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// -*- 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/month.h>
#include <__chrono/month_weekday.h>
#include <__chrono/monthday.h>
#include <__chrono/statically_widen.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 <__concepts/same_as.h>
#include <__config>
#include <__format/format_error.h>
#include <__memory/addressof.h>
#include <__type_traits/is_convertible.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();
} 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
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