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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___CHRONO_CONVERT_TO_TM_H11#define _LIBCPP___CHRONO_CONVERT_TO_TM_H12 13#include <__chrono/calendar.h>14#include <__chrono/concepts.h>15#include <__chrono/day.h>16#include <__chrono/duration.h>17#include <__chrono/file_clock.h>18#include <__chrono/gps_clock.h>19#include <__chrono/hh_mm_ss.h>20#include <__chrono/local_info.h>21#include <__chrono/month.h>22#include <__chrono/month_weekday.h>23#include <__chrono/monthday.h>24#include <__chrono/statically_widen.h>25#include <__chrono/sys_info.h>26#include <__chrono/system_clock.h>27#include <__chrono/tai_clock.h>28#include <__chrono/time_point.h>29#include <__chrono/utc_clock.h>30#include <__chrono/weekday.h>31#include <__chrono/year.h>32#include <__chrono/year_month.h>33#include <__chrono/year_month_day.h>34#include <__chrono/year_month_weekday.h>35#include <__chrono/zoned_time.h>36#include <__concepts/same_as.h>37#include <__config>38#include <__format/format_error.h>39#include <__memory/addressof.h>40#include <__type_traits/common_type.h>41#include <__type_traits/is_convertible.h>42#include <__type_traits/is_specialization.h>43#include <cstdint>44#include <ctime>45#include <limits>46 47#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)48# pragma GCC system_header49#endif50 51_LIBCPP_PUSH_MACROS52#include <__undef_macros>53 54_LIBCPP_BEGIN_NAMESPACE_STD55 56#if _LIBCPP_STD_VER >= 2057 58// Conerts a chrono date and weekday to a given _Tm type.59//60// This is an implementation detail for the function61// template <class _Tm, class _ChronoT>62// _Tm __convert_to_tm(const _ChronoT& __value)63//64// This manually converts the two values to the proper type. It is possible to65// convert from sys_days to time_t and then to _Tm. But this leads to the Y2K66// bug when time_t is a 32-bit signed integer. Chrono considers years beyond67// the year 2038 valid, so instead do the transformation manually.68template <class _Tm, class _Date>69 requires(same_as<_Date, chrono::year_month_day> || same_as<_Date, chrono::year_month_day_last>)70_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _Date& __date, chrono::weekday __weekday) {71 _Tm __result = {};72# ifdef __GLIBC__73 __result.tm_zone = "UTC";74# endif75 __result.tm_year = static_cast<int>(__date.year()) - 1900;76 __result.tm_mon = static_cast<unsigned>(__date.month()) - 1;77 __result.tm_mday = static_cast<unsigned>(__date.day());78 __result.tm_wday = static_cast<unsigned>(__weekday.c_encoding());79 __result.tm_yday =80 (static_cast<chrono::sys_days>(__date) -81 static_cast<chrono::sys_days>(chrono::year_month_day{__date.year(), chrono::January, chrono::day{1}}))82 .count();83 84 return __result;85}86 87template <class _Tm, class _Duration>88_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const chrono::sys_time<_Duration> __tp) {89 chrono::sys_days __days = chrono::floor<chrono::days>(__tp);90 chrono::year_month_day __ymd{__days};91 92 _Tm __result = std::__convert_to_tm<_Tm>(chrono::year_month_day{__ymd}, chrono::weekday{__days});93 94 uint64_t __sec =95 chrono::duration_cast<chrono::seconds>(__tp - chrono::time_point_cast<chrono::seconds>(__days)).count();96 __sec %= 24 * 3600;97 __result.tm_hour = __sec / 3600;98 __sec %= 3600;99 __result.tm_min = __sec / 60;100 __result.tm_sec = __sec % 60;101 102 return __result;103}104 105# if _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION106# if _LIBCPP_HAS_EXPERIMENTAL_TZDB107 108template <class _Tm, class _Duration>109_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(chrono::utc_time<_Duration> __tp) {110 _Tm __result = std::__convert_to_tm<_Tm>(chrono::utc_clock::to_sys(__tp));111 112 if (chrono::get_leap_second_info(__tp).is_leap_second)113 ++__result.tm_sec;114 115 return __result;116}117 118template <class _Tm, class _Duration>119_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(chrono::tai_time<_Duration> __tp) {120 using _Rp = common_type_t<_Duration, chrono::seconds>;121 // The time between the TAI epoch (1958-01-01) and UNIX epoch (1970-01-01).122 // This avoids leap second conversion when going from TAI to UTC.123 // (It also avoids issues when the date is before the UTC epoch.)124 constexpr chrono::seconds __offset{4383 * 24 * 60 * 60};125 return std::__convert_to_tm<_Tm>(chrono::sys_time<_Rp>{__tp.time_since_epoch() - __offset});126}127 128template <class _Tm, class _Duration>129_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(chrono::gps_time<_Duration> __tp) {130 return std::__convert_to_tm<_Tm>(chrono::utc_clock::to_sys(chrono::gps_clock::to_utc(__tp)));131}132 133# endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB134# endif // _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION135 136// Convert a chrono (calendar) time point, or dururation to the given _Tm type,137// which must have the same properties as std::tm.138template <class _Tm, class _ChronoT>139_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _ChronoT& __value) {140 _Tm __result = {};141# ifdef __GLIBC__142 __result.tm_zone = "UTC";143# endif144 145 if constexpr (__is_time_point<_ChronoT>) {146 if constexpr (same_as<typename _ChronoT::clock, chrono::file_clock>)147 return std::__convert_to_tm<_Tm>(_ChronoT::clock::to_sys(__value));148 else if constexpr (same_as<typename _ChronoT::clock, chrono::local_t>)149 return std::__convert_to_tm<_Tm>(chrono::sys_time<typename _ChronoT::duration>{__value.time_since_epoch()});150 else {151 // Note that some clocks have specializations __convert_to_tm for their152 // time_point. These don't need to be added here. They do not trigger153 // this assert.154 static_assert(sizeof(_ChronoT) == 0, "TODO: Add the missing clock specialization");155 }156 } else if constexpr (chrono::__is_duration_v<_ChronoT>) {157 // [time.format]/6158 // ... However, if a flag refers to a "time of day" (e.g. %H, %I, %p,159 // etc.), then a specialization of duration is interpreted as the time of160 // day elapsed since midnight.161 162 // Not all values can be converted to hours, it may run into ratio163 // conversion errors. In that case the conversion to seconds works.164 if constexpr (is_convertible_v<_ChronoT, chrono::hours>) {165 auto __hour = chrono::floor<chrono::hours>(__value);166 auto __sec = chrono::duration_cast<chrono::seconds>(__value - __hour);167 __result.tm_hour = __hour.count() % 24;168 __result.tm_min = __sec.count() / 60;169 __result.tm_sec = __sec.count() % 60;170 } else {171 uint64_t __sec = chrono::duration_cast<chrono::seconds>(__value).count();172 __sec %= 24 * 3600;173 __result.tm_hour = __sec / 3600;174 __sec %= 3600;175 __result.tm_min = __sec / 60;176 __result.tm_sec = __sec % 60;177 }178 } else if constexpr (same_as<_ChronoT, chrono::day>)179 __result.tm_mday = static_cast<unsigned>(__value);180 else if constexpr (same_as<_ChronoT, chrono::month>)181 __result.tm_mon = static_cast<unsigned>(__value) - 1;182 else if constexpr (same_as<_ChronoT, chrono::year>)183 __result.tm_year = static_cast<int>(__value) - 1900;184 else if constexpr (same_as<_ChronoT, chrono::weekday>)185 __result.tm_wday = __value.c_encoding();186 else if constexpr (same_as<_ChronoT, chrono::weekday_indexed> || same_as<_ChronoT, chrono::weekday_last>)187 __result.tm_wday = __value.weekday().c_encoding();188 else if constexpr (same_as<_ChronoT, chrono::month_day>) {189 __result.tm_mday = static_cast<unsigned>(__value.day());190 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1;191 } else if constexpr (same_as<_ChronoT, chrono::month_day_last>) {192 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1;193 } else if constexpr (same_as<_ChronoT, chrono::month_weekday> || same_as<_ChronoT, chrono::month_weekday_last>) {194 __result.tm_wday = __value.weekday_indexed().weekday().c_encoding();195 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1;196 } else if constexpr (same_as<_ChronoT, chrono::year_month>) {197 __result.tm_year = static_cast<int>(__value.year()) - 1900;198 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1;199 } else if constexpr (same_as<_ChronoT, chrono::year_month_day> || same_as<_ChronoT, chrono::year_month_day_last>) {200 return std::__convert_to_tm<_Tm>(201 chrono::year_month_day{__value}, chrono::weekday{static_cast<chrono::sys_days>(__value)});202 } else if constexpr (same_as<_ChronoT, chrono::year_month_weekday> ||203 same_as<_ChronoT, chrono::year_month_weekday_last>) {204 return std::__convert_to_tm<_Tm>(chrono::year_month_day{static_cast<chrono::sys_days>(__value)}, __value.weekday());205 } else if constexpr (__is_hh_mm_ss<_ChronoT>) {206 __result.tm_sec = __value.seconds().count();207 __result.tm_min = __value.minutes().count();208 // In libc++ hours is stored as a long. The type in std::tm is an int. So209 // the overflow can only occur when hour uses more bits than an int210 // provides.211 if constexpr (sizeof(std::chrono::hours::rep) > sizeof(__result.tm_hour))212 if (__value.hours().count() > std::numeric_limits<decltype(__result.tm_hour)>::max())213 std::__throw_format_error("Formatting hh_mm_ss, encountered an hour overflow");214 __result.tm_hour = __value.hours().count();215# if _LIBCPP_HAS_EXPERIMENTAL_TZDB216 } else if constexpr (same_as<_ChronoT, chrono::sys_info>) {217 // Has no time information.218 } else if constexpr (same_as<_ChronoT, chrono::local_info>) {219 // Has no time information.220# if _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION221 } else if constexpr (__is_specialization_v<_ChronoT, chrono::zoned_time>) {222 return std::__convert_to_tm<_Tm>(223 chrono::sys_time<typename _ChronoT::duration>{__value.get_local_time().time_since_epoch()});224# endif225# endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB226 } else227 static_assert(sizeof(_ChronoT) == 0, "Add the missing type specialization");228 229 return __result;230}231 232#endif // if _LIBCPP_STD_VER >= 20233 234_LIBCPP_END_NAMESPACE_STD235 236_LIBCPP_POP_MACROS237 238#endif // _LIBCPP___CHRONO_CONVERT_TO_TM_H239