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 #if defined(BOOST_HAS_FTIME) 24 #include <boost/winapi/time.hpp> 25 #endif 26 27 #ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK 28 29 namespace boost { 30 namespace date_time { 31 32 //! A clock providing microsecond level resolution 33 /*! A high precision clock that measures the local time 34 * at a resolution up to microseconds and adjusts to the 35 * resolution of the time system. For example, for the 36 * a library configuration with nano second resolution, 37 * the last 3 places of the fractional seconds will always 38 * be 000 since there are 1000 nano-seconds in a micro second. 39 */ 40 template<class time_type> 41 class microsec_clock 42 { 43 private: 44 //! Type for the function used to convert time_t to tm 45 typedef std::tm* (*time_converter)(const std::time_t*, std::tm*); 46 47 public: 48 typedef typename time_type::date_type date_type; 49 typedef typename time_type::time_duration_type time_duration_type; 50 typedef typename time_duration_type::rep_type resolution_traits_type; 51 52 //! return a local time object for the given zone, based on computer clock 53 //JKG -- looks like we could rewrite this against universal_time 54 template<class time_zone_type> local_time(shared_ptr<time_zone_type> tz_ptr)55 static time_type local_time(shared_ptr<time_zone_type> tz_ptr) 56 { 57 typedef typename time_type::utc_time_type utc_time_type; 58 typedef second_clock<utc_time_type> second_clock; 59 // we'll need to know the utc_offset this machine has 60 // in order to get a utc_time_type set to utc 61 utc_time_type utc_time = second_clock::universal_time(); 62 time_duration_type utc_offset = second_clock::local_time() - utc_time; 63 // use micro clock to get a local time with sub seconds 64 // and adjust it to get a true utc time reading with sub seconds 65 utc_time = microsec_clock<utc_time_type>::local_time() - utc_offset; 66 return time_type(utc_time, tz_ptr); 67 } 68 69 //! Returns the local time based on computer clock settings local_time()70 static time_type local_time() 71 { 72 return create_time(&c_time::localtime); 73 } 74 75 //! Returns the UTC time based on computer settings universal_time()76 static time_type universal_time() 77 { 78 return create_time(&c_time::gmtime); 79 } 80 81 private: create_time(time_converter converter)82 static time_type create_time(time_converter converter) 83 { 84 #ifdef BOOST_HAS_GETTIMEOFDAY 85 timeval tv; 86 gettimeofday(&tv, 0); //gettimeofday does not support TZ adjust on Linux. 87 std::time_t t = tv.tv_sec; 88 boost::uint32_t sub_sec = tv.tv_usec; 89 #elif defined(BOOST_HAS_FTIME) 90 boost::winapi::FILETIME_ ft; 91 boost::winapi::GetSystemTimeAsFileTime(&ft); 92 #if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3205)) 93 // Some runtime library implementations expect local times as the norm for ctime functions. 94 { 95 boost::winapi::FILETIME_ local_ft; 96 boost::winapi::FileTimeToLocalFileTime(&ft, &local_ft); 97 ft = local_ft; 98 } 99 #endif 100 101 boost::uint64_t micros = file_time_to_microseconds(ft); // it will not wrap, since ft is the current time 102 // and cannot be before 1970-Jan-01 103 std::time_t t = static_cast<std::time_t>(micros / 1000000UL); // seconds since epoch 104 // microseconds -- static casts suppress warnings 105 boost::uint32_t sub_sec = static_cast<boost::uint32_t>(micros % 1000000UL); 106 #else 107 #error Internal Boost.DateTime error: BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK is defined, however neither gettimeofday nor FILETIME support is detected. 108 #endif 109 110 std::tm curr; 111 std::tm* curr_ptr = converter(&t, &curr); 112 date_type d(static_cast< typename date_type::year_type::value_type >(curr_ptr->tm_year + 1900), 113 static_cast< typename date_type::month_type::value_type >(curr_ptr->tm_mon + 1), 114 static_cast< typename date_type::day_type::value_type >(curr_ptr->tm_mday)); 115 116 //The following line will adjust the fractional second tick in terms 117 //of the current time system. For example, if the time system 118 //doesn't support fractional seconds then res_adjust returns 0 119 //and all the fractional seconds return 0. 120 int adjust = static_cast< int >(resolution_traits_type::res_adjust() / 1000000); 121 122 time_duration_type td(static_cast< typename time_duration_type::hour_type >(curr_ptr->tm_hour), 123 static_cast< typename time_duration_type::min_type >(curr_ptr->tm_min), 124 static_cast< typename time_duration_type::sec_type >(curr_ptr->tm_sec), 125 sub_sec * adjust); 126 127 return time_type(d,td); 128 } 129 130 #if defined(BOOST_HAS_FTIME) 131 /*! 132 * The function converts file_time into number of microseconds elapsed since 1970-Jan-01 133 * 134 * \note Only dates after 1970-Jan-01 are supported. Dates before will be wrapped. 135 */ file_time_to_microseconds(boost::winapi::FILETIME_ const & ft)136 static boost::uint64_t file_time_to_microseconds(boost::winapi::FILETIME_ const& ft) 137 { 138 // shift is difference between 1970-Jan-01 & 1601-Jan-01 139 // in 100-nanosecond units 140 const boost::uint64_t shift = 116444736000000000ULL; // (27111902 << 32) + 3577643008 141 142 // 100-nanos since 1601-Jan-01 143 boost::uint64_t ft_as_integer = (static_cast< boost::uint64_t >(ft.dwHighDateTime) << 32) | static_cast< boost::uint64_t >(ft.dwLowDateTime); 144 145 ft_as_integer -= shift; // filetime is now 100-nanos since 1970-Jan-01 146 return (ft_as_integer / 10U); // truncate to microseconds 147 } 148 #endif 149 }; 150 151 152 } } //namespace date_time 153 154 #endif //BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK 155 156 157 #endif 158 159