1 | #ifndef DATE_TIME_HIGHRES_TIME_CLOCK_HPP___ |
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2 | #define DATE_TIME_HIGHRES_TIME_CLOCK_HPP___ |
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3 | |
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4 | /* Copyright (c) 2002,2003,2005 CrystalClear Software, Inc. |
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5 | * Use, modification and distribution is subject to the |
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6 | * Boost Software License, Version 1.0. (See accompanying |
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7 | * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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8 | * Author: Jeff Garland, Bart Garst |
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9 | * $Date: 2010-05-10 05:15:48 -0400 (Mon, 10 May 2010) $ |
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10 | */ |
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11 | |
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12 | |
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13 | /*! @file microsec_time_clock.hpp |
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14 | This file contains a high resolution time clock implementation. |
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15 | */ |
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16 | |
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17 | #include <boost/cstdint.hpp> |
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18 | #include <boost/shared_ptr.hpp> |
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19 | #include <boost/detail/workaround.hpp> |
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20 | #include <boost/date_time/compiler_config.hpp> |
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21 | #include <boost/date_time/c_time.hpp> |
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22 | #include <boost/date_time/time_clock.hpp> |
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23 | #include <boost/date_time/filetime_functions.hpp> |
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24 | |
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25 | #ifdef BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK |
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26 | |
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27 | namespace boost { |
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28 | namespace date_time { |
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29 | |
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30 | //! A clock providing microsecond level resolution |
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31 | /*! A high precision clock that measures the local time |
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32 | * at a resolution up to microseconds and adjusts to the |
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33 | * resolution of the time system. For example, for the |
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34 | * a library configuration with nano second resolution, |
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35 | * the last 3 places of the fractional seconds will always |
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36 | * be 000 since there are 1000 nano-seconds in a micro second. |
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37 | */ |
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38 | template<class time_type> |
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39 | class microsec_clock |
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40 | { |
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41 | private: |
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42 | //! Type for the function used to convert time_t to tm |
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43 | typedef std::tm* (*time_converter)(const std::time_t*, std::tm*); |
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44 | |
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45 | public: |
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46 | typedef typename time_type::date_type date_type; |
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47 | typedef typename time_type::time_duration_type time_duration_type; |
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48 | typedef typename time_duration_type::rep_type resolution_traits_type; |
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49 | |
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50 | //! return a local time object for the given zone, based on computer clock |
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51 | //JKG -- looks like we could rewrite this against universal_time |
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52 | template<class time_zone_type> |
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53 | static time_type local_time(shared_ptr<time_zone_type> tz_ptr) |
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54 | { |
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55 | typedef typename time_type::utc_time_type utc_time_type; |
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56 | typedef second_clock<utc_time_type> second_clock; |
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57 | // we'll need to know the utc_offset this machine has |
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58 | // in order to get a utc_time_type set to utc |
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59 | utc_time_type utc_time = second_clock::universal_time(); |
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60 | time_duration_type utc_offset = second_clock::local_time() - utc_time; |
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61 | // use micro clock to get a local time with sub seconds |
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62 | // and adjust it to get a true utc time reading with sub seconds |
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63 | utc_time = microsec_clock<utc_time_type>::local_time() - utc_offset; |
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64 | return time_type(utc_time, tz_ptr); |
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65 | } |
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66 | |
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67 | //! Returns the local time based on computer clock settings |
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68 | static time_type local_time() |
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69 | { |
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70 | return create_time(&c_time::localtime); |
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71 | } |
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72 | |
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73 | //! Returns the UTC time based on computer settings |
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74 | static time_type universal_time() |
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75 | { |
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76 | return create_time(&c_time::gmtime); |
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77 | } |
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78 | |
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79 | private: |
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80 | static time_type create_time(time_converter converter) |
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81 | { |
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82 | #ifdef BOOST_HAS_GETTIMEOFDAY |
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83 | timeval tv; |
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84 | gettimeofday(&tv, 0); //gettimeofday does not support TZ adjust on Linux. |
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85 | std::time_t t = tv.tv_sec; |
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86 | boost::uint32_t sub_sec = tv.tv_usec; |
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87 | #elif defined(BOOST_HAS_FTIME) |
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88 | winapi::file_time ft; |
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89 | winapi::get_system_time_as_file_time(ft); |
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90 | uint64_t micros = winapi::file_time_to_microseconds(ft); // it will not wrap, since ft is the current time |
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91 | // and cannot be before 1970-Jan-01 |
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92 | std::time_t t = static_cast<std::time_t>(micros / 1000000UL); // seconds since epoch |
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93 | // microseconds -- static casts supress warnings |
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94 | boost::uint32_t sub_sec = static_cast<boost::uint32_t>(micros % 1000000UL); |
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95 | #else |
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96 | #error Internal Boost.DateTime error: BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK is defined, however neither gettimeofday nor FILETIME support is detected. |
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97 | #endif |
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98 | |
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99 | std::tm curr; |
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100 | std::tm* curr_ptr = converter(&t, &curr); |
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101 | date_type d(static_cast< typename date_type::year_type::value_type >(curr_ptr->tm_year + 1900), |
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102 | static_cast< typename date_type::month_type::value_type >(curr_ptr->tm_mon + 1), |
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103 | static_cast< typename date_type::day_type::value_type >(curr_ptr->tm_mday)); |
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104 | |
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105 | //The following line will adjust the fractional second tick in terms |
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106 | //of the current time system. For example, if the time system |
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107 | //doesn't support fractional seconds then res_adjust returns 0 |
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108 | //and all the fractional seconds return 0. |
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109 | int adjust = static_cast< int >(resolution_traits_type::res_adjust() / 1000000); |
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110 | |
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111 | time_duration_type td(static_cast< typename time_duration_type::hour_type >(curr_ptr->tm_hour), |
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112 | static_cast< typename time_duration_type::min_type >(curr_ptr->tm_min), |
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113 | static_cast< typename time_duration_type::sec_type >(curr_ptr->tm_sec), |
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114 | sub_sec * adjust); |
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115 | |
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116 | return time_type(d,td); |
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117 | } |
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118 | }; |
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119 | |
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120 | |
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121 | } } //namespace date_time |
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122 | |
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123 | #endif //BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK |
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124 | |
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125 | |
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126 | #endif |
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127 | |
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