1 | // Pair implementation -*- C++ -*- |
2 | |
3 | // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, |
4 | // 2010, 2011, 2012 |
5 | // Free Software Foundation, Inc. |
6 | // |
7 | // This file is part of the GNU ISO C++ Library. This library is free |
8 | // software; you can redistribute it and/or modify it under the |
9 | // terms of the GNU General Public License as published by the |
10 | // Free Software Foundation; either version 3, or (at your option) |
11 | // any later version. |
12 | |
13 | // This library is distributed in the hope that it will be useful, |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | // GNU General Public License for more details. |
17 | |
18 | // Under Section 7 of GPL version 3, you are granted additional |
19 | // permissions described in the GCC Runtime Library Exception, version |
20 | // 3.1, as published by the Free Software Foundation. |
21 | |
22 | // You should have received a copy of the GNU General Public License and |
23 | // a copy of the GCC Runtime Library Exception along with this program; |
24 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
25 | // <http://www.gnu.org/licenses/>. |
26 | |
27 | /* |
28 | * |
29 | * Copyright (c) 1994 |
30 | * Hewlett-Packard Company |
31 | * |
32 | * Permission to use, copy, modify, distribute and sell this software |
33 | * and its documentation for any purpose is hereby granted without fee, |
34 | * provided that the above copyright notice appear in all copies and |
35 | * that both that copyright notice and this permission notice appear |
36 | * in supporting documentation. Hewlett-Packard Company makes no |
37 | * representations about the suitability of this software for any |
38 | * purpose. It is provided "as is" without express or implied warranty. |
39 | * |
40 | * |
41 | * Copyright (c) 1996,1997 |
42 | * Silicon Graphics Computer Systems, Inc. |
43 | * |
44 | * Permission to use, copy, modify, distribute and sell this software |
45 | * and its documentation for any purpose is hereby granted without fee, |
46 | * provided that the above copyright notice appear in all copies and |
47 | * that both that copyright notice and this permission notice appear |
48 | * in supporting documentation. Silicon Graphics makes no |
49 | * representations about the suitability of this software for any |
50 | * purpose. It is provided "as is" without express or implied warranty. |
51 | */ |
52 | |
53 | /** @file bits/stl_pair.h |
54 | * This is an internal header file, included by other library headers. |
55 | * Do not attempt to use it directly. @headername{utility} |
56 | */ |
57 | |
58 | #ifndef _STL_PAIR_H |
59 | #define _STL_PAIR_H 1 |
60 | |
61 | #include <bits/move.h> // for std::move / std::forward, and std::swap |
62 | |
63 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
64 | #include <type_traits> // for std::__decay_and_strip too |
65 | #endif |
66 | |
67 | namespace std _GLIBCXX_VISIBILITY(default) |
68 | { |
69 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
70 | |
71 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
72 | /// piecewise_construct_t |
73 | struct piecewise_construct_t { }; |
74 | |
75 | /// piecewise_construct |
76 | constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t(); |
77 | |
78 | // Forward declarations. |
79 | template<typename...> |
80 | class tuple; |
81 | |
82 | template<std::size_t...> |
83 | struct _Index_tuple; |
84 | #endif |
85 | |
86 | /// Struct holding two objects of arbitrary type. |
87 | template<class _T1, class _T2> |
88 | struct pair |
89 | { |
90 | typedef _T1 first_type; /// @c first_type is the first bound type |
91 | typedef _T2 second_type; /// @c second_type is the second bound type |
92 | |
93 | _T1 first; /// @c first is a copy of the first object |
94 | _T2 second; /// @c second is a copy of the second object |
95 | |
96 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
97 | // 265. std::pair::pair() effects overly restrictive |
98 | /** The default constructor creates @c first and @c second using their |
99 | * respective default constructors. */ |
100 | _GLIBCXX_CONSTEXPR pair() |
101 | : first(), second() { } |
102 | |
103 | /** Two objects may be passed to a @c pair constructor to be copied. */ |
104 | _GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b) |
105 | : first(__a), second(__b) { } |
106 | |
107 | /** There is also a templated copy ctor for the @c pair class itself. */ |
108 | #ifndef __GXX_EXPERIMENTAL_CXX0X__ |
109 | template<class _U1, class _U2> |
110 | pair(const pair<_U1, _U2>& __p) |
111 | : first(__p.first), second(__p.second) { } |
112 | #else |
113 | template<class _U1, class _U2, class = typename |
114 | enable_if<__and_<is_convertible<const _U1&, _T1>, |
115 | is_convertible<const _U2&, _T2>>::value>::type> |
116 | constexpr pair(const pair<_U1, _U2>& __p) |
117 | : first(__p.first), second(__p.second) { } |
118 | |
119 | constexpr pair(const pair&) = default; |
120 | constexpr pair(pair&&) = default; |
121 | |
122 | // DR 811. |
123 | template<class _U1, class = typename |
124 | enable_if<is_convertible<_U1, _T1>::value>::type> |
125 | constexpr pair(_U1&& __x, const _T2& __y) |
126 | : first(std::forward<_U1>(__x)), second(__y) { } |
127 | |
128 | template<class _U2, class = typename |
129 | enable_if<is_convertible<_U2, _T2>::value>::type> |
130 | constexpr pair(const _T1& __x, _U2&& __y) |
131 | : first(__x), second(std::forward<_U2>(__y)) { } |
132 | |
133 | template<class _U1, class _U2, class = typename |
134 | enable_if<__and_<is_convertible<_U1, _T1>, |
135 | is_convertible<_U2, _T2>>::value>::type> |
136 | constexpr pair(_U1&& __x, _U2&& __y) |
137 | : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } |
138 | |
139 | template<class _U1, class _U2, class = typename |
140 | enable_if<__and_<is_convertible<_U1, _T1>, |
141 | is_convertible<_U2, _T2>>::value>::type> |
142 | constexpr pair(pair<_U1, _U2>&& __p) |
143 | : first(std::forward<_U1>(__p.first)), |
144 | second(std::forward<_U2>(__p.second)) { } |
145 | |
146 | template<typename... _Args1, typename... _Args2> |
147 | pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); |
148 | |
149 | pair& |
150 | operator=(const pair& __p) |
151 | { |
152 | first = __p.first; |
153 | second = __p.second; |
154 | return *this; |
155 | } |
156 | |
157 | pair& |
158 | operator=(pair&& __p) |
159 | noexcept(__and_<is_nothrow_move_assignable<_T1>, |
160 | is_nothrow_move_assignable<_T2>>::value) |
161 | { |
162 | first = std::forward<first_type>(__p.first); |
163 | second = std::forward<second_type>(__p.second); |
164 | return *this; |
165 | } |
166 | |
167 | template<class _U1, class _U2> |
168 | pair& |
169 | operator=(const pair<_U1, _U2>& __p) |
170 | { |
171 | first = __p.first; |
172 | second = __p.second; |
173 | return *this; |
174 | } |
175 | |
176 | template<class _U1, class _U2> |
177 | pair& |
178 | operator=(pair<_U1, _U2>&& __p) |
179 | { |
180 | first = std::forward<_U1>(__p.first); |
181 | second = std::forward<_U2>(__p.second); |
182 | return *this; |
183 | } |
184 | |
185 | void |
186 | swap(pair& __p) |
187 | noexcept(noexcept(swap(first, __p.first)) |
188 | && noexcept(swap(second, __p.second))) |
189 | { |
190 | using std::swap; |
191 | swap(first, __p.first); |
192 | swap(second, __p.second); |
193 | } |
194 | |
195 | private: |
196 | template<typename... _Args1, std::size_t... _Indexes1, |
197 | typename... _Args2, std::size_t... _Indexes2> |
198 | pair(tuple<_Args1...>&, tuple<_Args2...>&, |
199 | _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); |
200 | #endif |
201 | }; |
202 | |
203 | /// Two pairs of the same type are equal iff their members are equal. |
204 | template<class _T1, class _T2> |
205 | inline _GLIBCXX_CONSTEXPR bool |
206 | operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
207 | { return __x.first == __y.first && __x.second == __y.second; } |
208 | |
209 | /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> |
210 | template<class _T1, class _T2> |
211 | inline _GLIBCXX_CONSTEXPR bool |
212 | operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
213 | { return __x.first < __y.first |
214 | || (!(__y.first < __x.first) && __x.second < __y.second); } |
215 | |
216 | /// Uses @c operator== to find the result. |
217 | template<class _T1, class _T2> |
218 | inline _GLIBCXX_CONSTEXPR bool |
219 | operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
220 | { return !(__x == __y); } |
221 | |
222 | /// Uses @c operator< to find the result. |
223 | template<class _T1, class _T2> |
224 | inline _GLIBCXX_CONSTEXPR bool |
225 | operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
226 | { return __y < __x; } |
227 | |
228 | /// Uses @c operator< to find the result. |
229 | template<class _T1, class _T2> |
230 | inline _GLIBCXX_CONSTEXPR bool |
231 | operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
232 | { return !(__y < __x); } |
233 | |
234 | /// Uses @c operator< to find the result. |
235 | template<class _T1, class _T2> |
236 | inline _GLIBCXX_CONSTEXPR bool |
237 | operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
238 | { return !(__x < __y); } |
239 | |
240 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
241 | /// See std::pair::swap(). |
242 | // Note: no std::swap overloads in C++03 mode, this has performance |
243 | // implications, see, eg, libstdc++/38466. |
244 | template<class _T1, class _T2> |
245 | inline void |
246 | swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) |
247 | noexcept(noexcept(__x.swap(__y))) |
248 | { __x.swap(__y); } |
249 | #endif |
250 | |
251 | /** |
252 | * @brief A convenience wrapper for creating a pair from two objects. |
253 | * @param __x The first object. |
254 | * @param __y The second object. |
255 | * @return A newly-constructed pair<> object of the appropriate type. |
256 | * |
257 | * The standard requires that the objects be passed by reference-to-const, |
258 | * but LWG issue #181 says they should be passed by const value. We follow |
259 | * the LWG by default. |
260 | */ |
261 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
262 | // 181. make_pair() unintended behavior |
263 | #ifdef __GXX_EXPERIMENTAL_CXX0X__ |
264 | // NB: DR 706. |
265 | template<class _T1, class _T2> |
266 | constexpr pair<typename __decay_and_strip<_T1>::__type, |
267 | typename __decay_and_strip<_T2>::__type> |
268 | make_pair(_T1&& __x, _T2&& __y) |
269 | { |
270 | typedef typename __decay_and_strip<_T1>::__type __ds_type1; |
271 | typedef typename __decay_and_strip<_T2>::__type __ds_type2; |
272 | typedef pair<__ds_type1, __ds_type2> __pair_type; |
273 | return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); |
274 | } |
275 | #else |
276 | template<class _T1, class _T2> |
277 | inline pair<_T1, _T2> |
278 | make_pair(_T1 __x, _T2 __y) |
279 | { return pair<_T1, _T2>(__x, __y); } |
280 | #endif |
281 | |
282 | _GLIBCXX_END_NAMESPACE_VERSION |
283 | } // namespace |
284 | |
285 | #endif /* _STL_PAIR_H */ |
286 | |