! Returns the UTC time based on computer settings |
| static time_type universal_time() |
| { |
| return create_time(&c_time::gmtime); |
| } |
| |
| private: |
| static time_type create_time(time_converter converter) |
| { |
| #ifdef BOOST_HAS_GETTIMEOFDAY |
| timeval tv; |
| gettimeofday(&tv, 0); //gettimeofday does not support TZ adjust on Linux. |
| std::time_t t = tv.tv_sec; |
| boost::uint32_t sub_sec = tv.tv_usec; |
| #elif defined(BOOST_HAS_FTIME) |
| winapi::file_time ft; |
| winapi::get_system_time_as_file_time(ft); |
| uint64_t micros = winapi::file_time_to_microseconds(ft); // it will not wrap, since ft is the current time |
| // and cannot be before 1970-Jan-01 |
| std::time_t t = static_cast<std::time_t>(micros / 1000000UL); // seconds since epoch |
| // microseconds -- static casts supress warnings |
| boost::uint32_t sub_sec = static_cast<boost::uint32_t>(micros % 1000000UL); |
| #else |
| #error Internal Boost.DateTime error: BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK is defined, however neither gettimeofday nor FILETIME support is detected. |
| #endif |
| |
| std::tm curr; |
| std::tm* curr_ptr = converter(&t, &curr); |
| date_type d(static_cast< typename date_type::year_type::value_type >(curr_ptr->tm_year + 1900), |
| static_cast< typename date_type::month_type::value_type >(curr_ptr->tm_mon + 1), |
| static_cast< typename date_type::day_type::value_type >(curr_ptr->tm_mday)); |
| |
| //The following line will adjust the fractional second tick in terms |
| //of the current time system. For example, if the time system |
| //doesn't support fractional seconds then res_adjust returns 0 |
| //and all the fractional seconds return 0. |
| int adjust = static_cast< int >(resolution_traits_type::res_adjust() / 1000000); |
| |
| time_duration_type td(static_cast< typename time_duration_type::hour_type >(curr_ptr->tm_hour), |
| static_cast< typename time_duration_type::min_type >(curr_ptr->tm_min), |
| static_cast< typename time_duration_type::sec_type >(curr_ptr->tm_sec), |
| sub_sec * adjust); |
| |
| return time_type(d,td); |
| } |
| }; |
| |
| |
| } } //namespace date_time |
| |
| #endif //BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK |
| |
| |
| #endif |
| |