1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2020 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/*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation.  Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose.  It is provided "as is" without express or implied warranty.
37 *
38 *
39 * Copyright (c) 1996,1997
40 * Silicon Graphics Computer Systems, Inc.
41 *
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation.  Silicon Graphics makes no
47 * representations about the suitability of this software for any
48 * purpose.  It is provided "as is" without express or implied warranty.
49 */
50
51/** @file include/utility
52 *  This is a Standard C++ Library header.
53 */
54
55#ifndef _GLIBCXX_UTILITY
56#define _GLIBCXX_UTILITY 1
57
58#pragma GCC system_header
59
60/**
61 * @defgroup utilities Utilities
62 *
63 * Components deemed generally useful. Includes pair, tuple,
64 * forward/move helpers, ratio, function object, metaprogramming and
65 * type traits, time, date, and memory functions.
66 */
67
68#include <bits/c++config.h>
69#include <bits/stl_relops.h>
70#include <bits/stl_pair.h>
71
72#if __cplusplus >= 201103L
73
74#include <type_traits>
75#include <bits/move.h>
76#include <initializer_list>
77
78#if __cplusplus > 201703L
79#include <ext/numeric_traits.h>
80#endif
81
82namespace std _GLIBCXX_VISIBILITY(default)
83{
84_GLIBCXX_BEGIN_NAMESPACE_VERSION
85
86  /// Finds the size of a given tuple type.
87  template<typename _Tp>
88    struct tuple_size;
89
90  // _GLIBCXX_RESOLVE_LIB_DEFECTS
91  // 2313. tuple_size should always derive from integral_constant<size_t, N>
92  // 2770. tuple_size<const T> specialization is not SFINAE compatible
93
94  template<typename _Tp,
95	   typename _Up = typename remove_cv<_Tp>::type,
96	   typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
97	   size_t = tuple_size<_Tp>::value>
98    using __enable_if_has_tuple_size = _Tp;
99
100  template<typename _Tp>
101    struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
102    : public tuple_size<_Tp> { };
103
104  template<typename _Tp>
105    struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
106    : public tuple_size<_Tp> { };
107
108  template<typename _Tp>
109    struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
110    : public tuple_size<_Tp> { };
111
112  /// Gives the type of the ith element of a given tuple type.
113  template<std::size_t __i, typename _Tp>
114    struct tuple_element;
115
116  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
117  template<std::size_t __i, typename _Tp>
118    using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
119
120  template<std::size_t __i, typename _Tp>
121    struct tuple_element<__i, const _Tp>
122    {
123      typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
124    };
125
126  template<std::size_t __i, typename _Tp>
127    struct tuple_element<__i, volatile _Tp>
128    {
129      typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
130    };
131
132  template<std::size_t __i, typename _Tp>
133    struct tuple_element<__i, const volatile _Tp>
134    {
135      typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
136    };
137
138#if __cplusplus >= 201402L
139// The standard says this macro and alias template should be in <tuple>
140// but we define them here, to be available when the partial specializations
141// of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined.
142#define __cpp_lib_tuple_element_t 201402L
143
144  template<std::size_t __i, typename _Tp>
145    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
146#endif
147
148  // Various functions which give std::pair a tuple-like interface.
149
150  /// Partial specialization for std::pair
151  template<typename _T1, typename _T2>
152    struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
153    { };
154
155  /// Partial specialization for std::pair
156  template<class _Tp1, class _Tp2>
157    struct tuple_size<std::pair<_Tp1, _Tp2>>
158    : public integral_constant<std::size_t, 2> { };
159
160  /// Partial specialization for std::pair
161  template<class _Tp1, class _Tp2>
162    struct tuple_element<0, std::pair<_Tp1, _Tp2>>
163    { typedef _Tp1 type; };
164
165  /// Partial specialization for std::pair
166  template<class _Tp1, class _Tp2>
167    struct tuple_element<1, std::pair<_Tp1, _Tp2>>
168    { typedef _Tp2 type; };
169
170  template<std::size_t _Int>
171    struct __pair_get;
172
173  template<>
174    struct __pair_get<0>
175    {
176      template<typename _Tp1, typename _Tp2>
177        static constexpr _Tp1&
178        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
179        { return __pair.first; }
180
181      template<typename _Tp1, typename _Tp2>
182        static constexpr _Tp1&&
183        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
184        { return std::forward<_Tp1>(__pair.first); }
185
186      template<typename _Tp1, typename _Tp2>
187        static constexpr const _Tp1&
188        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
189        { return __pair.first; }
190
191      template<typename _Tp1, typename _Tp2>
192        static constexpr const _Tp1&&
193        __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
194        { return std::forward<const _Tp1>(__pair.first); }
195    };
196
197  template<>
198    struct __pair_get<1>
199    {
200      template<typename _Tp1, typename _Tp2>
201        static constexpr _Tp2&
202        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
203        { return __pair.second; }
204
205      template<typename _Tp1, typename _Tp2>
206        static constexpr _Tp2&&
207        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
208        { return std::forward<_Tp2>(__pair.second); }
209
210      template<typename _Tp1, typename _Tp2>
211        static constexpr const _Tp2&
212        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
213        { return __pair.second; }
214
215      template<typename _Tp1, typename _Tp2>
216        static constexpr const _Tp2&&
217        __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
218        { return std::forward<const _Tp2>(__pair.second); }
219    };
220
221  template<std::size_t _Int, class _Tp1, class _Tp2>
222    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
223    get(std::pair<_Tp1, _Tp2>& __in) noexcept
224    { return __pair_get<_Int>::__get(__in); }
225
226  template<std::size_t _Int, class _Tp1, class _Tp2>
227    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
228    get(std::pair<_Tp1, _Tp2>&& __in) noexcept
229    { return __pair_get<_Int>::__move_get(std::move(__in)); }
230
231  template<std::size_t _Int, class _Tp1, class _Tp2>
232    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
233    get(const std::pair<_Tp1, _Tp2>& __in) noexcept
234    { return __pair_get<_Int>::__const_get(__in); }
235
236  template<std::size_t _Int, class _Tp1, class _Tp2>
237    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
238    get(const std::pair<_Tp1, _Tp2>&& __in) noexcept
239    { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
240
241#if __cplusplus >= 201402L
242
243#define __cpp_lib_tuples_by_type 201304
244
245  template <typename _Tp, typename _Up>
246    constexpr _Tp&
247    get(pair<_Tp, _Up>& __p) noexcept
248    { return __p.first; }
249
250  template <typename _Tp, typename _Up>
251    constexpr const _Tp&
252    get(const pair<_Tp, _Up>& __p) noexcept
253    { return __p.first; }
254
255  template <typename _Tp, typename _Up>
256    constexpr _Tp&&
257    get(pair<_Tp, _Up>&& __p) noexcept
258    { return std::move(__p.first); }
259
260  template <typename _Tp, typename _Up>
261    constexpr const _Tp&&
262    get(const pair<_Tp, _Up>&& __p) noexcept
263    { return std::move(__p.first); }
264
265  template <typename _Tp, typename _Up>
266    constexpr _Tp&
267    get(pair<_Up, _Tp>& __p) noexcept
268    { return __p.second; }
269
270  template <typename _Tp, typename _Up>
271    constexpr const _Tp&
272    get(const pair<_Up, _Tp>& __p) noexcept
273    { return __p.second; }
274
275  template <typename _Tp, typename _Up>
276    constexpr _Tp&&
277    get(pair<_Up, _Tp>&& __p) noexcept
278    { return std::move(__p.second); }
279
280  template <typename _Tp, typename _Up>
281    constexpr const _Tp&&
282    get(const pair<_Up, _Tp>&& __p) noexcept
283    { return std::move(__p.second); }
284
285#define __cpp_lib_exchange_function 201304
286
287  /// Assign @p __new_val to @p __obj and return its previous value.
288  template <typename _Tp, typename _Up = _Tp>
289    _GLIBCXX20_CONSTEXPR
290    inline _Tp
291    exchange(_Tp& __obj, _Up&& __new_val)
292    { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
293
294#endif // C++14
295
296  // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
297  // extract the elements in a tuple.
298  template<size_t... _Indexes> struct _Index_tuple { };
299
300#ifdef __has_builtin
301# if __has_builtin(__make_integer_seq)
302#  define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1
303# endif
304#endif
305
306  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
307  template<size_t _Num>
308    struct _Build_index_tuple
309    {
310#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
311      template<typename, size_t... _Indices>
312        using _IdxTuple = _Index_tuple<_Indices...>;
313
314      using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
315#else
316      using __type = _Index_tuple<__integer_pack(_Num)...>;
317#endif
318    };
319
320#if __cplusplus > 201103L
321
322#define __cpp_lib_integer_sequence 201304
323
324  /// Class template integer_sequence
325  template<typename _Tp, _Tp... _Idx>
326    struct integer_sequence
327    {
328      typedef _Tp value_type;
329      static constexpr size_t size() noexcept { return sizeof...(_Idx); }
330    };
331
332  /// Alias template make_integer_sequence
333  template<typename _Tp, _Tp _Num>
334    using make_integer_sequence
335#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
336      = __make_integer_seq<integer_sequence, _Tp, _Num>;
337#else
338      = integer_sequence<_Tp, __integer_pack(_Num)...>;
339#endif
340
341#undef _GLIBCXX_USE_MAKE_INTEGER_SEQ
342
343  /// Alias template index_sequence
344  template<size_t... _Idx>
345    using index_sequence = integer_sequence<size_t, _Idx...>;
346
347  /// Alias template make_index_sequence
348  template<size_t _Num>
349    using make_index_sequence = make_integer_sequence<size_t, _Num>;
350
351  /// Alias template index_sequence_for
352  template<typename... _Types>
353    using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
354#endif
355
356#if __cplusplus > 201402L
357
358  struct in_place_t {
359    explicit in_place_t() = default;
360  };
361
362  inline constexpr in_place_t in_place{};
363
364  template<typename _Tp> struct in_place_type_t
365  {
366    explicit in_place_type_t() = default;
367  };
368
369  template<typename _Tp>
370    inline constexpr in_place_type_t<_Tp> in_place_type{};
371
372  template<size_t _Idx> struct in_place_index_t
373  {
374    explicit in_place_index_t() = default;
375  };
376
377  template<size_t _Idx>
378    inline constexpr in_place_index_t<_Idx> in_place_index{};
379
380  template<typename>
381    struct __is_in_place_type_impl : false_type
382    { };
383
384  template<typename _Tp>
385    struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
386    { };
387
388  template<typename _Tp>
389    struct __is_in_place_type
390      : public __is_in_place_type_impl<_Tp>
391    { };
392
393#define  __cpp_lib_as_const 201510
394  template<typename _Tp>
395    constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
396
397  template<typename _Tp>
398    void as_const(const _Tp&&) = delete;
399
400#if __cplusplus > 201703L
401#define __cpp_lib_integer_comparison_functions 202002L
402
403  template<typename _Tp, typename _Up>
404    constexpr bool
405    cmp_equal(_Tp __t, _Up __u) noexcept
406    {
407      static_assert(__is_standard_integer<_Tp>::value);
408      static_assert(__is_standard_integer<_Up>::value);
409
410      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
411	return __t == __u;
412      else if constexpr (is_signed_v<_Tp>)
413	return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u;
414      else
415	return __u >= 0 && __t == make_unsigned_t<_Up>(__u);
416    }
417
418  template<typename _Tp, typename _Up>
419    constexpr bool
420    cmp_not_equal(_Tp __t, _Up __u) noexcept
421    { return !std::cmp_equal(__t, __u); }
422
423  template<typename _Tp, typename _Up>
424    constexpr bool
425    cmp_less(_Tp __t, _Up __u) noexcept
426    {
427      static_assert(__is_standard_integer<_Tp>::value);
428      static_assert(__is_standard_integer<_Up>::value);
429
430      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
431	return __t < __u;
432      else if constexpr (is_signed_v<_Tp>)
433	return __t < 0 || make_unsigned_t<_Tp>(__t) < __u;
434      else
435	return __u >= 0 && __t < make_unsigned_t<_Up>(__u);
436    }
437
438  template<typename _Tp, typename _Up>
439    constexpr bool
440    cmp_greater(_Tp __t, _Up __u) noexcept
441    { return std::cmp_less(__u, __t); }
442
443  template<typename _Tp, typename _Up>
444    constexpr bool
445    cmp_less_equal(_Tp __t, _Up __u) noexcept
446    { return !std::cmp_less(__u, __t); }
447
448  template<typename _Tp, typename _Up>
449    constexpr bool
450    cmp_greater_equal(_Tp __t, _Up __u) noexcept
451    { return !std::cmp_less(__t, __u); }
452
453  template<typename _Up, typename _Tp>
454    constexpr bool
455    in_range(_Tp __t) noexcept
456    {
457      static_assert(__is_standard_integer<_Up>::value);
458      static_assert(__is_standard_integer<_Tp>::value);
459      using __gnu_cxx::__int_traits;
460
461      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
462	return __int_traits<_Up>::__min <= __t
463	  && __t <= __int_traits<_Up>::__max;
464      else if constexpr (is_signed_v<_Tp>)
465	return __t >= 0
466	  && make_unsigned_t<_Tp>(__t) <= __int_traits<_Up>::__max;
467      else
468	return __t <= make_unsigned_t<_Up>(__int_traits<_Up>::__max);
469    }
470#endif // C++20
471#endif // C++17
472
473_GLIBCXX_END_NAMESPACE_VERSION
474} // namespace
475
476#endif
477
478#endif /* _GLIBCXX_UTILITY */
479