1 #ifndef DATE_TIME_HIGHRES_TIME_CLOCK_HPP___
2 #define DATE_TIME_HIGHRES_TIME_CLOCK_HPP___
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: 2010-05-10 05:15:48 -0400 (Mon, 10 May 2010) $
13 /*! @file microsec_time_clock.hpp
14 This file contains a high resolution time clock implementation.
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>
25 #ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK
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.
38 template<class time_type>
42 //! Type for the function used to convert time_t to tm
43 typedef std::tm* (*time_converter)(const std::time_t*, std::tm*);
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;
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)
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);
67 //! Returns the local time based on computer clock settings
68 static time_type local_time()
70 return create_time(&c_time::localtime);
73 //! Returns the UTC time based on computer settings
74 static time_type universal_time()
76 return create_time(&c_time::gmtime);
80 static time_type create_time(time_converter converter)
82 #ifdef BOOST_HAS_GETTIMEOFDAY
84 gettimeofday(&tv, 0); //gettimeofday does not support TZ adjust on Linux.
85 std::time_t t = tv.tv_sec;
86 boost::uint32_t sub_sec = tv.tv_usec;
87 #elif defined(BOOST_HAS_FTIME)
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 supress warnings
94 boost::uint32_t sub_sec = static_cast<boost::uint32_t>(micros % 1000000UL);
96 #error Internal Boost.DateTime error: BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK is defined, however neither gettimeofday nor FILETIME support is detected.
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));
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);
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),
116 return time_type(d,td);
121 } } //namespace date_time
123 #endif //BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK