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-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___CHRONO_CONVERT_TO_TM_H 11 #define _LIBCPP___CHRONO_CONVERT_TO_TM_H 12 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/hh_mm_ss.h> 19 #include <__chrono/local_info.h> 20 #include <__chrono/month.h> 21 #include <__chrono/month_weekday.h> 22 #include <__chrono/monthday.h> 23 #include <__chrono/statically_widen.h> 24 #include <__chrono/sys_info.h> 25 #include <__chrono/system_clock.h> 26 #include <__chrono/time_point.h> 27 #include <__chrono/utc_clock.h> 28 #include <__chrono/weekday.h> 29 #include <__chrono/year.h> 30 #include <__chrono/year_month.h> 31 #include <__chrono/year_month_day.h> 32 #include <__chrono/year_month_weekday.h> 33 #include <__chrono/zoned_time.h> 34 #include <__concepts/same_as.h> 35 #include <__config> 36 #include <__format/format_error.h> 37 #include <__memory/addressof.h> 38 #include <__type_traits/is_convertible.h> 39 #include <__type_traits/is_specialization.h> 40 #include <cstdint> 41 #include <ctime> 42 #include <limits> 43 44 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 45 # pragma GCC system_header 46 #endif 47 48 _LIBCPP_PUSH_MACROS 49 #include <__undef_macros> 50 51 _LIBCPP_BEGIN_NAMESPACE_STD 52 53 #if _LIBCPP_STD_VER >= 20 54 55 // Conerts a chrono date and weekday to a given _Tm type. 56 // 57 // This is an implementation detail for the function 58 // template <class _Tm, class _ChronoT> 59 // _Tm __convert_to_tm(const _ChronoT& __value) 60 // 61 // This manually converts the two values to the proper type. It is possible to 62 // convert from sys_days to time_t and then to _Tm. But this leads to the Y2K 63 // bug when time_t is a 32-bit signed integer. Chrono considers years beyond 64 // the year 2038 valid, so instead do the transformation manually. 65 template <class _Tm, class _Date> 66 requires(same_as<_Date, chrono::year_month_day> || same_as<_Date, chrono::year_month_day_last>) 67 _LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _Date& __date, chrono::weekday __weekday) { 68 _Tm __result = {}; 69 # ifdef __GLIBC__ 70 __result.tm_zone = "UTC"; 71 # endif 72 __result.tm_year = static_cast<int>(__date.year()) - 1900; 73 __result.tm_mon = static_cast<unsigned>(__date.month()) - 1; 74 __result.tm_mday = static_cast<unsigned>(__date.day()); 75 __result.tm_wday = static_cast<unsigned>(__weekday.c_encoding()); 76 __result.tm_yday = 77 (static_cast<chrono::sys_days>(__date) - 78 static_cast<chrono::sys_days>(chrono::year_month_day{__date.year(), chrono::January, chrono::day{1}})) 79 .count(); 80 81 return __result; 82 } 83 84 template <class _Tm, class _Duration> 85 _LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const chrono::sys_time<_Duration> __tp) { 86 chrono::sys_days __days = chrono::floor<chrono::days>(__tp); 87 chrono::year_month_day __ymd{__days}; 88 89 _Tm __result = std::__convert_to_tm<_Tm>(chrono::year_month_day{__ymd}, chrono::weekday{__days}); 90 91 uint64_t __sec = 92 chrono::duration_cast<chrono::seconds>(__tp - chrono::time_point_cast<chrono::seconds>(__days)).count(); 93 __sec %= 24 * 3600; 94 __result.tm_hour = __sec / 3600; 95 __sec %= 3600; 96 __result.tm_min = __sec / 60; 97 __result.tm_sec = __sec % 60; 98 99 return __result; 100 } 101 102 # if _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION 103 # if _LIBCPP_HAS_EXPERIMENTAL_TZDB 104 105 template <class _Tm, class _Duration> 106 _LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(chrono::utc_time<_Duration> __tp) { 107 _Tm __result = std::__convert_to_tm<_Tm>(chrono::utc_clock::to_sys(__tp)); 108 109 if (chrono::get_leap_second_info(__tp).is_leap_second) 110 ++__result.tm_sec; 111 112 return __result; 113 } 114 115 # endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB 116 # endif // _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION 117 118 // Convert a chrono (calendar) time point, or dururation to the given _Tm type, 119 // which must have the same properties as std::tm. 120 template <class _Tm, class _ChronoT> 121 _LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _ChronoT& __value) { 122 _Tm __result = {}; 123 # ifdef __GLIBC__ 124 __result.tm_zone = "UTC"; 125 # endif 126 127 if constexpr (__is_time_point<_ChronoT>) { 128 if constexpr (same_as<typename _ChronoT::clock, chrono::system_clock>) 129 return std::__convert_to_tm<_Tm>(__value); 130 # if _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION 131 # if _LIBCPP_HAS_EXPERIMENTAL_TZDB 132 else if constexpr (same_as<typename _ChronoT::clock, chrono::utc_clock>) 133 return std::__convert_to_tm<_Tm>(__value); 134 # endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB 135 # endif // _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION 136 else if constexpr (same_as<typename _ChronoT::clock, chrono::file_clock>) 137 return std::__convert_to_tm<_Tm>(_ChronoT::clock::to_sys(__value)); 138 else if constexpr (same_as<typename _ChronoT::clock, chrono::local_t>) 139 return std::__convert_to_tm<_Tm>(chrono::sys_time<typename _ChronoT::duration>{__value.time_since_epoch()}); 140 else 141 static_assert(sizeof(_ChronoT) == 0, "TODO: Add the missing clock specialization"); 142 } else if constexpr (chrono::__is_duration_v<_ChronoT>) { 143 // [time.format]/6 144 // ... However, if a flag refers to a "time of day" (e.g. %H, %I, %p, 145 // etc.), then a specialization of duration is interpreted as the time of 146 // day elapsed since midnight. 147 148 // Not all values can be converted to hours, it may run into ratio 149 // conversion errors. In that case the conversion to seconds works. 150 if constexpr (is_convertible_v<_ChronoT, chrono::hours>) { 151 auto __hour = chrono::floor<chrono::hours>(__value); 152 auto __sec = chrono::duration_cast<chrono::seconds>(__value - __hour); 153 __result.tm_hour = __hour.count() % 24; 154 __result.tm_min = __sec.count() / 60; 155 __result.tm_sec = __sec.count() % 60; 156 } else { 157 uint64_t __sec = chrono::duration_cast<chrono::seconds>(__value).count(); 158 __sec %= 24 * 3600; 159 __result.tm_hour = __sec / 3600; 160 __sec %= 3600; 161 __result.tm_min = __sec / 60; 162 __result.tm_sec = __sec % 60; 163 } 164 } else if constexpr (same_as<_ChronoT, chrono::day>) 165 __result.tm_mday = static_cast<unsigned>(__value); 166 else if constexpr (same_as<_ChronoT, chrono::month>) 167 __result.tm_mon = static_cast<unsigned>(__value) - 1; 168 else if constexpr (same_as<_ChronoT, chrono::year>) 169 __result.tm_year = static_cast<int>(__value) - 1900; 170 else if constexpr (same_as<_ChronoT, chrono::weekday>) 171 __result.tm_wday = __value.c_encoding(); 172 else if constexpr (same_as<_ChronoT, chrono::weekday_indexed> || same_as<_ChronoT, chrono::weekday_last>) 173 __result.tm_wday = __value.weekday().c_encoding(); 174 else if constexpr (same_as<_ChronoT, chrono::month_day>) { 175 __result.tm_mday = static_cast<unsigned>(__value.day()); 176 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; 177 } else if constexpr (same_as<_ChronoT, chrono::month_day_last>) { 178 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; 179 } else if constexpr (same_as<_ChronoT, chrono::month_weekday> || same_as<_ChronoT, chrono::month_weekday_last>) { 180 __result.tm_wday = __value.weekday_indexed().weekday().c_encoding(); 181 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; 182 } else if constexpr (same_as<_ChronoT, chrono::year_month>) { 183 __result.tm_year = static_cast<int>(__value.year()) - 1900; 184 __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; 185 } else if constexpr (same_as<_ChronoT, chrono::year_month_day> || same_as<_ChronoT, chrono::year_month_day_last>) { 186 return std::__convert_to_tm<_Tm>( 187 chrono::year_month_day{__value}, chrono::weekday{static_cast<chrono::sys_days>(__value)}); 188 } else if constexpr (same_as<_ChronoT, chrono::year_month_weekday> || 189 same_as<_ChronoT, chrono::year_month_weekday_last>) { 190 return std::__convert_to_tm<_Tm>(chrono::year_month_day{static_cast<chrono::sys_days>(__value)}, __value.weekday()); 191 } else if constexpr (__is_hh_mm_ss<_ChronoT>) { 192 __result.tm_sec = __value.seconds().count(); 193 __result.tm_min = __value.minutes().count(); 194 // In libc++ hours is stored as a long. The type in std::tm is an int. So 195 // the overflow can only occur when hour uses more bits than an int 196 // provides. 197 if constexpr (sizeof(std::chrono::hours::rep) > sizeof(__result.tm_hour)) 198 if (__value.hours().count() > std::numeric_limits<decltype(__result.tm_hour)>::max()) 199 std::__throw_format_error("Formatting hh_mm_ss, encountered an hour overflow"); 200 __result.tm_hour = __value.hours().count(); 201 # if _LIBCPP_HAS_EXPERIMENTAL_TZDB 202 } else if constexpr (same_as<_ChronoT, chrono::sys_info>) { 203 // Has no time information. 204 } else if constexpr (same_as<_ChronoT, chrono::local_info>) { 205 // Has no time information. 206 # if _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION 207 } else if constexpr (__is_specialization_v<_ChronoT, chrono::zoned_time>) { 208 return std::__convert_to_tm<_Tm>( 209 chrono::sys_time<typename _ChronoT::duration>{__value.get_local_time().time_since_epoch()}); 210 # endif 211 # endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB 212 } else 213 static_assert(sizeof(_ChronoT) == 0, "Add the missing type specialization"); 214 215 return __result; 216 } 217 218 #endif // if _LIBCPP_STD_VER >= 20 219 220 _LIBCPP_END_NAMESPACE_STD 221 222 _LIBCPP_POP_MACROS 223 224 #endif // _LIBCPP___CHRONO_CONVERT_TO_TM_H 225