libcxx/include/__chrono/leap_second.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 // For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html
  11
  12 #ifndef _LIBCPP___CHRONO_LEAP_SECOND_H
  13 #define _LIBCPP___CHRONO_LEAP_SECOND_H
  14
  15 #include <version>
  16 // Enable the contents of the header only when libc++ was built with experimental features enabled.
  17 #if !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
  18
  19 #  include <__chrono/duration.h>
  20 #  include <__chrono/system_clock.h>
  21 #  include <__chrono/time_point.h>
  22 #  include <__compare/ordering.h>
  23 #  include <__compare/three_way_comparable.h>
  24 #  include <__config>
  25 #  include <__utility/private_constructor_tag.h>
  26
  27 #  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  28 #    pragma GCC system_header
  29 #  endif
  30
  31 _LIBCPP_BEGIN_NAMESPACE_STD
  32
  33 #  if _LIBCPP_STD_VER >= 20
  34
  35 namespace chrono {
  36
  37 class leap_second {
  38 public:
  39   [[nodiscard]]
  40   _LIBCPP_HIDE_FROM_ABI explicit constexpr leap_second(__private_constructor_tag, sys_seconds __date, seconds __value)
  41       : __date_(__date), __value_(__value) {}
  42
  43   _LIBCPP_HIDE_FROM_ABI leap_second(const leap_second&)            = default;
  44   _LIBCPP_HIDE_FROM_ABI leap_second& operator=(const leap_second&) = default;
  45
  46   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr sys_seconds date() const noexcept { return __date_; }
  47
  48   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr seconds value() const noexcept { return __value_; }
  49
  50 private:
  51   sys_seconds __date_;
  52   seconds __value_;
  53
  54   // The function
  55   //   template<class Duration>
  56   //    requires three_way_comparable_with<sys_seconds, sys_time<Duration>>
  57   //    constexpr auto operator<=>(const leap_second& x, const sys_time<Duration>& y) noexcept;
  58   //
  59   // Has constraints that are recursive (LWG4139). The proposed resolution is
  60   // to make the funcion a hidden friend. For consistency make this change for
  61   // all comparison functions.
  62
  63   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const leap_second& __x, const leap_second& __y) {
  64     return __x.date() == __y.date();
  65   }
  66
  67   _LIBCPP_HIDE_FROM_ABI friend constexpr strong_ordering operator<=>(const leap_second& __x, const leap_second& __y) {
  68     return __x.date() <=> __y.date();
  69   }
  70
  71   template <class _Duration>
  72   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const leap_second& __x, const sys_time<_Duration>& __y) {
  73     return __x.date() == __y;
  74   }
  75
  76   template <class _Duration>
  77   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const leap_second& __x, const sys_time<_Duration>& __y) {
  78     return __x.date() < __y;
  79   }
  80
  81   template <class _Duration>
  82   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const sys_time<_Duration>& __x, const leap_second& __y) {
  83     return __x < __y.date();
  84   }
  85
  86   template <class _Duration>
  87   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const leap_second& __x, const sys_time<_Duration>& __y) {
  88     return __y < __x;
  89   }
  90
  91   template <class _Duration>
  92   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const sys_time<_Duration>& __x, const leap_second& __y) {
  93     return __y < __x;
  94   }
  95
  96   template <class _Duration>
  97   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const leap_second& __x, const sys_time<_Duration>& __y) {
  98     return !(__y < __x);
  99   }
 100
 101   template <class _Duration>
 102   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const sys_time<_Duration>& __x, const leap_second& __y) {
 103     return !(__y < __x);
 104   }
 105
 106   template <class _Duration>
 107   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const leap_second& __x, const sys_time<_Duration>& __y) {
 108     return !(__x < __y);
 109   }
 110
 111   template <class _Duration>
 112   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const sys_time<_Duration>& __x, const leap_second& __y) {
 113     return !(__x < __y);
 114   }
 115
 116   template <class _Duration>
 117     requires three_way_comparable_with<sys_seconds, sys_time<_Duration>>
 118   _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const leap_second& __x, const sys_time<_Duration>& __y) {
 119     return __x.date() <=> __y;
 120   }
 121 };
 122
 123 } // namespace chrono
 124
 125 #  endif // _LIBCPP_STD_VER >= 20
 126
 127 _LIBCPP_END_NAMESPACE_STD
 128
 129 #endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
 130
 131 #endif // _LIBCPP___CHRONO_LEAP_SECOND_H