1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2017 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/*
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  // 2770. tuple_size<const T> specialization is not SFINAE compatible
88
89#if __cplusplus <= 201402L
90  template<typename _Tp, typename = void>
91    struct __tuple_size_cv_impl { };
92
93  template<typename _Tp>
94    struct __tuple_size_cv_impl<_Tp, __void_t<decltype(tuple_size<_Tp>::value)>>
95    : integral_constant<size_t, tuple_size<_Tp>::value> { };
96
97  // _GLIBCXX_RESOLVE_LIB_DEFECTS
98  // 2313. tuple_size should always derive from integral_constant<size_t, N>
99  template<typename _Tp>
100    struct tuple_size<const _Tp> : __tuple_size_cv_impl<_Tp> { };
101
102  template<typename _Tp>
103    struct tuple_size<volatile _Tp> : __tuple_size_cv_impl<_Tp> { };
104
105  template<typename _Tp>
106    struct tuple_size<const volatile _Tp> : __tuple_size_cv_impl<_Tp> { };
107#else
108  template<typename _Tp,
109	   typename _Up = typename remove_cv<_Tp>::type,
110	   typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
111	   size_t = tuple_size<_Tp>::value>
112    using __enable_if_has_tuple_size = _Tp;
113
114  template<typename _Tp>
115    struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
116    : public tuple_size<_Tp> { };
117
118  template<typename _Tp>
119    struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
120    : public tuple_size<_Tp> { };
121
122  template<typename _Tp>
123    struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
124    : public tuple_size<_Tp> { };
125#endif
126
127  /// Gives the type of the ith element of a given tuple type.
128  template<std::size_t __i, typename _Tp>
129    struct tuple_element;
130
131  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
132  template<std::size_t __i, typename _Tp>
133    using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
134
135  template<std::size_t __i, typename _Tp>
136    struct tuple_element<__i, const _Tp>
137    {
138      typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
139    };
140
141  template<std::size_t __i, typename _Tp>
142    struct tuple_element<__i, volatile _Tp>
143    {
144      typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
145    };
146
147  template<std::size_t __i, typename _Tp>
148    struct tuple_element<__i, const volatile _Tp>
149    {
150      typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
151    };
152
153#if __cplusplus > 201103L
154#define __cpp_lib_tuple_element_t 201402
155
156  template<std::size_t __i, typename _Tp>
157    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
158#endif
159
160  // Various functions which give std::pair a tuple-like interface.
161
162  /// Partial specialization for std::pair
163  template<typename _T1, typename _T2>
164    struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
165    { };
166
167  /// Partial specialization for std::pair
168  template<class _Tp1, class _Tp2>
169    struct tuple_size<std::pair<_Tp1, _Tp2>>
170    : public integral_constant<std::size_t, 2> { };
171
172  /// Partial specialization for std::pair
173  template<class _Tp1, class _Tp2>
174    struct tuple_element<0, std::pair<_Tp1, _Tp2>>
175    { typedef _Tp1 type; };
176
177  /// Partial specialization for std::pair
178  template<class _Tp1, class _Tp2>
179    struct tuple_element<1, std::pair<_Tp1, _Tp2>>
180    { typedef _Tp2 type; };
181
182  template<std::size_t _Int>
183    struct __pair_get;
184
185  template<>
186    struct __pair_get<0>
187    {
188      template<typename _Tp1, typename _Tp2>
189        static constexpr _Tp1&
190        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
191        { return __pair.first; }
192
193      template<typename _Tp1, typename _Tp2>
194        static constexpr _Tp1&&
195        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
196        { return std::forward<_Tp1>(__pair.first); }
197
198      template<typename _Tp1, typename _Tp2>
199        static constexpr const _Tp1&
200        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
201        { return __pair.first; }
202    };
203
204  template<>
205    struct __pair_get<1>
206    {
207      template<typename _Tp1, typename _Tp2>
208        static constexpr _Tp2&
209        __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
210        { return __pair.second; }
211
212      template<typename _Tp1, typename _Tp2>
213        static constexpr _Tp2&&
214        __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
215        { return std::forward<_Tp2>(__pair.second); }
216
217      template<typename _Tp1, typename _Tp2>
218        static constexpr const _Tp2&
219        __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
220        { return __pair.second; }
221    };
222
223  template<std::size_t _Int, class _Tp1, class _Tp2>
224    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
225    get(std::pair<_Tp1, _Tp2>& __in) noexcept
226    { return __pair_get<_Int>::__get(__in); }
227
228  template<std::size_t _Int, class _Tp1, class _Tp2>
229    constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
230    get(std::pair<_Tp1, _Tp2>&& __in) noexcept
231    { return __pair_get<_Int>::__move_get(std::move(__in)); }
232
233  template<std::size_t _Int, class _Tp1, class _Tp2>
234    constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
235    get(const std::pair<_Tp1, _Tp2>& __in) noexcept
236    { return __pair_get<_Int>::__const_get(__in); }
237
238#if __cplusplus > 201103L
239
240#define __cpp_lib_tuples_by_type 201304
241
242  template <typename _Tp, typename _Up>
243    constexpr _Tp&
244    get(pair<_Tp, _Up>& __p) noexcept
245    { return __p.first; }
246
247  template <typename _Tp, typename _Up>
248    constexpr const _Tp&
249    get(const pair<_Tp, _Up>& __p) noexcept
250    { return __p.first; }
251
252  template <typename _Tp, typename _Up>
253    constexpr _Tp&&
254    get(pair<_Tp, _Up>&& __p) noexcept
255    { return std::move(__p.first); }
256
257  template <typename _Tp, typename _Up>
258    constexpr _Tp&
259    get(pair<_Up, _Tp>& __p) noexcept
260    { return __p.second; }
261
262  template <typename _Tp, typename _Up>
263    constexpr const _Tp&
264    get(const pair<_Up, _Tp>& __p) noexcept
265    { return __p.second; }
266
267  template <typename _Tp, typename _Up>
268    constexpr _Tp&&
269    get(pair<_Up, _Tp>&& __p) noexcept
270    { return std::move(__p.second); }
271
272#define __cpp_lib_exchange_function 201304
273
274  /// Assign @p __new_val to @p __obj and return its previous value.
275  template <typename _Tp, typename _Up = _Tp>
276    inline _Tp
277    exchange(_Tp& __obj, _Up&& __new_val)
278    { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
279#endif
280
281  // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
282  // extract the elements in a tuple.
283  template<size_t... _Indexes> struct _Index_tuple { };
284
285  // Concatenates two _Index_tuples.
286  template<typename _Itup1, typename _Itup2> struct _Itup_cat;
287
288  template<size_t... _Ind1, size_t... _Ind2>
289    struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
290    {
291      using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
292    };
293
294  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
295  template<size_t _Num>
296    struct _Build_index_tuple
297    : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
298		typename _Build_index_tuple<_Num - _Num / 2>::__type>
299    { };
300
301  template<>
302    struct _Build_index_tuple<1>
303    {
304      typedef _Index_tuple<0> __type;
305    };
306
307  template<>
308    struct _Build_index_tuple<0>
309    {
310      typedef _Index_tuple<> __type;
311    };
312
313#if __cplusplus > 201103L
314
315#define __cpp_lib_integer_sequence 201304
316
317  /// Class template integer_sequence
318  template<typename _Tp, _Tp... _Idx>
319    struct integer_sequence
320    {
321      typedef _Tp value_type;
322      static constexpr size_t size() noexcept { return sizeof...(_Idx); }
323    };
324
325  template<typename _Tp, _Tp _Num,
326	   typename _ISeq = typename _Build_index_tuple<_Num>::__type>
327    struct _Make_integer_sequence;
328
329  template<typename _Tp, _Tp _Num,  size_t... _Idx>
330    struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
331    {
332      static_assert( _Num >= 0,
333		     "Cannot make integer sequence of negative length" );
334
335      typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
336    };
337
338  /// Alias template make_integer_sequence
339  template<typename _Tp, _Tp _Num>
340    using make_integer_sequence
341      = typename _Make_integer_sequence<_Tp, _Num>::__type;
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#endif // C++17
401
402_GLIBCXX_END_NAMESPACE_VERSION
403} // namespace
404
405#endif
406
407#endif /* _GLIBCXX_UTILITY */
408