1 // Pair implementation -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 // Free Software Foundation, Inc.
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
29 * Hewlett-Packard Company
31 * Permission to use, copy, modify, distribute and sell this software
32 * and its documentation for any purpose is hereby granted without fee,
33 * provided that the above copyright notice appear in all copies and
34 * that both that copyright notice and this permission notice appear
35 * in supporting documentation. Hewlett-Packard Company makes no
36 * representations about the suitability of this software for any
37 * purpose. It is provided "as is" without express or implied warranty.
40 * Copyright (c) 1996,1997
41 * Silicon Graphics Computer Systems, Inc.
43 * Permission to use, copy, modify, distribute and sell this software
44 * and its documentation for any purpose is hereby granted without fee,
45 * provided that the above copyright notice appear in all copies and
46 * that both that copyright notice and this permission notice appear
47 * in supporting documentation. Silicon Graphics makes no
48 * representations about the suitability of this software for any
49 * purpose. It is provided "as is" without express or implied warranty.
52 /** @file bits/stl_pair.h
53 * This is an internal header file, included by other library headers.
54 * Do not attempt to use it directly. @headername{utility}
60 #include <bits/move.h> // for std::move / std::forward, and std::swap
62 #ifdef __GXX_EXPERIMENTAL_CXX0X__
63 #include <type_traits> // for std::__decay_and_strip too
66 _GLIBCXX_BEGIN_NAMESPACE(std
)
68 #ifdef __GXX_EXPERIMENTAL_CXX0X__
69 /// piecewise_construct_t
70 struct piecewise_construct_t
{ };
72 /// piecewise_construct
73 constexpr piecewise_construct_t piecewise_construct
= piecewise_construct_t();
75 // Forward declarations.
83 /// Struct holding two objects of arbitrary type.
84 template<class _T1
, class _T2
>
87 typedef _T1 first_type
; /// @c first_type is the first bound type
88 typedef _T2 second_type
; /// @c second_type is the second bound type
90 _T1 first
; /// @c first is a copy of the first object
91 _T2 second
; /// @c second is a copy of the second object
93 // _GLIBCXX_RESOLVE_LIB_DEFECTS
94 // 265. std::pair::pair() effects overly restrictive
95 /** The default constructor creates @c first and @c second using their
96 * respective default constructors. */
97 _GLIBCXX_CONSTEXPR
pair()
98 : first(), second() { }
100 /** Two objects may be passed to a @c pair constructor to be copied. */
101 _GLIBCXX_CONSTEXPR
pair(const _T1
& __a
, const _T2
& __b
)
102 : first(__a
), second(__b
) { }
104 /** There is also a templated copy ctor for the @c pair class itself. */
105 template<class _U1
, class _U2
>
106 _GLIBCXX_CONSTEXPR
pair(const pair
<_U1
, _U2
>& __p
)
107 : first(__p
.first
), second(__p
.second
) { }
109 #ifdef __GXX_EXPERIMENTAL_CXX0X__
110 constexpr pair(const pair
&) = default;
113 // pair(pair&&) = default;
116 template<class _U1
, class = typename
117 std::enable_if
<std::is_convertible
<_U1
, _T1
>::value
>::type
>
118 pair(_U1
&& __x
, const _T2
& __y
)
119 : first(std::forward
<_U1
>(__x
)), second(__y
) { }
121 template<class _U2
, class = typename
122 std::enable_if
<std::is_convertible
<_U2
, _T2
>::value
>::type
>
123 pair(const _T1
& __x
, _U2
&& __y
)
124 : first(__x
), second(std::forward
<_U2
>(__y
)) { }
126 template<class _U1
, class _U2
, class = typename
127 std::enable_if
<std::is_convertible
<_U1
, _T1
>::value
128 && std::is_convertible
<_U2
, _T2
>::value
>::type
>
129 pair(_U1
&& __x
, _U2
&& __y
)
130 : first(std::forward
<_U1
>(__x
)), second(std::forward
<_U2
>(__y
)) { }
132 template<class _U1
, class _U2
>
133 pair(pair
<_U1
, _U2
>&& __p
)
134 : first(std::forward
<_U1
>(__p
.first
)),
135 second(std::forward
<_U2
>(__p
.second
)) { }
137 template<class... _Args1
, class... _Args2
>
138 pair(piecewise_construct_t
,
139 tuple
<_Args1
...> __first
, tuple
<_Args2
...> __second
)
140 : first(__cons
<first_type
>(std::move(__first
))),
141 second(__cons
<second_type
>(std::move(__second
))) { }
144 operator=(const pair
& __p
)
152 operator=(pair
&& __p
)
154 first
= std::move(__p
.first
);
155 second
= std::move(__p
.second
);
159 template<class _U1
, class _U2
>
161 operator=(const pair
<_U1
, _U2
>& __p
)
168 template<class _U1
, class _U2
>
170 operator=(pair
<_U1
, _U2
>&& __p
)
172 first
= std::move(__p
.first
);
173 second
= std::move(__p
.second
);
181 swap(first
, __p
.first
);
182 swap(second
, __p
.second
);
186 template<typename _Tp
, typename
... _Args
>
188 __cons(tuple
<_Args
...>&&);
190 template<typename _Tp
, typename
... _Args
, int... _Indexes
>
192 __do_cons(tuple
<_Args
...>&&, const _Index_tuple
<_Indexes
...>&);
196 /// Two pairs of the same type are equal iff their members are equal.
197 template<class _T1
, class _T2
>
198 inline _GLIBCXX_CONSTEXPR
bool
199 operator==(const pair
<_T1
, _T2
>& __x
, const pair
<_T1
, _T2
>& __y
)
200 { return __x
.first
== __y
.first
&& __x
.second
== __y
.second
; }
202 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
203 template<class _T1
, class _T2
>
204 inline _GLIBCXX_CONSTEXPR
bool
205 operator<(const pair
<_T1
, _T2
>& __x
, const pair
<_T1
, _T2
>& __y
)
206 { return __x
.first
< __y
.first
207 || (!(__y
.first
< __x
.first
) && __x
.second
< __y
.second
); }
209 /// Uses @c operator== to find the result.
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
== __y
); }
215 /// Uses @c operator< to find the result.
216 template<class _T1
, class _T2
>
217 inline _GLIBCXX_CONSTEXPR
bool
218 operator>(const pair
<_T1
, _T2
>& __x
, const pair
<_T1
, _T2
>& __y
)
219 { return __y
< __x
; }
221 /// Uses @c operator< to find the result.
222 template<class _T1
, class _T2
>
223 inline _GLIBCXX_CONSTEXPR
bool
224 operator<=(const pair
<_T1
, _T2
>& __x
, const pair
<_T1
, _T2
>& __y
)
225 { return !(__y
< __x
); }
227 /// Uses @c operator< to find the result.
228 template<class _T1
, class _T2
>
229 inline _GLIBCXX_CONSTEXPR
bool
230 operator>=(const pair
<_T1
, _T2
>& __x
, const pair
<_T1
, _T2
>& __y
)
231 { return !(__x
< __y
); }
233 #ifdef __GXX_EXPERIMENTAL_CXX0X__
234 /// See std::pair::swap().
235 // Note: no std::swap overloads in C++03 mode, this has performance
236 // implications, see, eg, libstdc++/38466.
237 template<class _T1
, class _T2
>
239 swap(pair
<_T1
, _T2
>& __x
, pair
<_T1
, _T2
>& __y
)
244 * @brief A convenience wrapper for creating a pair from two objects.
245 * @param x The first object.
246 * @param y The second object.
247 * @return A newly-constructed pair<> object of the appropriate type.
249 * The standard requires that the objects be passed by reference-to-const,
250 * but LWG issue #181 says they should be passed by const value. We follow
251 * the LWG by default.
253 // _GLIBCXX_RESOLVE_LIB_DEFECTS
254 // 181. make_pair() unintended behavior
255 #ifdef __GXX_EXPERIMENTAL_CXX0X__
257 template<class _T1
, class _T2
>
258 inline pair
<typename __decay_and_strip
<_T1
>::__type
,
259 typename __decay_and_strip
<_T2
>::__type
>
260 make_pair(_T1
&& __x
, _T2
&& __y
)
262 typedef typename __decay_and_strip
<_T1
>::__type __ds_type1
;
263 typedef typename __decay_and_strip
<_T2
>::__type __ds_type2
;
264 typedef pair
<__ds_type1
, __ds_type2
> __pair_type
;
265 return __pair_type(std::forward
<_T1
>(__x
), std::forward
<_T2
>(__y
));
268 template<class _T1
, class _T2
>
269 inline pair
<_T1
, _T2
>
270 make_pair(_T1 __x
, _T2 __y
)
271 { return pair
<_T1
, _T2
>(__x
, __y
); }
274 _GLIBCXX_END_NAMESPACE
276 #endif /* _STL_PAIR_H */