xref: /netbsd-src/external/gpl3/gcc.old/dist/libstdc++-v3/include/std/chrono (revision f3cfa6f6ce31685c6c4a758bc430e69eb99f50a4)
1// <chrono> -*- C++ -*-
2
3// Copyright (C) 2008-2016 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 */
28
29#ifndef _GLIBCXX_CHRONO
30#define _GLIBCXX_CHRONO 1
31
32#pragma GCC system_header
33
34#if __cplusplus < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <ratio>
39#include <type_traits>
40#include <limits>
41#include <ctime>
42#include <bits/parse_numbers.h> // for literals support.
43
44#ifdef _GLIBCXX_USE_C99_STDINT_TR1
45
46namespace std _GLIBCXX_VISIBILITY(default)
47{
48  /**
49   * @defgroup chrono Time
50   * @ingroup utilities
51   *
52   * Classes and functions for time.
53   * @{
54   */
55
56  /** @namespace std::chrono
57   *  @brief ISO C++ 2011 entities sub-namespace for time and date.
58   */
59  namespace chrono
60  {
61  _GLIBCXX_BEGIN_NAMESPACE_VERSION
62
63    template<typename _Rep, typename _Period = ratio<1>>
64      struct duration;
65
66    template<typename _Clock, typename _Dur = typename _Clock::duration>
67      struct time_point;
68
69  _GLIBCXX_END_NAMESPACE_VERSION
70  }
71
72_GLIBCXX_BEGIN_NAMESPACE_VERSION
73
74  // 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
75
76  template<typename _CT, typename _Period1, typename _Period2>
77    struct __duration_common_type_wrapper
78    {
79    private:
80      typedef __static_gcd<_Period1::num, _Period2::num> __gcd_num;
81      typedef __static_gcd<_Period1::den, _Period2::den> __gcd_den;
82      typedef typename _CT::type __cr;
83      typedef ratio<__gcd_num::value,
84        (_Period1::den / __gcd_den::value) * _Period2::den> __r;
85    public:
86      typedef __success_type<chrono::duration<__cr, __r>> type;
87    };
88
89  template<typename _Period1, typename _Period2>
90    struct __duration_common_type_wrapper<__failure_type, _Period1, _Period2>
91    { typedef __failure_type type; };
92
93  template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
94    struct common_type<chrono::duration<_Rep1, _Period1>,
95             chrono::duration<_Rep2, _Period2>>
96    : public __duration_common_type_wrapper<typename __member_type_wrapper<
97             common_type<_Rep1, _Rep2>>::type, _Period1, _Period2>::type
98    { };
99
100  // 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
101
102  template<typename _CT, typename _Clock>
103    struct __timepoint_common_type_wrapper
104    {
105      typedef __success_type<chrono::time_point<_Clock, typename _CT::type>>
106        type;
107    };
108
109  template<typename _Clock>
110    struct __timepoint_common_type_wrapper<__failure_type, _Clock>
111    { typedef __failure_type type; };
112
113  template<typename _Clock, typename _Duration1, typename _Duration2>
114    struct common_type<chrono::time_point<_Clock, _Duration1>,
115             chrono::time_point<_Clock, _Duration2>>
116    : public __timepoint_common_type_wrapper<typename __member_type_wrapper<
117             common_type<_Duration1, _Duration2>>::type, _Clock>::type
118    { };
119
120_GLIBCXX_END_NAMESPACE_VERSION
121
122  namespace chrono
123  {
124  _GLIBCXX_BEGIN_NAMESPACE_VERSION
125
126    // Primary template for duration_cast impl.
127    template<typename _ToDur, typename _CF, typename _CR,
128	     bool _NumIsOne = false, bool _DenIsOne = false>
129      struct __duration_cast_impl
130      {
131	template<typename _Rep, typename _Period>
132	  static constexpr _ToDur
133	  __cast(const duration<_Rep, _Period>& __d)
134	  {
135	    typedef typename _ToDur::rep			__to_rep;
136	    return _ToDur(static_cast<__to_rep>(static_cast<_CR>(__d.count())
137	      * static_cast<_CR>(_CF::num)
138	      / static_cast<_CR>(_CF::den)));
139	  }
140      };
141
142    template<typename _ToDur, typename _CF, typename _CR>
143      struct __duration_cast_impl<_ToDur, _CF, _CR, true, true>
144      {
145	template<typename _Rep, typename _Period>
146	  static constexpr _ToDur
147	  __cast(const duration<_Rep, _Period>& __d)
148	  {
149	    typedef typename _ToDur::rep			__to_rep;
150	    return _ToDur(static_cast<__to_rep>(__d.count()));
151	  }
152      };
153
154    template<typename _ToDur, typename _CF, typename _CR>
155      struct __duration_cast_impl<_ToDur, _CF, _CR, true, false>
156      {
157	template<typename _Rep, typename _Period>
158	  static constexpr _ToDur
159	  __cast(const duration<_Rep, _Period>& __d)
160	  {
161	    typedef typename _ToDur::rep			__to_rep;
162	    return _ToDur(static_cast<__to_rep>(
163	      static_cast<_CR>(__d.count()) / static_cast<_CR>(_CF::den)));
164	  }
165      };
166
167    template<typename _ToDur, typename _CF, typename _CR>
168      struct __duration_cast_impl<_ToDur, _CF, _CR, false, true>
169      {
170	template<typename _Rep, typename _Period>
171	  static constexpr _ToDur
172	  __cast(const duration<_Rep, _Period>& __d)
173	  {
174	    typedef typename _ToDur::rep			__to_rep;
175	    return _ToDur(static_cast<__to_rep>(
176	      static_cast<_CR>(__d.count()) * static_cast<_CR>(_CF::num)));
177	  }
178      };
179
180    template<typename _Tp>
181      struct __is_duration
182      : std::false_type
183      { };
184
185    template<typename _Rep, typename _Period>
186      struct __is_duration<duration<_Rep, _Period>>
187      : std::true_type
188      { };
189
190    /// duration_cast
191    template<typename _ToDur, typename _Rep, typename _Period>
192      constexpr typename enable_if<__is_duration<_ToDur>::value,
193				   _ToDur>::type
194      duration_cast(const duration<_Rep, _Period>& __d)
195      {
196	typedef typename _ToDur::period				__to_period;
197	typedef typename _ToDur::rep				__to_rep;
198	typedef ratio_divide<_Period, __to_period> 		__cf;
199	typedef typename common_type<__to_rep, _Rep, intmax_t>::type
200	  							__cr;
201	typedef  __duration_cast_impl<_ToDur, __cf, __cr,
202				      __cf::num == 1, __cf::den == 1> __dc;
203	return __dc::__cast(__d);
204      }
205
206    /// treat_as_floating_point
207    template<typename _Rep>
208      struct treat_as_floating_point
209      : is_floating_point<_Rep>
210      { };
211
212    /// duration_values
213    template<typename _Rep>
214      struct duration_values
215      {
216	static constexpr _Rep
217	zero()
218	{ return _Rep(0); }
219
220	static constexpr _Rep
221	max()
222	{ return numeric_limits<_Rep>::max(); }
223
224	static constexpr _Rep
225	min()
226	{ return numeric_limits<_Rep>::lowest(); }
227      };
228
229    template<typename _Tp>
230      struct __is_ratio
231      : std::false_type
232      { };
233
234    template<intmax_t _Num, intmax_t _Den>
235      struct __is_ratio<ratio<_Num, _Den>>
236      : std::true_type
237      { };
238
239    /// duration
240    template<typename _Rep, typename _Period>
241      struct duration
242      {
243	typedef _Rep						rep;
244	typedef _Period 					period;
245
246	static_assert(!__is_duration<_Rep>::value, "rep cannot be a duration");
247	static_assert(__is_ratio<_Period>::value,
248		      "period must be a specialization of ratio");
249	static_assert(_Period::num > 0, "period must be positive");
250
251	// 20.11.5.1 construction / copy / destroy
252	constexpr duration() = default;
253
254	// NB: Make constexpr implicit. This cannot be explicitly
255	// constexpr, as any UDT that is not a literal type with a
256	// constexpr copy constructor will be ill-formed.
257	duration(const duration&) = default;
258
259	// _GLIBCXX_RESOLVE_LIB_DEFECTS
260	// 3050. Conversion specification problem in chrono::duration
261	template<typename _Rep2, typename = typename
262	       enable_if<is_convertible<const _Rep2&, rep>::value
263			 && (treat_as_floating_point<rep>::value
264			     || !treat_as_floating_point<_Rep2>::value)>::type>
265	  constexpr explicit duration(const _Rep2& __rep)
266	  : __r(static_cast<rep>(__rep)) { }
267
268	template<typename _Rep2, typename _Period2, typename = typename
269	       enable_if<treat_as_floating_point<rep>::value
270			 || (ratio_divide<_Period2, period>::den == 1
271			     && !treat_as_floating_point<_Rep2>::value)>::type>
272	  constexpr duration(const duration<_Rep2, _Period2>& __d)
273	  : __r(duration_cast<duration>(__d).count()) { }
274
275	~duration() = default;
276	duration& operator=(const duration&) = default;
277
278	// 20.11.5.2 observer
279	constexpr rep
280	count() const
281	{ return __r; }
282
283	// 20.11.5.3 arithmetic
284	constexpr duration
285	operator+() const
286	{ return *this; }
287
288	constexpr duration
289	operator-() const
290	{ return duration(-__r); }
291
292	duration&
293	operator++()
294	{
295	  ++__r;
296	  return *this;
297	}
298
299	duration
300	operator++(int)
301	{ return duration(__r++); }
302
303	duration&
304	operator--()
305	{
306	  --__r;
307	  return *this;
308	}
309
310	duration
311	operator--(int)
312	{ return duration(__r--); }
313
314	duration&
315	operator+=(const duration& __d)
316	{
317	  __r += __d.count();
318	  return *this;
319	}
320
321	duration&
322	operator-=(const duration& __d)
323	{
324	  __r -= __d.count();
325	  return *this;
326	}
327
328	duration&
329	operator*=(const rep& __rhs)
330	{
331	  __r *= __rhs;
332	  return *this;
333	}
334
335	duration&
336	operator/=(const rep& __rhs)
337	{
338	  __r /= __rhs;
339	  return *this;
340	}
341
342	// DR 934.
343	template<typename _Rep2 = rep>
344	  typename enable_if<!treat_as_floating_point<_Rep2>::value,
345			     duration&>::type
346	  operator%=(const rep& __rhs)
347	  {
348	    __r %= __rhs;
349	    return *this;
350	  }
351
352	template<typename _Rep2 = rep>
353	  typename enable_if<!treat_as_floating_point<_Rep2>::value,
354			     duration&>::type
355	  operator%=(const duration& __d)
356	  {
357	    __r %= __d.count();
358	    return *this;
359	  }
360
361	// 20.11.5.4 special values
362	static constexpr duration
363	zero()
364	{ return duration(duration_values<rep>::zero()); }
365
366	static constexpr duration
367	min()
368	{ return duration(duration_values<rep>::min()); }
369
370	static constexpr duration
371	max()
372	{ return duration(duration_values<rep>::max()); }
373
374      private:
375	rep __r;
376      };
377
378    template<typename _Rep1, typename _Period1,
379	     typename _Rep2, typename _Period2>
380      constexpr typename common_type<duration<_Rep1, _Period1>,
381				     duration<_Rep2, _Period2>>::type
382      operator+(const duration<_Rep1, _Period1>& __lhs,
383		const duration<_Rep2, _Period2>& __rhs)
384      {
385	typedef duration<_Rep1, _Period1>			__dur1;
386	typedef duration<_Rep2, _Period2>			__dur2;
387	typedef typename common_type<__dur1,__dur2>::type	__cd;
388	return __cd(__cd(__lhs).count() + __cd(__rhs).count());
389      }
390
391    template<typename _Rep1, typename _Period1,
392	     typename _Rep2, typename _Period2>
393      constexpr typename common_type<duration<_Rep1, _Period1>,
394				     duration<_Rep2, _Period2>>::type
395      operator-(const duration<_Rep1, _Period1>& __lhs,
396		const duration<_Rep2, _Period2>& __rhs)
397      {
398	typedef duration<_Rep1, _Period1>			__dur1;
399	typedef duration<_Rep2, _Period2>			__dur2;
400	typedef typename common_type<__dur1,__dur2>::type	__cd;
401	return __cd(__cd(__lhs).count() - __cd(__rhs).count());
402      }
403
404    // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
405    // is implicitly convertible to it.
406    // _GLIBCXX_RESOLVE_LIB_DEFECTS
407    // 3050. Conversion specification problem in chrono::duration constructor
408    template<typename _Rep1, typename _Rep2, bool =
409	     is_convertible<const _Rep2&,
410			    typename common_type<_Rep1, _Rep2>::type>::value>
411      struct __common_rep_type { };
412
413    template<typename _Rep1, typename _Rep2>
414      struct __common_rep_type<_Rep1, _Rep2, true>
415      { typedef typename common_type<_Rep1, _Rep2>::type type; };
416
417    template<typename _Rep1, typename _Period, typename _Rep2>
418      constexpr
419      duration<typename __common_rep_type<_Rep1, _Rep2>::type, _Period>
420      operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
421      {
422	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
423	  __cd;
424	return __cd(__cd(__d).count() * __s);
425      }
426
427    template<typename _Rep1, typename _Rep2, typename _Period>
428      constexpr
429      duration<typename __common_rep_type<_Rep2, _Rep1>::type, _Period>
430      operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
431      { return __d * __s; }
432
433    template<typename _Rep1, typename _Period, typename _Rep2>
434      constexpr duration<typename __common_rep_type<_Rep1, typename
435	enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
436      operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
437      {
438	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
439	  __cd;
440	return __cd(__cd(__d).count() / __s);
441      }
442
443    template<typename _Rep1, typename _Period1,
444	     typename _Rep2, typename _Period2>
445      constexpr typename common_type<_Rep1, _Rep2>::type
446      operator/(const duration<_Rep1, _Period1>& __lhs,
447		const duration<_Rep2, _Period2>& __rhs)
448      {
449	typedef duration<_Rep1, _Period1>			__dur1;
450	typedef duration<_Rep2, _Period2>			__dur2;
451	typedef typename common_type<__dur1,__dur2>::type	__cd;
452	return __cd(__lhs).count() / __cd(__rhs).count();
453      }
454
455    // DR 934.
456    template<typename _Rep1, typename _Period, typename _Rep2>
457      constexpr duration<typename __common_rep_type<_Rep1, typename
458	enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
459      operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
460      {
461	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
462	  __cd;
463	return __cd(__cd(__d).count() % __s);
464      }
465
466    template<typename _Rep1, typename _Period1,
467	     typename _Rep2, typename _Period2>
468      constexpr typename common_type<duration<_Rep1, _Period1>,
469				     duration<_Rep2, _Period2>>::type
470      operator%(const duration<_Rep1, _Period1>& __lhs,
471		const duration<_Rep2, _Period2>& __rhs)
472      {
473	typedef duration<_Rep1, _Period1>			__dur1;
474	typedef duration<_Rep2, _Period2>			__dur2;
475	typedef typename common_type<__dur1,__dur2>::type	__cd;
476	return __cd(__cd(__lhs).count() % __cd(__rhs).count());
477      }
478
479    // comparisons
480    template<typename _Rep1, typename _Period1,
481	     typename _Rep2, typename _Period2>
482      constexpr bool
483      operator==(const duration<_Rep1, _Period1>& __lhs,
484		 const duration<_Rep2, _Period2>& __rhs)
485      {
486	typedef duration<_Rep1, _Period1>			__dur1;
487	typedef duration<_Rep2, _Period2>			__dur2;
488	typedef typename common_type<__dur1,__dur2>::type	__ct;
489	return __ct(__lhs).count() == __ct(__rhs).count();
490      }
491
492    template<typename _Rep1, typename _Period1,
493	     typename _Rep2, typename _Period2>
494      constexpr bool
495      operator<(const duration<_Rep1, _Period1>& __lhs,
496		const duration<_Rep2, _Period2>& __rhs)
497      {
498	typedef duration<_Rep1, _Period1>			__dur1;
499	typedef duration<_Rep2, _Period2>			__dur2;
500	typedef typename common_type<__dur1,__dur2>::type	__ct;
501	return __ct(__lhs).count() < __ct(__rhs).count();
502      }
503
504    template<typename _Rep1, typename _Period1,
505	     typename _Rep2, typename _Period2>
506      constexpr bool
507      operator!=(const duration<_Rep1, _Period1>& __lhs,
508		 const duration<_Rep2, _Period2>& __rhs)
509      { return !(__lhs == __rhs); }
510
511    template<typename _Rep1, typename _Period1,
512	     typename _Rep2, typename _Period2>
513      constexpr bool
514      operator<=(const duration<_Rep1, _Period1>& __lhs,
515		 const duration<_Rep2, _Period2>& __rhs)
516      { return !(__rhs < __lhs); }
517
518    template<typename _Rep1, typename _Period1,
519	     typename _Rep2, typename _Period2>
520      constexpr bool
521      operator>(const duration<_Rep1, _Period1>& __lhs,
522		const duration<_Rep2, _Period2>& __rhs)
523      { return __rhs < __lhs; }
524
525    template<typename _Rep1, typename _Period1,
526	     typename _Rep2, typename _Period2>
527      constexpr bool
528      operator>=(const duration<_Rep1, _Period1>& __lhs,
529		 const duration<_Rep2, _Period2>& __rhs)
530      { return !(__lhs < __rhs); }
531
532    /// nanoseconds
533    typedef duration<int64_t, nano> 	    nanoseconds;
534
535    /// microseconds
536    typedef duration<int64_t, micro> 	    microseconds;
537
538    /// milliseconds
539    typedef duration<int64_t, milli> 	    milliseconds;
540
541    /// seconds
542    typedef duration<int64_t> 		    seconds;
543
544    /// minutes
545    typedef duration<int64_t, ratio< 60>>   minutes;
546
547    /// hours
548    typedef duration<int64_t, ratio<3600>>  hours;
549
550    /// time_point
551    template<typename _Clock, typename _Dur>
552      struct time_point
553      {
554	typedef _Clock			  			clock;
555	typedef _Dur		  				duration;
556	typedef typename duration::rep	  			rep;
557	typedef typename duration::period			period;
558
559	constexpr time_point() : __d(duration::zero())
560	{ }
561
562	constexpr explicit time_point(const duration& __dur)
563	: __d(__dur)
564	{ }
565
566	// conversions
567	template<typename _Dur2,
568		 typename = _Require<is_convertible<_Dur2, _Dur>>>
569	  constexpr time_point(const time_point<clock, _Dur2>& __t)
570	  : __d(__t.time_since_epoch())
571	  { }
572
573	// observer
574	constexpr duration
575	time_since_epoch() const
576	{ return __d; }
577
578	// arithmetic
579	time_point&
580	operator+=(const duration& __dur)
581	{
582	  __d += __dur;
583	  return *this;
584	}
585
586	time_point&
587	operator-=(const duration& __dur)
588	{
589	  __d -= __dur;
590	  return *this;
591	}
592
593	// special values
594	static constexpr time_point
595	min()
596	{ return time_point(duration::min()); }
597
598	static constexpr time_point
599	max()
600	{ return time_point(duration::max()); }
601
602      private:
603	duration __d;
604      };
605
606    /// time_point_cast
607    template<typename _ToDur, typename _Clock, typename _Dur>
608      constexpr typename enable_if<__is_duration<_ToDur>::value,
609				   time_point<_Clock, _ToDur>>::type
610      time_point_cast(const time_point<_Clock, _Dur>& __t)
611      {
612	typedef time_point<_Clock, _ToDur> 			__time_point;
613	return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
614      }
615
616    template<typename _Clock, typename _Dur1,
617	     typename _Rep2, typename _Period2>
618      constexpr time_point<_Clock,
619	typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
620      operator+(const time_point<_Clock, _Dur1>& __lhs,
621		const duration<_Rep2, _Period2>& __rhs)
622      {
623	typedef duration<_Rep2, _Period2>			__dur2;
624	typedef typename common_type<_Dur1,__dur2>::type	__ct;
625	typedef time_point<_Clock, __ct> 			__time_point;
626	return __time_point(__lhs.time_since_epoch() + __rhs);
627      }
628
629    template<typename _Rep1, typename _Period1,
630	     typename _Clock, typename _Dur2>
631      constexpr time_point<_Clock,
632	typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
633      operator+(const duration<_Rep1, _Period1>& __lhs,
634		const time_point<_Clock, _Dur2>& __rhs)
635      {
636	typedef duration<_Rep1, _Period1>			__dur1;
637	typedef typename common_type<__dur1,_Dur2>::type	__ct;
638	typedef time_point<_Clock, __ct> 			__time_point;
639	return __time_point(__rhs.time_since_epoch() + __lhs);
640      }
641
642    template<typename _Clock, typename _Dur1,
643	     typename _Rep2, typename _Period2>
644      constexpr time_point<_Clock,
645	typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
646      operator-(const time_point<_Clock, _Dur1>& __lhs,
647		const duration<_Rep2, _Period2>& __rhs)
648      {
649	typedef duration<_Rep2, _Period2>			__dur2;
650	typedef typename common_type<_Dur1,__dur2>::type	__ct;
651	typedef time_point<_Clock, __ct> 			__time_point;
652	return __time_point(__lhs.time_since_epoch() -__rhs);
653      }
654
655    template<typename _Clock, typename _Dur1, typename _Dur2>
656      constexpr typename common_type<_Dur1, _Dur2>::type
657      operator-(const time_point<_Clock, _Dur1>& __lhs,
658		const time_point<_Clock, _Dur2>& __rhs)
659      { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
660
661    template<typename _Clock, typename _Dur1, typename _Dur2>
662      constexpr bool
663      operator==(const time_point<_Clock, _Dur1>& __lhs,
664		 const time_point<_Clock, _Dur2>& __rhs)
665      { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
666
667    template<typename _Clock, typename _Dur1, typename _Dur2>
668      constexpr bool
669      operator!=(const time_point<_Clock, _Dur1>& __lhs,
670		 const time_point<_Clock, _Dur2>& __rhs)
671      { return !(__lhs == __rhs); }
672
673    template<typename _Clock, typename _Dur1, typename _Dur2>
674      constexpr bool
675      operator<(const time_point<_Clock, _Dur1>& __lhs,
676		const time_point<_Clock, _Dur2>& __rhs)
677      { return  __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
678
679    template<typename _Clock, typename _Dur1, typename _Dur2>
680      constexpr bool
681      operator<=(const time_point<_Clock, _Dur1>& __lhs,
682		 const time_point<_Clock, _Dur2>& __rhs)
683      { return !(__rhs < __lhs); }
684
685    template<typename _Clock, typename _Dur1, typename _Dur2>
686      constexpr bool
687      operator>(const time_point<_Clock, _Dur1>& __lhs,
688		const time_point<_Clock, _Dur2>& __rhs)
689      { return __rhs < __lhs; }
690
691    template<typename _Clock, typename _Dur1, typename _Dur2>
692      constexpr bool
693      operator>=(const time_point<_Clock, _Dur1>& __lhs,
694		 const time_point<_Clock, _Dur2>& __rhs)
695      { return !(__lhs < __rhs); }
696
697
698    // Clocks.
699
700    // Why nanosecond resolution as the default?
701    // Why have std::system_clock always count in the higest
702    // resolution (ie nanoseconds), even if on some OSes the low 3
703    // or 9 decimal digits will be always zero? This allows later
704    // implementations to change the system_clock::now()
705    // implementation any time to provide better resolution without
706    // changing function signature or units.
707
708    // To support the (forward) evolution of the library's defined
709    // clocks, wrap inside inline namespace so that the current
710    // defintions of system_clock, steady_clock, and
711    // high_resolution_clock types are uniquely mangled. This way, new
712    // code can use the latests clocks, while the library can contain
713    // compatibility definitions for previous versions.  At some
714    // point, when these clocks settle down, the inlined namespaces
715    // can be removed.  XXX GLIBCXX_ABI Deprecated
716    inline namespace _V2 {
717
718    /**
719     *  @brief System clock.
720     *
721     *  Time returned represents wall time from the system-wide clock.
722    */
723    struct system_clock
724    {
725      typedef chrono::nanoseconds     				duration;
726      typedef duration::rep    					rep;
727      typedef duration::period 					period;
728      typedef chrono::time_point<system_clock, duration> 	time_point;
729
730      static_assert(system_clock::duration::min()
731		    < system_clock::duration::zero(),
732		    "a clock's minimum duration cannot be less than its epoch");
733
734      static constexpr bool is_steady = false;
735
736      static time_point
737      now() noexcept;
738
739      // Map to C API
740      static std::time_t
741      to_time_t(const time_point& __t) noexcept
742      {
743	return std::time_t(duration_cast<chrono::seconds>
744			   (__t.time_since_epoch()).count());
745      }
746
747      static time_point
748      from_time_t(std::time_t __t) noexcept
749      {
750	typedef chrono::time_point<system_clock, seconds>	__from;
751	return time_point_cast<system_clock::duration>
752	       (__from(chrono::seconds(__t)));
753      }
754    };
755
756
757    /**
758     *  @brief Monotonic clock
759     *
760     *  Time returned has the property of only increasing at a uniform rate.
761    */
762    struct steady_clock
763    {
764      typedef chrono::nanoseconds 				duration;
765      typedef duration::rep	  				rep;
766      typedef duration::period	  				period;
767      typedef chrono::time_point<steady_clock, duration> 	time_point;
768
769      static constexpr bool is_steady = true;
770
771      static time_point
772      now() noexcept;
773    };
774
775
776    /**
777     *  @brief Highest-resolution clock
778     *
779     *  This is the clock "with the shortest tick period." Alias to
780     *  std::system_clock until higher-than-nanosecond definitions
781     *  become feasible.
782    */
783    using high_resolution_clock = system_clock;
784
785    } // end inline namespace _V2
786
787  _GLIBCXX_END_NAMESPACE_VERSION
788  } // namespace chrono
789
790#if __cplusplus > 201103L
791
792#define __cpp_lib_chrono_udls 201304
793
794  inline namespace literals
795  {
796  inline namespace chrono_literals
797  {
798  _GLIBCXX_BEGIN_NAMESPACE_VERSION
799
800    template<typename _Rep, unsigned long long _Val>
801      struct _Checked_integral_constant
802      : integral_constant<_Rep, static_cast<_Rep>(_Val)>
803      {
804	static_assert(_Checked_integral_constant::value >= 0
805		      && _Checked_integral_constant::value == _Val,
806		      "literal value cannot be represented by duration type");
807      };
808
809    template<typename _Dur, char... _Digits>
810      constexpr _Dur __check_overflow()
811      {
812	using _Val = __parse_int::_Parse_int<_Digits...>;
813	using _Rep = typename _Dur::rep;
814	// TODO: should be simply integral_constant<_Rep, _Val::value>
815	// but GCC doesn't reject narrowing conversions to _Rep.
816	using _CheckedVal = _Checked_integral_constant<_Rep, _Val::value>;
817	return _Dur{_CheckedVal::value};
818      }
819
820    constexpr chrono::duration<long double, ratio<3600,1>>
821    operator""h(long double __hours)
822    { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
823
824    template <char... _Digits>
825      constexpr chrono::hours
826      operator""h()
827      { return __check_overflow<chrono::hours, _Digits...>(); }
828
829    constexpr chrono::duration<long double, ratio<60,1>>
830    operator""min(long double __mins)
831    { return chrono::duration<long double, ratio<60,1>>{__mins}; }
832
833    template <char... _Digits>
834      constexpr chrono::minutes
835      operator""min()
836      { return __check_overflow<chrono::minutes, _Digits...>(); }
837
838    constexpr chrono::duration<long double>
839    operator""s(long double __secs)
840    { return chrono::duration<long double>{__secs}; }
841
842    template <char... _Digits>
843      constexpr chrono::seconds
844      operator""s()
845      { return __check_overflow<chrono::seconds, _Digits...>(); }
846
847    constexpr chrono::duration<long double, milli>
848    operator""ms(long double __msecs)
849    { return chrono::duration<long double, milli>{__msecs}; }
850
851    template <char... _Digits>
852      constexpr chrono::milliseconds
853      operator""ms()
854      { return __check_overflow<chrono::milliseconds, _Digits...>(); }
855
856    constexpr chrono::duration<long double, micro>
857    operator""us(long double __usecs)
858    { return chrono::duration<long double, micro>{__usecs}; }
859
860    template <char... _Digits>
861      constexpr chrono::microseconds
862      operator""us()
863      { return __check_overflow<chrono::microseconds, _Digits...>(); }
864
865    constexpr chrono::duration<long double, nano>
866    operator""ns(long double __nsecs)
867    { return chrono::duration<long double, nano>{__nsecs}; }
868
869    template <char... _Digits>
870      constexpr chrono::nanoseconds
871      operator""ns()
872      { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
873
874  _GLIBCXX_END_NAMESPACE_VERSION
875  } // inline namespace chrono_literals
876  } // inline namespace literals
877
878  namespace chrono
879  {
880  _GLIBCXX_BEGIN_NAMESPACE_VERSION
881
882  using namespace literals::chrono_literals;
883
884  _GLIBCXX_END_NAMESPACE_VERSION
885  } // namespace chrono
886
887#endif // __cplusplus > 201103L
888
889  // @} group chrono
890} // namespace std
891
892#endif //_GLIBCXX_USE_C99_STDINT_TR1
893
894#endif // C++11
895
896#endif //_GLIBCXX_CHRONO
897