utility revision 256281 
1// -*- C++ -*-
2//===-------------------------- utility -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_UTILITY
12#define _LIBCPP_UTILITY
13
14/*
15    utility synopsis
16
17namespace std
18{
19
20template <class T>
21    void
22    swap(T& a, T& b);
23
24namespace rel_ops
25{
26    template<class T> bool operator!=(const T&, const T&);
27    template<class T> bool operator> (const T&, const T&);
28    template<class T> bool operator<=(const T&, const T&);
29    template<class T> bool operator>=(const T&, const T&);
30}
31
32template<class T>
33void
34swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
35                          is_nothrow_move_assignable<T>::value);
36
37template <class T, size_t N>
38void
39swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));
40
41template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;
42template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept;
43
44template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;
45
46template <class T>
47    typename conditional
48    <
49        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
50        const T&,
51        T&&
52    >::type
53    move_if_noexcept(T& x) noexcept;
54
55template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
56
57template <class T1, class T2>
58struct pair
59{
60    typedef T1 first_type;
61    typedef T2 second_type;
62
63    T1 first;
64    T2 second;
65
66    pair(const pair&) = default;
67    pair(pair&&) = default;
68    constexpr pair();
69    pair(const T1& x, const T2& y);
70    template <class U, class V> pair(U&& x, V&& y);
71    template <class U, class V> pair(const pair<U, V>& p);
72    template <class U, class V> pair(pair<U, V>&& p);
73    template <class... Args1, class... Args2>
74        pair(piecewise_construct_t, tuple<Args1...> first_args,
75             tuple<Args2...> second_args);
76
77    template <class U, class V> pair& operator=(const pair<U, V>& p);
78    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
79                                       is_nothrow_move_assignable<T2>::value);
80    template <class U, class V> pair& operator=(pair<U, V>&& p);
81
82    void swap(pair& p) noexcept(noexcept(swap(first, p.first)) &&
83                                noexcept(swap(second, p.second)));
84};
85
86template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&);
87template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&);
88template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&);
89template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&);
90template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&);
91template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&);
92
93template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);
94template <class T1, class T2>
95void
96swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
97
98struct piecewise_construct_t { };
99constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
100
101template <class T> class tuple_size;
102template <size_t I, class T> class tuple_element;
103
104template <class T1, class T2> struct tuple_size<std::pair<T1, T2> >;
105template <class T1, class T2> struct tuple_element<0, std::pair<T1, T2> >;
106template <class T1, class T2> struct tuple_element<1, std::pair<T1, T2> >;
107
108template<size_t I, class T1, class T2>
109    typename tuple_element<I, std::pair<T1, T2> >::type&
110    get(std::pair<T1, T2>&) noexcept;
111
112template<size_t I, class T1, class T2>
113    const typename const tuple_element<I, std::pair<T1, T2> >::type&
114    get(const std::pair<T1, T2>&) noexcept;
115
116template<size_t I, class T1, class T2>
117    typename tuple_element<I, std::pair<T1, T2> >::type&&
118    get(std::pair<T1, T2>&&) noexcept;
119
120// C++14
121
122template<class T, T... I>
123struct integer_sequence
124{
125    typedef T value_type;
126
127    static constexpr size_t size() noexcept;
128};
129
130template<size_t... I>
131  using index_sequence = integer_sequence<size_t, I...>;
132
133template<class T, T N>
134  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
135template<size_t N>
136  using make_index_sequence = make_integer_sequence<size_t, N>;
137
138template<class... T>
139  using index_sequence_for = make_index_sequence<sizeof...(T)>;
140
141}  // std
142
143*/
144
145#include <__config>
146#include <__tuple>
147#include <type_traits>
148
149#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
150#pragma GCC system_header
151#endif
152
153_LIBCPP_BEGIN_NAMESPACE_STD
154
155namespace rel_ops
156{
157
158template<class _Tp>
159inline _LIBCPP_INLINE_VISIBILITY
160bool
161operator!=(const _Tp& __x, const _Tp& __y)
162{
163    return !(__x == __y);
164}
165
166template<class _Tp>
167inline _LIBCPP_INLINE_VISIBILITY
168bool
169operator> (const _Tp& __x, const _Tp& __y)
170{
171    return __y < __x;
172}
173
174template<class _Tp>
175inline _LIBCPP_INLINE_VISIBILITY
176bool
177operator<=(const _Tp& __x, const _Tp& __y)
178{
179    return !(__y < __x);
180}
181
182template<class _Tp>
183inline _LIBCPP_INLINE_VISIBILITY
184bool
185operator>=(const _Tp& __x, const _Tp& __y)
186{
187    return !(__x < __y);
188}
189
190}  // rel_ops
191
192// swap_ranges
193
194template <class _ForwardIterator1, class _ForwardIterator2>
195inline _LIBCPP_INLINE_VISIBILITY
196_ForwardIterator2
197swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
198{
199    for(; __first1 != __last1; ++__first1, ++__first2)
200        swap(*__first1, *__first2);
201    return __first2;
202}
203
204template<class _Tp, size_t _Np>
205inline _LIBCPP_INLINE_VISIBILITY
206void
207swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
208{
209    _VSTD::swap_ranges(__a, __a + _Np, __b);
210}
211
212template <class _Tp>
213inline _LIBCPP_INLINE_VISIBILITY
214#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
215typename conditional
216<
217    !is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value,
218    const _Tp&,
219    _Tp&&
220>::type
221#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
222const _Tp&
223#endif
224move_if_noexcept(_Tp& __x) _NOEXCEPT
225{
226    return _VSTD::move(__x);
227}
228
229struct _LIBCPP_TYPE_VIS piecewise_construct_t { };
230#if defined(_LIBCPP_HAS_NO_CONSTEXPR) || defined(_LIBCPP_BUILDING_UTILITY)
231extern const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
232#else
233constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
234#endif
235
236template <class _T1, class _T2>
237struct _LIBCPP_TYPE_VIS pair
238{
239    typedef _T1 first_type;
240    typedef _T2 second_type;
241
242    _T1 first;
243    _T2 second;
244
245    // pair(const pair&) = default;
246    // pair(pair&&) = default;
247
248    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
249
250    _LIBCPP_INLINE_VISIBILITY pair(const _T1& __x, const _T2& __y)
251        : first(__x), second(__y) {}
252
253    template<class _U1, class _U2>
254        _LIBCPP_INLINE_VISIBILITY
255        pair(const pair<_U1, _U2>& __p
256#ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
257                 ,typename enable_if<is_convertible<const _U1&, _T1>::value &&
258                                    is_convertible<const _U2&, _T2>::value>::type* = 0
259#endif
260                                      )
261            : first(__p.first), second(__p.second) {}
262
263    _LIBCPP_INLINE_VISIBILITY
264    pair(const pair& __p)
265        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
266                   is_nothrow_copy_constructible<second_type>::value)
267        : first(__p.first),
268          second(__p.second)
269    {
270    }
271
272    _LIBCPP_INLINE_VISIBILITY
273    pair& operator=(const pair& __p)
274        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
275                   is_nothrow_copy_assignable<second_type>::value)
276    {
277        first = __p.first;
278        second = __p.second;
279        return *this;
280    }
281
282#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
283
284    template <class _U1, class _U2,
285              class = typename enable_if<is_convertible<_U1, first_type>::value &&
286                                         is_convertible<_U2, second_type>::value>::type>
287        _LIBCPP_INLINE_VISIBILITY
288        pair(_U1&& __u1, _U2&& __u2)
289            : first(_VSTD::forward<_U1>(__u1)),
290              second(_VSTD::forward<_U2>(__u2))
291            {}
292
293    template<class _U1, class _U2>
294        _LIBCPP_INLINE_VISIBILITY
295        pair(pair<_U1, _U2>&& __p,
296                 typename enable_if<is_convertible<_U1, _T1>::value &&
297                                    is_convertible<_U2, _T2>::value>::type* = 0)
298            : first(_VSTD::forward<_U1>(__p.first)),
299              second(_VSTD::forward<_U2>(__p.second)) {}
300
301    _LIBCPP_INLINE_VISIBILITY
302    pair(pair&& __p) _NOEXCEPT_(is_nothrow_move_constructible<first_type>::value &&
303                                is_nothrow_move_constructible<second_type>::value)
304        : first(_VSTD::forward<first_type>(__p.first)),
305          second(_VSTD::forward<second_type>(__p.second))
306    {
307    }
308
309    _LIBCPP_INLINE_VISIBILITY
310    pair&
311    operator=(pair&& __p) _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
312                                     is_nothrow_move_assignable<second_type>::value)
313    {
314        first = _VSTD::forward<first_type>(__p.first);
315        second = _VSTD::forward<second_type>(__p.second);
316        return *this;
317    }
318
319#ifndef _LIBCPP_HAS_NO_VARIADICS
320
321    template<class _Tuple,
322             class = typename enable_if<__tuple_convertible<_Tuple, pair>::value>::type>
323        _LIBCPP_INLINE_VISIBILITY
324        pair(_Tuple&& __p)
325            : first(_VSTD::forward<typename tuple_element<0,
326                                  typename __make_tuple_types<_Tuple>::type>::type>(get<0>(__p))),
327              second(_VSTD::forward<typename tuple_element<1,
328                                   typename __make_tuple_types<_Tuple>::type>::type>(get<1>(__p)))
329            {}
330
331
332
333    template <class... _Args1, class... _Args2>
334        _LIBCPP_INLINE_VISIBILITY
335        pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
336                                    tuple<_Args2...> __second_args)
337            : pair(__pc, __first_args, __second_args,
338                   typename __make_tuple_indices<sizeof...(_Args1)>::type(),
339                   typename __make_tuple_indices<sizeof...(_Args2) >::type())
340            {}
341
342    template <class _Tuple,
343              class = typename enable_if<__tuple_assignable<_Tuple, pair>::value>::type>
344        _LIBCPP_INLINE_VISIBILITY
345        pair&
346        operator=(_Tuple&& __p)
347        {
348            typedef typename __make_tuple_types<_Tuple>::type _TupleRef;
349            typedef typename tuple_element<0, _TupleRef>::type _U0;
350            typedef typename tuple_element<1, _TupleRef>::type _U1;
351            first  = _VSTD::forward<_U0>(_VSTD::get<0>(__p));
352            second = _VSTD::forward<_U1>(_VSTD::get<1>(__p));
353            return *this;
354        }
355
356#endif  // _LIBCPP_HAS_NO_VARIADICS
357
358#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
359    _LIBCPP_INLINE_VISIBILITY
360    void
361    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
362                               __is_nothrow_swappable<second_type>::value)
363    {
364        _VSTD::iter_swap(&first, &__p.first);
365        _VSTD::iter_swap(&second, &__p.second);
366    }
367private:
368
369#ifndef _LIBCPP_HAS_NO_VARIADICS
370    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
371        _LIBCPP_INLINE_VISIBILITY
372        pair(piecewise_construct_t,
373             tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
374             __tuple_indices<_I1...>, __tuple_indices<_I2...>);
375#endif  // _LIBCPP_HAS_NO_VARIADICS
376};
377
378template <class _T1, class _T2>
379inline _LIBCPP_INLINE_VISIBILITY
380bool
381operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
382{
383    return __x.first == __y.first && __x.second == __y.second;
384}
385
386template <class _T1, class _T2>
387inline _LIBCPP_INLINE_VISIBILITY
388bool
389operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
390{
391    return !(__x == __y);
392}
393
394template <class _T1, class _T2>
395inline _LIBCPP_INLINE_VISIBILITY
396bool
397operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
398{
399    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
400}
401
402template <class _T1, class _T2>
403inline _LIBCPP_INLINE_VISIBILITY
404bool
405operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
406{
407    return __y < __x;
408}
409
410template <class _T1, class _T2>
411inline _LIBCPP_INLINE_VISIBILITY
412bool
413operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
414{
415    return !(__x < __y);
416}
417
418template <class _T1, class _T2>
419inline _LIBCPP_INLINE_VISIBILITY
420bool
421operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
422{
423    return !(__y < __x);
424}
425
426template <class _T1, class _T2>
427inline _LIBCPP_INLINE_VISIBILITY
428typename enable_if
429<
430    __is_swappable<_T1>::value &&
431    __is_swappable<_T2>::value,
432    void
433>::type
434swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
435                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
436                                 __is_nothrow_swappable<_T2>::value))
437{
438    __x.swap(__y);
439}
440
441#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
442
443template <class _Tp> class _LIBCPP_TYPE_VIS reference_wrapper;
444
445template <class _Tp>
446struct ___make_pair_return
447{
448    typedef _Tp type;
449};
450
451template <class _Tp>
452struct ___make_pair_return<reference_wrapper<_Tp>>
453{
454    typedef _Tp& type;
455};
456
457template <class _Tp>
458struct __make_pair_return
459{
460    typedef typename ___make_pair_return<typename decay<_Tp>::type>::type type;
461};
462
463template <class _T1, class _T2>
464inline _LIBCPP_INLINE_VISIBILITY
465pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
466make_pair(_T1&& __t1, _T2&& __t2)
467{
468    return pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
469               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
470}
471
472#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
473
474template <class _T1, class _T2>
475inline _LIBCPP_INLINE_VISIBILITY
476pair<_T1,_T2>
477make_pair(_T1 __x, _T2 __y)
478{
479    return pair<_T1, _T2>(__x, __y);
480}
481
482#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
483
484template <class _T1, class _T2>
485  class _LIBCPP_TYPE_VIS tuple_size<pair<_T1, _T2> >
486    : public integral_constant<size_t, 2> {};
487
488template <class _T1, class _T2>
489  class _LIBCPP_TYPE_VIS tuple_size<const pair<_T1, _T2> >
490    : public integral_constant<size_t, 2> {};
491
492template <class _T1, class _T2>
493class _LIBCPP_TYPE_VIS tuple_element<0, pair<_T1, _T2> >
494{
495public:
496    typedef _T1 type;
497};
498
499template <class _T1, class _T2>
500class _LIBCPP_TYPE_VIS tuple_element<1, pair<_T1, _T2> >
501{
502public:
503    typedef _T2 type;
504};
505
506template <class _T1, class _T2>
507class _LIBCPP_TYPE_VIS tuple_element<0, const pair<_T1, _T2> >
508{
509public:
510    typedef const _T1 type;
511};
512
513template <class _T1, class _T2>
514class _LIBCPP_TYPE_VIS tuple_element<1, const pair<_T1, _T2> >
515{
516public:
517    typedef const _T2 type;
518};
519
520template <size_t _Ip> struct __get_pair;
521
522template <>
523struct __get_pair<0>
524{
525    template <class _T1, class _T2>
526    static
527    _LIBCPP_INLINE_VISIBILITY
528    _T1&
529    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
530
531    template <class _T1, class _T2>
532    static
533    _LIBCPP_INLINE_VISIBILITY
534    const _T1&
535    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
536
537#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
538
539    template <class _T1, class _T2>
540    static
541    _LIBCPP_INLINE_VISIBILITY
542    _T1&&
543    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
544
545#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
546};
547
548template <>
549struct __get_pair<1>
550{
551    template <class _T1, class _T2>
552    static
553    _LIBCPP_INLINE_VISIBILITY
554    _T2&
555    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
556
557    template <class _T1, class _T2>
558    static
559    _LIBCPP_INLINE_VISIBILITY
560    const _T2&
561    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
562
563#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
564
565    template <class _T1, class _T2>
566    static
567    _LIBCPP_INLINE_VISIBILITY
568    _T2&&
569    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
570
571#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
572};
573
574template <size_t _Ip, class _T1, class _T2>
575_LIBCPP_INLINE_VISIBILITY inline
576typename tuple_element<_Ip, pair<_T1, _T2> >::type&
577get(pair<_T1, _T2>& __p) _NOEXCEPT
578{
579    return __get_pair<_Ip>::get(__p);
580}
581
582template <size_t _Ip, class _T1, class _T2>
583_LIBCPP_INLINE_VISIBILITY inline
584const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
585get(const pair<_T1, _T2>& __p) _NOEXCEPT
586{
587    return __get_pair<_Ip>::get(__p);
588}
589
590#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
591
592template <size_t _Ip, class _T1, class _T2>
593_LIBCPP_INLINE_VISIBILITY inline
594typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
595get(pair<_T1, _T2>&& __p) _NOEXCEPT
596{
597    return __get_pair<_Ip>::get(_VSTD::move(__p));
598}
599
600#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
601
602#if _LIBCPP_STD_VER > 11
603
604template<class _Tp, _Tp... _Ip>
605struct _LIBCPP_TYPE_VIS integer_sequence
606{
607    typedef _Tp value_type;
608    static_assert( is_integral<_Tp>::value,
609                  "std::integer_sequence can only be instantiated with an integral type" );
610    static
611    _LIBCPP_INLINE_VISIBILITY
612    constexpr
613    size_t
614    size() noexcept { return sizeof...(_Ip); }
615};
616
617template<size_t... _Ip>
618    using index_sequence = integer_sequence<size_t, _Ip...>;
619
620namespace __detail {
621
622template<typename _Tp, size_t ..._Extra> struct __repeat;
623template<typename _Tp, _Tp ..._Np, size_t ..._Extra> struct __repeat<integer_sequence<_Tp, _Np...>, _Extra...> {
624  typedef integer_sequence<_Tp,
625                           _Np...,
626                           sizeof...(_Np) + _Np...,
627                           2 * sizeof...(_Np) + _Np...,
628                           3 * sizeof...(_Np) + _Np...,
629                           4 * sizeof...(_Np) + _Np...,
630                           5 * sizeof...(_Np) + _Np...,
631                           6 * sizeof...(_Np) + _Np...,
632                           7 * sizeof...(_Np) + _Np...,
633                           _Extra...> type;
634};
635
636template<size_t _Np> struct __parity;
637template<size_t _Np> struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
638
639template<> struct __make<0> { typedef integer_sequence<size_t> type; };
640template<> struct __make<1> { typedef integer_sequence<size_t, 0> type; };
641template<> struct __make<2> { typedef integer_sequence<size_t, 0, 1> type; };
642template<> struct __make<3> { typedef integer_sequence<size_t, 0, 1, 2> type; };
643template<> struct __make<4> { typedef integer_sequence<size_t, 0, 1, 2, 3> type; };
644template<> struct __make<5> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
645template<> struct __make<6> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
646template<> struct __make<7> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
647
648template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
649template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
650template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
651template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
652template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
653template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
654template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
655template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
656
657template<typename _Tp, typename _Up> struct __convert {
658  template<typename> struct __result;
659  template<_Tp ..._Np> struct __result<integer_sequence<_Tp, _Np...> > { typedef integer_sequence<_Up, _Np...> type; };
660};
661template<typename _Tp> struct __convert<_Tp, _Tp> { template<typename _Up> struct __result { typedef _Up type; }; };
662
663}
664
665template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
666  typename __detail::__convert<size_t, _Tp>::template __result<typename __detail::__make<_Np>::type>::type;
667
668template <class _Tp, _Tp _Ep>
669struct __make_integer_sequence
670{
671    static_assert(is_integral<_Tp>::value,
672                  "std::make_integer_sequence can only be instantiated with an integral type" );
673    static_assert(0 <= _Ep, "std::make_integer_sequence input shall not be negative");
674    typedef __make_integer_sequence_unchecked<_Tp, _Ep> type;
675};
676
677template<class _Tp, _Tp _Np>
678    using make_integer_sequence = typename __make_integer_sequence<_Tp, _Np>::type;
679
680template<size_t _Np>
681    using make_index_sequence = make_integer_sequence<size_t, _Np>;
682
683template<class... _Tp>
684    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
685  
686#endif  // _LIBCPP_STD_VER > 11
687
688_LIBCPP_END_NAMESPACE_STD
689
690#endif  // _LIBCPP_UTILITY
691