libstdc++
chrono
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1 // <chrono> -*- C++ -*-
2 
3 // Copyright (C) 2008-2017 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 
46 namespace 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 #if __cplusplus > 201402L
213  template <typename _Rep>
214  inline constexpr bool treat_as_floating_point_v =
215  treat_as_floating_point<_Rep>::value;
216 #endif // C++17
217 
218 #if __cplusplus >= 201703L
219 # define __cpp_lib_chrono 201611
220 
221  template<typename _ToDur, typename _Rep, typename _Period>
222  constexpr enable_if_t<__is_duration<_ToDur>::value, _ToDur>
223  floor(const duration<_Rep, _Period>& __d)
224  {
225  auto __to = chrono::duration_cast<_ToDur>(__d);
226  if (__to > __d)
227  return __to - _ToDur{1};
228  return __to;
229  }
230 
231  template<typename _ToDur, typename _Rep, typename _Period>
232  constexpr enable_if_t<__is_duration<_ToDur>::value, _ToDur>
233  ceil(const duration<_Rep, _Period>& __d)
234  {
235  auto __to = chrono::duration_cast<_ToDur>(__d);
236  if (__to < __d)
237  return __to + _ToDur{1};
238  return __to;
239  }
240 
241  template <typename _ToDur, typename _Rep, typename _Period>
242  constexpr enable_if_t<
243  __and_<__is_duration<_ToDur>,
244  __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
245  _ToDur>
246  round(const duration<_Rep, _Period>& __d)
247  {
248  _ToDur __t0 = chrono::floor<_ToDur>(__d);
249  _ToDur __t1 = __t0 + _ToDur{1};
250  auto __diff0 = __d - __t0;
251  auto __diff1 = __t1 - __d;
252  if (__diff0 == __diff1)
253  {
254  if (__t0.count() & 1)
255  return __t1;
256  return __t0;
257  }
258  else if (__diff0 < __diff1)
259  return __t0;
260  return __t1;
261  }
262 
263  template<typename _Rep, typename _Period>
264  constexpr
265  enable_if_t<numeric_limits<_Rep>::is_signed, duration<_Rep, _Period>>
266  abs(duration<_Rep, _Period> __d)
267  {
268  if (__d >= __d.zero())
269  return __d;
270  return -__d;
271  }
272 #endif // C++17
273 
274  /// duration_values
275  template<typename _Rep>
276  struct duration_values
277  {
278  static constexpr _Rep
279  zero()
280  { return _Rep(0); }
281 
282  static constexpr _Rep
283  max()
284  { return numeric_limits<_Rep>::max(); }
285 
286  static constexpr _Rep
287  min()
288  { return numeric_limits<_Rep>::lowest(); }
289  };
290 
291  template<typename _Tp>
292  struct __is_ratio
293  : std::false_type
294  { };
295 
296  template<intmax_t _Num, intmax_t _Den>
297  struct __is_ratio<ratio<_Num, _Den>>
298  : std::true_type
299  { };
300 
301  /// duration
302  template<typename _Rep, typename _Period>
303  struct duration
304  {
305  typedef _Rep rep;
306  typedef _Period period;
307 
308  static_assert(!__is_duration<_Rep>::value, "rep cannot be a duration");
309  static_assert(__is_ratio<_Period>::value,
310  "period must be a specialization of ratio");
311  static_assert(_Period::num > 0, "period must be positive");
312 
313  // 20.11.5.1 construction / copy / destroy
314  constexpr duration() = default;
315 
316  // NB: Make constexpr implicit. This cannot be explicitly
317  // constexpr, as any UDT that is not a literal type with a
318  // constexpr copy constructor will be ill-formed.
319  duration(const duration&) = default;
320 
321  // _GLIBCXX_RESOLVE_LIB_DEFECTS
322  // 3050. Conversion specification problem in chrono::duration
323  template<typename _Rep2, typename = typename
324  enable_if<is_convertible<const _Rep2&, rep>::value
325  && (treat_as_floating_point<rep>::value
326  || !treat_as_floating_point<_Rep2>::value)>::type>
327  constexpr explicit duration(const _Rep2& __rep)
328  : __r(static_cast<rep>(__rep)) { }
329 
330  template<typename _Rep2, typename _Period2, typename = typename
331  enable_if<treat_as_floating_point<rep>::value
332  || (ratio_divide<_Period2, period>::den == 1
333  && !treat_as_floating_point<_Rep2>::value)>::type>
334  constexpr duration(const duration<_Rep2, _Period2>& __d)
335  : __r(duration_cast<duration>(__d).count()) { }
336 
337  ~duration() = default;
338  duration& operator=(const duration&) = default;
339 
340  // 20.11.5.2 observer
341  constexpr rep
342  count() const
343  { return __r; }
344 
345  // 20.11.5.3 arithmetic
346  constexpr duration
347  operator+() const
348  { return *this; }
349 
350  constexpr duration
351  operator-() const
352  { return duration(-__r); }
353 
354  _GLIBCXX17_CONSTEXPR duration&
355  operator++()
356  {
357  ++__r;
358  return *this;
359  }
360 
361  _GLIBCXX17_CONSTEXPR duration
362  operator++(int)
363  { return duration(__r++); }
364 
365  _GLIBCXX17_CONSTEXPR duration&
366  operator--()
367  {
368  --__r;
369  return *this;
370  }
371 
372  _GLIBCXX17_CONSTEXPR duration
373  operator--(int)
374  { return duration(__r--); }
375 
376  _GLIBCXX17_CONSTEXPR duration&
377  operator+=(const duration& __d)
378  {
379  __r += __d.count();
380  return *this;
381  }
382 
383  _GLIBCXX17_CONSTEXPR duration&
384  operator-=(const duration& __d)
385  {
386  __r -= __d.count();
387  return *this;
388  }
389 
390  _GLIBCXX17_CONSTEXPR duration&
391  operator*=(const rep& __rhs)
392  {
393  __r *= __rhs;
394  return *this;
395  }
396 
397  _GLIBCXX17_CONSTEXPR duration&
398  operator/=(const rep& __rhs)
399  {
400  __r /= __rhs;
401  return *this;
402  }
403 
404  // DR 934.
405  template<typename _Rep2 = rep>
406  _GLIBCXX17_CONSTEXPR
407  typename enable_if<!treat_as_floating_point<_Rep2>::value,
408  duration&>::type
409  operator%=(const rep& __rhs)
410  {
411  __r %= __rhs;
412  return *this;
413  }
414 
415  template<typename _Rep2 = rep>
416  _GLIBCXX17_CONSTEXPR
417  typename enable_if<!treat_as_floating_point<_Rep2>::value,
418  duration&>::type
419  operator%=(const duration& __d)
420  {
421  __r %= __d.count();
422  return *this;
423  }
424 
425  // 20.11.5.4 special values
426  static constexpr duration
427  zero()
428  { return duration(duration_values<rep>::zero()); }
429 
430  static constexpr duration
431  min()
432  { return duration(duration_values<rep>::min()); }
433 
434  static constexpr duration
435  max()
436  { return duration(duration_values<rep>::max()); }
437 
438  private:
439  rep __r;
440  };
441 
442  template<typename _Rep1, typename _Period1,
443  typename _Rep2, typename _Period2>
444  constexpr typename common_type<duration<_Rep1, _Period1>,
445  duration<_Rep2, _Period2>>::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(__cd(__lhs).count() + __cd(__rhs).count());
453  }
454 
455  template<typename _Rep1, typename _Period1,
456  typename _Rep2, typename _Period2>
457  constexpr typename common_type<duration<_Rep1, _Period1>,
458  duration<_Rep2, _Period2>>::type
459  operator-(const duration<_Rep1, _Period1>& __lhs,
460  const duration<_Rep2, _Period2>& __rhs)
461  {
462  typedef duration<_Rep1, _Period1> __dur1;
463  typedef duration<_Rep2, _Period2> __dur2;
464  typedef typename common_type<__dur1,__dur2>::type __cd;
465  return __cd(__cd(__lhs).count() - __cd(__rhs).count());
466  }
467 
468  // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
469  // is implicitly convertible to it.
470  // _GLIBCXX_RESOLVE_LIB_DEFECTS
471  // 3050. Conversion specification problem in chrono::duration constructor
472  template<typename _Rep1, typename _Rep2, bool =
473  is_convertible<const _Rep2&,
474  typename common_type<_Rep1, _Rep2>::type>::value>
475  struct __common_rep_type { };
476 
477  template<typename _Rep1, typename _Rep2>
478  struct __common_rep_type<_Rep1, _Rep2, true>
479  { typedef typename common_type<_Rep1, _Rep2>::type type; };
480 
481  template<typename _Rep1, typename _Period, typename _Rep2>
482  constexpr
483  duration<typename __common_rep_type<_Rep1, _Rep2>::type, _Period>
484  operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
485  {
486  typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
487  __cd;
488  return __cd(__cd(__d).count() * __s);
489  }
490 
491  template<typename _Rep1, typename _Rep2, typename _Period>
492  constexpr
493  duration<typename __common_rep_type<_Rep2, _Rep1>::type, _Period>
494  operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
495  { return __d * __s; }
496 
497  template<typename _Rep1, typename _Period, typename _Rep2>
498  constexpr duration<typename __common_rep_type<_Rep1, typename
499  enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
500  operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
501  {
502  typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
503  __cd;
504  return __cd(__cd(__d).count() / __s);
505  }
506 
507  template<typename _Rep1, typename _Period1,
508  typename _Rep2, typename _Period2>
509  constexpr typename common_type<_Rep1, _Rep2>::type
510  operator/(const duration<_Rep1, _Period1>& __lhs,
511  const duration<_Rep2, _Period2>& __rhs)
512  {
513  typedef duration<_Rep1, _Period1> __dur1;
514  typedef duration<_Rep2, _Period2> __dur2;
515  typedef typename common_type<__dur1,__dur2>::type __cd;
516  return __cd(__lhs).count() / __cd(__rhs).count();
517  }
518 
519  // DR 934.
520  template<typename _Rep1, typename _Period, typename _Rep2>
521  constexpr duration<typename __common_rep_type<_Rep1, typename
522  enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period>
523  operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
524  {
525  typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
526  __cd;
527  return __cd(__cd(__d).count() % __s);
528  }
529 
530  template<typename _Rep1, typename _Period1,
531  typename _Rep2, typename _Period2>
532  constexpr typename common_type<duration<_Rep1, _Period1>,
533  duration<_Rep2, _Period2>>::type
534  operator%(const duration<_Rep1, _Period1>& __lhs,
535  const duration<_Rep2, _Period2>& __rhs)
536  {
537  typedef duration<_Rep1, _Period1> __dur1;
538  typedef duration<_Rep2, _Period2> __dur2;
539  typedef typename common_type<__dur1,__dur2>::type __cd;
540  return __cd(__cd(__lhs).count() % __cd(__rhs).count());
541  }
542 
543  // comparisons
544  template<typename _Rep1, typename _Period1,
545  typename _Rep2, typename _Period2>
546  constexpr bool
547  operator==(const duration<_Rep1, _Period1>& __lhs,
548  const duration<_Rep2, _Period2>& __rhs)
549  {
550  typedef duration<_Rep1, _Period1> __dur1;
551  typedef duration<_Rep2, _Period2> __dur2;
552  typedef typename common_type<__dur1,__dur2>::type __ct;
553  return __ct(__lhs).count() == __ct(__rhs).count();
554  }
555 
556  template<typename _Rep1, typename _Period1,
557  typename _Rep2, typename _Period2>
558  constexpr bool
559  operator<(const duration<_Rep1, _Period1>& __lhs,
560  const duration<_Rep2, _Period2>& __rhs)
561  {
562  typedef duration<_Rep1, _Period1> __dur1;
563  typedef duration<_Rep2, _Period2> __dur2;
564  typedef typename common_type<__dur1,__dur2>::type __ct;
565  return __ct(__lhs).count() < __ct(__rhs).count();
566  }
567 
568  template<typename _Rep1, typename _Period1,
569  typename _Rep2, typename _Period2>
570  constexpr bool
571  operator!=(const duration<_Rep1, _Period1>& __lhs,
572  const duration<_Rep2, _Period2>& __rhs)
573  { return !(__lhs == __rhs); }
574 
575  template<typename _Rep1, typename _Period1,
576  typename _Rep2, typename _Period2>
577  constexpr bool
578  operator<=(const duration<_Rep1, _Period1>& __lhs,
579  const duration<_Rep2, _Period2>& __rhs)
580  { return !(__rhs < __lhs); }
581 
582  template<typename _Rep1, typename _Period1,
583  typename _Rep2, typename _Period2>
584  constexpr bool
585  operator>(const duration<_Rep1, _Period1>& __lhs,
586  const duration<_Rep2, _Period2>& __rhs)
587  { return __rhs < __lhs; }
588 
589  template<typename _Rep1, typename _Period1,
590  typename _Rep2, typename _Period2>
591  constexpr bool
592  operator>=(const duration<_Rep1, _Period1>& __lhs,
593  const duration<_Rep2, _Period2>& __rhs)
594  { return !(__lhs < __rhs); }
595 
596  /// nanoseconds
597  typedef duration<int64_t, nano> nanoseconds;
598 
599  /// microseconds
600  typedef duration<int64_t, micro> microseconds;
601 
602  /// milliseconds
603  typedef duration<int64_t, milli> milliseconds;
604 
605  /// seconds
606  typedef duration<int64_t> seconds;
607 
608  /// minutes
609  typedef duration<int64_t, ratio< 60>> minutes;
610 
611  /// hours
612  typedef duration<int64_t, ratio<3600>> hours;
613 
614  /// time_point
615  template<typename _Clock, typename _Dur>
616  struct time_point
617  {
618  typedef _Clock clock;
619  typedef _Dur duration;
620  typedef typename duration::rep rep;
621  typedef typename duration::period period;
622 
623  constexpr time_point() : __d(duration::zero())
624  { }
625 
626  constexpr explicit time_point(const duration& __dur)
627  : __d(__dur)
628  { }
629 
630  // conversions
631  template<typename _Dur2,
632  typename = _Require<is_convertible<_Dur2, _Dur>>>
633  constexpr time_point(const time_point<clock, _Dur2>& __t)
634  : __d(__t.time_since_epoch())
635  { }
636 
637  // observer
638  constexpr duration
639  time_since_epoch() const
640  { return __d; }
641 
642  // arithmetic
643  _GLIBCXX17_CONSTEXPR time_point&
644  operator+=(const duration& __dur)
645  {
646  __d += __dur;
647  return *this;
648  }
649 
650  _GLIBCXX17_CONSTEXPR time_point&
651  operator-=(const duration& __dur)
652  {
653  __d -= __dur;
654  return *this;
655  }
656 
657  // special values
658  static constexpr time_point
659  min()
660  { return time_point(duration::min()); }
661 
662  static constexpr time_point
663  max()
664  { return time_point(duration::max()); }
665 
666  private:
667  duration __d;
668  };
669 
670  /// time_point_cast
671  template<typename _ToDur, typename _Clock, typename _Dur>
672  constexpr typename enable_if<__is_duration<_ToDur>::value,
673  time_point<_Clock, _ToDur>>::type
674  time_point_cast(const time_point<_Clock, _Dur>& __t)
675  {
676  typedef time_point<_Clock, _ToDur> __time_point;
677  return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
678  }
679 
680 #if __cplusplus > 201402L
681  template<typename _ToDur, typename _Clock, typename _Dur>
682  constexpr
683  enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
684  floor(const time_point<_Clock, _Dur>& __tp)
685  {
686  return time_point<_Clock, _ToDur>{
687  chrono::floor<_ToDur>(__tp.time_since_epoch())};
688  }
689 
690  template<typename _ToDur, typename _Clock, typename _Dur>
691  constexpr
692  enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
693  ceil(const time_point<_Clock, _Dur>& __tp)
694  {
695  return time_point<_Clock, _ToDur>{
696  chrono::ceil<_ToDur>(__tp.time_since_epoch())};
697  }
698 
699  template<typename _ToDur, typename _Clock, typename _Dur>
700  constexpr enable_if_t<
701  __and_<__is_duration<_ToDur>,
702  __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
703  time_point<_Clock, _ToDur>>
704  round(const time_point<_Clock, _Dur>& __tp)
705  {
706  return time_point<_Clock, _ToDur>{
707  chrono::round<_ToDur>(__tp.time_since_epoch())};
708  }
709 #endif // C++17
710 
711  template<typename _Clock, typename _Dur1,
712  typename _Rep2, typename _Period2>
713  constexpr time_point<_Clock,
714  typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
715  operator+(const time_point<_Clock, _Dur1>& __lhs,
716  const duration<_Rep2, _Period2>& __rhs)
717  {
718  typedef duration<_Rep2, _Period2> __dur2;
719  typedef typename common_type<_Dur1,__dur2>::type __ct;
720  typedef time_point<_Clock, __ct> __time_point;
721  return __time_point(__lhs.time_since_epoch() + __rhs);
722  }
723 
724  template<typename _Rep1, typename _Period1,
725  typename _Clock, typename _Dur2>
726  constexpr time_point<_Clock,
727  typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
728  operator+(const duration<_Rep1, _Period1>& __lhs,
729  const time_point<_Clock, _Dur2>& __rhs)
730  {
731  typedef duration<_Rep1, _Period1> __dur1;
732  typedef typename common_type<__dur1,_Dur2>::type __ct;
733  typedef time_point<_Clock, __ct> __time_point;
734  return __time_point(__rhs.time_since_epoch() + __lhs);
735  }
736 
737  template<typename _Clock, typename _Dur1,
738  typename _Rep2, typename _Period2>
739  constexpr time_point<_Clock,
740  typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
741  operator-(const time_point<_Clock, _Dur1>& __lhs,
742  const duration<_Rep2, _Period2>& __rhs)
743  {
744  typedef duration<_Rep2, _Period2> __dur2;
745  typedef typename common_type<_Dur1,__dur2>::type __ct;
746  typedef time_point<_Clock, __ct> __time_point;
747  return __time_point(__lhs.time_since_epoch() -__rhs);
748  }
749 
750  template<typename _Clock, typename _Dur1, typename _Dur2>
751  constexpr typename common_type<_Dur1, _Dur2>::type
752  operator-(const time_point<_Clock, _Dur1>& __lhs,
753  const time_point<_Clock, _Dur2>& __rhs)
754  { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
755 
756  template<typename _Clock, typename _Dur1, typename _Dur2>
757  constexpr bool
758  operator==(const time_point<_Clock, _Dur1>& __lhs,
759  const time_point<_Clock, _Dur2>& __rhs)
760  { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
761 
762  template<typename _Clock, typename _Dur1, typename _Dur2>
763  constexpr bool
764  operator!=(const time_point<_Clock, _Dur1>& __lhs,
765  const time_point<_Clock, _Dur2>& __rhs)
766  { return !(__lhs == __rhs); }
767 
768  template<typename _Clock, typename _Dur1, typename _Dur2>
769  constexpr bool
770  operator<(const time_point<_Clock, _Dur1>& __lhs,
771  const time_point<_Clock, _Dur2>& __rhs)
772  { return __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
773 
774  template<typename _Clock, typename _Dur1, typename _Dur2>
775  constexpr bool
776  operator<=(const time_point<_Clock, _Dur1>& __lhs,
777  const time_point<_Clock, _Dur2>& __rhs)
778  { return !(__rhs < __lhs); }
779 
780  template<typename _Clock, typename _Dur1, typename _Dur2>
781  constexpr bool
782  operator>(const time_point<_Clock, _Dur1>& __lhs,
783  const time_point<_Clock, _Dur2>& __rhs)
784  { return __rhs < __lhs; }
785 
786  template<typename _Clock, typename _Dur1, typename _Dur2>
787  constexpr bool
788  operator>=(const time_point<_Clock, _Dur1>& __lhs,
789  const time_point<_Clock, _Dur2>& __rhs)
790  { return !(__lhs < __rhs); }
791 
792 
793  // Clocks.
794 
795  // Why nanosecond resolution as the default?
796  // Why have std::system_clock always count in the highest
797  // resolution (ie nanoseconds), even if on some OSes the low 3
798  // or 9 decimal digits will be always zero? This allows later
799  // implementations to change the system_clock::now()
800  // implementation any time to provide better resolution without
801  // changing function signature or units.
802 
803  // To support the (forward) evolution of the library's defined
804  // clocks, wrap inside inline namespace so that the current
805  // defintions of system_clock, steady_clock, and
806  // high_resolution_clock types are uniquely mangled. This way, new
807  // code can use the latests clocks, while the library can contain
808  // compatibility definitions for previous versions. At some
809  // point, when these clocks settle down, the inlined namespaces
810  // can be removed. XXX GLIBCXX_ABI Deprecated
811  inline namespace _V2 {
812 
813  /**
814  * @brief System clock.
815  *
816  * Time returned represents wall time from the system-wide clock.
817  */
818  struct system_clock
819  {
820  typedef chrono::nanoseconds duration;
821  typedef duration::rep rep;
822  typedef duration::period period;
823  typedef chrono::time_point<system_clock, duration> time_point;
824 
825  static_assert(system_clock::duration::min()
826  < system_clock::duration::zero(),
827  "a clock's minimum duration cannot be less than its epoch");
828 
829  static constexpr bool is_steady = false;
830 
831  static time_point
832  now() noexcept;
833 
834  // Map to C API
835  static std::time_t
836  to_time_t(const time_point& __t) noexcept
837  {
838  return std::time_t(duration_cast<chrono::seconds>
839  (__t.time_since_epoch()).count());
840  }
841 
842  static time_point
843  from_time_t(std::time_t __t) noexcept
844  {
845  typedef chrono::time_point<system_clock, seconds> __from;
846  return time_point_cast<system_clock::duration>
847  (__from(chrono::seconds(__t)));
848  }
849  };
850 
851 
852  /**
853  * @brief Monotonic clock
854  *
855  * Time returned has the property of only increasing at a uniform rate.
856  */
857  struct steady_clock
858  {
859  typedef chrono::nanoseconds duration;
860  typedef duration::rep rep;
861  typedef duration::period period;
862  typedef chrono::time_point<steady_clock, duration> time_point;
863 
864  static constexpr bool is_steady = true;
865 
866  static time_point
867  now() noexcept;
868  };
869 
870 
871  /**
872  * @brief Highest-resolution clock
873  *
874  * This is the clock "with the shortest tick period." Alias to
875  * std::system_clock until higher-than-nanosecond definitions
876  * become feasible.
877  */
878  using high_resolution_clock = system_clock;
879 
880  } // end inline namespace _V2
881 
882  _GLIBCXX_END_NAMESPACE_VERSION
883  } // namespace chrono
884 
885 #if __cplusplus > 201103L
886 
887 #define __cpp_lib_chrono_udls 201304
888 
889  inline namespace literals
890  {
891  inline namespace chrono_literals
892  {
893  _GLIBCXX_BEGIN_NAMESPACE_VERSION
894 
895  template<typename _Rep, unsigned long long _Val>
896  struct _Checked_integral_constant
897  : integral_constant<_Rep, static_cast<_Rep>(_Val)>
898  {
899  static_assert(_Checked_integral_constant::value >= 0
900  && _Checked_integral_constant::value == _Val,
901  "literal value cannot be represented by duration type");
902  };
903 
904  template<typename _Dur, char... _Digits>
905  constexpr _Dur __check_overflow()
906  {
907  using _Val = __parse_int::_Parse_int<_Digits...>;
908  using _Rep = typename _Dur::rep;
909  // TODO: should be simply integral_constant<_Rep, _Val::value>
910  // but GCC doesn't reject narrowing conversions to _Rep.
911  using _CheckedVal = _Checked_integral_constant<_Rep, _Val::value>;
912  return _Dur{_CheckedVal::value};
913  }
914 
915  constexpr chrono::duration<long double, ratio<3600,1>>
916  operator""h(long double __hours)
917  { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
918 
919  template <char... _Digits>
920  constexpr chrono::hours
921  operator""h()
922  { return __check_overflow<chrono::hours, _Digits...>(); }
923 
924  constexpr chrono::duration<long double, ratio<60,1>>
925  operator""min(long double __mins)
926  { return chrono::duration<long double, ratio<60,1>>{__mins}; }
927 
928  template <char... _Digits>
929  constexpr chrono::minutes
930  operator""min()
931  { return __check_overflow<chrono::minutes, _Digits...>(); }
932 
933  constexpr chrono::duration<long double>
934  operator""s(long double __secs)
935  { return chrono::duration<long double>{__secs}; }
936 
937  template <char... _Digits>
938  constexpr chrono::seconds
939  operator""s()
940  { return __check_overflow<chrono::seconds, _Digits...>(); }
941 
942  constexpr chrono::duration<long double, milli>
943  operator""ms(long double __msecs)
944  { return chrono::duration<long double, milli>{__msecs}; }
945 
946  template <char... _Digits>
947  constexpr chrono::milliseconds
948  operator""ms()
949  { return __check_overflow<chrono::milliseconds, _Digits...>(); }
950 
951  constexpr chrono::duration<long double, micro>
952  operator""us(long double __usecs)
953  { return chrono::duration<long double, micro>{__usecs}; }
954 
955  template <char... _Digits>
956  constexpr chrono::microseconds
957  operator""us()
958  { return __check_overflow<chrono::microseconds, _Digits...>(); }
959 
960  constexpr chrono::duration<long double, nano>
961  operator""ns(long double __nsecs)
962  { return chrono::duration<long double, nano>{__nsecs}; }
963 
964  template <char... _Digits>
965  constexpr chrono::nanoseconds
966  operator""ns()
967  { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
968 
969  _GLIBCXX_END_NAMESPACE_VERSION
970  } // inline namespace chrono_literals
971  } // inline namespace literals
972 
973  namespace chrono
974  {
975  _GLIBCXX_BEGIN_NAMESPACE_VERSION
976 
977  using namespace literals::chrono_literals;
978 
979  _GLIBCXX_END_NAMESPACE_VERSION
980  } // namespace chrono
981 
982 #endif // __cplusplus > 201103L
983 
984  // @} group chrono
985 } // namespace std
986 
987 #endif //_GLIBCXX_USE_C99_STDINT_TR1
988 
989 #endif // C++11
990 
991 #endif //_GLIBCXX_CHRONO