1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2019 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
78namespace std _GLIBCXX_VISIBILITY(default)
79{
80_GLIBCXX_BEGIN_NAMESPACE_VERSION
81
82  /// Finds the size of a given tuple type.
83  template<typename _Tp>
84    struct tuple_size;
85
86  // _GLIBCXX_RESOLVE_LIB_DEFECTS
87  // 2313. tuple_size should always derive from integral_constant<size_t, N>
88  // 2770. tuple_size<const T> specialization is not SFINAE compatible
89
90  template<typename _Tp,
91	   typename _Up = typename remove_cv<_Tp>::type,
92	   typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
93	   size_t = tuple_size<_Tp>::value>
94    using __enable_if_has_tuple_size = _Tp;
95
96  template<typename _Tp>
97    struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
98    : public tuple_size<_Tp> { };
99
100  template<typename _Tp>
101    struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
102    : public tuple_size<_Tp> { };
103
104  template<typename _Tp>
105    struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
106    : public tuple_size<_Tp> { };
107
108  /// Gives the type of the ith element of a given tuple type.
109  template<std::size_t __i, typename _Tp>
110    struct tuple_element;
111
112  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
113  template<std::size_t __i, typename _Tp>
114    using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
115
116  template<std::size_t __i, typename _Tp>
117    struct tuple_element<__i, const _Tp>
118    {
119      typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
120    };
121
122  template<std::size_t __i, typename _Tp>
123    struct tuple_element<__i, volatile _Tp>
124    {
125      typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
126    };
127
128  template<std::size_t __i, typename _Tp>
129    struct tuple_element<__i, const volatile _Tp>
130    {
131      typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
132    };
133
134#if __cplusplus >= 201402L
135// The standard says this macro and alias template should be in <tuple>
136// but we define them here, to be available when the partial specializations
137// of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined.
138#define __cpp_lib_tuple_element_t 201402L
139
140  template<std::size_t __i, typename _Tp>
141    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
142#endif
143
144  // Various functions which give std::pair a tuple-like interface.
145
146  /// Partial specialization for std::pair
147  template<typename _T1, typename _T2>
148    struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
149    { };
150
151  /// Partial specialization for std::pair
152  template<class _Tp1, class _Tp2>
153    struct tuple_size<std::pair<_Tp1, _Tp2>>
154    : public integral_constant<std::size_t, 2> { };
155
156  /// Partial specialization for std::pair
157  template<class _Tp1, class _Tp2>
158    struct tuple_element<0, std::pair<_Tp1, _Tp2>>
159    { typedef _Tp1 type; };
160
161  /// Partial specialization for std::pair
162  template<class _Tp1, class _Tp2>
163    struct tuple_element<1, std::pair<_Tp1, _Tp2>>
164    { typedef _Tp2 type; };
165
166  template<std::size_t _Int>
167    struct __pair_get;
168
169  template<>
170    struct __pair_get<0>
171    {
172      template<typename _Tp1, typename _Tp2>
173        static constexpr _Tp1&
174        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
175        { return __pair.first; }
176
177      template<typename _Tp1, typename _Tp2>
178        static constexpr _Tp1&&
179        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
180        { return std::forward<_Tp1>(__pair.first); }
181
182      template<typename _Tp1, typename _Tp2>
183        static constexpr const _Tp1&
184        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
185        { return __pair.first; }
186
187      template<typename _Tp1, typename _Tp2>
188        static constexpr const _Tp1&&
189        __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
190        { return std::forward<const _Tp1>(__pair.first); }
191    };
192
193  template<>
194    struct __pair_get<1>
195    {
196      template<typename _Tp1, typename _Tp2>
197        static constexpr _Tp2&
198        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
199        { return __pair.second; }
200
201      template<typename _Tp1, typename _Tp2>
202        static constexpr _Tp2&&
203        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
204        { return std::forward<_Tp2>(__pair.second); }
205
206      template<typename _Tp1, typename _Tp2>
207        static constexpr const _Tp2&
208        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
209        { return __pair.second; }
210
211      template<typename _Tp1, typename _Tp2>
212        static constexpr const _Tp2&&
213        __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
214        { return std::forward<const _Tp2>(__pair.second); }
215    };
216
217  template<std::size_t _Int, class _Tp1, class _Tp2>
218    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
219    get(std::pair<_Tp1, _Tp2>& __in) noexcept
220    { return __pair_get<_Int>::__get(__in); }
221
222  template<std::size_t _Int, class _Tp1, class _Tp2>
223    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
224    get(std::pair<_Tp1, _Tp2>&& __in) noexcept
225    { return __pair_get<_Int>::__move_get(std::move(__in)); }
226
227  template<std::size_t _Int, class _Tp1, class _Tp2>
228    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
229    get(const std::pair<_Tp1, _Tp2>& __in) noexcept
230    { return __pair_get<_Int>::__const_get(__in); }
231
232  template<std::size_t _Int, class _Tp1, class _Tp2>
233    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
234    get(const std::pair<_Tp1, _Tp2>&& __in) noexcept
235    { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
236
237#if __cplusplus > 201103L
238
239#define __cpp_lib_tuples_by_type 201304
240
241  template <typename _Tp, typename _Up>
242    constexpr _Tp&
243    get(pair<_Tp, _Up>& __p) noexcept
244    { return __p.first; }
245
246  template <typename _Tp, typename _Up>
247    constexpr const _Tp&
248    get(const pair<_Tp, _Up>& __p) noexcept
249    { return __p.first; }
250
251  template <typename _Tp, typename _Up>
252    constexpr _Tp&&
253    get(pair<_Tp, _Up>&& __p) noexcept
254    { return std::move(__p.first); }
255
256  template <typename _Tp, typename _Up>
257    constexpr const _Tp&&
258    get(const pair<_Tp, _Up>&& __p) noexcept
259    { return std::move(__p.first); }
260
261  template <typename _Tp, typename _Up>
262    constexpr _Tp&
263    get(pair<_Up, _Tp>& __p) noexcept
264    { return __p.second; }
265
266  template <typename _Tp, typename _Up>
267    constexpr const _Tp&
268    get(const pair<_Up, _Tp>& __p) noexcept
269    { return __p.second; }
270
271  template <typename _Tp, typename _Up>
272    constexpr _Tp&&
273    get(pair<_Up, _Tp>&& __p) noexcept
274    { return std::move(__p.second); }
275
276  template <typename _Tp, typename _Up>
277    constexpr const _Tp&&
278    get(const pair<_Up, _Tp>&& __p) noexcept
279    { return std::move(__p.second); }
280
281#define __cpp_lib_exchange_function 201304
282
283  /// Assign @p __new_val to @p __obj and return its previous value.
284  template <typename _Tp, typename _Up = _Tp>
285    inline _Tp
286    exchange(_Tp& __obj, _Up&& __new_val)
287    { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
288#endif
289
290  // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
291  // extract the elements in a tuple.
292  template<size_t... _Indexes> struct _Index_tuple { };
293
294#ifdef __has_builtin
295# if __has_builtin(__make_integer_seq)
296#  define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1
297# endif
298#endif
299
300  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
301  template<size_t _Num>
302    struct _Build_index_tuple
303    {
304#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
305      template<typename, size_t... _Indices>
306        using _IdxTuple = _Index_tuple<_Indices...>;
307
308      using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
309#else
310      using __type = _Index_tuple<__integer_pack(_Num)...>;
311#endif
312    };
313
314#if __cplusplus > 201103L
315
316#define __cpp_lib_integer_sequence 201304
317
318  /// Class template integer_sequence
319  template<typename _Tp, _Tp... _Idx>
320    struct integer_sequence
321    {
322      typedef _Tp value_type;
323      static constexpr size_t size() noexcept { return sizeof...(_Idx); }
324    };
325
326  /// Alias template make_integer_sequence
327  template<typename _Tp, _Tp _Num>
328    using make_integer_sequence
329#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
330      = __make_integer_seq<integer_sequence, _Tp, _Num>;
331#else
332      = integer_sequence<_Tp, __integer_pack(_Num)...>;
333#endif
334
335#undef _GLIBCXX_USE_MAKE_INTEGER_SEQ
336
337  /// Alias template index_sequence
338  template<size_t... _Idx>
339    using index_sequence = integer_sequence<size_t, _Idx...>;
340
341  /// Alias template make_index_sequence
342  template<size_t _Num>
343    using make_index_sequence = make_integer_sequence<size_t, _Num>;
344
345  /// Alias template index_sequence_for
346  template<typename... _Types>
347    using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
348#endif
349
350#if __cplusplus > 201402L
351
352  struct in_place_t {
353    explicit in_place_t() = default;
354  };
355
356  inline constexpr in_place_t in_place{};
357
358  template<typename _Tp> struct in_place_type_t
359  {
360    explicit in_place_type_t() = default;
361  };
362
363  template<typename _Tp>
364    inline constexpr in_place_type_t<_Tp> in_place_type{};
365
366  template<size_t _Idx> struct in_place_index_t
367  {
368    explicit in_place_index_t() = default;
369  };
370
371  template<size_t _Idx>
372    inline constexpr in_place_index_t<_Idx> in_place_index{};
373
374  template<typename>
375    struct __is_in_place_type_impl : false_type
376    { };
377
378  template<typename _Tp>
379    struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
380    { };
381
382  template<typename _Tp>
383    struct __is_in_place_type
384      : public __is_in_place_type_impl<_Tp>
385    { };
386
387#define  __cpp_lib_as_const 201510
388  template<typename _Tp>
389    constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
390
391  template<typename _Tp>
392    void as_const(const _Tp&&) = delete;
393
394#endif // C++17
395
396_GLIBCXX_END_NAMESPACE_VERSION
397} // namespace
398
399#endif
400
401#endif /* _GLIBCXX_UTILITY */
402