1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2016 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 template<typename _Tp>
89 struct tuple_size<const _Tp>
90 : integral_constant<size_t, tuple_size<_Tp>::value> { };
91
92 template<typename _Tp>
93 struct tuple_size<volatile _Tp>
94 : integral_constant<size_t, tuple_size<_Tp>::value> { };
95
96 template<typename _Tp>
97 struct tuple_size<const volatile _Tp>
98 : integral_constant<size_t, tuple_size<_Tp>::value> { };
99
100 /// Gives the type of the ith element of a given tuple type.
101 template<std::size_t __i, typename _Tp>
102 struct tuple_element;
103
104 // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
105 template<std::size_t __i, typename _Tp>
106 using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
107
108 template<std::size_t __i, typename _Tp>
109 struct tuple_element<__i, const _Tp>
110 {
111 typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
112 };
113
114 template<std::size_t __i, typename _Tp>
115 struct tuple_element<__i, volatile _Tp>
116 {
117 typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
118 };
119
120 template<std::size_t __i, typename _Tp>
121 struct tuple_element<__i, const volatile _Tp>
122 {
123 typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
124 };
125
126#if __cplusplus > 201103L
127#define __cpp_lib_tuple_element_t 201402
128
129 template<std::size_t __i, typename _Tp>
130 using tuple_element_t = typename tuple_element<__i, _Tp>::type;
131#endif
132
133 template<typename>
134 struct __is_tuple_like_impl : false_type
135 { };
136
137 // Various functions which give std::pair a tuple-like interface.
138
139 /// Partial specialization for std::pair
140 template<typename _T1, typename _T2>
141 struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
142 { };
143
144 /// Partial specialization for std::pair
145 template<class _Tp1, class _Tp2>
146 struct tuple_size<std::pair<_Tp1, _Tp2>>
147 : public integral_constant<std::size_t, 2> { };
148
149 /// Partial specialization for std::pair
150 template<class _Tp1, class _Tp2>
151 struct tuple_element<0, std::pair<_Tp1, _Tp2>>
152 { typedef _Tp1 type; };
153
154 /// Partial specialization for std::pair
155 template<class _Tp1, class _Tp2>
156 struct tuple_element<1, std::pair<_Tp1, _Tp2>>
157 { typedef _Tp2 type; };
158
159 template<std::size_t _Int>
160 struct __pair_get;
161
162 template<>
163 struct __pair_get<0>
164 {
165 template<typename _Tp1, typename _Tp2>
166 static constexpr _Tp1&
167 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
168 { return __pair.first; }
169
170 template<typename _Tp1, typename _Tp2>
171 static constexpr _Tp1&&
172 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
173 { return std::forward<_Tp1>(__pair.first); }
174
175 template<typename _Tp1, typename _Tp2>
176 static constexpr const _Tp1&
177 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
178 { return __pair.first; }
179 };
180
181 template<>
182 struct __pair_get<1>
183 {
184 template<typename _Tp1, typename _Tp2>
185 static constexpr _Tp2&
186 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
187 { return __pair.second; }
188
189 template<typename _Tp1, typename _Tp2>
190 static constexpr _Tp2&&
191 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
192 { return std::forward<_Tp2>(__pair.second); }
193
194 template<typename _Tp1, typename _Tp2>
195 static constexpr const _Tp2&
196 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
197 { return __pair.second; }
198 };
199
200 template<std::size_t _Int, class _Tp1, class _Tp2>
201 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
202 get(std::pair<_Tp1, _Tp2>& __in) noexcept
203 { return __pair_get<_Int>::__get(__in); }
204
205 template<std::size_t _Int, class _Tp1, class _Tp2>
206 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
207 get(std::pair<_Tp1, _Tp2>&& __in) noexcept
208 { return __pair_get<_Int>::__move_get(std::move(__in)); }
209
210 template<std::size_t _Int, class _Tp1, class _Tp2>
211 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
212 get(const std::pair<_Tp1, _Tp2>& __in) noexcept
213 { return __pair_get<_Int>::__const_get(__in); }
214
215#if __cplusplus > 201103L
216
217#define __cpp_lib_tuples_by_type 201304
218
219 template <typename _Tp, typename _Up>
220 constexpr _Tp&
221 get(pair<_Tp, _Up>& __p) noexcept
222 { return __p.first; }
223
224 template <typename _Tp, typename _Up>
225 constexpr const _Tp&
226 get(const pair<_Tp, _Up>& __p) noexcept
227 { return __p.first; }
228
229 template <typename _Tp, typename _Up>
230 constexpr _Tp&&
231 get(pair<_Tp, _Up>&& __p) noexcept
232 { return std::move(__p.first); }
233
234 template <typename _Tp, typename _Up>
235 constexpr _Tp&
236 get(pair<_Up, _Tp>& __p) noexcept
237 { return __p.second; }
238
239 template <typename _Tp, typename _Up>
240 constexpr const _Tp&
241 get(const pair<_Up, _Tp>& __p) noexcept
242 { return __p.second; }
243
244 template <typename _Tp, typename _Up>
245 constexpr _Tp&&
246 get(pair<_Up, _Tp>&& __p) noexcept
247 { return std::move(__p.second); }
248
249#define __cpp_lib_exchange_function 201304
250
251 /// Assign @p __new_val to @p __obj and return its previous value.
252 template <typename _Tp, typename _Up = _Tp>
253 inline _Tp
254 exchange(_Tp& __obj, _Up&& __new_val)
255 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
256#endif
257
258 // Stores a tuple of indices. Used by tuple and pair, and by bind() to
259 // extract the elements in a tuple.
260 template<size_t... _Indexes> struct _Index_tuple { };
261
262 // Concatenates two _Index_tuples.
263 template<typename _Itup1, typename _Itup2> struct _Itup_cat;
264
265 template<size_t... _Ind1, size_t... _Ind2>
266 struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
267 {
268 using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
269 };
270
271 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
272 template<size_t _Num>
273 struct _Build_index_tuple
274 : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
275 typename _Build_index_tuple<_Num - _Num / 2>::__type>
276 { };
277
278 template<>
279 struct _Build_index_tuple<1>
280 {
281 typedef _Index_tuple<0> __type;
282 };
283
284 template<>
285 struct _Build_index_tuple<0>
286 {
287 typedef _Index_tuple<> __type;
288 };
289
290#if __cplusplus > 201103L
291
292#define __cpp_lib_integer_sequence 201304
293
294 /// Class template integer_sequence
295 template<typename _Tp, _Tp... _Idx>
296 struct integer_sequence
297 {
298 typedef _Tp value_type;
299 static constexpr size_t size() { return sizeof...(_Idx); }
300 };
301
302 template<typename _Tp, _Tp _Num,
303 typename _ISeq = typename _Build_index_tuple<_Num>::__type>
304 struct _Make_integer_sequence;
305
306 template<typename _Tp, _Tp _Num, size_t... _Idx>
307 struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
308 {
309 static_assert( _Num >= 0,
310 "Cannot make integer sequence of negative length" );
311
312 typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
313 };
314
315 /// Alias template make_integer_sequence
316 template<typename _Tp, _Tp _Num>
317 using make_integer_sequence
318 = typename _Make_integer_sequence<_Tp, _Num>::__type;
319
320 /// Alias template index_sequence
321 template<size_t... _Idx>
322 using index_sequence = integer_sequence<size_t, _Idx...>;
323
324 /// Alias template make_index_sequence
325 template<size_t _Num>
326 using make_index_sequence = make_integer_sequence<size_t, _Num>;
327
328 /// Alias template index_sequence_for
329 template<typename... _Types>
330 using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
331#endif
332
333_GLIBCXX_END_NAMESPACE_VERSION
334} // namespace
335
336#endif
337
338#endif /* _GLIBCXX_UTILITY */
339