1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2018 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 > 201103L
135#define __cpp_lib_tuple_element_t 201402
136
137  template<std::size_t __i, typename _Tp>
138    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
139#endif
140
141  // Various functions which give std::pair a tuple-like interface.
142
143  /// Partial specialization for std::pair
144  template<typename _T1, typename _T2>
145    struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
146    { };
147
148  /// Partial specialization for std::pair
149  template<class _Tp1, class _Tp2>
150    struct tuple_size<std::pair<_Tp1, _Tp2>>
151    : public integral_constant<std::size_t, 2> { };
152
153  /// Partial specialization for std::pair
154  template<class _Tp1, class _Tp2>
155    struct tuple_element<0, std::pair<_Tp1, _Tp2>>
156    { typedef _Tp1 type; };
157
158  /// Partial specialization for std::pair
159  template<class _Tp1, class _Tp2>
160    struct tuple_element<1, std::pair<_Tp1, _Tp2>>
161    { typedef _Tp2 type; };
162
163  template<std::size_t _Int>
164    struct __pair_get;
165
166  template<>
167    struct __pair_get<0>
168    {
169      template<typename _Tp1, typename _Tp2>
170        static constexpr _Tp1&
171        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
172        { return __pair.first; }
173
174      template<typename _Tp1, typename _Tp2>
175        static constexpr _Tp1&&
176        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
177        { return std::forward<_Tp1>(__pair.first); }
178
179      template<typename _Tp1, typename _Tp2>
180        static constexpr const _Tp1&
181        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
182        { return __pair.first; }
183
184      template<typename _Tp1, typename _Tp2>
185        static constexpr const _Tp1&&
186        __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
187        { return std::forward<const _Tp1>(__pair.first); }
188    };
189
190  template<>
191    struct __pair_get<1>
192    {
193      template<typename _Tp1, typename _Tp2>
194        static constexpr _Tp2&
195        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
196        { return __pair.second; }
197
198      template<typename _Tp1, typename _Tp2>
199        static constexpr _Tp2&&
200        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
201        { return std::forward<_Tp2>(__pair.second); }
202
203      template<typename _Tp1, typename _Tp2>
204        static constexpr const _Tp2&
205        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
206        { return __pair.second; }
207
208      template<typename _Tp1, typename _Tp2>
209        static constexpr const _Tp2&&
210        __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
211        { return std::forward<const _Tp2>(__pair.second); }
212    };
213
214  template<std::size_t _Int, class _Tp1, class _Tp2>
215    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
216    get(std::pair<_Tp1, _Tp2>& __in) noexcept
217    { return __pair_get<_Int>::__get(__in); }
218
219  template<std::size_t _Int, class _Tp1, class _Tp2>
220    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
221    get(std::pair<_Tp1, _Tp2>&& __in) noexcept
222    { return __pair_get<_Int>::__move_get(std::move(__in)); }
223
224  template<std::size_t _Int, class _Tp1, class _Tp2>
225    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
226    get(const std::pair<_Tp1, _Tp2>& __in) noexcept
227    { return __pair_get<_Int>::__const_get(__in); }
228
229  template<std::size_t _Int, class _Tp1, class _Tp2>
230    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
231    get(const std::pair<_Tp1, _Tp2>&& __in) noexcept
232    { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
233
234#if __cplusplus > 201103L
235
236#define __cpp_lib_tuples_by_type 201304
237
238  template <typename _Tp, typename _Up>
239    constexpr _Tp&
240    get(pair<_Tp, _Up>& __p) noexcept
241    { return __p.first; }
242
243  template <typename _Tp, typename _Up>
244    constexpr const _Tp&
245    get(const pair<_Tp, _Up>& __p) noexcept
246    { return __p.first; }
247
248  template <typename _Tp, typename _Up>
249    constexpr _Tp&&
250    get(pair<_Tp, _Up>&& __p) noexcept
251    { return std::move(__p.first); }
252
253  template <typename _Tp, typename _Up>
254    constexpr const _Tp&&
255    get(const pair<_Tp, _Up>&& __p) noexcept
256    { return std::move(__p.first); }
257
258  template <typename _Tp, typename _Up>
259    constexpr _Tp&
260    get(pair<_Up, _Tp>& __p) noexcept
261    { return __p.second; }
262
263  template <typename _Tp, typename _Up>
264    constexpr const _Tp&
265    get(const pair<_Up, _Tp>& __p) noexcept
266    { return __p.second; }
267
268  template <typename _Tp, typename _Up>
269    constexpr _Tp&&
270    get(pair<_Up, _Tp>&& __p) noexcept
271    { return std::move(__p.second); }
272
273  template <typename _Tp, typename _Up>
274    constexpr const _Tp&&
275    get(const pair<_Up, _Tp>&& __p) noexcept
276    { return std::move(__p.second); }
277
278#define __cpp_lib_exchange_function 201304
279
280  /// Assign @p __new_val to @p __obj and return its previous value.
281  template <typename _Tp, typename _Up = _Tp>
282    inline _Tp
283    exchange(_Tp& __obj, _Up&& __new_val)
284    { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
285#endif
286
287  // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
288  // extract the elements in a tuple.
289  template<size_t... _Indexes> struct _Index_tuple { };
290
291#ifdef __has_builtin
292# if __has_builtin(__make_integer_seq)
293#  define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1
294# endif
295#endif
296
297  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
298  template<size_t _Num>
299    struct _Build_index_tuple
300    {
301#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
302      template<typename, size_t... _Indices>
303        using _IdxTuple = _Index_tuple<_Indices...>;
304
305      using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
306#else
307      using __type = _Index_tuple<__integer_pack(_Num)...>;
308#endif
309    };
310
311#if __cplusplus > 201103L
312
313#define __cpp_lib_integer_sequence 201304
314
315  /// Class template integer_sequence
316  template<typename _Tp, _Tp... _Idx>
317    struct integer_sequence
318    {
319      typedef _Tp value_type;
320      static constexpr size_t size() noexcept { return sizeof...(_Idx); }
321    };
322
323  /// Alias template make_integer_sequence
324  template<typename _Tp, _Tp _Num>
325    using make_integer_sequence
326#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
327      = __make_integer_seq<integer_sequence, _Tp, _Num>;
328#else
329      = integer_sequence<_Tp, __integer_pack(_Num)...>;
330#endif
331
332#undef _GLIBCXX_USE_MAKE_INTEGER_SEQ
333
334  /// Alias template index_sequence
335  template<size_t... _Idx>
336    using index_sequence = integer_sequence<size_t, _Idx...>;
337
338  /// Alias template make_index_sequence
339  template<size_t _Num>
340    using make_index_sequence = make_integer_sequence<size_t, _Num>;
341
342  /// Alias template index_sequence_for
343  template<typename... _Types>
344    using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
345#endif
346
347#if __cplusplus > 201402L
348
349  struct in_place_t {
350    explicit in_place_t() = default;
351  };
352
353  inline constexpr in_place_t in_place{};
354
355  template<typename _Tp> struct in_place_type_t
356  {
357    explicit in_place_type_t() = default;
358  };
359
360  template<typename _Tp>
361    inline constexpr in_place_type_t<_Tp> in_place_type{};
362
363  template<size_t _Idx> struct in_place_index_t
364  {
365    explicit in_place_index_t() = default;
366  };
367
368  template<size_t _Idx>
369    inline constexpr in_place_index_t<_Idx> in_place_index{};
370
371  template<typename>
372    struct __is_in_place_type_impl : false_type
373    { };
374
375  template<typename _Tp>
376    struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
377    { };
378
379  template<typename _Tp>
380    struct __is_in_place_type
381      : public __is_in_place_type_impl<_Tp>
382    { };
383
384#define  __cpp_lib_as_const 201510
385  template<typename _Tp>
386    constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
387
388  template<typename _Tp>
389    void as_const(const _Tp&&) = delete;
390
391#endif // C++17
392
393_GLIBCXX_END_NAMESPACE_VERSION
394} // namespace
395
396#endif
397
398#endif /* _GLIBCXX_UTILITY */
399