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