1 | // Pair implementation -*- C++ -*- |
2 | |
3 | // Copyright (C) 2001-2014 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 bits/stl_pair.h |
52 | * This is an internal header file, included by other library headers. |
53 | * Do not attempt to use it directly. @headername{utility} |
54 | */ |
55 | |
56 | #ifndef _STL_PAIR_H |
57 | #define _STL_PAIR_H 1 |
58 | |
59 | #include <bits/move.h> // for std::move / std::forward, and std::swap |
60 | |
61 | #if __cplusplus >= 201103L |
62 | #include <type_traits> // for std::__decay_and_strip too |
63 | #endif |
64 | |
65 | namespace std _GLIBCXX_VISIBILITY(default) |
66 | { |
67 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
68 | |
69 | /** |
70 | * @addtogroup utilities |
71 | * @{ |
72 | */ |
73 | |
74 | #if __cplusplus >= 201103L |
75 | /// piecewise_construct_t |
76 | struct piecewise_construct_t { }; |
77 | |
78 | /// piecewise_construct |
79 | constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t(); |
80 | |
81 | // Forward declarations. |
82 | template<typename...> |
83 | class tuple; |
84 | |
85 | template<std::size_t...> |
86 | struct _Index_tuple; |
87 | #endif |
88 | |
89 | /** |
90 | * @brief Struct holding two objects of arbitrary type. |
91 | * |
92 | * @tparam _T1 Type of first object. |
93 | * @tparam _T2 Type of second object. |
94 | */ |
95 | template<class _T1, class _T2> |
96 | struct pair |
97 | { |
98 | typedef _T1 first_type; /// @c first_type is the first bound type |
99 | typedef _T2 second_type; /// @c second_type is the second bound type |
100 | |
101 | _T1 first; /// @c first is a copy of the first object |
102 | _T2 second; /// @c second is a copy of the second object |
103 | |
104 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
105 | // 265. std::pair::pair() effects overly restrictive |
106 | /** The default constructor creates @c first and @c second using their |
107 | * respective default constructors. */ |
108 | _GLIBCXX_CONSTEXPR pair() |
109 | : first(), second() { } |
110 | |
111 | /** Two objects may be passed to a @c pair constructor to be copied. */ |
112 | _GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b) |
113 | : first(__a), second(__b) { } |
114 | |
115 | /** There is also a templated copy ctor for the @c pair class itself. */ |
116 | #if __cplusplus < 201103L |
117 | template<class _U1, class _U2> |
118 | pair(const pair<_U1, _U2>& __p) |
119 | : first(__p.first), second(__p.second) { } |
120 | #else |
121 | template<class _U1, class _U2, class = typename |
122 | enable_if<__and_<is_convertible<const _U1&, _T1>, |
123 | is_convertible<const _U2&, _T2>>::value>::type> |
124 | constexpr pair(const pair<_U1, _U2>& __p) |
125 | : first(__p.first), second(__p.second) { } |
126 | |
127 | constexpr pair(const pair&) = default; |
128 | constexpr pair(pair&&) = default; |
129 | |
130 | // DR 811. |
131 | template<class _U1, class = typename |
132 | enable_if<is_convertible<_U1, _T1>::value>::type> |
133 | constexpr pair(_U1&& __x, const _T2& __y) |
134 | : first(std::forward<_U1>(__x)), second(__y) { } |
135 | |
136 | template<class _U2, class = typename |
137 | enable_if<is_convertible<_U2, _T2>::value>::type> |
138 | constexpr pair(const _T1& __x, _U2&& __y) |
139 | : first(__x), second(std::forward<_U2>(__y)) { } |
140 | |
141 | template<class _U1, class _U2, class = typename |
142 | enable_if<__and_<is_convertible<_U1, _T1>, |
143 | is_convertible<_U2, _T2>>::value>::type> |
144 | constexpr pair(_U1&& __x, _U2&& __y) |
145 | : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } |
146 | |
147 | template<class _U1, class _U2, class = typename |
148 | enable_if<__and_<is_convertible<_U1, _T1>, |
149 | is_convertible<_U2, _T2>>::value>::type> |
150 | constexpr pair(pair<_U1, _U2>&& __p) |
151 | : first(std::forward<_U1>(__p.first)), |
152 | second(std::forward<_U2>(__p.second)) { } |
153 | |
154 | template<typename... _Args1, typename... _Args2> |
155 | pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); |
156 | |
157 | pair& |
158 | operator=(const pair& __p) |
159 | { |
160 | first = __p.first; |
161 | second = __p.second; |
162 | return *this; |
163 | } |
164 | |
165 | pair& |
166 | operator=(pair&& __p) |
167 | noexcept(__and_<is_nothrow_move_assignable<_T1>, |
168 | is_nothrow_move_assignable<_T2>>::value) |
169 | { |
170 | first = std::forward<first_type>(__p.first); |
171 | second = std::forward<second_type>(__p.second); |
172 | return *this; |
173 | } |
174 | |
175 | template<class _U1, class _U2> |
176 | pair& |
177 | operator=(const pair<_U1, _U2>& __p) |
178 | { |
179 | first = __p.first; |
180 | second = __p.second; |
181 | return *this; |
182 | } |
183 | |
184 | template<class _U1, class _U2> |
185 | pair& |
186 | operator=(pair<_U1, _U2>&& __p) |
187 | { |
188 | first = std::forward<_U1>(__p.first); |
189 | second = std::forward<_U2>(__p.second); |
190 | return *this; |
191 | } |
192 | |
193 | void |
194 | swap(pair& __p) |
195 | noexcept(noexcept(swap(first, __p.first)) |
196 | && noexcept(swap(second, __p.second))) |
197 | { |
198 | using std::swap; |
199 | swap(first, __p.first); |
200 | swap(second, __p.second); |
201 | } |
202 | |
203 | private: |
204 | template<typename... _Args1, std::size_t... _Indexes1, |
205 | typename... _Args2, std::size_t... _Indexes2> |
206 | pair(tuple<_Args1...>&, tuple<_Args2...>&, |
207 | _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); |
208 | #endif |
209 | }; |
210 | |
211 | /// Two pairs of the same type are equal iff their members are equal. |
212 | template<class _T1, class _T2> |
213 | inline _GLIBCXX_CONSTEXPR bool |
214 | operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
215 | { return __x.first == __y.first && __x.second == __y.second; } |
216 | |
217 | /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> |
218 | template<class _T1, class _T2> |
219 | inline _GLIBCXX_CONSTEXPR bool |
220 | operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
221 | { return __x.first < __y.first |
222 | || (!(__y.first < __x.first) && __x.second < __y.second); } |
223 | |
224 | /// Uses @c operator== to find the result. |
225 | template<class _T1, class _T2> |
226 | inline _GLIBCXX_CONSTEXPR bool |
227 | operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
228 | { return !(__x == __y); } |
229 | |
230 | /// Uses @c operator< to find the result. |
231 | template<class _T1, class _T2> |
232 | inline _GLIBCXX_CONSTEXPR bool |
233 | operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
234 | { return __y < __x; } |
235 | |
236 | /// Uses @c operator< to find the result. |
237 | template<class _T1, class _T2> |
238 | inline _GLIBCXX_CONSTEXPR bool |
239 | operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
240 | { return !(__y < __x); } |
241 | |
242 | /// Uses @c operator< to find the result. |
243 | template<class _T1, class _T2> |
244 | inline _GLIBCXX_CONSTEXPR bool |
245 | operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
246 | { return !(__x < __y); } |
247 | |
248 | #if __cplusplus >= 201103L |
249 | /// See std::pair::swap(). |
250 | // Note: no std::swap overloads in C++03 mode, this has performance |
251 | // implications, see, eg, libstdc++/38466. |
252 | template<class _T1, class _T2> |
253 | inline void |
254 | swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) |
255 | noexcept(noexcept(__x.swap(__y))) |
256 | { __x.swap(__y); } |
257 | #endif |
258 | |
259 | /** |
260 | * @brief A convenience wrapper for creating a pair from two objects. |
261 | * @param __x The first object. |
262 | * @param __y The second object. |
263 | * @return A newly-constructed pair<> object of the appropriate type. |
264 | * |
265 | * The standard requires that the objects be passed by reference-to-const, |
266 | * but LWG issue #181 says they should be passed by const value. We follow |
267 | * the LWG by default. |
268 | */ |
269 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
270 | // 181. make_pair() unintended behavior |
271 | #if __cplusplus >= 201103L |
272 | // NB: DR 706. |
273 | template<class _T1, class _T2> |
274 | constexpr pair<typename __decay_and_strip<_T1>::__type, |
275 | typename __decay_and_strip<_T2>::__type> |
276 | make_pair(_T1&& __x, _T2&& __y) |
277 | { |
278 | typedef typename __decay_and_strip<_T1>::__type __ds_type1; |
279 | typedef typename __decay_and_strip<_T2>::__type __ds_type2; |
280 | typedef pair<__ds_type1, __ds_type2> __pair_type; |
281 | return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); |
282 | } |
283 | #else |
284 | template<class _T1, class _T2> |
285 | inline pair<_T1, _T2> |
286 | make_pair(_T1 __x, _T2 __y) |
287 | { return pair<_T1, _T2>(__x, __y); } |
288 | #endif |
289 | |
290 | /// @} |
291 | |
292 | _GLIBCXX_END_NAMESPACE_VERSION |
293 | } // namespace std |
294 | |
295 | #endif /* _STL_PAIR_H */ |
296 | |