1// <chrono> -*- C++ -*-
2
3// Copyright (C) 2008-2020 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file include/chrono
26 *  This is a Standard C++ Library header.
27 *  @ingroup chrono
28 */
29
30#ifndef _GLIBCXX_CHRONO
31#define _GLIBCXX_CHRONO 1
32
33#pragma GCC system_header
34
35#if __cplusplus < 201103L
36# include <bits/c++0x_warning.h>
37#else
38
39#include <ratio>
40#include <type_traits>
41#include <limits>
42#include <ctime>
43#include <bits/parse_numbers.h> // for literals support.
44#if __cplusplus > 201703L
45# include <concepts>
46# include <compare>
47#endif
48
49namespace std _GLIBCXX_VISIBILITY(default)
50{
51_GLIBCXX_BEGIN_NAMESPACE_VERSION
52
53#if __cplusplus >= 201703L
54  namespace filesystem { struct __file_clock; };
55#endif
56
57  /**
58   * @defgroup chrono Time
59   * @ingroup utilities
60   *
61   * Classes and functions for time.
62   * @{
63   */
64
65  /** @namespace std::chrono
66   *  @brief ISO C++ 2011 namespace for date and time utilities
67   */
68  namespace chrono
69  {
70    template<typename _Rep, typename _Period = ratio<1>>
71      struct duration;
72
73    template<typename _Clock, typename _Dur = typename _Clock::duration>
74      struct time_point;
75  }
76
77  // 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
78
79  /// @cond undocumented
80
81  template<typename _CT, typename _Period1, typename _Period2, typename = void>
82    struct __duration_common_type
83    { };
84
85  template<typename _CT, typename _Period1, typename _Period2>
86    struct __duration_common_type<_CT, _Period1, _Period2,
87				  __void_t<typename _CT::type>>
88    {
89    private:
90      using __gcd_num = __static_gcd<_Period1::num, _Period2::num>;
91      using __gcd_den = __static_gcd<_Period1::den, _Period2::den>;
92      using __cr = typename _CT::type;
93      using __r = ratio<__gcd_num::value,
94			(_Period1::den / __gcd_den::value) * _Period2::den>;
95
96    public:
97      using type = chrono::duration<__cr, typename __r::type>;
98    };
99
100  /// @endcond
101
102  /// Specialization of common_type for chrono::duration types.
103  /// @relates duration
104  template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
105    struct common_type<chrono::duration<_Rep1, _Period1>,
106		       chrono::duration<_Rep2, _Period2>>
107    : __duration_common_type<common_type<_Rep1, _Rep2>,
108			     typename _Period1::type,
109			     typename _Period2::type>
110    { };
111
112  /// Specialization of common_type for two identical chrono::duration types.
113  /// @relates duration
114  template<typename _Rep, typename _Period>
115    struct common_type<chrono::duration<_Rep, _Period>,
116		       chrono::duration<_Rep, _Period>>
117    {
118      using type = chrono::duration<typename common_type<_Rep>::type,
119				    typename _Period::type>;
120    };
121
122  /// Specialization of common_type for one chrono::duration type.
123  /// @relates duration
124  template<typename _Rep, typename _Period>
125    struct common_type<chrono::duration<_Rep, _Period>>
126    {
127      using type = chrono::duration<typename common_type<_Rep>::type,
128				    typename _Period::type>;
129    };
130
131  // 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
132
133  /// @cond undocumented
134
135  template<typename _CT, typename _Clock, typename = void>
136    struct __timepoint_common_type
137    { };
138
139  template<typename _CT, typename _Clock>
140    struct __timepoint_common_type<_CT, _Clock, __void_t<typename _CT::type>>
141    {
142      using type = chrono::time_point<_Clock, typename _CT::type>;
143    };
144
145  /// @endcond
146
147  /// Specialization of common_type for chrono::time_point types.
148  /// @relates time_point
149  template<typename _Clock, typename _Duration1, typename _Duration2>
150    struct common_type<chrono::time_point<_Clock, _Duration1>,
151		       chrono::time_point<_Clock, _Duration2>>
152    : __timepoint_common_type<common_type<_Duration1, _Duration2>, _Clock>
153    { };
154
155  /// Specialization of common_type for two identical chrono::time_point types.
156  /// @relates time_point
157  template<typename _Clock, typename _Duration>
158    struct common_type<chrono::time_point<_Clock, _Duration>,
159		       chrono::time_point<_Clock, _Duration>>
160    { using type = chrono::time_point<_Clock, _Duration>; };
161
162  /// Specialization of common_type for one chrono::time_point type.
163  /// @relates time_point
164  template<typename _Clock, typename _Duration>
165    struct common_type<chrono::time_point<_Clock, _Duration>>
166    { using type = chrono::time_point<_Clock, _Duration>; };
167
168  /// @} group chrono
169
170  namespace chrono
171  {
172    /// @addtogroup chrono
173    /// @{
174
175    /// @cond undocumented
176
177    // Primary template for duration_cast impl.
178    template<typename _ToDur, typename _CF, typename _CR,
179	     bool _NumIsOne = false, bool _DenIsOne = false>
180      struct __duration_cast_impl
181      {
182	template<typename _Rep, typename _Period>
183	  static constexpr _ToDur
184	  __cast(const duration<_Rep, _Period>& __d)
185	  {
186	    typedef typename _ToDur::rep			__to_rep;
187	    return _ToDur(static_cast<__to_rep>(static_cast<_CR>(__d.count())
188	      * static_cast<_CR>(_CF::num)
189	      / static_cast<_CR>(_CF::den)));
190	  }
191      };
192
193    template<typename _ToDur, typename _CF, typename _CR>
194      struct __duration_cast_impl<_ToDur, _CF, _CR, true, true>
195      {
196	template<typename _Rep, typename _Period>
197	  static constexpr _ToDur
198	  __cast(const duration<_Rep, _Period>& __d)
199	  {
200	    typedef typename _ToDur::rep			__to_rep;
201	    return _ToDur(static_cast<__to_rep>(__d.count()));
202	  }
203      };
204
205    template<typename _ToDur, typename _CF, typename _CR>
206      struct __duration_cast_impl<_ToDur, _CF, _CR, true, false>
207      {
208	template<typename _Rep, typename _Period>
209	  static constexpr _ToDur
210	  __cast(const duration<_Rep, _Period>& __d)
211	  {
212	    typedef typename _ToDur::rep			__to_rep;
213	    return _ToDur(static_cast<__to_rep>(
214	      static_cast<_CR>(__d.count()) / static_cast<_CR>(_CF::den)));
215	  }
216      };
217
218    template<typename _ToDur, typename _CF, typename _CR>
219      struct __duration_cast_impl<_ToDur, _CF, _CR, false, true>
220      {
221	template<typename _Rep, typename _Period>
222	  static constexpr _ToDur
223	  __cast(const duration<_Rep, _Period>& __d)
224	  {
225	    typedef typename _ToDur::rep			__to_rep;
226	    return _ToDur(static_cast<__to_rep>(
227	      static_cast<_CR>(__d.count()) * static_cast<_CR>(_CF::num)));
228	  }
229      };
230
231    template<typename _Tp>
232      struct __is_duration
233      : std::false_type
234      { };
235
236    template<typename _Rep, typename _Period>
237      struct __is_duration<duration<_Rep, _Period>>
238      : std::true_type
239      { };
240
241    template<typename _Tp>
242      using __enable_if_is_duration
243	= typename enable_if<__is_duration<_Tp>::value, _Tp>::type;
244
245    template<typename _Tp>
246      using __disable_if_is_duration
247	= typename enable_if<!__is_duration<_Tp>::value, _Tp>::type;
248
249    /// @endcond
250
251    /// duration_cast
252    template<typename _ToDur, typename _Rep, typename _Period>
253      constexpr __enable_if_is_duration<_ToDur>
254      duration_cast(const duration<_Rep, _Period>& __d)
255      {
256	typedef typename _ToDur::period				__to_period;
257	typedef typename _ToDur::rep				__to_rep;
258	typedef ratio_divide<_Period, __to_period> 		__cf;
259	typedef typename common_type<__to_rep, _Rep, intmax_t>::type
260	  							__cr;
261	typedef  __duration_cast_impl<_ToDur, __cf, __cr,
262				      __cf::num == 1, __cf::den == 1> __dc;
263	return __dc::__cast(__d);
264      }
265
266    /// treat_as_floating_point
267    template<typename _Rep>
268      struct treat_as_floating_point
269      : is_floating_point<_Rep>
270      { };
271
272#if __cplusplus > 201402L
273    template <typename _Rep>
274      inline constexpr bool treat_as_floating_point_v =
275        treat_as_floating_point<_Rep>::value;
276#endif // C++17
277
278#if __cplusplus > 201703L
279    template<typename _Tp>
280      struct is_clock;
281
282    template<typename _Tp>
283      inline constexpr bool is_clock_v = is_clock<_Tp>::value;
284
285#if __cpp_lib_concepts
286    template<typename _Tp>
287      struct is_clock : false_type
288      { };
289
290    template<typename _Tp>
291      requires requires {
292	typename _Tp::rep;
293	typename _Tp::period;
294	typename _Tp::duration;
295	typename _Tp::time_point::clock;
296	typename _Tp::time_point::duration;
297	{ &_Tp::is_steady } -> same_as<const bool*>;
298	{ _Tp::now() } -> same_as<typename _Tp::time_point>;
299	requires same_as<typename _Tp::duration,
300			 duration<typename _Tp::rep, typename _Tp::period>>;
301	requires same_as<typename _Tp::time_point::duration,
302			 typename _Tp::duration>;
303      }
304      struct is_clock<_Tp> : true_type
305      { };
306#else
307    template<typename _Tp, typename = void>
308      struct __is_clock_impl : false_type
309      { };
310
311    template<typename _Tp>
312      struct __is_clock_impl<_Tp,
313			     void_t<typename _Tp::rep, typename _Tp::period,
314				    typename _Tp::duration,
315				    typename _Tp::time_point::duration,
316				    decltype(_Tp::is_steady),
317				    decltype(_Tp::now())>>
318      : __and_<is_same<typename _Tp::duration,
319		       duration<typename _Tp::rep, typename _Tp::period>>,
320	       is_same<typename _Tp::time_point::duration,
321		       typename _Tp::duration>,
322	       is_same<decltype(&_Tp::is_steady), const bool*>,
323	       is_same<decltype(_Tp::now()), typename _Tp::time_point>>::type
324      { };
325
326    template<typename _Tp>
327      struct is_clock : __is_clock_impl<_Tp>::type
328      { };
329#endif
330#endif // C++20
331
332#if __cplusplus >= 201703L
333# define __cpp_lib_chrono 201611
334
335    template<typename _ToDur, typename _Rep, typename _Period>
336      constexpr __enable_if_is_duration<_ToDur>
337      floor(const duration<_Rep, _Period>& __d)
338      {
339	auto __to = chrono::duration_cast<_ToDur>(__d);
340	if (__to > __d)
341	  return __to - _ToDur{1};
342	return __to;
343      }
344
345    template<typename _ToDur, typename _Rep, typename _Period>
346      constexpr __enable_if_is_duration<_ToDur>
347      ceil(const duration<_Rep, _Period>& __d)
348      {
349	auto __to = chrono::duration_cast<_ToDur>(__d);
350	if (__to < __d)
351	  return __to + _ToDur{1};
352	return __to;
353      }
354
355    template <typename _ToDur, typename _Rep, typename _Period>
356      constexpr enable_if_t<
357	__and_<__is_duration<_ToDur>,
358	       __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
359	_ToDur>
360      round(const duration<_Rep, _Period>& __d)
361      {
362	_ToDur __t0 = chrono::floor<_ToDur>(__d);
363	_ToDur __t1 = __t0 + _ToDur{1};
364	auto __diff0 = __d - __t0;
365	auto __diff1 = __t1 - __d;
366	if (__diff0 == __diff1)
367	{
368	    if (__t0.count() & 1)
369		return __t1;
370	    return __t0;
371	}
372	else if (__diff0 < __diff1)
373	    return __t0;
374	return __t1;
375      }
376
377    template<typename _Rep, typename _Period>
378      constexpr
379      enable_if_t<numeric_limits<_Rep>::is_signed, duration<_Rep, _Period>>
380      abs(duration<_Rep, _Period> __d)
381      {
382	if (__d >= __d.zero())
383	  return __d;
384	return -__d;
385      }
386#endif // C++17
387
388    /// duration_values
389    template<typename _Rep>
390      struct duration_values
391      {
392	static constexpr _Rep
393	zero() noexcept
394	{ return _Rep(0); }
395
396	static constexpr _Rep
397	max() noexcept
398	{ return numeric_limits<_Rep>::max(); }
399
400	static constexpr _Rep
401	min() noexcept
402	{ return numeric_limits<_Rep>::lowest(); }
403      };
404
405    /// @cond undocumented
406
407    template<typename _Tp>
408      struct __is_ratio
409      : std::false_type
410      { };
411
412    template<intmax_t _Num, intmax_t _Den>
413      struct __is_ratio<ratio<_Num, _Den>>
414      : std::true_type
415      { };
416
417    /// @endcond
418
419    /// duration
420    template<typename _Rep, typename _Period>
421      struct duration
422      {
423      private:
424	template<typename _Rep2>
425	  using __is_float = treat_as_floating_point<_Rep2>;
426
427	static constexpr intmax_t
428	_S_gcd(intmax_t __m, intmax_t __n) noexcept
429	{
430	  // Duration only allows positive periods so we don't need to
431	  // support negative values here (unlike __static_gcd and std::gcd).
432	  return (__m == 0) ? __n : (__n == 0) ? __m : _S_gcd(__n, __m % __n);
433	}
434
435	// _GLIBCXX_RESOLVE_LIB_DEFECTS
436	// 2094. overflow shouldn't participate in overload resolution
437	// 3090. What is [2094] intended to mean?
438	// This only produces a valid type if no overflow occurs.
439	template<typename _R1, typename _R2,
440		 intmax_t __gcd1 = _S_gcd(_R1::num, _R2::num),
441		 intmax_t __gcd2 = _S_gcd(_R1::den, _R2::den)>
442	  using __divide = ratio<(_R1::num / __gcd1) * (_R2::den / __gcd2),
443				 (_R1::den / __gcd2) * (_R2::num / __gcd1)>;
444
445	// _Period2 is an exact multiple of _Period
446	template<typename _Period2>
447	  using __is_harmonic
448	    = __bool_constant<__divide<_Period2, _Period>::den == 1>;
449
450      public:
451
452	using rep = _Rep;
453	using period = typename _Period::type;
454
455	static_assert(!__is_duration<_Rep>::value, "rep cannot be a duration");
456	static_assert(__is_ratio<_Period>::value,
457		      "period must be a specialization of ratio");
458	static_assert(_Period::num > 0, "period must be positive");
459
460	// 20.11.5.1 construction / copy / destroy
461	constexpr duration() = default;
462
463	duration(const duration&) = default;
464
465	// _GLIBCXX_RESOLVE_LIB_DEFECTS
466	// 3050. Conversion specification problem in chrono::duration
467	template<typename _Rep2, typename = _Require<
468		 is_convertible<const _Rep2&, rep>,
469		 __or_<__is_float<rep>, __not_<__is_float<_Rep2>>>>>
470	  constexpr explicit duration(const _Rep2& __rep)
471	  : __r(static_cast<rep>(__rep)) { }
472
473	template<typename _Rep2, typename _Period2, typename = _Require<
474		 is_convertible<const _Rep2&, rep>,
475		 __or_<__is_float<rep>,
476		       __and_<__is_harmonic<_Period2>,
477			      __not_<__is_float<_Rep2>>>>>>
478	  constexpr duration(const duration<_Rep2, _Period2>& __d)
479	  : __r(duration_cast<duration>(__d).count()) { }
480
481	~duration() = default;
482	duration& operator=(const duration&) = default;
483
484	// 20.11.5.2 observer
485	constexpr rep
486	count() const
487	{ return __r; }
488
489	// 20.11.5.3 arithmetic
490
491	constexpr duration<typename common_type<rep>::type, period>
492	operator+() const
493	{ return duration<typename common_type<rep>::type, period>(__r); }
494
495	constexpr duration<typename common_type<rep>::type, period>
496	operator-() const
497	{ return duration<typename common_type<rep>::type, period>(-__r); }
498
499	_GLIBCXX17_CONSTEXPR duration&
500	operator++()
501	{
502	  ++__r;
503	  return *this;
504	}
505
506	_GLIBCXX17_CONSTEXPR duration
507	operator++(int)
508	{ return duration(__r++); }
509
510	_GLIBCXX17_CONSTEXPR duration&
511	operator--()
512	{
513	  --__r;
514	  return *this;
515	}
516
517	_GLIBCXX17_CONSTEXPR duration
518	operator--(int)
519	{ return duration(__r--); }
520
521	_GLIBCXX17_CONSTEXPR duration&
522	operator+=(const duration& __d)
523	{
524	  __r += __d.count();
525	  return *this;
526	}
527
528	_GLIBCXX17_CONSTEXPR duration&
529	operator-=(const duration& __d)
530	{
531	  __r -= __d.count();
532	  return *this;
533	}
534
535	_GLIBCXX17_CONSTEXPR duration&
536	operator*=(const rep& __rhs)
537	{
538	  __r *= __rhs;
539	  return *this;
540	}
541
542	_GLIBCXX17_CONSTEXPR duration&
543	operator/=(const rep& __rhs)
544	{
545	  __r /= __rhs;
546	  return *this;
547	}
548
549	// DR 934.
550	template<typename _Rep2 = rep>
551	  _GLIBCXX17_CONSTEXPR
552	  typename enable_if<!treat_as_floating_point<_Rep2>::value,
553			     duration&>::type
554	  operator%=(const rep& __rhs)
555	  {
556	    __r %= __rhs;
557	    return *this;
558	  }
559
560	template<typename _Rep2 = rep>
561	  _GLIBCXX17_CONSTEXPR
562	  typename enable_if<!treat_as_floating_point<_Rep2>::value,
563			     duration&>::type
564	  operator%=(const duration& __d)
565	  {
566	    __r %= __d.count();
567	    return *this;
568	  }
569
570	// 20.11.5.4 special values
571	static constexpr duration
572	zero() noexcept
573	{ return duration(duration_values<rep>::zero()); }
574
575	static constexpr duration
576	min() noexcept
577	{ return duration(duration_values<rep>::min()); }
578
579	static constexpr duration
580	max() noexcept
581	{ return duration(duration_values<rep>::max()); }
582
583      private:
584	rep __r;
585      };
586
587    /// @relates duration @{
588
589    /// The sum of two durations.
590    template<typename _Rep1, typename _Period1,
591	     typename _Rep2, typename _Period2>
592      constexpr typename common_type<duration<_Rep1, _Period1>,
593				     duration<_Rep2, _Period2>>::type
594      operator+(const duration<_Rep1, _Period1>& __lhs,
595		const duration<_Rep2, _Period2>& __rhs)
596      {
597	typedef duration<_Rep1, _Period1>			__dur1;
598	typedef duration<_Rep2, _Period2>			__dur2;
599	typedef typename common_type<__dur1,__dur2>::type	__cd;
600	return __cd(__cd(__lhs).count() + __cd(__rhs).count());
601      }
602
603    /// The difference between two durations.
604    template<typename _Rep1, typename _Period1,
605	     typename _Rep2, typename _Period2>
606      constexpr typename common_type<duration<_Rep1, _Period1>,
607				     duration<_Rep2, _Period2>>::type
608      operator-(const duration<_Rep1, _Period1>& __lhs,
609		const duration<_Rep2, _Period2>& __rhs)
610      {
611	typedef duration<_Rep1, _Period1>			__dur1;
612	typedef duration<_Rep2, _Period2>			__dur2;
613	typedef typename common_type<__dur1,__dur2>::type	__cd;
614	return __cd(__cd(__lhs).count() - __cd(__rhs).count());
615      }
616
617    /// @}
618
619    /// @cond undocumented
620
621    // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
622    // is implicitly convertible to it.
623    // _GLIBCXX_RESOLVE_LIB_DEFECTS
624    // 3050. Conversion specification problem in chrono::duration constructor
625    template<typename _Rep1, typename _Rep2,
626	     typename _CRep = typename common_type<_Rep1, _Rep2>::type>
627      using __common_rep_t = typename
628	enable_if<is_convertible<const _Rep2&, _CRep>::value, _CRep>::type;
629
630    /// @endcond
631
632    /// @relates duration @{
633
634    /// Multiply a duration by a scalar value.
635    template<typename _Rep1, typename _Period, typename _Rep2>
636      constexpr duration<__common_rep_t<_Rep1, _Rep2>, _Period>
637      operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
638      {
639	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
640	  __cd;
641	return __cd(__cd(__d).count() * __s);
642      }
643
644    /// Multiply a duration by a scalar value.
645    template<typename _Rep1, typename _Rep2, typename _Period>
646      constexpr duration<__common_rep_t<_Rep2, _Rep1>, _Period>
647      operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
648      { return __d * __s; }
649
650    template<typename _Rep1, typename _Period, typename _Rep2>
651      constexpr
652      duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
653      operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
654      {
655	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
656	  __cd;
657	return __cd(__cd(__d).count() / __s);
658      }
659
660    template<typename _Rep1, typename _Period1,
661	     typename _Rep2, typename _Period2>
662      constexpr typename common_type<_Rep1, _Rep2>::type
663      operator/(const duration<_Rep1, _Period1>& __lhs,
664		const duration<_Rep2, _Period2>& __rhs)
665      {
666	typedef duration<_Rep1, _Period1>			__dur1;
667	typedef duration<_Rep2, _Period2>			__dur2;
668	typedef typename common_type<__dur1,__dur2>::type	__cd;
669	return __cd(__lhs).count() / __cd(__rhs).count();
670      }
671
672    // DR 934.
673    template<typename _Rep1, typename _Period, typename _Rep2>
674      constexpr
675      duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
676      operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
677      {
678	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
679	  __cd;
680	return __cd(__cd(__d).count() % __s);
681      }
682
683    template<typename _Rep1, typename _Period1,
684	     typename _Rep2, typename _Period2>
685      constexpr typename common_type<duration<_Rep1, _Period1>,
686				     duration<_Rep2, _Period2>>::type
687      operator%(const duration<_Rep1, _Period1>& __lhs,
688		const duration<_Rep2, _Period2>& __rhs)
689      {
690	typedef duration<_Rep1, _Period1>			__dur1;
691	typedef duration<_Rep2, _Period2>			__dur2;
692	typedef typename common_type<__dur1,__dur2>::type	__cd;
693	return __cd(__cd(__lhs).count() % __cd(__rhs).count());
694      }
695
696    // comparisons
697
698    template<typename _Rep1, typename _Period1,
699	     typename _Rep2, typename _Period2>
700      constexpr bool
701      operator==(const duration<_Rep1, _Period1>& __lhs,
702		 const duration<_Rep2, _Period2>& __rhs)
703      {
704	typedef duration<_Rep1, _Period1>			__dur1;
705	typedef duration<_Rep2, _Period2>			__dur2;
706	typedef typename common_type<__dur1,__dur2>::type	__ct;
707	return __ct(__lhs).count() == __ct(__rhs).count();
708      }
709
710    template<typename _Rep1, typename _Period1,
711	     typename _Rep2, typename _Period2>
712      constexpr bool
713      operator<(const duration<_Rep1, _Period1>& __lhs,
714		const duration<_Rep2, _Period2>& __rhs)
715      {
716	typedef duration<_Rep1, _Period1>			__dur1;
717	typedef duration<_Rep2, _Period2>			__dur2;
718	typedef typename common_type<__dur1,__dur2>::type	__ct;
719	return __ct(__lhs).count() < __ct(__rhs).count();
720      }
721
722#if __cpp_lib_three_way_comparison
723    template<typename _Rep1, typename _Period1,
724	     typename _Rep2, typename _Period2>
725      requires three_way_comparable<common_type_t<_Rep1, _Rep2>>
726      constexpr auto
727      operator<=>(const duration<_Rep1, _Period1>& __lhs,
728		  const duration<_Rep2, _Period2>& __rhs)
729      {
730	using __ct = common_type_t<duration<_Rep1, _Period1>,
731				   duration<_Rep2, _Period2>>;
732	return __ct(__lhs).count() <=> __ct(__rhs).count();
733      }
734#else
735    template<typename _Rep1, typename _Period1,
736	     typename _Rep2, typename _Period2>
737      constexpr bool
738      operator!=(const duration<_Rep1, _Period1>& __lhs,
739		 const duration<_Rep2, _Period2>& __rhs)
740      { return !(__lhs == __rhs); }
741#endif
742
743    template<typename _Rep1, typename _Period1,
744	     typename _Rep2, typename _Period2>
745      constexpr bool
746      operator<=(const duration<_Rep1, _Period1>& __lhs,
747		 const duration<_Rep2, _Period2>& __rhs)
748      { return !(__rhs < __lhs); }
749
750    template<typename _Rep1, typename _Period1,
751	     typename _Rep2, typename _Period2>
752      constexpr bool
753      operator>(const duration<_Rep1, _Period1>& __lhs,
754		const duration<_Rep2, _Period2>& __rhs)
755      { return __rhs < __lhs; }
756
757    template<typename _Rep1, typename _Period1,
758	     typename _Rep2, typename _Period2>
759      constexpr bool
760      operator>=(const duration<_Rep1, _Period1>& __lhs,
761		 const duration<_Rep2, _Period2>& __rhs)
762      { return !(__lhs < __rhs); }
763
764    /// @}
765
766#ifdef _GLIBCXX_USE_C99_STDINT_TR1
767# define _GLIBCXX_CHRONO_INT64_T int64_t
768#elif defined __INT64_TYPE__
769# define _GLIBCXX_CHRONO_INT64_T __INT64_TYPE__
770#else
771    static_assert(std::numeric_limits<unsigned long long>::digits >= 64,
772	"Representation type for nanoseconds must have at least 64 bits");
773# define _GLIBCXX_CHRONO_INT64_T long long
774#endif
775
776    /// nanoseconds
777    using nanoseconds	= duration<_GLIBCXX_CHRONO_INT64_T, nano>;
778
779    /// microseconds
780    using microseconds	= duration<_GLIBCXX_CHRONO_INT64_T, micro>;
781
782    /// milliseconds
783    using milliseconds	= duration<_GLIBCXX_CHRONO_INT64_T, milli>;
784
785    /// seconds
786    using seconds	= duration<_GLIBCXX_CHRONO_INT64_T>;
787
788    /// minutes
789    using minutes	= duration<_GLIBCXX_CHRONO_INT64_T, ratio< 60>>;
790
791    /// hours
792    using hours		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<3600>>;
793
794#if __cplusplus > 201703L
795    /// days
796    using days		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<86400>>;
797
798    /// weeks
799    using weeks		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<604800>>;
800
801    /// years
802    using years		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<31556952>>;
803
804    /// months
805    using months	= duration<_GLIBCXX_CHRONO_INT64_T, ratio<2629746>>;
806#endif // C++20
807
808#undef _GLIBCXX_CHRONO_INT64_T
809
810    /// time_point
811    template<typename _Clock, typename _Dur>
812      struct time_point
813      {
814	static_assert(__is_duration<_Dur>::value,
815	    "duration must be a specialization of std::chrono::duration");
816
817	typedef _Clock						clock;
818	typedef _Dur						duration;
819	typedef typename duration::rep				rep;
820	typedef typename duration::period			period;
821
822	constexpr time_point() : __d(duration::zero())
823	{ }
824
825	constexpr explicit time_point(const duration& __dur)
826	: __d(__dur)
827	{ }
828
829	// conversions
830	template<typename _Dur2,
831		 typename = _Require<is_convertible<_Dur2, _Dur>>>
832	  constexpr time_point(const time_point<clock, _Dur2>& __t)
833	  : __d(__t.time_since_epoch())
834	  { }
835
836	// observer
837	constexpr duration
838	time_since_epoch() const
839	{ return __d; }
840
841	// arithmetic
842	_GLIBCXX17_CONSTEXPR time_point&
843	operator+=(const duration& __dur)
844	{
845	  __d += __dur;
846	  return *this;
847	}
848
849	_GLIBCXX17_CONSTEXPR time_point&
850	operator-=(const duration& __dur)
851	{
852	  __d -= __dur;
853	  return *this;
854	}
855
856	// special values
857	static constexpr time_point
858	min() noexcept
859	{ return time_point(duration::min()); }
860
861	static constexpr time_point
862	max() noexcept
863	{ return time_point(duration::max()); }
864
865      private:
866	duration __d;
867      };
868
869    /// time_point_cast
870    template<typename _ToDur, typename _Clock, typename _Dur>
871      constexpr typename enable_if<__is_duration<_ToDur>::value,
872				   time_point<_Clock, _ToDur>>::type
873      time_point_cast(const time_point<_Clock, _Dur>& __t)
874      {
875	typedef time_point<_Clock, _ToDur>			__time_point;
876	return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
877      }
878
879#if __cplusplus > 201402L
880    template<typename _ToDur, typename _Clock, typename _Dur>
881      constexpr
882      enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
883      floor(const time_point<_Clock, _Dur>& __tp)
884      {
885	return time_point<_Clock, _ToDur>{
886	    chrono::floor<_ToDur>(__tp.time_since_epoch())};
887      }
888
889    template<typename _ToDur, typename _Clock, typename _Dur>
890      constexpr
891      enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
892      ceil(const time_point<_Clock, _Dur>& __tp)
893      {
894	return time_point<_Clock, _ToDur>{
895	    chrono::ceil<_ToDur>(__tp.time_since_epoch())};
896      }
897
898    template<typename _ToDur, typename _Clock, typename _Dur>
899      constexpr enable_if_t<
900	__and_<__is_duration<_ToDur>,
901	       __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
902	time_point<_Clock, _ToDur>>
903      round(const time_point<_Clock, _Dur>& __tp)
904      {
905	return time_point<_Clock, _ToDur>{
906	    chrono::round<_ToDur>(__tp.time_since_epoch())};
907      }
908#endif // C++17
909
910    /// @relates time_point @{
911
912    /// Adjust a time point forwards by the given duration.
913    template<typename _Clock, typename _Dur1,
914	     typename _Rep2, typename _Period2>
915      constexpr time_point<_Clock,
916	typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
917      operator+(const time_point<_Clock, _Dur1>& __lhs,
918		const duration<_Rep2, _Period2>& __rhs)
919      {
920	typedef duration<_Rep2, _Period2>			__dur2;
921	typedef typename common_type<_Dur1,__dur2>::type	__ct;
922	typedef time_point<_Clock, __ct>			__time_point;
923	return __time_point(__lhs.time_since_epoch() + __rhs);
924      }
925
926    /// Adjust a time point forwards by the given duration.
927    template<typename _Rep1, typename _Period1,
928	     typename _Clock, typename _Dur2>
929      constexpr time_point<_Clock,
930	typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
931      operator+(const duration<_Rep1, _Period1>& __lhs,
932		const time_point<_Clock, _Dur2>& __rhs)
933      {
934	typedef duration<_Rep1, _Period1>			__dur1;
935	typedef typename common_type<__dur1,_Dur2>::type	__ct;
936	typedef time_point<_Clock, __ct>			__time_point;
937	return __time_point(__rhs.time_since_epoch() + __lhs);
938      }
939
940    /// Adjust a time point backwards by the given duration.
941    template<typename _Clock, typename _Dur1,
942	     typename _Rep2, typename _Period2>
943      constexpr time_point<_Clock,
944	typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
945      operator-(const time_point<_Clock, _Dur1>& __lhs,
946		const duration<_Rep2, _Period2>& __rhs)
947      {
948	typedef duration<_Rep2, _Period2>			__dur2;
949	typedef typename common_type<_Dur1,__dur2>::type	__ct;
950	typedef time_point<_Clock, __ct>			__time_point;
951	return __time_point(__lhs.time_since_epoch() -__rhs);
952      }
953
954    /// @}
955
956    /// @relates time_point @{
957
958    /// The difference between two time points (as a duration)
959    template<typename _Clock, typename _Dur1, typename _Dur2>
960      constexpr typename common_type<_Dur1, _Dur2>::type
961      operator-(const time_point<_Clock, _Dur1>& __lhs,
962		const time_point<_Clock, _Dur2>& __rhs)
963      { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
964
965    template<typename _Clock, typename _Dur1, typename _Dur2>
966      constexpr bool
967      operator==(const time_point<_Clock, _Dur1>& __lhs,
968		 const time_point<_Clock, _Dur2>& __rhs)
969      { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
970
971#if __cpp_lib_three_way_comparison
972    template<typename _Clock, typename _Dur1,
973	     three_way_comparable_with<_Dur1> _Dur2>
974      constexpr auto
975      operator<=>(const time_point<_Clock, _Dur1>& __lhs,
976		  const time_point<_Clock, _Dur2>& __rhs)
977      { return __lhs.time_since_epoch() <=> __rhs.time_since_epoch(); }
978#else
979    template<typename _Clock, typename _Dur1, typename _Dur2>
980      constexpr bool
981      operator!=(const time_point<_Clock, _Dur1>& __lhs,
982		 const time_point<_Clock, _Dur2>& __rhs)
983      { return !(__lhs == __rhs); }
984#endif
985
986    template<typename _Clock, typename _Dur1, typename _Dur2>
987      constexpr bool
988      operator<(const time_point<_Clock, _Dur1>& __lhs,
989		const time_point<_Clock, _Dur2>& __rhs)
990      { return  __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
991
992    template<typename _Clock, typename _Dur1, typename _Dur2>
993      constexpr bool
994      operator<=(const time_point<_Clock, _Dur1>& __lhs,
995		 const time_point<_Clock, _Dur2>& __rhs)
996      { return !(__rhs < __lhs); }
997
998    template<typename _Clock, typename _Dur1, typename _Dur2>
999      constexpr bool
1000      operator>(const time_point<_Clock, _Dur1>& __lhs,
1001		const time_point<_Clock, _Dur2>& __rhs)
1002      { return __rhs < __lhs; }
1003
1004    template<typename _Clock, typename _Dur1, typename _Dur2>
1005      constexpr bool
1006      operator>=(const time_point<_Clock, _Dur1>& __lhs,
1007		 const time_point<_Clock, _Dur2>& __rhs)
1008      { return !(__lhs < __rhs); }
1009
1010    /// @}
1011
1012    // Clocks.
1013
1014    // Why nanosecond resolution as the default?
1015    // Why have std::system_clock always count in the highest
1016    // resolution (ie nanoseconds), even if on some OSes the low 3
1017    // or 9 decimal digits will be always zero? This allows later
1018    // implementations to change the system_clock::now()
1019    // implementation any time to provide better resolution without
1020    // changing function signature or units.
1021
1022    // To support the (forward) evolution of the library's defined
1023    // clocks, wrap inside inline namespace so that the current
1024    // defintions of system_clock, steady_clock, and
1025    // high_resolution_clock types are uniquely mangled. This way, new
1026    // code can use the latests clocks, while the library can contain
1027    // compatibility definitions for previous versions.  At some
1028    // point, when these clocks settle down, the inlined namespaces
1029    // can be removed.  XXX GLIBCXX_ABI Deprecated
1030    inline namespace _V2 {
1031
1032    /**
1033     *  @brief System clock.
1034     *
1035     *  Time returned represents wall time from the system-wide clock.
1036     *  @ingroup chrono
1037    */
1038    struct system_clock
1039    {
1040      typedef chrono::nanoseconds				duration;
1041      typedef duration::rep					rep;
1042      typedef duration::period					period;
1043      typedef chrono::time_point<system_clock, duration> 	time_point;
1044
1045      static_assert(system_clock::duration::min()
1046		    < system_clock::duration::zero(),
1047		    "a clock's minimum duration cannot be less than its epoch");
1048
1049      static constexpr bool is_steady = false;
1050
1051      static time_point
1052      now() noexcept;
1053
1054      // Map to C API
1055      static std::time_t
1056      to_time_t(const time_point& __t) noexcept
1057      {
1058	return std::time_t(duration_cast<chrono::seconds>
1059			   (__t.time_since_epoch()).count());
1060      }
1061
1062      static time_point
1063      from_time_t(std::time_t __t) noexcept
1064      {
1065	typedef chrono::time_point<system_clock, seconds>	__from;
1066	return time_point_cast<system_clock::duration>
1067	       (__from(chrono::seconds(__t)));
1068      }
1069    };
1070
1071
1072    /**
1073     *  @brief Monotonic clock
1074     *
1075     *  Time returned has the property of only increasing at a uniform rate.
1076     *  @ingroup chrono
1077    */
1078    struct steady_clock
1079    {
1080      typedef chrono::nanoseconds				duration;
1081      typedef duration::rep					rep;
1082      typedef duration::period					period;
1083      typedef chrono::time_point<steady_clock, duration>	time_point;
1084
1085      static constexpr bool is_steady = true;
1086
1087      static time_point
1088      now() noexcept;
1089    };
1090
1091
1092    /**
1093     *  @brief Highest-resolution clock
1094     *
1095     *  This is the clock "with the shortest tick period." Alias to
1096     *  std::system_clock until higher-than-nanosecond definitions
1097     *  become feasible.
1098     *  @ingroup chrono
1099    */
1100    using high_resolution_clock = system_clock;
1101
1102    } // end inline namespace _V2
1103
1104#if __cplusplus > 201703L
1105    template<typename _Duration>
1106      using sys_time = time_point<system_clock, _Duration>;
1107    using sys_seconds = sys_time<seconds>;
1108    using sys_days = sys_time<days>;
1109
1110    using file_clock = ::std::filesystem::__file_clock;
1111
1112    template<typename _Duration>
1113      using file_time = time_point<file_clock, _Duration>;
1114
1115    template<> struct is_clock<system_clock> : true_type { };
1116    template<> struct is_clock<steady_clock> : true_type { };
1117    template<> struct is_clock<file_clock> : true_type { };
1118
1119    template<> inline constexpr bool is_clock_v<system_clock> = true;
1120    template<> inline constexpr bool is_clock_v<steady_clock> = true;
1121    template<> inline constexpr bool is_clock_v<file_clock> = true;
1122
1123    struct local_t { };
1124    template<typename _Duration>
1125      using local_time = time_point<local_t, _Duration>;
1126    using local_seconds = local_time<seconds>;
1127    using local_days = local_time<days>;
1128#endif // C++20
1129
1130    /// @}
1131  } // namespace chrono
1132
1133#if __cplusplus > 201103L
1134
1135#define __cpp_lib_chrono_udls 201304
1136
1137  inline namespace literals
1138  {
1139  /** ISO C++ 2014  namespace for suffixes for duration literals.
1140   *
1141   * These suffixes can be used to create `chrono::duration` values with
1142   * tick periods of hours, minutes, seconds, milliseconds, microseconds
1143   * or nanoseconds. For example, `std::chrono::seconds(5)` can be written
1144   * as `5s` after making the suffix visible in the current scope.
1145   * The suffixes can be made visible by a using-directive or
1146   * using-declaration such as:
1147   *  - `using namespace std::chrono_literals;`
1148   *  - `using namespace std::literals;`
1149   *  - `using namespace std::chrono;`
1150   *  - `using namespace std;`
1151   *  - `using std::chrono_literals::operator""s;`
1152   *
1153   * The result of these suffixes on an integer literal is one of the
1154   * standard typedefs such as `std::chrono::hours`.
1155   * The result on a floating-point literal is a duration type with the
1156   * specified tick period and an unspecified floating-point representation,
1157   * for example `1.5e2ms` might be equivalent to
1158   * `chrono::duration<long double, chrono::milli>(1.5e2)`.
1159   *
1160   * @ingroup chrono
1161   */
1162  inline namespace chrono_literals
1163  {
1164#pragma GCC diagnostic push
1165#pragma GCC diagnostic ignored "-Wliteral-suffix"
1166    /// @cond undocumented
1167    template<typename _Dur, char... _Digits>
1168      constexpr _Dur __check_overflow()
1169      {
1170	using _Val = __parse_int::_Parse_int<_Digits...>;
1171	constexpr typename _Dur::rep __repval = _Val::value;
1172	static_assert(__repval >= 0 && __repval == _Val::value,
1173		      "literal value cannot be represented by duration type");
1174	return _Dur(__repval);
1175      }
1176    /// @endcond
1177
1178    /// Literal suffix for durations representing non-integer hours
1179    constexpr chrono::duration<long double, ratio<3600,1>>
1180    operator""h(long double __hours)
1181    { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
1182
1183    /// Literal suffix for durations of type `std::chrono::hours`
1184    template <char... _Digits>
1185      constexpr chrono::hours
1186      operator""h()
1187      { return __check_overflow<chrono::hours, _Digits...>(); }
1188
1189    /// Literal suffix for durations representing non-integer minutes
1190    constexpr chrono::duration<long double, ratio<60,1>>
1191    operator""min(long double __mins)
1192    { return chrono::duration<long double, ratio<60,1>>{__mins}; }
1193
1194    /// Literal suffix for durations of type `std::chrono::minutes`
1195    template <char... _Digits>
1196      constexpr chrono::minutes
1197      operator""min()
1198      { return __check_overflow<chrono::minutes, _Digits...>(); }
1199
1200    /// Literal suffix for durations representing non-integer seconds
1201    constexpr chrono::duration<long double>
1202    operator""s(long double __secs)
1203    { return chrono::duration<long double>{__secs}; }
1204
1205    /// Literal suffix for durations of type `std::chrono::seconds`
1206    template <char... _Digits>
1207      constexpr chrono::seconds
1208      operator""s()
1209      { return __check_overflow<chrono::seconds, _Digits...>(); }
1210
1211    /// Literal suffix for durations representing non-integer milliseconds
1212    constexpr chrono::duration<long double, milli>
1213    operator""ms(long double __msecs)
1214    { return chrono::duration<long double, milli>{__msecs}; }
1215
1216    /// Literal suffix for durations of type `std::chrono::milliseconds`
1217    template <char... _Digits>
1218      constexpr chrono::milliseconds
1219      operator""ms()
1220      { return __check_overflow<chrono::milliseconds, _Digits...>(); }
1221
1222    /// Literal suffix for durations representing non-integer microseconds
1223    constexpr chrono::duration<long double, micro>
1224    operator""us(long double __usecs)
1225    { return chrono::duration<long double, micro>{__usecs}; }
1226
1227    /// Literal suffix for durations of type `std::chrono::microseconds`
1228    template <char... _Digits>
1229      constexpr chrono::microseconds
1230      operator""us()
1231      { return __check_overflow<chrono::microseconds, _Digits...>(); }
1232
1233    /// Literal suffix for durations representing non-integer nanoseconds
1234    constexpr chrono::duration<long double, nano>
1235    operator""ns(long double __nsecs)
1236    { return chrono::duration<long double, nano>{__nsecs}; }
1237
1238    /// Literal suffix for durations of type `std::chrono::nanoseconds`
1239    template <char... _Digits>
1240      constexpr chrono::nanoseconds
1241      operator""ns()
1242      { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
1243
1244#pragma GCC diagnostic pop
1245  } // inline namespace chrono_literals
1246  } // inline namespace literals
1247
1248  namespace chrono
1249  {
1250    using namespace literals::chrono_literals;
1251  } // namespace chrono
1252
1253#if __cplusplus >= 201703L
1254  namespace filesystem
1255  {
1256    struct __file_clock
1257    {
1258      using duration                  = chrono::nanoseconds;
1259      using rep                       = duration::rep;
1260      using period                    = duration::period;
1261      using time_point                = chrono::time_point<__file_clock>;
1262      static constexpr bool is_steady = false;
1263
1264      static time_point
1265      now() noexcept
1266      { return _S_from_sys(chrono::system_clock::now()); }
1267
1268#if __cplusplus > 201703L
1269      template<typename _Dur>
1270	static
1271	chrono::file_time<_Dur>
1272	from_sys(const chrono::sys_time<_Dur>& __t) noexcept
1273	{ return _S_from_sys(__t); }
1274
1275      // For internal use only
1276      template<typename _Dur>
1277	static
1278	chrono::sys_time<_Dur>
1279	to_sys(const chrono::file_time<_Dur>& __t) noexcept
1280	{ return _S_to_sys(__t); }
1281#endif // C++20
1282
1283    private:
1284      using __sys_clock = chrono::system_clock;
1285
1286      // This clock's (unspecified) epoch is 2174-01-01 00:00:00 UTC.
1287      // A signed 64-bit duration with nanosecond resolution gives roughly
1288      // +/- 292 years, which covers the 1901-2446 date range for ext4.
1289      static constexpr chrono::seconds _S_epoch_diff{6437664000};
1290
1291    protected:
1292      // For internal use only
1293      template<typename _Dur>
1294	static
1295	chrono::time_point<__file_clock, _Dur>
1296	_S_from_sys(const chrono::time_point<__sys_clock, _Dur>& __t) noexcept
1297	{
1298	  using __file_time = chrono::time_point<__file_clock, _Dur>;
1299	  return __file_time{__t.time_since_epoch()} - _S_epoch_diff;
1300	}
1301
1302      // For internal use only
1303      template<typename _Dur>
1304	static
1305	chrono::time_point<__sys_clock, _Dur>
1306	_S_to_sys(const chrono::time_point<__file_clock, _Dur>& __t) noexcept
1307	{
1308	  using __sys_time = chrono::time_point<__sys_clock, _Dur>;
1309	  return __sys_time{__t.time_since_epoch()} + _S_epoch_diff;
1310	}
1311    };
1312  } // namespace filesystem
1313#endif // C++17
1314#endif // C++14
1315
1316_GLIBCXX_END_NAMESPACE_VERSION
1317} // namespace std
1318
1319#endif // C++11
1320
1321#endif //_GLIBCXX_CHRONO
1322