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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(&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 | 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 |