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gcc/libstdc++-v3/include/std/chrono
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// <chrono> -*- C++ -*-
// Copyright (C) 2008-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/chrono
* This is a Standard C++ Library header.
* @ingroup chrono
*/
#ifndef _GLIBCXX_CHRONO
#define _GLIBCXX_CHRONO 1
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
#ifdef _GLIBCXX_NO_FREESTANDING_CHRONO
# include <bits/requires_hosted.h> // for <ctime> and clocks
#endif
#if __cplusplus < 201103L
# include <bits/c++0x_warning.h>
#else
#include <bits/chrono.h>
#if __cplusplus >= 202002L
# include <bit> // __countr_zero
#endif
#if __cplusplus >= 202002L && _GLIBCXX_HOSTED
# include <sstream>
# include <string>
# include <vector>
# include <bits/stl_algo.h> // upper_bound
# include <bits/shared_ptr.h>
# include <bits/unique_ptr.h>
#endif
#define __glibcxx_want_chrono
#define __glibcxx_want_chrono_udls
#include <bits/version.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @defgroup chrono Time
* @ingroup utilities
*
* Classes and functions for time.
*
* @since C++11
*/
/** @namespace std::chrono
* @brief ISO C++ 2011 namespace for date and time utilities
* @ingroup chrono
*/
namespace chrono
{
#if __cplusplus >= 202002L
/// @addtogroup chrono
/// @{
struct local_t { };
template<typename _Duration>
using local_time = time_point<local_t, _Duration>;
using local_seconds = local_time<seconds>;
using local_days = local_time<days>;
#if _GLIBCXX_HOSTED
class utc_clock;
class tai_clock;
class gps_clock;
template<typename _Duration>
using utc_time = time_point<utc_clock, _Duration>;
using utc_seconds = utc_time<seconds>;
template<typename _Duration>
using tai_time = time_point<tai_clock, _Duration>;
using tai_seconds = tai_time<seconds>;
template<typename _Duration>
using gps_time = time_point<gps_clock, _Duration>;
using gps_seconds = gps_time<seconds>;
template<> struct is_clock<utc_clock> : true_type { };
template<> struct is_clock<tai_clock> : true_type { };
template<> struct is_clock<gps_clock> : true_type { };
template<> inline constexpr bool is_clock_v<utc_clock> = true;
template<> inline constexpr bool is_clock_v<tai_clock> = true;
template<> inline constexpr bool is_clock_v<gps_clock> = true;
struct leap_second_info
{
bool is_leap_second;
seconds elapsed;
};
template<typename _Duration>
leap_second_info
get_leap_second_info(const utc_time<_Duration>& __ut);
/** A clock that measures Universal Coordinated Time (UTC).
*
* The epoch is 1970-01-01 00:00:00.
*
* @since C++20
*/
class utc_clock
{
public:
using rep = system_clock::rep;
using period = system_clock::period;
using duration = chrono::duration<rep, period>;
using time_point = chrono::time_point<utc_clock>;
static constexpr bool is_steady = false;
[[nodiscard]]
static time_point
now()
{ return from_sys(system_clock::now()); }
template<typename _Duration>
[[nodiscard]]
static sys_time<common_type_t<_Duration, seconds>>
to_sys(const utc_time<_Duration>& __t)
{
using _CDur = common_type_t<_Duration, seconds>;
const auto __li = chrono::get_leap_second_info(__t);
sys_time<_CDur> __s{__t.time_since_epoch() - __li.elapsed};
if (__li.is_leap_second)
__s = chrono::floor<seconds>(__s) + seconds{1} - _CDur{1};
return __s;
}
template<typename _Duration>
[[nodiscard]]
static utc_time<common_type_t<_Duration, seconds>>
from_sys(const sys_time<_Duration>& __t);
};
/** A clock that measures International Atomic Time.
*
* The epoch is 1958-01-01 00:00:00.
*
* @since C++20
*/
class tai_clock
{
public:
using rep = system_clock::rep;
using period = system_clock::period;
using duration = chrono::duration<rep, period>;
using time_point = chrono::time_point<tai_clock>;
static constexpr bool is_steady = false; // XXX true for CLOCK_TAI?
// TODO move into lib, use CLOCK_TAI on linux, add extension point.
[[nodiscard]]
static time_point
now()
{ return from_utc(utc_clock::now()); }
template<typename _Duration>
[[nodiscard]]
static utc_time<common_type_t<_Duration, seconds>>
to_utc(const tai_time<_Duration>& __t)
{
using _CDur = common_type_t<_Duration, seconds>;
return utc_time<_CDur>{__t.time_since_epoch()} - 378691210s;
}
template<typename _Duration>
[[nodiscard]]
static tai_time<common_type_t<_Duration, seconds>>
from_utc(const utc_time<_Duration>& __t)
{
using _CDur = common_type_t<_Duration, seconds>;
return tai_time<_CDur>{__t.time_since_epoch()} + 378691210s;
}
};
/** A clock that measures GPS time.
*
* The epoch is 1980-01-06 00:00:00.
*
* @since C++20
*/
class gps_clock
{
public:
using rep = system_clock::rep;
using period = system_clock::period;
using duration = chrono::duration<rep, period>;
using time_point = chrono::time_point<gps_clock>;
static constexpr bool is_steady = false; // XXX
// TODO move into lib, add extension point.
[[nodiscard]]
static time_point
now()
{ return from_utc(utc_clock::now()); }
template<typename _Duration>
[[nodiscard]]
static utc_time<common_type_t<_Duration, seconds>>
to_utc(const gps_time<_Duration>& __t)
{
using _CDur = common_type_t<_Duration, seconds>;
return utc_time<_CDur>{__t.time_since_epoch()} + 315964809s;
}
template<typename _Duration>
[[nodiscard]]
static gps_time<common_type_t<_Duration, seconds>>
from_utc(const utc_time<_Duration>& __t)
{
using _CDur = common_type_t<_Duration, seconds>;
return gps_time<_CDur>{__t.time_since_epoch()} - 315964809s;
}
};
#endif // _GLIBCXX_HOSTED
template<typename _DestClock, typename _SourceClock>
struct clock_time_conversion
{ };
// Identity conversions
template<typename _Clock>
struct clock_time_conversion<_Clock, _Clock>
{
template<typename _Duration>
time_point<_Clock, _Duration>
operator()(const time_point<_Clock, _Duration>& __t) const
{ return __t; }
};
#if _GLIBCXX_HOSTED
template<>
struct clock_time_conversion<system_clock, system_clock>
{
template<typename _Duration>
sys_time<_Duration>
operator()(const sys_time<_Duration>& __t) const
{ return __t; }
};
template<>
struct clock_time_conversion<utc_clock, utc_clock>
{
template<typename _Duration>
utc_time<_Duration>
operator()(const utc_time<_Duration>& __t) const
{ return __t; }
};
// Conversions between system_clock and utc_clock
template<>
struct clock_time_conversion<utc_clock, system_clock>
{
template<typename _Duration>
utc_time<common_type_t<_Duration, seconds>>
operator()(const sys_time<_Duration>& __t) const
{ return utc_clock::from_sys(__t); }
};
template<>
struct clock_time_conversion<system_clock, utc_clock>
{
template<typename _Duration>
sys_time<common_type_t<_Duration, seconds>>
operator()(const utc_time<_Duration>& __t) const
{ return utc_clock::to_sys(__t); }
};
template<typename _Tp, typename _Clock>
inline constexpr bool __is_time_point_for_v = false;
template<typename _Clock, typename _Duration>
inline constexpr bool
__is_time_point_for_v<time_point<_Clock, _Duration>, _Clock> = true;
// Conversions between system_clock and other clocks
template<typename _SourceClock>
struct clock_time_conversion<system_clock, _SourceClock>
{
template<typename _Duration, typename _Src = _SourceClock>
auto
operator()(const time_point<_SourceClock, _Duration>& __t) const
-> decltype(_Src::to_sys(__t))
{
using _Ret = decltype(_SourceClock::to_sys(__t));
static_assert(__is_time_point_for_v<_Ret, system_clock>);
return _SourceClock::to_sys(__t);
}
};
template<typename _DestClock>
struct clock_time_conversion<_DestClock, system_clock>
{
template<typename _Duration, typename _Dest = _DestClock>
auto
operator()(const sys_time<_Duration>& __t) const
-> decltype(_Dest::from_sys(__t))
{
using _Ret = decltype(_DestClock::from_sys(__t));
static_assert(__is_time_point_for_v<_Ret, _DestClock>);
return _DestClock::from_sys(__t);
}
};
// Conversions between utc_clock and other clocks
template<typename _SourceClock>
struct clock_time_conversion<utc_clock, _SourceClock>
{
template<typename _Duration, typename _Src = _SourceClock>
auto
operator()(const time_point<_SourceClock, _Duration>& __t) const
-> decltype(_Src::to_utc(__t))
{
using _Ret = decltype(_SourceClock::to_utc(__t));
static_assert(__is_time_point_for_v<_Ret, utc_clock>);
return _SourceClock::to_utc(__t);
}
};
template<typename _DestClock>
struct clock_time_conversion<_DestClock, utc_clock>
{
template<typename _Duration, typename _Dest = _DestClock>
auto
operator()(const utc_time<_Duration>& __t) const
-> decltype(_Dest::from_utc(__t))
{
using _Ret = decltype(_DestClock::from_utc(__t));
static_assert(__is_time_point_for_v<_Ret, _DestClock>);
return _DestClock::from_utc(__t);
}
};
#endif // _GLIBCXX_HOSTED
/// @cond undocumented
namespace __detail
{
template<typename _DestClock, typename _SourceClock, typename _Duration>
concept __clock_convs
= requires (const time_point<_SourceClock, _Duration>& __t) {
clock_time_conversion<_DestClock, _SourceClock>{}(__t);
};
#if _GLIBCXX_HOSTED
template<typename _DestClock, typename _SourceClock, typename _Duration>
concept __clock_convs_sys
= requires (const time_point<_SourceClock, _Duration>& __t) {
clock_time_conversion<_DestClock, system_clock>{}(
clock_time_conversion<system_clock, _SourceClock>{}(__t));
};
template<typename _DestClock, typename _SourceClock, typename _Duration>
concept __clock_convs_utc
= requires (const time_point<_SourceClock, _Duration>& __t) {
clock_time_conversion<_DestClock, utc_clock>{}(
clock_time_conversion<utc_clock, _SourceClock>{}(__t));
};
template<typename _DestClock, typename _SourceClock, typename _Duration>
concept __clock_convs_sys_utc
= requires (const time_point<_SourceClock, _Duration>& __t) {
clock_time_conversion<_DestClock, utc_clock>{}(
clock_time_conversion<utc_clock, system_clock>{}(
clock_time_conversion<system_clock, _SourceClock>{}(__t)));
};
template<typename _DestClock, typename _SourceClock, typename _Duration>
concept __clock_convs_utc_sys
= requires (const time_point<_SourceClock, _Duration>& __t) {
clock_time_conversion<_DestClock, system_clock>{}(
clock_time_conversion<system_clock, utc_clock>{}(
clock_time_conversion<utc_clock, _SourceClock>{}(__t)));
};
#endif // _GLIBCXX_HOSTED
} // namespace __detail
/// @endcond
/// Convert a time point to a different clock.
template<typename _DestClock, typename _SourceClock, typename _Duration>
[[nodiscard]]
inline auto
clock_cast(const time_point<_SourceClock, _Duration>& __t)
requires __detail::__clock_convs<_DestClock, _SourceClock, _Duration>
#if _GLIBCXX_HOSTED
|| __detail::__clock_convs_sys<_DestClock, _SourceClock, _Duration>
|| __detail::__clock_convs_utc<_DestClock, _SourceClock, _Duration>
|| __detail::__clock_convs_sys_utc<_DestClock, _SourceClock, _Duration>
|| __detail::__clock_convs_utc_sys<_DestClock, _SourceClock, _Duration>
#endif // _GLIBCXX_HOSTED
{
constexpr bool __direct
= __detail::__clock_convs<_DestClock, _SourceClock, _Duration>;
if constexpr (__direct)
{
return clock_time_conversion<_DestClock, _SourceClock>{}(__t);
}
#if _GLIBCXX_HOSTED
else
{
constexpr bool __convert_via_sys_clock
= __detail::__clock_convs_sys<_DestClock, _SourceClock, _Duration>;
constexpr bool __convert_via_utc_clock
= __detail::__clock_convs_utc<_DestClock, _SourceClock, _Duration>;
if constexpr (__convert_via_sys_clock)
{
static_assert(!__convert_via_utc_clock,
"clock_cast requires a unique best conversion, but "
"conversion is possible via system_clock and also via"
"utc_clock");
return clock_time_conversion<_DestClock, system_clock>{}(
clock_time_conversion<system_clock, _SourceClock>{}(__t));
}
else if constexpr (__convert_via_utc_clock)
{
return clock_time_conversion<_DestClock, utc_clock>{}(
clock_time_conversion<utc_clock, _SourceClock>{}(__t));
}
else
{
constexpr bool __convert_via_sys_and_utc_clocks
= __detail::__clock_convs_sys_utc<_DestClock,
_SourceClock,
_Duration>;
if constexpr (__convert_via_sys_and_utc_clocks)
{
constexpr bool __convert_via_utc_and_sys_clocks
= __detail::__clock_convs_utc_sys<_DestClock,
_SourceClock,
_Duration>;
static_assert(!__convert_via_utc_and_sys_clocks,
"clock_cast requires a unique best conversion, but "
"conversion is possible via system_clock followed by "
"utc_clock, and also via utc_clock followed by "
"system_clock");
return clock_time_conversion<_DestClock, utc_clock>{}(
clock_time_conversion<utc_clock, system_clock>{}(
clock_time_conversion<system_clock, _SourceClock>{}(__t)));
}
else
{
return clock_time_conversion<_DestClock, system_clock>{}(
clock_time_conversion<system_clock, utc_clock>{}(
clock_time_conversion<utc_clock, _SourceClock>{}(__t)));
}
}
}
#endif // _GLIBCXX_HOSTED
}
// CALENDRICAL TYPES
// CLASS DECLARATIONS
class day;
class month;
class year;
class weekday;
class weekday_indexed;
class weekday_last;
class month_day;
class month_day_last;
class month_weekday;
class month_weekday_last;
class year_month;
class year_month_day;
class year_month_day_last;
class year_month_weekday;
class year_month_weekday_last;
struct last_spec
{
explicit last_spec() = default;
friend constexpr month_day_last
operator/(int __m, last_spec) noexcept;
friend constexpr month_day_last
operator/(last_spec, int __m) noexcept;
};
inline constexpr last_spec last{};
namespace __detail
{
// Helper to __add_modulo and __sub_modulo.
template <unsigned __d, typename _Tp>
consteval auto
__modulo_offset()
{
using _Up = make_unsigned_t<_Tp>;
auto constexpr __a = _Up(-1) - _Up(255 + __d - 2);
auto constexpr __b = _Up(__d * (__a / __d) - 1);
// Notice: b <= a - 1 <= _Up(-1) - (255 + d - 1) and b % d = d - 1.
return _Up(-1) - __b; // >= 255 + d - 1
}
// Compute the remainder of the Euclidean division of __x + __y divided by
// __d without overflowing. Typically, __x <= 255 + d - 1 is sum of
// weekday/month with a shift in [0, d - 1] and __y is a duration count.
template <unsigned __d, typename _Tp>
constexpr unsigned
__add_modulo(unsigned __x, _Tp __y)
{
using _Up = make_unsigned_t<_Tp>;
// For __y >= 0, _Up(__y) has the same mathematical value as __y and
// this function simply returns (__x + _Up(__y)) % d. Typically, this
// doesn't overflow since the range of _Up contains many more positive
// values than _Tp's. For __y < 0, _Up(__y) has a mathematical value in
// the upper-half range of _Up so that adding a positive value to it
// might overflow. Moreover, most likely, _Up(__y) != __y mod d. To
// fix both issues we subtract from _Up(__y) an __offset >=
// 255 + d - 1 to make room for the addition to __x and shift the modulo
// to the correct value.
auto const __offset = __y >= 0 ? _Up(0) : __modulo_offset<__d, _Tp>();
return (__x + _Up(__y) - __offset) % __d;
}
// Similar to __add_modulo but for __x - __y.
template <unsigned __d, typename _Tp>
constexpr unsigned
__sub_modulo(unsigned __x, _Tp __y)
{
using _Up = make_unsigned_t<_Tp>;
auto const __offset = __y <= 0 ? _Up(0) : __modulo_offset<__d, _Tp>();
return (__x - _Up(__y) - __offset) % __d;
}
inline constexpr unsigned __days_per_month[12]
= { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
}
// DAY
class day
{
private:
unsigned char _M_d;
public:
day() = default;
explicit constexpr
day(unsigned __d) noexcept
: _M_d(__d)
{ }
constexpr day&
operator++() noexcept
{
++_M_d;
return *this;
}
constexpr day
operator++(int) noexcept
{
auto __ret = *this;
++(*this);
return __ret;
}
constexpr day&
operator--() noexcept
{
--_M_d;
return *this;
}
constexpr day
operator--(int) noexcept
{
auto __ret = *this;
--(*this);
return __ret;
}
constexpr day&
operator+=(const days& __d) noexcept
{
*this = *this + __d;
return *this;
}
constexpr day&
operator-=(const days& __d) noexcept
{
*this = *this - __d;
return *this;
}
constexpr explicit
operator unsigned() const noexcept
{ return _M_d; }
constexpr bool
ok() const noexcept
{ return 1 <= _M_d && _M_d <= 31; }
friend constexpr bool
operator==(const day& __x, const day& __y) noexcept
{ return unsigned{__x} == unsigned{__y}; }
friend constexpr strong_ordering
operator<=>(const day& __x, const day& __y) noexcept
{ return unsigned{__x} <=> unsigned{__y}; }
friend constexpr day
operator+(const day& __x, const days& __y) noexcept
{ return day(unsigned{__x} + __y.count()); }
friend constexpr day
operator+(const days& __x, const day& __y) noexcept
{ return __y + __x; }
friend constexpr day
operator-(const day& __x, const days& __y) noexcept
{ return __x + -__y; }
friend constexpr days
operator-(const day& __x, const day& __y) noexcept
{ return days{int(unsigned{__x}) - int(unsigned{__y})}; }
friend constexpr month_day
operator/(const month& __m, const day& __d) noexcept;
friend constexpr month_day
operator/(int __m, const day& __d) noexcept;
friend constexpr month_day
operator/(const day& __d, const month& __m) noexcept;
friend constexpr month_day
operator/(const day& __d, int __m) noexcept;
friend constexpr year_month_day
operator/(const year_month& __ym, const day& __d) noexcept;
};
// MONTH
class month
{
private:
unsigned char _M_m;
public:
month() = default;
explicit constexpr
month(unsigned __m) noexcept
: _M_m(__m)
{ }
constexpr month&
operator++() noexcept
{
*this += months{1};
return *this;
}
constexpr month
operator++(int) noexcept
{
auto __ret = *this;
++(*this);
return __ret;
}
constexpr month&
operator--() noexcept
{
*this -= months{1};
return *this;
}
constexpr month
operator--(int) noexcept
{
auto __ret = *this;
--(*this);
return __ret;
}
constexpr month&
operator+=(const months& __m) noexcept
{
*this = *this + __m;
return *this;
}
constexpr month&
operator-=(const months& __m) noexcept
{
*this = *this - __m;
return *this;
}
explicit constexpr
operator unsigned() const noexcept
{ return _M_m; }
constexpr bool
ok() const noexcept
{ return 1 <= _M_m && _M_m <= 12; }
friend constexpr bool
operator==(const month& __x, const month& __y) noexcept
{ return unsigned{__x} == unsigned{__y}; }
friend constexpr strong_ordering
operator<=>(const month& __x, const month& __y) noexcept
{ return unsigned{__x} <=> unsigned{__y}; }
friend constexpr month
operator+(const month& __x, const months& __y) noexcept
{
// modulo(x + (y - 1), 12) = modulo(x + (y - 1) + 12, 12)
// = modulo((x + 11) + y , 12)
return month{1 + __detail::__add_modulo<12>(
unsigned{__x} + 11, __y.count())};
}
friend constexpr month
operator+(const months& __x, const month& __y) noexcept
{ return __y + __x; }
friend constexpr month
operator-(const month& __x, const months& __y) noexcept
{
// modulo(x + (-y - 1), 12) = modulo(x + (-y - 1) + 12, 12)
// = modulo((x + 11) - y , 12)
return month{1 + __detail::__sub_modulo<12>(
unsigned{__x} + 11, __y.count())};
}
friend constexpr months
operator-(const month& __x, const month& __y) noexcept
{
const auto __dm = int(unsigned(__x)) - int(unsigned(__y));
return months{__dm < 0 ? 12 + __dm : __dm};
}
friend constexpr year_month
operator/(const year& __y, const month& __m) noexcept;
friend constexpr month_day
operator/(const month& __m, int __d) noexcept;
friend constexpr month_day_last
operator/(const month& __m, last_spec) noexcept;
friend constexpr month_day_last
operator/(last_spec, const month& __m) noexcept;
friend constexpr month_weekday
operator/(const month& __m, const weekday_indexed& __wdi) noexcept;
friend constexpr month_weekday
operator/(const weekday_indexed& __wdi, const month& __m) noexcept;
friend constexpr month_weekday_last
operator/(const month& __m, const weekday_last& __wdl) noexcept;
friend constexpr month_weekday_last
operator/(const weekday_last& __wdl, const month& __m) noexcept;
};
inline constexpr month January{1};
inline constexpr month February{2};
inline constexpr month March{3};
inline constexpr month April{4};
inline constexpr month May{5};
inline constexpr month June{6};
inline constexpr month July{7};
inline constexpr month August{8};
inline constexpr month September{9};
inline constexpr month October{10};
inline constexpr month November{11};
inline constexpr month December{12};
// YEAR
class year
{
private:
short _M_y;
public:
year() = default;
explicit constexpr
year(int __y) noexcept
: _M_y{static_cast<short>(__y)}
{ }
static constexpr year
min() noexcept
{ return year{-32767}; }
static constexpr year
max() noexcept
{ return year{32767}; }
constexpr year&
operator++() noexcept
{
++_M_y;
return *this;
}
constexpr year
operator++(int) noexcept
{
auto __ret = *this;
++(*this);
return __ret;
}
constexpr year&
operator--() noexcept
{
--_M_y;
return *this;
}
constexpr year
operator--(int) noexcept
{
auto __ret = *this;
--(*this);
return __ret;
}
constexpr year&
operator+=(const years& __y) noexcept
{
*this = *this + __y;
return *this;
}
constexpr year&
operator-=(const years& __y) noexcept
{
*this = *this - __y;
return *this;
}
constexpr year
operator+() const noexcept
{ return *this; }
constexpr year
operator-() const noexcept
{ return year{-_M_y}; }
constexpr bool
is_leap() const noexcept
{
// Testing divisibility by 100 first gives better performance [1], i.e.,
// return _M_y % 100 == 0 ? _M_y % 400 == 0 : _M_y % 16 == 0;
// Furthermore, if _M_y % 100 == 0, then _M_y % 400 == 0 is equivalent
// to _M_y % 16 == 0, so we can simplify it to
// return _M_y % 100 == 0 ? _M_y % 16 == 0 : _M_y % 4 == 0. // #1
// Similarly, we can replace 100 with 25 (which is good since
// _M_y % 25 == 0 requires one fewer instruction than _M_y % 100 == 0
// [2]):
// return _M_y % 25 == 0 ? _M_y % 16 == 0 : _M_y % 4 == 0. // #2
// Indeed, first assume _M_y % 4 != 0. Then _M_y % 16 != 0 and hence,
// _M_y % 4 == 0 and _M_y % 16 == 0 are both false. Therefore, #2
// returns false as it should (regardless of _M_y % 25.) Now assume
// _M_y % 4 == 0. In this case, _M_y % 25 == 0 if, and only if,
// _M_y % 100 == 0, that is, #1 and #2 are equivalent. Finally, #2 is
// equivalent to
// return (_M_y & (_M_y % 25 == 0 ? 15 : 3)) == 0.
// References:
// [1] https://github.com/cassioneri/calendar
// [2] https://godbolt.org/z/55G8rn77e
// [3] https://gcc.gnu.org/pipermail/libstdc++/2021-June/052815.html
return (_M_y & (_M_y % 25 == 0 ? 15 : 3)) == 0;
}
explicit constexpr
operator int() const noexcept
{ return _M_y; }
constexpr bool
ok() const noexcept
{ return min()._M_y <= _M_y && _M_y <= max()._M_y; }
friend constexpr bool
operator==(const year& __x, const year& __y) noexcept
{ return int{__x} == int{__y}; }
friend constexpr strong_ordering
operator<=>(const year& __x, const year& __y) noexcept
{ return int{__x} <=> int{__y}; }
friend constexpr year
operator+(const year& __x, const years& __y) noexcept
{ return year{int{__x} + static_cast<int>(__y.count())}; }
friend constexpr year
operator+(const years& __x, const year& __y) noexcept
{ return __y + __x; }
friend constexpr year
operator-(const year& __x, const years& __y) noexcept
{ return __x + -__y; }
friend constexpr years
operator-(const year& __x, const year& __y) noexcept
{ return years{int{__x} - int{__y}}; }
friend constexpr year_month
operator/(const year& __y, int __m) noexcept;
friend constexpr year_month_day
operator/(const year& __y, const month_day& __md) noexcept;
friend constexpr year_month_day
operator/(const month_day& __md, const year& __y) noexcept;
friend constexpr year_month_day_last
operator/(const year& __y, const month_day_last& __mdl) noexcept;
friend constexpr year_month_day_last
operator/(const month_day_last& __mdl, const year& __y) noexcept;
friend constexpr year_month_weekday
operator/(const year& __y, const month_weekday& __mwd) noexcept;
friend constexpr year_month_weekday
operator/(const month_weekday& __mwd, const year& __y) noexcept;
friend constexpr year_month_weekday_last
operator/(const year& __y, const month_weekday_last& __mwdl) noexcept;
friend constexpr year_month_weekday_last
operator/(const month_weekday_last& __mwdl, const year& __y) noexcept;
};
// WEEKDAY
class weekday
{
private:
unsigned char _M_wd;
static constexpr weekday
_S_from_days(const days& __d)
{
return weekday{__detail::__add_modulo<7>(4, __d.count())};
}
public:
weekday() = default;
explicit constexpr
weekday(unsigned __wd) noexcept
: _M_wd(__wd == 7 ? 0 : __wd) // __wd % 7 ?
{ }
constexpr
weekday(const sys_days& __dp) noexcept
: weekday{_S_from_days(__dp.time_since_epoch())}
{ }
explicit constexpr
weekday(const local_days& __dp) noexcept
: weekday{sys_days{__dp.time_since_epoch()}}
{ }
constexpr weekday&
operator++() noexcept
{
*this += days{1};
return *this;
}
constexpr weekday
operator++(int) noexcept
{
auto __ret = *this;
++(*this);
return __ret;
}
constexpr weekday&
operator--() noexcept
{
*this -= days{1};
return *this;
}
constexpr weekday
operator--(int) noexcept
{
auto __ret = *this;
--(*this);
return __ret;
}
constexpr weekday&
operator+=(const days& __d) noexcept
{
*this = *this + __d;
return *this;
}
constexpr weekday&
operator-=(const days& __d) noexcept
{
*this = *this - __d;
return *this;
}
constexpr unsigned
c_encoding() const noexcept
{ return _M_wd; }
constexpr unsigned
iso_encoding() const noexcept
{ return _M_wd == 0u ? 7u : _M_wd; }
constexpr bool
ok() const noexcept
{ return _M_wd <= 6; }
constexpr weekday_indexed
operator[](unsigned __index) const noexcept;
constexpr weekday_last
operator[](last_spec) const noexcept;
friend constexpr bool
operator==(const weekday& __x, const weekday& __y) noexcept
{ return __x._M_wd == __y._M_wd; }
friend constexpr weekday
operator+(const weekday& __x, const days& __y) noexcept
{
return weekday{__detail::__add_modulo<7>(__x._M_wd, __y.count())};
}
friend constexpr weekday
operator+(const days& __x, const weekday& __y) noexcept
{ return __y + __x; }
friend constexpr weekday
operator-(const weekday& __x, const days& __y) noexcept
{
return weekday{__detail::__sub_modulo<7>(__x._M_wd, __y.count())};
}
friend constexpr days
operator-(const weekday& __x, const weekday& __y) noexcept
{
const auto __n = __x.c_encoding() - __y.c_encoding();
return static_cast<int>(__n) >= 0 ? days{__n} : days{__n + 7};
}
};
inline constexpr weekday Sunday{0};
inline constexpr weekday Monday{1};
inline constexpr weekday Tuesday{2};
inline constexpr weekday Wednesday{3};
inline constexpr weekday Thursday{4};
inline constexpr weekday Friday{5};
inline constexpr weekday Saturday{6};
// WEEKDAY_INDEXED
class weekday_indexed
{
private:
chrono::weekday _M_wd;
unsigned char _M_index;
public:
weekday_indexed() = default;
constexpr
weekday_indexed(const chrono::weekday& __wd, unsigned __index) noexcept
: _M_wd(__wd), _M_index(__index)
{ }
constexpr chrono::weekday
weekday() const noexcept
{ return _M_wd; }
constexpr unsigned
index() const noexcept
{ return _M_index; };
constexpr bool
ok() const noexcept
{ return _M_wd.ok() && 1 <= _M_index && _M_index <= 5; }
friend constexpr bool
operator==(const weekday_indexed& __x, const weekday_indexed& __y) noexcept
{ return __x.weekday() == __y.weekday() && __x.index() == __y.index(); }
friend constexpr month_weekday
operator/(const month& __m, const weekday_indexed& __wdi) noexcept;
friend constexpr month_weekday
operator/(int __m, const weekday_indexed& __wdi) noexcept;
friend constexpr month_weekday
operator/(const weekday_indexed& __wdi, const month& __m) noexcept;
friend constexpr month_weekday
operator/(const weekday_indexed& __wdi, int __m) noexcept;
friend constexpr year_month_weekday
operator/(const year_month& __ym, const weekday_indexed& __wdi) noexcept;
};
constexpr weekday_indexed
weekday::operator[](unsigned __index) const noexcept
{ return {*this, __index}; }
// WEEKDAY_LAST
class weekday_last
{
private:
chrono::weekday _M_wd;
public:
explicit constexpr
weekday_last(const chrono::weekday& __wd) noexcept
: _M_wd{__wd}
{ }
constexpr chrono::weekday
weekday() const noexcept
{ return _M_wd; }
constexpr bool
ok() const noexcept
{ return _M_wd.ok(); }
friend constexpr bool
operator==(const weekday_last& __x, const weekday_last& __y) noexcept
{ return __x.weekday() == __y.weekday(); }
friend constexpr month_weekday_last
operator/(int __m, const weekday_last& __wdl) noexcept;
friend constexpr month_weekday_last
operator/(const weekday_last& __wdl, int __m) noexcept;
friend constexpr year_month_weekday_last
operator/(const year_month& __ym, const weekday_last& __wdl) noexcept;
};
constexpr weekday_last
weekday::operator[](last_spec) const noexcept
{ return weekday_last{*this}; }
// MONTH_DAY
class month_day
{
private:
chrono::month _M_m;
chrono::day _M_d;
public:
month_day() = default;
constexpr
month_day(const chrono::month& __m, const chrono::day& __d) noexcept
: _M_m{__m}, _M_d{__d}
{ }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr chrono::day
day() const noexcept
{ return _M_d; }
constexpr bool
ok() const noexcept
{
return _M_m.ok()
&& 1u <= unsigned(_M_d)
&& unsigned(_M_d) <= __detail::__days_per_month[unsigned(_M_m) - 1];
}
friend constexpr bool
operator==(const month_day& __x, const month_day& __y) noexcept
{ return __x.month() == __y.month() && __x.day() == __y.day(); }
friend constexpr strong_ordering
operator<=>(const month_day& __x, const month_day& __y) noexcept
= default;
friend constexpr month_day
operator/(const chrono::month& __m, const chrono::day& __d) noexcept
{ return {__m, __d}; }
friend constexpr month_day
operator/(const chrono::month& __m, int __d) noexcept
{ return {__m, chrono::day(unsigned(__d))}; }
friend constexpr month_day
operator/(int __m, const chrono::day& __d) noexcept
{ return {chrono::month(unsigned(__m)), __d}; }
friend constexpr month_day
operator/(const chrono::day& __d, const chrono::month& __m) noexcept
{ return {__m, __d}; }
friend constexpr month_day
operator/(const chrono::day& __d, int __m) noexcept
{ return {chrono::month(unsigned(__m)), __d}; }
friend constexpr year_month_day
operator/(int __y, const month_day& __md) noexcept;
friend constexpr year_month_day
operator/(const month_day& __md, int __y) noexcept;
};
// MONTH_DAY_LAST
class month_day_last
{
private:
chrono::month _M_m;
public:
explicit constexpr
month_day_last(const chrono::month& __m) noexcept
: _M_m{__m}
{ }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr bool
ok() const noexcept
{ return _M_m.ok(); }
friend constexpr bool
operator==(const month_day_last& __x, const month_day_last& __y) noexcept
{ return __x.month() == __y.month(); }
friend constexpr strong_ordering
operator<=>(const month_day_last& __x, const month_day_last& __y) noexcept
= default;
friend constexpr month_day_last
operator/(const chrono::month& __m, last_spec) noexcept
{ return month_day_last{__m}; }
friend constexpr month_day_last
operator/(int __m, last_spec) noexcept
{ return chrono::month(unsigned(__m)) / last; }
friend constexpr month_day_last
operator/(last_spec, const chrono::month& __m) noexcept
{ return __m / last; }
friend constexpr month_day_last
operator/(last_spec, int __m) noexcept
{ return __m / last; }
friend constexpr year_month_day_last
operator/(int __y, const month_day_last& __mdl) noexcept;
friend constexpr year_month_day_last
operator/(const month_day_last& __mdl, int __y) noexcept;
};
// MONTH_WEEKDAY
class month_weekday
{
private:
chrono::month _M_m;
chrono::weekday_indexed _M_wdi;
public:
constexpr
month_weekday(const chrono::month& __m,
const chrono::weekday_indexed& __wdi) noexcept
: _M_m{__m}, _M_wdi{__wdi}
{ }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr chrono::weekday_indexed
weekday_indexed() const noexcept
{ return _M_wdi; }
constexpr bool
ok() const noexcept
{ return _M_m.ok() && _M_wdi.ok(); }
friend constexpr bool
operator==(const month_weekday& __x, const month_weekday& __y) noexcept
{
return __x.month() == __y.month()
&& __x.weekday_indexed() == __y.weekday_indexed();
}
friend constexpr month_weekday
operator/(const chrono::month& __m,
const chrono::weekday_indexed& __wdi) noexcept
{ return {__m, __wdi}; }
friend constexpr month_weekday
operator/(int __m, const chrono::weekday_indexed& __wdi) noexcept
{ return chrono::month(unsigned(__m)) / __wdi; }
friend constexpr month_weekday
operator/(const chrono::weekday_indexed& __wdi,
const chrono::month& __m) noexcept
{ return __m / __wdi; }
friend constexpr month_weekday
operator/(const chrono::weekday_indexed& __wdi, int __m) noexcept
{ return __m / __wdi; }
friend constexpr year_month_weekday
operator/(int __y, const month_weekday& __mwd) noexcept;
friend constexpr year_month_weekday
operator/(const month_weekday& __mwd, int __y) noexcept;
};
// MONTH_WEEKDAY_LAST
class month_weekday_last
{
private:
chrono::month _M_m;
chrono::weekday_last _M_wdl;
public:
constexpr
month_weekday_last(const chrono::month& __m,
const chrono::weekday_last& __wdl) noexcept
:_M_m{__m}, _M_wdl{__wdl}
{ }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr chrono::weekday_last
weekday_last() const noexcept
{ return _M_wdl; }
constexpr bool
ok() const noexcept
{ return _M_m.ok() && _M_wdl.ok(); }
friend constexpr bool
operator==(const month_weekday_last& __x,
const month_weekday_last& __y) noexcept
{
return __x.month() == __y.month()
&& __x.weekday_last() == __y.weekday_last();
}
friend constexpr month_weekday_last
operator/(const chrono::month& __m,
const chrono::weekday_last& __wdl) noexcept
{ return {__m, __wdl}; }
friend constexpr month_weekday_last
operator/(int __m, const chrono::weekday_last& __wdl) noexcept
{ return chrono::month(unsigned(__m)) / __wdl; }
friend constexpr month_weekday_last
operator/(const chrono::weekday_last& __wdl,
const chrono::month& __m) noexcept
{ return __m / __wdl; }
friend constexpr month_weekday_last
operator/(const chrono::weekday_last& __wdl, int __m) noexcept
{ return chrono::month(unsigned(__m)) / __wdl; }
friend constexpr year_month_weekday_last
operator/(int __y, const month_weekday_last& __mwdl) noexcept;
friend constexpr year_month_weekday_last
operator/(const month_weekday_last& __mwdl, int __y) noexcept;
};
// YEAR_MONTH
namespace __detail
{
// [time.cal.ym], [time.cal.ymd], etc constrain the 'months'-based
// addition/subtraction operator overloads like so:
//
// Constraints: if the argument supplied by the caller for the months
// parameter is convertible to years, its implicit conversion sequence
// to years is worse than its implicit conversion sequence to months.
//
// We realize this constraint by templatizing the 'months'-based
// overloads (using a dummy defaulted template parameter), so that
// overload resolution doesn't select the 'months'-based overload unless
// the implicit conversion sequence to 'months' is better than that to
// 'years'.
using __months_years_conversion_disambiguator = void;
}
class year_month
{
private:
chrono::year _M_y;
chrono::month _M_m;
public:
year_month() = default;
constexpr
year_month(const chrono::year& __y, const chrono::month& __m) noexcept
: _M_y{__y}, _M_m{__m}
{ }
constexpr chrono::year
year() const noexcept
{ return _M_y; }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month&
operator+=(const months& __dm) noexcept
{
*this = *this + __dm;
return *this;
}
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month&
operator-=(const months& __dm) noexcept
{
*this = *this - __dm;
return *this;
}
constexpr year_month&
operator+=(const years& __dy) noexcept
{
*this = *this + __dy;
return *this;
}
constexpr year_month&
operator-=(const years& __dy) noexcept
{
*this = *this - __dy;
return *this;
}
constexpr bool
ok() const noexcept
{ return _M_y.ok() && _M_m.ok(); }
friend constexpr bool
operator==(const year_month& __x, const year_month& __y) noexcept
{ return __x.year() == __y.year() && __x.month() == __y.month(); }
friend constexpr strong_ordering
operator<=>(const year_month& __x, const year_month& __y) noexcept
= default;
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month
operator+(const year_month& __ym, const months& __dm) noexcept
{
// TODO: Optimize?
auto __m = __ym.month() + __dm;
auto __i = int(unsigned(__ym.month())) - 1 + __dm.count();
auto __y = (__i < 0
? __ym.year() + years{(__i - 11) / 12}
: __ym.year() + years{__i / 12});
return __y / __m;
}
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month
operator+(const months& __dm, const year_month& __ym) noexcept
{ return __ym + __dm; }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month
operator-(const year_month& __ym, const months& __dm) noexcept
{ return __ym + -__dm; }
friend constexpr months
operator-(const year_month& __x, const year_month& __y) noexcept
{
return (__x.year() - __y.year()
+ months{static_cast<int>(unsigned{__x.month()})
- static_cast<int>(unsigned{__y.month()})});
}
friend constexpr year_month
operator+(const year_month& __ym, const years& __dy) noexcept
{ return (__ym.year() + __dy) / __ym.month(); }
friend constexpr year_month
operator+(const years& __dy, const year_month& __ym) noexcept
{ return __ym + __dy; }
friend constexpr year_month
operator-(const year_month& __ym, const years& __dy) noexcept
{ return __ym + -__dy; }
friend constexpr year_month
operator/(const chrono::year& __y, const chrono::month& __m) noexcept
{ return {__y, __m}; }
friend constexpr year_month
operator/(const chrono::year& __y, int __m) noexcept
{ return {__y, chrono::month(unsigned(__m))}; }
friend constexpr year_month_day
operator/(const year_month& __ym, int __d) noexcept;
friend constexpr year_month_day_last
operator/(const year_month& __ym, last_spec) noexcept;
};
// YEAR_MONTH_DAY
class year_month_day
{
private:
chrono::year _M_y;
chrono::month _M_m;
chrono::day _M_d;
static constexpr year_month_day _S_from_days(const days& __dp) noexcept;
constexpr days _M_days_since_epoch() const noexcept;
public:
year_month_day() = default;
constexpr
year_month_day(const chrono::year& __y, const chrono::month& __m,
const chrono::day& __d) noexcept
: _M_y{__y}, _M_m{__m}, _M_d{__d}
{ }
constexpr
year_month_day(const year_month_day_last& __ymdl) noexcept;
constexpr
year_month_day(const sys_days& __dp) noexcept
: year_month_day(_S_from_days(__dp.time_since_epoch()))
{ }
explicit constexpr
year_month_day(const local_days& __dp) noexcept
: year_month_day(sys_days{__dp.time_since_epoch()})
{ }
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_day&
operator+=(const months& __m) noexcept
{
*this = *this + __m;
return *this;
}
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_day&
operator-=(const months& __m) noexcept
{
*this = *this - __m;
return *this;
}
constexpr year_month_day&
operator+=(const years& __y) noexcept
{
*this = *this + __y;
return *this;
}
constexpr year_month_day&
operator-=(const years& __y) noexcept
{
*this = *this - __y;
return *this;
}
constexpr chrono::year
year() const noexcept
{ return _M_y; }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr chrono::day
day() const noexcept
{ return _M_d; }
constexpr
operator sys_days() const noexcept
{ return sys_days{_M_days_since_epoch()}; }
explicit constexpr
operator local_days() const noexcept
{ return local_days{sys_days{*this}.time_since_epoch()}; }
constexpr bool ok() const noexcept;
friend constexpr bool
operator==(const year_month_day& __x, const year_month_day& __y) noexcept
{
return __x.year() == __y.year()
&& __x.month() == __y.month()
&& __x.day() == __y.day();
}
friend constexpr strong_ordering
operator<=>(const year_month_day& __x, const year_month_day& __y) noexcept
= default;
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_day
operator+(const year_month_day& __ymd, const months& __dm) noexcept
{ return (__ymd.year() / __ymd.month() + __dm) / __ymd.day(); }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_day
operator+(const months& __dm, const year_month_day& __ymd) noexcept
{ return __ymd + __dm; }
friend constexpr year_month_day
operator+(const year_month_day& __ymd, const years& __dy) noexcept
{ return (__ymd.year() + __dy) / __ymd.month() / __ymd.day(); }
friend constexpr year_month_day
operator+(const years& __dy, const year_month_day& __ymd) noexcept
{ return __ymd + __dy; }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_day
operator-(const year_month_day& __ymd, const months& __dm) noexcept
{ return __ymd + -__dm; }
friend constexpr year_month_day
operator-(const year_month_day& __ymd, const years& __dy) noexcept
{ return __ymd + -__dy; }
friend constexpr year_month_day
operator/(const year_month& __ym, const chrono::day& __d) noexcept
{ return {__ym.year(), __ym.month(), __d}; }
friend constexpr year_month_day
operator/(const year_month& __ym, int __d) noexcept
{ return __ym / chrono::day{unsigned(__d)}; }
friend constexpr year_month_day
operator/(const chrono::year& __y, const month_day& __md) noexcept
{ return __y / __md.month() / __md.day(); }
friend constexpr year_month_day
operator/(int __y, const month_day& __md) noexcept
{ return chrono::year{__y} / __md; }
friend constexpr year_month_day
operator/(const month_day& __md, const chrono::year& __y) noexcept
{ return __y / __md; }
friend constexpr year_month_day
operator/(const month_day& __md, int __y) noexcept
{ return chrono::year(__y) / __md; }
};
// Construct from days since 1970/01/01.
// Proposition 6.3 of Neri and Schneider,
// "Euclidean Affine Functions and Applications to Calendar Algorithms".
// https://arxiv.org/abs/2102.06959
constexpr year_month_day
year_month_day::_S_from_days(const days& __dp) noexcept
{
constexpr auto __z2 = static_cast<uint32_t>(-1468000);
constexpr auto __r2_e3 = static_cast<uint32_t>(536895458);
const auto __r0 = static_cast<uint32_t>(__dp.count()) + __r2_e3;
const auto __n1 = 4 * __r0 + 3;
const auto __q1 = __n1 / 146097;
const auto __r1 = __n1 % 146097 / 4;
constexpr auto __p32 = static_cast<uint64_t>(1) << 32;
const auto __n2 = 4 * __r1 + 3;
const auto __u2 = static_cast<uint64_t>(2939745) * __n2;
const auto __q2 = static_cast<uint32_t>(__u2 / __p32);
const auto __r2 = static_cast<uint32_t>(__u2 % __p32) / 2939745 / 4;
constexpr auto __p16 = static_cast<uint32_t>(1) << 16;
const auto __n3 = 2141 * __r2 + 197913;
const auto __q3 = __n3 / __p16;
const auto __r3 = __n3 % __p16 / 2141;
const auto __y0 = 100 * __q1 + __q2;
const auto __m0 = __q3;
const auto __d0 = __r3;
const auto __j = __r2 >= 306;
const auto __y1 = __y0 + __j;
const auto __m1 = __j ? __m0 - 12 : __m0;
const auto __d1 = __d0 + 1;
return year_month_day{chrono::year{static_cast<int>(__y1 + __z2)},
chrono::month{__m1}, chrono::day{__d1}};
}
// Days since 1970/01/01.
// Proposition 6.2 of Neri and Schneider,
// "Euclidean Affine Functions and Applications to Calendar Algorithms".
// https://arxiv.org/abs/2102.06959
constexpr days
year_month_day::_M_days_since_epoch() const noexcept
{
auto constexpr __z2 = static_cast<uint32_t>(-1468000);
auto constexpr __r2_e3 = static_cast<uint32_t>(536895458);
const auto __y1 = static_cast<uint32_t>(static_cast<int>(_M_y)) - __z2;
const auto __m1 = static_cast<uint32_t>(static_cast<unsigned>(_M_m));
const auto __d1 = static_cast<uint32_t>(static_cast<unsigned>(_M_d));
const auto __j = static_cast<uint32_t>(__m1 < 3);
const auto __y0 = __y1 - __j;
const auto __m0 = __j ? __m1 + 12 : __m1;
const auto __d0 = __d1 - 1;
const auto __q1 = __y0 / 100;
const auto __yc = 1461 * __y0 / 4 - __q1 + __q1 / 4;
const auto __mc = (979 *__m0 - 2919) / 32;
const auto __dc = __d0;
return days{static_cast<int32_t>(__yc + __mc + __dc - __r2_e3)};
}
// YEAR_MONTH_DAY_LAST
class year_month_day_last
{
private:
chrono::year _M_y;
chrono::month_day_last _M_mdl;
public:
constexpr
year_month_day_last(const chrono::year& __y,
const chrono::month_day_last& __mdl) noexcept
: _M_y{__y}, _M_mdl{__mdl}
{ }
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_day_last&
operator+=(const months& __m) noexcept
{
*this = *this + __m;
return *this;
}
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_day_last&
operator-=(const months& __m) noexcept
{
*this = *this - __m;
return *this;
}
constexpr year_month_day_last&
operator+=(const years& __y) noexcept
{
*this = *this + __y;
return *this;
}
constexpr year_month_day_last&
operator-=(const years& __y) noexcept
{
*this = *this - __y;
return *this;
}
constexpr chrono::year
year() const noexcept
{ return _M_y; }
constexpr chrono::month
month() const noexcept
{ return _M_mdl.month(); }
constexpr chrono::month_day_last
month_day_last() const noexcept
{ return _M_mdl; }
// Return A day representing the last day of this year, month pair.
constexpr chrono::day
day() const noexcept
{
const auto __m = static_cast<unsigned>(month());
// The result is unspecified if __m < 1 or __m > 12. Hence, assume
// 1 <= __m <= 12. For __m != 2, day() == 30 or day() == 31 or, in
// other words, day () == 30 | b, where b is in {0, 1}.
// If __m in {1, 3, 4, 5, 6, 7}, then b is 1 if, and only if, __m is
// odd. Hence, b = __m & 1 = (__m ^ 0) & 1.
// If __m in {8, 9, 10, 11, 12}, then b is 1 if, and only if, __m is
// even. Hence, b = (__m ^ 1) & 1.
// Therefore, b = (__m ^ c) & 1, where c = 0, if __m < 8, or c = 1 if
// __m >= 8, that is, c = __m >> 3.
// Since 30 = (11110)_2 and __m <= 31 = (11111)_2, the "& 1" in b's
// calculation is unnecessary.
// The performance of this implementation does not depend on look-up
// tables being on the L1 cache.
return chrono::day{__m != 2 ? (__m ^ (__m >> 3)) | 30
: _M_y.is_leap() ? 29 : 28};
}
constexpr
operator sys_days() const noexcept
{ return sys_days{year() / month() / day()}; }
explicit constexpr
operator local_days() const noexcept
{ return local_days{sys_days{*this}.time_since_epoch()}; }
constexpr bool
ok() const noexcept
{ return _M_y.ok() && _M_mdl.ok(); }
friend constexpr bool
operator==(const year_month_day_last& __x,
const year_month_day_last& __y) noexcept
{
return __x.year() == __y.year()
&& __x.month_day_last() == __y.month_day_last();
}
friend constexpr strong_ordering
operator<=>(const year_month_day_last& __x,
const year_month_day_last& __y) noexcept
= default;
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_day_last
operator+(const year_month_day_last& __ymdl,
const months& __dm) noexcept
{ return (__ymdl.year() / __ymdl.month() + __dm) / last; }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_day_last
operator+(const months& __dm,
const year_month_day_last& __ymdl) noexcept
{ return __ymdl + __dm; }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_day_last
operator-(const year_month_day_last& __ymdl,
const months& __dm) noexcept
{ return __ymdl + -__dm; }
friend constexpr year_month_day_last
operator+(const year_month_day_last& __ymdl,
const years& __dy) noexcept
{ return {__ymdl.year() + __dy, __ymdl.month_day_last()}; }
friend constexpr year_month_day_last
operator+(const years& __dy,
const year_month_day_last& __ymdl) noexcept
{ return __ymdl + __dy; }
friend constexpr year_month_day_last
operator-(const year_month_day_last& __ymdl,
const years& __dy) noexcept
{ return __ymdl + -__dy; }
friend constexpr year_month_day_last
operator/(const year_month& __ym, last_spec) noexcept
{ return {__ym.year(), chrono::month_day_last{__ym.month()}}; }
friend constexpr year_month_day_last
operator/(const chrono::year& __y,
const chrono::month_day_last& __mdl) noexcept
{ return {__y, __mdl}; }
friend constexpr year_month_day_last
operator/(int __y, const chrono::month_day_last& __mdl) noexcept
{ return chrono::year(__y) / __mdl; }
friend constexpr year_month_day_last
operator/(const chrono::month_day_last& __mdl,
const chrono::year& __y) noexcept
{ return __y / __mdl; }
friend constexpr year_month_day_last
operator/(const chrono::month_day_last& __mdl, int __y) noexcept
{ return chrono::year(__y) / __mdl; }
};
// year_month_day ctor from year_month_day_last
constexpr
year_month_day::year_month_day(const year_month_day_last& __ymdl) noexcept
: _M_y{__ymdl.year()}, _M_m{__ymdl.month()}, _M_d{__ymdl.day()}
{ }
constexpr bool
year_month_day::ok() const noexcept
{
if (!_M_y.ok() || !_M_m.ok())
return false;
return chrono::day{1} <= _M_d && _M_d <= (_M_y / _M_m / last).day();
}
// YEAR_MONTH_WEEKDAY
class year_month_weekday
{
private:
chrono::year _M_y;
chrono::month _M_m;
chrono::weekday_indexed _M_wdi;
static constexpr year_month_weekday
_S_from_sys_days(const sys_days& __dp)
{
year_month_day __ymd{__dp};
chrono::weekday __wd{__dp};
auto __index = __wd[(unsigned{__ymd.day()} - 1) / 7 + 1];
return {__ymd.year(), __ymd.month(), __index};
}
public:
year_month_weekday() = default;
constexpr
year_month_weekday(const chrono::year& __y, const chrono::month& __m,
const chrono::weekday_indexed& __wdi) noexcept
: _M_y{__y}, _M_m{__m}, _M_wdi{__wdi}
{ }
constexpr
year_month_weekday(const sys_days& __dp) noexcept
: year_month_weekday{_S_from_sys_days(__dp)}
{ }
explicit constexpr
year_month_weekday(const local_days& __dp) noexcept
: year_month_weekday{sys_days{__dp.time_since_epoch()}}
{ }
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_weekday&
operator+=(const months& __m) noexcept
{
*this = *this + __m;
return *this;
}
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_weekday&
operator-=(const months& __m) noexcept
{
*this = *this - __m;
return *this;
}
constexpr year_month_weekday&
operator+=(const years& __y) noexcept
{
*this = *this + __y;
return *this;
}
constexpr year_month_weekday&
operator-=(const years& __y) noexcept
{
*this = *this - __y;
return *this;
}
constexpr chrono::year
year() const noexcept
{ return _M_y; }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr chrono::weekday
weekday() const noexcept
{ return _M_wdi.weekday(); }
constexpr unsigned
index() const noexcept
{ return _M_wdi.index(); }
constexpr chrono::weekday_indexed
weekday_indexed() const noexcept
{ return _M_wdi; }
constexpr
operator sys_days() const noexcept
{
auto __d = sys_days{year() / month() / 1};
return __d + (weekday() - chrono::weekday(__d)
+ days{(static_cast<int>(index())-1)*7});
}
explicit constexpr
operator local_days() const noexcept
{ return local_days{sys_days{*this}.time_since_epoch()}; }
constexpr bool
ok() const noexcept
{
if (!_M_y.ok() || !_M_m.ok() || !_M_wdi.ok())
return false;
if (_M_wdi.index() <= 4)
return true;
days __d = (_M_wdi.weekday()
- chrono::weekday{sys_days{_M_y / _M_m / 1}}
+ days((_M_wdi.index()-1)*7 + 1));
__glibcxx_assert(__d.count() >= 1);
return (unsigned)__d.count() <= (unsigned)(_M_y / _M_m / last).day();
}
friend constexpr bool
operator==(const year_month_weekday& __x,
const year_month_weekday& __y) noexcept
{
return __x.year() == __y.year()
&& __x.month() == __y.month()
&& __x.weekday_indexed() == __y.weekday_indexed();
}
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_weekday
operator+(const year_month_weekday& __ymwd, const months& __dm) noexcept
{
return ((__ymwd.year() / __ymwd.month() + __dm)
/ __ymwd.weekday_indexed());
}
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_weekday
operator+(const months& __dm, const year_month_weekday& __ymwd) noexcept
{ return __ymwd + __dm; }
friend constexpr year_month_weekday
operator+(const year_month_weekday& __ymwd, const years& __dy) noexcept
{ return {__ymwd.year() + __dy, __ymwd.month(), __ymwd.weekday_indexed()}; }
friend constexpr year_month_weekday
operator+(const years& __dy, const year_month_weekday& __ymwd) noexcept
{ return __ymwd + __dy; }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_weekday
operator-(const year_month_weekday& __ymwd, const months& __dm) noexcept
{ return __ymwd + -__dm; }
friend constexpr year_month_weekday
operator-(const year_month_weekday& __ymwd, const years& __dy) noexcept
{ return __ymwd + -__dy; }
friend constexpr year_month_weekday
operator/(const year_month& __ym,
const chrono::weekday_indexed& __wdi) noexcept
{ return {__ym.year(), __ym.month(), __wdi}; }
friend constexpr year_month_weekday
operator/(const chrono::year& __y, const month_weekday& __mwd) noexcept
{ return {__y, __mwd.month(), __mwd.weekday_indexed()}; }
friend constexpr year_month_weekday
operator/(int __y, const month_weekday& __mwd) noexcept
{ return chrono::year(__y) / __mwd; }
friend constexpr year_month_weekday
operator/(const month_weekday& __mwd, const chrono::year& __y) noexcept
{ return __y / __mwd; }
friend constexpr year_month_weekday
operator/(const month_weekday& __mwd, int __y) noexcept
{ return chrono::year(__y) / __mwd; }
};
// YEAR_MONTH_WEEKDAY_LAST
class year_month_weekday_last
{
private:
chrono::year _M_y;
chrono::month _M_m;
chrono::weekday_last _M_wdl;
public:
constexpr
year_month_weekday_last(const chrono::year& __y, const chrono::month& __m,
const chrono::weekday_last& __wdl) noexcept
: _M_y{__y}, _M_m{__m}, _M_wdl{__wdl}
{ }
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_weekday_last&
operator+=(const months& __m) noexcept
{
*this = *this + __m;
return *this;
}
template<typename = __detail::__months_years_conversion_disambiguator>
constexpr year_month_weekday_last&
operator-=(const months& __m) noexcept
{
*this = *this - __m;
return *this;
}
constexpr year_month_weekday_last&
operator+=(const years& __y) noexcept
{
*this = *this + __y;
return *this;
}
constexpr year_month_weekday_last&
operator-=(const years& __y) noexcept
{
*this = *this - __y;
return *this;
}
constexpr chrono::year
year() const noexcept
{ return _M_y; }
constexpr chrono::month
month() const noexcept
{ return _M_m; }
constexpr chrono::weekday
weekday() const noexcept
{ return _M_wdl.weekday(); }
constexpr chrono::weekday_last
weekday_last() const noexcept
{ return _M_wdl; }
constexpr
operator sys_days() const noexcept
{
const auto __d = sys_days{_M_y / _M_m / last};
return sys_days{(__d - (chrono::weekday{__d}
- _M_wdl.weekday())).time_since_epoch()};
}
explicit constexpr
operator local_days() const noexcept
{ return local_days{sys_days{*this}.time_since_epoch()}; }
constexpr bool
ok() const noexcept
{ return _M_y.ok() && _M_m.ok() && _M_wdl.ok(); }
friend constexpr bool
operator==(const year_month_weekday_last& __x,
const year_month_weekday_last& __y) noexcept
{
return __x.year() == __y.year()
&& __x.month() == __y.month()
&& __x.weekday_last() == __y.weekday_last();
}
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_weekday_last
operator+(const year_month_weekday_last& __ymwdl,
const months& __dm) noexcept
{
return ((__ymwdl.year() / __ymwdl.month() + __dm)
/ __ymwdl.weekday_last());
}
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_weekday_last
operator+(const months& __dm,
const year_month_weekday_last& __ymwdl) noexcept
{ return __ymwdl + __dm; }
friend constexpr year_month_weekday_last
operator+(const year_month_weekday_last& __ymwdl,
const years& __dy) noexcept
{ return {__ymwdl.year() + __dy, __ymwdl.month(), __ymwdl.weekday_last()}; }
friend constexpr year_month_weekday_last
operator+(const years& __dy,
const year_month_weekday_last& __ymwdl) noexcept
{ return __ymwdl + __dy; }
template<typename = __detail::__months_years_conversion_disambiguator>
friend constexpr year_month_weekday_last
operator-(const year_month_weekday_last& __ymwdl,
const months& __dm) noexcept
{ return __ymwdl + -__dm; }
friend constexpr year_month_weekday_last
operator-(const year_month_weekday_last& __ymwdl,
const years& __dy) noexcept
{ return __ymwdl + -__dy; }
friend constexpr year_month_weekday_last
operator/(const year_month& __ym,
const chrono::weekday_last& __wdl) noexcept
{ return {__ym.year(), __ym.month(), __wdl}; }
friend constexpr year_month_weekday_last
operator/(const chrono::year& __y,
const chrono::month_weekday_last& __mwdl) noexcept
{ return {__y, __mwdl.month(), __mwdl.weekday_last()}; }
friend constexpr year_month_weekday_last
operator/(int __y, const chrono::month_weekday_last& __mwdl) noexcept
{ return chrono::year(__y) / __mwdl; }
friend constexpr year_month_weekday_last
operator/(const chrono::month_weekday_last& __mwdl,
const chrono::year& __y) noexcept
{ return __y / __mwdl; }
friend constexpr year_month_weekday_last
operator/(const chrono::month_weekday_last& __mwdl, int __y) noexcept
{ return chrono::year(__y) / __mwdl; }
};
// HH_MM_SS
/// @cond undocumented
namespace __detail
{
consteval long long
__pow10(unsigned __n)
{
long long __r = 1;
while (__n-- > 0)
__r *= 10;
return __r;
}
template<typename _Duration> struct __utc_leap_second;
}
/// @endcond
/** Utility for splitting a duration into hours, minutes, and seconds
*
* This is a convenience type that provides accessors for the constituent
* parts (hours, minutes, seconds and subseconds) of a duration.
*
* @since C++20
*/
template<typename _Duration>
class hh_mm_ss
{
static_assert( __is_duration<_Duration>::value );
private:
static consteval int
_S_fractional_width()
{
auto __den = _Duration::period::den;
const int __multiplicity_2 = std::__countr_zero((uintmax_t)__den);
__den >>= __multiplicity_2;
int __multiplicity_5 = 0;
while ((__den % 5) == 0)
{
++__multiplicity_5;
__den /= 5;
}
if (__den != 1)
return 6;
int __width = (__multiplicity_2 > __multiplicity_5
? __multiplicity_2 : __multiplicity_5);
if (__width > 18)
__width = 18;
return __width;
}
constexpr
hh_mm_ss(_Duration __d, bool __is_neg)
: _M_h (duration_cast<chrono::hours>(__d)),
_M_m (duration_cast<chrono::minutes>(__d - hours())),
_M_s (duration_cast<chrono::seconds>(__d - hours() - minutes())),
_M_is_neg(__is_neg)
{
auto __ss = __d - hours() - minutes() - seconds();
if constexpr (treat_as_floating_point_v<typename precision::rep>)
_M_ss._M_r = __ss.count();
else if constexpr (precision::period::den != 1)
_M_ss._M_r = duration_cast<precision>(__ss).count();
}
static constexpr _Duration
_S_abs(_Duration __d)
{
if constexpr (numeric_limits<typename _Duration::rep>::is_signed)
return chrono::abs(__d);
else
return __d;
}
public:
static constexpr unsigned fractional_width = {_S_fractional_width()};
using precision
= duration<common_type_t<typename _Duration::rep,
chrono::seconds::rep>,
ratio<1, __detail::__pow10(fractional_width)>>;
constexpr hh_mm_ss() noexcept = default;
constexpr explicit
hh_mm_ss(_Duration __d)
: hh_mm_ss(_S_abs(__d), __d < _Duration::zero())
{ }
constexpr bool
is_negative() const noexcept
{
if constexpr (!_S_is_unsigned)
return _M_is_neg;
else
return false;
}
constexpr chrono::hours
hours() const noexcept
{ return _M_h; }
constexpr chrono::minutes
minutes() const noexcept
{ return _M_m; }
constexpr chrono::seconds
seconds() const noexcept
{ return _M_s; }
constexpr precision
subseconds() const noexcept
{ return static_cast<precision>(_M_ss); }
constexpr explicit
operator precision() const noexcept
{ return to_duration(); }
constexpr precision
to_duration() const noexcept
{
if constexpr (!_S_is_unsigned)
if (_M_is_neg)
return -(_M_h + _M_m + _M_s + subseconds());
return _M_h + _M_m + _M_s + subseconds();
}
private:
static constexpr bool _S_is_unsigned
= __and_v<is_integral<typename _Duration::rep>,
is_unsigned<typename _Duration::rep>>;
template<typename _Ratio>
using __byte_duration = duration<unsigned char, _Ratio>;
// The type of the _M_ss member that holds the subsecond precision.
template<typename _Dur>
struct __subseconds
{
typename _Dur::rep _M_r{};
constexpr explicit
operator _Dur() const noexcept
{ return _Dur(_M_r); }
};
// An empty class if this precision doesn't need subseconds.
template<typename _Rep>
requires (!treat_as_floating_point_v<_Rep>)
struct __subseconds<duration<_Rep, ratio<1>>>
{
constexpr explicit
operator duration<_Rep, ratio<1>>() const noexcept
{ return {}; }
};
template<typename _Rep, typename _Period>
requires (!treat_as_floating_point_v<_Rep>)
&& ratio_less_v<_Period, ratio<1, 1>>
&& ratio_greater_equal_v<_Period, ratio<1, 250>>
struct __subseconds<duration<_Rep, _Period>>
{
unsigned char _M_r{};
constexpr explicit
operator duration<_Rep, _Period>() const noexcept
{ return duration<_Rep, _Period>(_M_r); }
};
template<typename _Rep, typename _Period>
requires (!treat_as_floating_point_v<_Rep>)
&& ratio_less_v<_Period, ratio<1, 250>>
&& ratio_greater_equal_v<_Period, ratio<1, 4000000000>>
struct __subseconds<duration<_Rep, _Period>>
{
uint_least32_t _M_r{};
constexpr explicit
operator duration<_Rep, _Period>() const noexcept
{ return duration<_Rep, _Period>(_M_r); }
};
chrono::hours _M_h{};
__byte_duration<ratio<60>> _M_m{};
__byte_duration<ratio<1>> _M_s{};
bool _M_is_neg{};
__subseconds<precision> _M_ss{};
template<typename> friend struct __detail::__utc_leap_second;
};
/// @cond undocumented
namespace __detail
{
// Represents a time that is within a leap second insertion.
template<typename _Duration>
struct __utc_leap_second
{
explicit
__utc_leap_second(const sys_time<_Duration>& __s)
: _M_date(chrono::floor<days>(__s)), _M_time(__s - _M_date)
{
++_M_time._M_s;
}
sys_days _M_date;
hh_mm_ss<common_type_t<_Duration, days>> _M_time;
};
}
/// @endcond
// 12/24 HOURS FUNCTIONS
constexpr bool
is_am(const hours& __h) noexcept
{ return 0h <= __h && __h <= 11h; }
constexpr bool
is_pm(const hours& __h) noexcept
{ return 12h <= __h && __h <= 23h; }
constexpr hours
make12(const hours& __h) noexcept
{
if (__h == 0h)
return 12h;
else if (__h > 12h)
return __h - 12h;
return __h;
}
constexpr hours
make24(const hours& __h, bool __is_pm) noexcept
{
if (!__is_pm)
{
if (__h == 12h)
return 0h;
else
return __h;
}
else
{
if (__h == 12h)
return __h;
else
return __h + 12h;
}
}
#if _GLIBCXX_HOSTED
#if _GLIBCXX_USE_CXX11_ABI || ! _GLIBCXX_USE_DUAL_ABI
// C++20 [time.zones] Time zones
struct tzdb;
struct sys_info
{
sys_seconds begin;
sys_seconds end;
seconds offset;
minutes save;
string abbrev;
};
struct local_info
{
static constexpr int unique = 0;
static constexpr int nonexistent = 1;
static constexpr int ambiguous = 2;
int result;
sys_info first;
sys_info second;
};
class nonexistent_local_time : public runtime_error
{
public:
template<typename _Duration>
nonexistent_local_time(const local_time<_Duration>& __tp,
const local_info& __i)
: runtime_error(_S_make_what_str(__tp, __i))
{ __glibcxx_assert(__i.result == local_info::nonexistent); }
private:
template<typename _Duration>
static string
_S_make_what_str(const local_time<_Duration>& __tp,
const local_info& __i)
{
std::ostringstream __os;
__os << __tp << " is in a gap between\n"
<< local_seconds(__i.first.end.time_since_epoch())
+ __i.first.offset << ' ' << __i.first.abbrev << " and\n"
<< local_seconds(__i.second.begin.time_since_epoch())
+ __i.second.offset << ' ' << __i.second.abbrev
<< " which are both equivalent to\n"
<< __i.first.end << " UTC";
return std::move(__os).str();
}
};
class ambiguous_local_time : public runtime_error
{
public:
template<typename _Duration>
ambiguous_local_time(const local_time<_Duration>& __tp,
const local_info& __i)
: runtime_error(_S_make_what_str(__tp, __i))
{ __glibcxx_assert(__i.result == local_info::ambiguous); }
private:
template<typename _Duration>
static string
_S_make_what_str(const local_time<_Duration>& __tp,
const local_info& __i)
{
std::ostringstream __os;
__os << __tp << " is ambiguous. It could be\n"
<< __tp << ' ' << __i.first.abbrev << " == "
<< __tp - __i.first.offset << " UTC or\n"
<< __tp << ' ' << __i.second.abbrev << " == "
<< __tp - __i.second.offset << " UTC";
return std::move(__os).str();
}
};
template<typename _Duration>
[[noreturn]] void
__throw_bad_local_time(const local_time<_Duration>& __tp,
const local_info& __i)
{
#if __cpp_exceptions
if (__i.result == local_info::nonexistent)
throw nonexistent_local_time(__tp, __i);
throw ambiguous_local_time(__tp, __i);
#else
__builtin_abort();
#endif
}
enum class choose { earliest, latest };
class time_zone
{
public:
time_zone(time_zone&&) = default;
time_zone& operator=(time_zone&&) = default;
~time_zone();
[[nodiscard]]
string_view name() const noexcept { return _M_name; }
template<typename _Duration>
sys_info
get_info(const sys_time<_Duration>& __st) const
{ return _M_get_sys_info(chrono::floor<seconds>(__st)); }
template<typename _Duration>
local_info
get_info(const local_time<_Duration>& __tp) const
{ return _M_get_local_info(chrono::floor<seconds>(__tp)); }
template<typename _Duration>
sys_time<common_type_t<_Duration, seconds>>
to_sys(const local_time<_Duration>& __tp) const
{
local_info __info = get_info(__tp);
if (__info.result != local_info::unique)
__throw_bad_local_time(__tp, __info);
return sys_time<_Duration>(__tp.time_since_epoch())
- __info.first.offset;
}
template<typename _Duration>
sys_time<common_type_t<_Duration, seconds>>
to_sys(const local_time<_Duration>& __tp, choose __z) const
{
local_info __info = get_info(__tp);
if (__info.result == local_info::nonexistent)
return __info.first.end; // Last second of the previous sys_info.
sys_time<_Duration> __st(__tp.time_since_epoch());
if (__info.result == local_info::ambiguous && __z == choose::latest)
return __st - __info.second.offset; // Time in the later sys_info.
// else if __z == earliest, use __info.first.offset as below:
return __st - __info.first.offset;
}
template<typename _Duration>
local_time<common_type_t<_Duration, seconds>>
to_local(const sys_time<_Duration>& __tp) const
{
auto __d = (__tp + get_info(__tp).offset).time_since_epoch();
return local_time<common_type_t<_Duration, seconds>>(__d);
}
[[nodiscard]] friend bool
operator==(const time_zone& __x, const time_zone& __y) noexcept
{ return __x._M_name == __y._M_name; }
[[nodiscard]] friend strong_ordering
operator<=>(const time_zone& __x, const time_zone& __y) noexcept
{ return __x._M_name <=> __y._M_name; }
private:
sys_info _M_get_sys_info(sys_seconds) const;
local_info _M_get_local_info(local_seconds) const;
friend const tzdb& reload_tzdb();
friend struct tzdb;
friend class tzdb_list;
struct _Impl;
explicit time_zone(unique_ptr<_Impl> __p);
string _M_name;
unique_ptr<_Impl> _M_impl;
};
const time_zone* locate_zone(string_view __tz_name);
const time_zone* current_zone();
/** The list of `chrono::tzdb` objects
*
* A single object of this type is constructed by the C++ runtime,
* and can be accessed by calling `chrono::get_tzdb_list()`.
*
* The front of the list is the current `tzdb` object and can be accessed
* via `chrono::get_tzdb_list().front()` or `chrono::get_tzdb()` or
* `*chrono::get_tzdb_list().begin()`.
*
* The `chrono::reload_tzdb()` function will check for a newer version
* and if found, insert it at the front of the list.
*
* @since C++20
*/
class tzdb_list
{
struct _Node;
public:
tzdb_list(const tzdb_list&) = delete;
tzdb_list& operator=(const tzdb_list&) = delete;
/** An iterator into the `tzdb_list`
*
* As a extension, in libstdc++ each `tzdb` is reference-counted
* and the `const_iterator` type shares ownership of the object it
* refers to. This ensures that a `tzdb` erased from the list will
* not be destroyed while there is an iterator that refers to it.
*/
class const_iterator
{
public:
using value_type = tzdb;
using reference = const tzdb&;
using pointer = const tzdb*;
using difference_type = ptrdiff_t;
using iterator_category = forward_iterator_tag;
constexpr const_iterator() = default;
const_iterator(const const_iterator&) = default;
const_iterator(const_iterator&&) = default;
const_iterator& operator=(const const_iterator&) = default;
const_iterator& operator=(const_iterator&&) = default;
reference operator*() const noexcept;
pointer operator->() const noexcept { return &**this; }
const_iterator& operator++();
const_iterator operator++(int);
bool operator==(const const_iterator&) const noexcept = default;
private:
explicit const_iterator(const shared_ptr<_Node>&) noexcept;
friend class tzdb_list;
shared_ptr<_Node> _M_node;
void* _M_reserved = nullptr;
};
/** Access the current `tzdb` at the front of the list.
*
* This returns a reference to the same object as `chrono::get_tzdb()`.
*
* @returns A reference to the current tzdb object.
* @since C++20
*/
const tzdb& front() const noexcept;
/** Remove the tzdb object _after_ the one the iterator refers to.
*
* Calling this function concurrently with any of `front()`, `begin()`,
* or `end()` does not cause a data race, but in general this function
* is not thread-safe. The behaviour may be undefined if erasing an
* element from the list while another thread is calling the same
* function, or incrementing an iterator into the list, or accessing
* the element being erased (unless it is accessed through an iterator).
*
* @param __p A dereferenceable iterator.
* @returns An iterator the element after the one that was erased
* (or `end()` if there is no such element).
* @since C++20
*/
const_iterator erase_after(const_iterator __p);
const_iterator begin() const noexcept;
const_iterator end() const noexcept { return {}; }
const_iterator cbegin() const noexcept { return begin(); }
const_iterator cend() const noexcept { return end(); }
private:
constexpr explicit tzdb_list(nullptr_t);
friend tzdb_list& get_tzdb_list();
friend const tzdb& get_tzdb();
friend const tzdb& reload_tzdb();
friend struct tzdb;
friend class leap_second;
friend struct time_zone::_Impl;
friend class time_zone_link;
};
class time_zone_link
{
public:
time_zone_link(time_zone_link&&) = default;
time_zone_link& operator=(time_zone_link&&) = default;
string_view name() const noexcept { return _M_name; }
string_view target() const noexcept { return _M_target; }
friend bool
operator==(const time_zone_link& __x, const time_zone_link& __y) noexcept
{ return __x.name() == __y.name(); }
friend strong_ordering
operator<=>(const time_zone_link& __x, const time_zone_link& __y) noexcept
{ return __x.name() <=> __y.name(); }
private:
friend const tzdb& reload_tzdb();
friend struct tzdb_list::_Node;
explicit time_zone_link(nullptr_t) { }
string _M_name;
string _M_target;
};
class leap_second
{
public:
leap_second(const leap_second&) = default;
leap_second& operator=(const leap_second&) = default;
[[nodiscard]]
constexpr sys_seconds
date() const noexcept
{
if (_M_s >= _M_s.zero()) [[likely]]
return sys_seconds(_M_s);
return sys_seconds(-_M_s);
}
[[nodiscard]]
constexpr seconds
value() const noexcept
{
if (_M_s >= _M_s.zero()) [[likely]]
return seconds(1);
return seconds(-1);
}
// This can be defaulted because the database will never contain two
// leap_second objects with the same date but different signs.
[[nodiscard]] friend constexpr bool
operator==(const leap_second&, const leap_second&) noexcept = default;
[[nodiscard]] friend constexpr strong_ordering
operator<=>(const leap_second& __x, const leap_second& __y) noexcept
{ return __x.date() <=> __y.date(); }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator==(const leap_second& __x,
const sys_time<_Duration>& __y) noexcept
{ return __x.date() == __y; }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator<(const leap_second& __x,
const sys_time<_Duration>& __y) noexcept
{ return __x.date() < __y; }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator<(const sys_time<_Duration>& __x,
const leap_second& __y) noexcept
{ return __x < __y.date(); }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator>(const leap_second& __x,
const sys_time<_Duration>& __y) noexcept
{ return __y < __x.date(); }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator>(const sys_time<_Duration>& __x,
const leap_second& __y) noexcept
{ return __y.date() < __x; }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator<=(const leap_second& __x,
const sys_time<_Duration>& __y) noexcept
{ return !(__y < __x.date()); }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator<=(const sys_time<_Duration>& __x,
const leap_second& __y) noexcept
{ return !(__y.date() < __x); }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator>=(const leap_second& __x,
const sys_time<_Duration>& __y) noexcept
{ return !(__x.date() < __y); }
template<typename _Duration>
[[nodiscard]] friend constexpr bool
operator>=(const sys_time<_Duration>& __x,
const leap_second& __y) noexcept
{ return !(__x < __y.date()); }
// This is a simplified form of the constraint specified in the standard,
// three_way_comparable_with<sys_seconds, sys_time<_Duration>>.
template<three_way_comparable_with<seconds> _Duration>
[[nodiscard]] friend constexpr auto
operator<=>(const leap_second& __x,
const sys_time<_Duration>& __y) noexcept
{ return __x.date() <=> __y; }
private:
explicit leap_second(seconds::rep __s) : _M_s(__s) { }
friend struct tzdb_list::_Node;
friend const tzdb& reload_tzdb();
template<typename _Duration>
friend leap_second_info
get_leap_second_info(const utc_time<_Duration>&);
seconds _M_s; // == date().time_since_epoch() * value().count()
};
template<class _Tp> struct zoned_traits { };
template<>
struct zoned_traits<const time_zone*>
{
static const time_zone*
default_zone()
{ return std::chrono::locate_zone("UTC"); }
static const time_zone*
locate_zone(string_view __name)
{ return std::chrono::locate_zone(__name); }
};
struct tzdb
{
string version;
_GLIBCXX_STD_C::vector<time_zone> zones;
_GLIBCXX_STD_C::vector<time_zone_link> links;
_GLIBCXX_STD_C::vector<leap_second> leap_seconds;
const time_zone*
locate_zone(string_view __tz_name) const;
const time_zone*
current_zone() const;
private:
friend const tzdb& reload_tzdb();
friend class time_zone;
friend struct tzdb_list::_Node;
};
tzdb_list& get_tzdb_list();
const tzdb& get_tzdb();
const tzdb& reload_tzdb();
string remote_version();
template<typename _Duration, typename _TimeZonePtr = const time_zone*>
class zoned_time
{
static_assert(__is_duration_v<_Duration>);
using _Traits = zoned_traits<_TimeZonePtr>;
// Every constructor that accepts a string_view as its first parameter
// does not participate in class template argument deduction.
using string_view = type_identity_t<std::string_view>;
public:
using duration = common_type_t<_Duration, seconds>;
zoned_time() requires requires { _Traits::default_zone(); }
{ }
zoned_time(const zoned_time&) = default;
zoned_time& operator=(const zoned_time&) = default;
zoned_time(const sys_time<_Duration>& __st)
requires requires { _Traits::default_zone(); }
: _M_tp(__st)
{ }
explicit
zoned_time(_TimeZonePtr __z) : _M_zone(std::move(__z)) { }
explicit
zoned_time(string_view __name)
requires requires {
_TimeZonePtr{_Traits::locate_zone(std::string_view{})};
}
: _M_zone(_Traits::locate_zone(__name))
{ }
template<typename _Duration2>
zoned_time(const zoned_time<_Duration2, _TimeZonePtr>& __zt)
requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
: _M_zone(__zt._M_zone), _M_tp(__zt._M_tp)
{ }
zoned_time(_TimeZonePtr __z, const sys_time<_Duration>& __st)
: _M_zone(std::move(__z)), _M_tp(__st)
{ }
zoned_time(string_view __name, const sys_time<_Duration>& __st)
: zoned_time(_Traits::locate_zone(__name), __st)
{ }
zoned_time(_TimeZonePtr __z, const local_time<_Duration>& __tp)
requires requires {
{ __z->to_sys(__tp) } -> convertible_to<sys_time<_Duration>>;
}
: _M_zone(std::move(__z)), _M_tp(_M_zone->to_sys(__tp))
{ }
zoned_time(string_view __name, const local_time<_Duration>& __tp)
requires requires (_TimeZonePtr __z) {
{ _Traits::locate_zone(__name) } -> convertible_to<_TimeZonePtr>;
{ __z->to_sys(__tp) } -> convertible_to<sys_time<_Duration>>;
}
: zoned_time(_Traits::locate_zone(__name), __tp)
{ }
zoned_time(_TimeZonePtr __z, const local_time<_Duration>& __tp,
choose __c)
requires requires {
{ __z->to_sys(__tp, __c) } -> convertible_to<sys_time<_Duration>>;
}
: _M_zone(std::move(__z)), _M_tp(_M_zone->to_sys(__tp, __c))
{ }
zoned_time(string_view __name, const local_time<_Duration>& __tp,
choose __c)
requires requires (_TimeZonePtr __z) {
{ _Traits::locate_zone(__name) } -> convertible_to<_TimeZonePtr>;
{ __z->to_sys(__tp, __c) } -> convertible_to<sys_time<_Duration>>;
}
: _M_zone(_Traits::locate_zone(__name)),
_M_tp(_M_zone->to_sys(__tp, __c))
{ }
template<typename _Duration2, typename _TimeZonePtr2>
zoned_time(_TimeZonePtr __z,
const zoned_time<_Duration2, _TimeZonePtr2>& __zt)
requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
: _M_zone(__z), _M_tp(__zt._M_tp)
{ }
template<typename _Duration2, typename _TimeZonePtr2>
zoned_time(_TimeZonePtr __z,
const zoned_time<_Duration2, _TimeZonePtr2>& __zt,
choose)
requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
: _M_zone(__z), _M_tp(__zt._M_tp)
{ }
template<typename _Duration2, typename _TimeZonePtr2>
zoned_time(string_view __name,
const zoned_time<_Duration2, _TimeZonePtr2>& __zt)
requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
&& requires {
{ _Traits::locate_zone(__name) } -> convertible_to<_TimeZonePtr>;
}
: _M_zone(_Traits::locate_zone(__name)), _M_tp(__zt._M_tp)
{ }
template<typename _Duration2, typename _TimeZonePtr2>
zoned_time(string_view __name,
const zoned_time<_Duration2, _TimeZonePtr2>& __zt,
choose)
requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
&& requires {
{ _Traits::locate_zone(__name) } -> convertible_to<_TimeZonePtr>;
}
: _M_zone(_Traits::locate_zone(__name)), _M_tp(__zt._M_tp)
{ }
zoned_time&
operator=(const sys_time<_Duration>& __st)
{
_M_tp = __st;
return *this;
}
zoned_time&
operator=(const local_time<_Duration>& __lt)
{
_M_tp = _M_zone->to_sys(__lt);
return *this;
}
[[nodiscard]]
operator sys_time<duration>() const { return _M_tp; }
[[nodiscard]]
explicit operator local_time<duration>() const
{ return get_local_time(); }
[[nodiscard]]
_TimeZonePtr
get_time_zone() const
{ return _M_zone; }
[[nodiscard]]
local_time<duration>
get_local_time() const
{ return _M_zone->to_local(_M_tp); }
[[nodiscard]]
sys_time<duration>
get_sys_time() const
{ return _M_tp; }
[[nodiscard]]
sys_info
get_info() const
{ return _M_zone->get_info(_M_tp); }
[[nodiscard]] friend bool
operator==(const zoned_time&, const zoned_time&) = default;
private:
_TimeZonePtr _M_zone{ _Traits::default_zone() };
sys_time<duration> _M_tp{};
template<typename _Duration2, typename _TimeZonePtr2>
friend class zoned_time;
};
zoned_time() -> zoned_time<seconds>;
template<typename _Duration>
zoned_time(sys_time<_Duration>)
-> zoned_time<common_type_t<_Duration, seconds>>;
/// @cond undocumented
template<typename _TimeZonePtrOrName>
using __time_zone_representation
= __conditional_t<is_convertible_v<_TimeZonePtrOrName, string_view>,
const time_zone*,
remove_cvref_t<_TimeZonePtrOrName>>;
/// @endcond
template<typename _TimeZonePtrOrName>
zoned_time(_TimeZonePtrOrName&&)
-> zoned_time<seconds, __time_zone_representation<_TimeZonePtrOrName>>;
template<typename _TimeZonePtrOrName, typename _Duration>
zoned_time(_TimeZonePtrOrName&&, sys_time<_Duration>)
-> zoned_time<common_type_t<_Duration, seconds>,
__time_zone_representation<_TimeZonePtrOrName>>;
template<typename _TimeZonePtrOrName, typename _Duration>
zoned_time(_TimeZonePtrOrName&&, local_time<_Duration>,
choose = choose::earliest)
-> zoned_time<common_type_t<_Duration, seconds>,
__time_zone_representation<_TimeZonePtrOrName>>;
template<typename _Duration, typename _TimeZonePtrOrName,
typename _TimeZonePtr2>
zoned_time(_TimeZonePtrOrName&&, zoned_time<_Duration, _TimeZonePtr2>,
choose = choose::earliest)
-> zoned_time<common_type_t<_Duration, seconds>,
__time_zone_representation<_TimeZonePtrOrName>>;
template<typename _Dur1, typename _TZPtr1, typename _Dur2, typename _TZPtr2>
[[nodiscard]]
inline bool
operator==(const zoned_time<_Dur1, _TZPtr1>& __x,
const zoned_time<_Dur2, _TZPtr2>& __y)
{
return __x.get_time_zone() == __y.get_time_zone()
&& __x.get_sys_time() == __y.get_sys_time();
}
using zoned_seconds = zoned_time<seconds>;
#endif // _GLIBCXX_USE_CXX11_ABI || ! _GLIBCXX_USE_DUAL_ABI
namespace __detail
{
inline leap_second_info
__get_leap_second_info(sys_seconds __ss, bool __is_utc)
{
if (__ss < sys_seconds{}) [[unlikely]]
return {};
const seconds::rep __leaps[] {
78796800, // 1 Jul 1972
94694400, // 1 Jan 1973
126230400, // 1 Jan 1974
157766400, // 1 Jan 1975
189302400, // 1 Jan 1976
220924800, // 1 Jan 1977
252460800, // 1 Jan 1978
283996800, // 1 Jan 1979
315532800, // 1 Jan 1980
362793600, // 1 Jul 1981
394329600, // 1 Jul 1982
425865600, // 1 Jul 1983
489024000, // 1 Jul 1985
567993600, // 1 Jan 1988
631152000, // 1 Jan 1990
662688000, // 1 Jan 1991
709948800, // 1 Jul 1992
741484800, // 1 Jul 1993
773020800, // 1 Jul 1994
820454400, // 1 Jan 1996
867715200, // 1 Jul 1997
915148800, // 1 Jan 1999
1136073600, // 1 Jan 2006
1230768000, // 1 Jan 2009
1341100800, // 1 Jul 2012
1435708800, // 1 Jul 2015
1483228800, // 1 Jan 2017
};
// The list above is known to be valid until (at least) this date
// and only contains positive leap seconds.
const sys_seconds __expires(1735344000s); // 2024-12-28 00:00:00 UTC
#if _GLIBCXX_USE_CXX11_ABI || ! _GLIBCXX_USE_DUAL_ABI
if (__ss > __expires)
{
// Use updated leap_seconds from tzdb.
size_t __n = std::size(__leaps);
auto __db = get_tzdb_list().begin();
auto __first = __db->leap_seconds.begin() + __n;
auto __last = __db->leap_seconds.end();
auto __pos = std::upper_bound(__first, __last, __ss);
seconds __elapsed(__n);
for (auto __i = __first; __i != __pos; ++__i)
__elapsed += __i->value();
if (__is_utc)
{
// Convert utc_time to sys_time:
__ss -= __elapsed;
// See if that sys_time is before (or during) previous leap sec:
if (__pos != __first && __ss < __pos[-1])
{
if ((__ss + 1s) >= __pos[-1])
return {true, __elapsed};
__elapsed -= __pos[-1].value();
}
}
return {false, __elapsed};
}
else
#endif
{
seconds::rep __s = __ss.time_since_epoch().count();
const seconds::rep* __first = std::begin(__leaps);
const seconds::rep* __last = std::end(__leaps);
// Don't bother searching the list if we're after the last one.
if (__s > (__last[-1] + (__last - __first) + 1))
return { false, seconds(__last - __first) };
auto __pos = std::upper_bound(__first, __last, __s);
seconds __elapsed{__pos - __first};
if (__is_utc)
{
// Convert utc_time to sys_time:
__s -= __elapsed.count();
// See if that sys_time is before (or during) previous leap sec:
if (__pos != __first && __s < __pos[-1])
{
if ((__s + 1) >= __pos[-1])
return {true, __elapsed};
--__elapsed;
}
}
return {false, __elapsed};
}
}
} // namespace __detail
template<typename _Duration>
[[nodiscard]]
inline leap_second_info
get_leap_second_info(const utc_time<_Duration>& __ut)
{
auto __s = chrono::duration_cast<seconds>(__ut.time_since_epoch());
return __detail::__get_leap_second_info(sys_seconds(__s), true);
}
template<typename _Duration>
[[nodiscard]]
inline utc_time<common_type_t<_Duration, seconds>>
utc_clock::from_sys(const sys_time<_Duration>& __t)
{
using _CDur = common_type_t<_Duration, seconds>;
auto __s = chrono::time_point_cast<seconds>(__t);
const auto __li = __detail::__get_leap_second_info(__s, false);
return utc_time<_CDur>{__t.time_since_epoch()} + __li.elapsed;
}
#endif // _GLIBCXX_HOSTED
/// @} group chrono
#endif // C++20
} // namespace chrono
#if __cplusplus >= 202002L
inline namespace literals
{
inline namespace chrono_literals
{
/// @addtogroup chrono
/// @{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wliteral-suffix"
/// Literal suffix for creating chrono::day objects.
/// @since C++20
constexpr chrono::day
operator""d(unsigned long long __d) noexcept
{ return chrono::day{static_cast<unsigned>(__d)}; }
/// Literal suffix for creating chrono::year objects.
/// @since C++20
constexpr chrono::year
operator""y(unsigned long long __y) noexcept
{ return chrono::year{static_cast<int>(__y)}; }
#pragma GCC diagnostic pop
/// @}
} // inline namespace chrono_literals
} // inline namespace literals
#endif // C++20
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#if __cplusplus >= 202002L && _GLIBCXX_HOSTED
# include <bits/chrono_io.h>
#endif
#endif // C++11
#endif //_GLIBCXX_CHRONO
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