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 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(converter: &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(converter: &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: &tv, tz: 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) |
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 | boost::uint32_t sub_sec = static_cast<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 | |