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Diffstat (limited to 'contrib/llvm-project/libcxx/include/__chrono/convert_to_tm.h')
| -rw-r--r-- | contrib/llvm-project/libcxx/include/__chrono/convert_to_tm.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__chrono/convert_to_tm.h b/contrib/llvm-project/libcxx/include/__chrono/convert_to_tm.h new file mode 100644 index 000000000000..3a51019b8078 --- /dev/null +++ b/contrib/llvm-project/libcxx/include/__chrono/convert_to_tm.h @@ -0,0 +1,202 @@ +// -*- C++ -*- +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef _LIBCPP___CHRONO_CONVERT_TO_TM_H +#define _LIBCPP___CHRONO_CONVERT_TO_TM_H + +#include <__chrono/calendar.h> +#include <__chrono/concepts.h> +#include <__chrono/day.h> +#include <__chrono/duration.h> +#include <__chrono/file_clock.h> +#include <__chrono/hh_mm_ss.h> +#include <__chrono/local_info.h> +#include <__chrono/month.h> +#include <__chrono/month_weekday.h> +#include <__chrono/monthday.h> +#include <__chrono/statically_widen.h> +#include <__chrono/sys_info.h> +#include <__chrono/system_clock.h> +#include <__chrono/time_point.h> +#include <__chrono/weekday.h> +#include <__chrono/year.h> +#include <__chrono/year_month.h> +#include <__chrono/year_month_day.h> +#include <__chrono/year_month_weekday.h> +#include <__chrono/zoned_time.h> +#include <__concepts/same_as.h> +#include <__config> +#include <__format/format_error.h> +#include <__memory/addressof.h> +#include <__type_traits/is_convertible.h> +#include <__type_traits/is_specialization.h> +#include <cstdint> +#include <ctime> +#include <limits> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +#endif + +_LIBCPP_PUSH_MACROS +#include <__undef_macros> + +_LIBCPP_BEGIN_NAMESPACE_STD + +#if _LIBCPP_STD_VER >= 20 + +// Conerts a chrono date and weekday to a given _Tm type. +// +// This is an implementation detail for the function +// template <class _Tm, class _ChronoT> +// _Tm __convert_to_tm(const _ChronoT& __value) +// +// This manually converts the two values to the proper type. It is possible to +// convert from sys_days to time_t and then to _Tm. But this leads to the Y2K +// bug when time_t is a 32-bit signed integer. Chrono considers years beyond +// the year 2038 valid, so instead do the transformation manually. +template <class _Tm, class _Date> + requires(same_as<_Date, chrono::year_month_day> || same_as<_Date, chrono::year_month_day_last>) +_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _Date& __date, chrono::weekday __weekday) { + _Tm __result = {}; +# ifdef __GLIBC__ + __result.tm_zone = "UTC"; +# endif + __result.tm_year = static_cast<int>(__date.year()) - 1900; + __result.tm_mon = static_cast<unsigned>(__date.month()) - 1; + __result.tm_mday = static_cast<unsigned>(__date.day()); + __result.tm_wday = static_cast<unsigned>(__weekday.c_encoding()); + __result.tm_yday = + (static_cast<chrono::sys_days>(__date) - + static_cast<chrono::sys_days>(chrono::year_month_day{__date.year(), chrono::January, chrono::day{1}})) + .count(); + + return __result; +} + +template <class _Tm, class _Duration> +_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const chrono::sys_time<_Duration> __tp) { + chrono::sys_days __days = chrono::floor<chrono::days>(__tp); + chrono::year_month_day __ymd{__days}; + + _Tm __result = std::__convert_to_tm<_Tm>(chrono::year_month_day{__ymd}, chrono::weekday{__days}); + + uint64_t __sec = + chrono::duration_cast<chrono::seconds>(__tp - chrono::time_point_cast<chrono::seconds>(__days)).count(); + __sec %= 24 * 3600; + __result.tm_hour = __sec / 3600; + __sec %= 3600; + __result.tm_min = __sec / 60; + __result.tm_sec = __sec % 60; + + return __result; +} + +// Convert a chrono (calendar) time point, or dururation to the given _Tm type, +// which must have the same properties as std::tm. +template <class _Tm, class _ChronoT> +_LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _ChronoT& __value) { + _Tm __result = {}; +# ifdef __GLIBC__ + __result.tm_zone = "UTC"; +# endif + + if constexpr (__is_time_point<_ChronoT>) { + if constexpr (same_as<typename _ChronoT::clock, chrono::system_clock>) + return std::__convert_to_tm<_Tm>(__value); + else if constexpr (same_as<typename _ChronoT::clock, chrono::file_clock>) + return std::__convert_to_tm<_Tm>(_ChronoT::clock::to_sys(__value)); + else if constexpr (same_as<typename _ChronoT::clock, chrono::local_t>) + return std::__convert_to_tm<_Tm>(chrono::sys_time<typename _ChronoT::duration>{__value.time_since_epoch()}); + else + static_assert(sizeof(_ChronoT) == 0, "TODO: Add the missing clock specialization"); + } else if constexpr (chrono::__is_duration<_ChronoT>::value) { + // [time.format]/6 + // ... However, if a flag refers to a "time of day" (e.g. %H, %I, %p, + // etc.), then a specialization of duration is interpreted as the time of + // day elapsed since midnight. + + // Not all values can be converted to hours, it may run into ratio + // conversion errors. In that case the conversion to seconds works. + if constexpr (is_convertible_v<_ChronoT, chrono::hours>) { + auto __hour = chrono::floor<chrono::hours>(__value); + auto __sec = chrono::duration_cast<chrono::seconds>(__value - __hour); + __result.tm_hour = __hour.count() % 24; + __result.tm_min = __sec.count() / 60; + __result.tm_sec = __sec.count() % 60; + } else { + uint64_t __sec = chrono::duration_cast<chrono::seconds>(__value).count(); + __sec %= 24 * 3600; + __result.tm_hour = __sec / 3600; + __sec %= 3600; + __result.tm_min = __sec / 60; + __result.tm_sec = __sec % 60; + } + } else if constexpr (same_as<_ChronoT, chrono::day>) + __result.tm_mday = static_cast<unsigned>(__value); + else if constexpr (same_as<_ChronoT, chrono::month>) + __result.tm_mon = static_cast<unsigned>(__value) - 1; + else if constexpr (same_as<_ChronoT, chrono::year>) + __result.tm_year = static_cast<int>(__value) - 1900; + else if constexpr (same_as<_ChronoT, chrono::weekday>) + __result.tm_wday = __value.c_encoding(); + else if constexpr (same_as<_ChronoT, chrono::weekday_indexed> || same_as<_ChronoT, chrono::weekday_last>) + __result.tm_wday = __value.weekday().c_encoding(); + else if constexpr (same_as<_ChronoT, chrono::month_day>) { + __result.tm_mday = static_cast<unsigned>(__value.day()); + __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; + } else if constexpr (same_as<_ChronoT, chrono::month_day_last>) { + __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; + } else if constexpr (same_as<_ChronoT, chrono::month_weekday> || same_as<_ChronoT, chrono::month_weekday_last>) { + __result.tm_wday = __value.weekday_indexed().weekday().c_encoding(); + __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; + } else if constexpr (same_as<_ChronoT, chrono::year_month>) { + __result.tm_year = static_cast<int>(__value.year()) - 1900; + __result.tm_mon = static_cast<unsigned>(__value.month()) - 1; + } else if constexpr (same_as<_ChronoT, chrono::year_month_day> || same_as<_ChronoT, chrono::year_month_day_last>) { + return std::__convert_to_tm<_Tm>( + chrono::year_month_day{__value}, chrono::weekday{static_cast<chrono::sys_days>(__value)}); + } else if constexpr (same_as<_ChronoT, chrono::year_month_weekday> || + same_as<_ChronoT, chrono::year_month_weekday_last>) { + return std::__convert_to_tm<_Tm>(chrono::year_month_day{static_cast<chrono::sys_days>(__value)}, __value.weekday()); + } else if constexpr (__is_hh_mm_ss<_ChronoT>) { + __result.tm_sec = __value.seconds().count(); + __result.tm_min = __value.minutes().count(); + // In libc++ hours is stored as a long. The type in std::tm is an int. So + // the overflow can only occur when hour uses more bits than an int + // provides. + if constexpr (sizeof(std::chrono::hours::rep) > sizeof(__result.tm_hour)) + if (__value.hours().count() > std::numeric_limits<decltype(__result.tm_hour)>::max()) + std::__throw_format_error("Formatting hh_mm_ss, encountered an hour overflow"); + __result.tm_hour = __value.hours().count(); +# if !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB) + } else if constexpr (same_as<_ChronoT, chrono::sys_info>) { + // Has no time information. + } else if constexpr (same_as<_ChronoT, chrono::local_info>) { + // Has no time information. +# if !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM) && \ + !defined(_LIBCPP_HAS_NO_LOCALIZATION) + } else if constexpr (__is_specialization_v<_ChronoT, chrono::zoned_time>) { + return std::__convert_to_tm<_Tm>( + chrono::sys_time<typename _ChronoT::duration>{__value.get_local_time().time_since_epoch()}); +# endif +# endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB) + } else + static_assert(sizeof(_ChronoT) == 0, "Add the missing type specialization"); + + return __result; +} + +#endif // if _LIBCPP_STD_VER >= 20 + +_LIBCPP_END_NAMESPACE_STD + +_LIBCPP_POP_MACROS + +#endif // _LIBCPP___CHRONO_CONVERT_TO_TM_H |