1// Pair implementation -*- 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 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
65namespace 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 { explicit piecewise_construct_t() = default; };
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
88 // Concept utility functions, reused in conditionally-explicit
89 // constructors.
90 // See PR 70437, don't look at is_constructible or
91 // is_convertible if the decayed types are the same to
92 // avoid querying those properties for incomplete types.
93 template <typename _T1, typename _T2, typename _U1, typename _U2>
94 constexpr bool _ConstructiblePair()
95 {
96 return __and_<__or_<is_same<typename decay<_T1>::type,
97 typename decay<_U1>::type>,
98 is_constructible<_T1, const _U1&>>,
99 __or_<is_same<typename decay<_T2>::type,
100 typename decay<_U2>::type>,
101 is_constructible<_T2, const _U2&>>>::value;
102 }
103
104 template <typename _T1, typename _T2, typename _U1, typename _U2>
105 constexpr bool _ImplicitlyConvertiblePair()
106 {
107 return __and_<__or_<is_same<typename decay<_T1>::type,
108 typename decay<_U1>::type>,
109 is_convertible<const _U1&, _T1>>,
110 __or_<is_same<typename decay<_T2>::type,
111 typename decay<_U2>::type>,
112 is_convertible<const _U2&, _T2>>>::value;
113 }
114
115 template <typename _T1, typename _T2, typename _U1, typename _U2>
116 constexpr bool _MoveConstructiblePair()
117 {
118 return __and_<__or_<is_same<typename decay<_T1>::type,
119 typename decay<_U1>::type>,
120 is_constructible<_T1, _U1&&>>,
121 __or_<is_same<typename decay<_T2>::type,
122 typename decay<_U2>::type>,
123 is_constructible<_T2, _U2&&>>>::value;
124 }
125
126 template <typename _T1, typename _T2, typename _U1, typename _U2>
127 constexpr bool _ImplicitlyMoveConvertiblePair()
128 {
129 return __and_<__or_<is_same<typename decay<_T1>::type,
130 typename decay<_U1>::type>,
131 is_convertible<_U1&&, _T1>>,
132 __or_<is_same<typename decay<_T2>::type,
133 typename decay<_U2>::type>,
134 is_convertible<_U2&&, _T2>>>::value;
135 }
136
137
138#endif
139
140 /**
141 * @brief Struct holding two objects of arbitrary type.
142 *
143 * @tparam _T1 Type of first object.
144 * @tparam _T2 Type of second object.
145 */
146 template<typename _T1, typename _T2>
147 struct pair
148 {
149 typedef _T1 first_type; /// @c first_type is the first bound type
150 typedef _T2 second_type; /// @c second_type is the second bound type
151
152 _T1 first; /// @c first is a copy of the first object
153 _T2 second; /// @c second is a copy of the second object
154
155 // _GLIBCXX_RESOLVE_LIB_DEFECTS
156 // 265. std::pair::pair() effects overly restrictive
157 /** The default constructor creates @c first and @c second using their
158 * respective default constructors. */
159#if __cplusplus >= 201103L
160 template <typename _U1 = _T1,
161 typename _U2 = _T2,
162 typename enable_if<__and_<
163 __is_implicitly_default_constructible<_U1>,
164 __is_implicitly_default_constructible<_U2>>
165 ::value, bool>::type = true>
166#endif
167 _GLIBCXX_CONSTEXPR pair()
168 : first(), second() { }
169
170#if __cplusplus >= 201103L
171 template <typename _U1 = _T1,
172 typename _U2 = _T2,
173 typename enable_if<__and_<
174 is_default_constructible<_U1>,
175 is_default_constructible<_U2>,
176 __not_<
177 __and_<__is_implicitly_default_constructible<_U1>,
178 __is_implicitly_default_constructible<_U2>>>>
179 ::value, bool>::type = false>
180 explicit constexpr pair()
181 : first(), second() { }
182#endif
183
184 /** Two objects may be passed to a @c pair constructor to be copied. */
185#if __cplusplus < 201103L
186 pair(const _T1& __a, const _T2& __b)
187 : first(__a), second(__b) { }
188#else
189 template<typename _U1 = _T1, typename _U2=_T2, typename
190 enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
191 && _ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
192 bool>::type=true>
193 constexpr pair(const _T1& __a, const _T2& __b)
194 : first(__a), second(__b) { }
195
196 template<typename _U1 = _T1, typename _U2=_T2, typename
197 enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
198 && !_ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
199 bool>::type=false>
200 explicit constexpr pair(const _T1& __a, const _T2& __b)
201 : first(__a), second(__b) { }
202#endif
203
204 /** There is also a templated copy ctor for the @c pair class itself. */
205#if __cplusplus < 201103L
206 template<typename _U1, typename _U2>
207 pair(const pair<_U1, _U2>& __p)
208 : first(__p.first), second(__p.second) { }
209#else
210 template<typename _U1, typename _U2, typename
211 enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
212 && _ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
213 bool>::type=true>
214 constexpr pair(const pair<_U1, _U2>& __p)
215 : first(__p.first), second(__p.second) { }
216
217 template<typename _U1, typename _U2, typename
218 enable_if<_ConstructiblePair<_T1, _T2, _U1, _U2>()
219 && !_ImplicitlyConvertiblePair<_T1, _T2, _U1, _U2>(),
220 bool>::type=false>
221 explicit constexpr pair(const pair<_U1, _U2>& __p)
222 : first(__p.first), second(__p.second) { }
223
224 constexpr pair(const pair&) = default;
225 constexpr pair(pair&&) = default;
226
227 // DR 811.
228 template<typename _U1, typename
229 enable_if<_ConstructiblePair<_T2, _T2, _T2, _T2>()
230 && _MoveConstructiblePair<_T1, _T2, _U1, _T2>()
231 && _ImplicitlyConvertiblePair<_T2, _T2, _T2, _T2>()
232 && _ImplicitlyMoveConvertiblePair<_T1, _T2,
233 _U1, _T2>(),
234 bool>::type=true>
235 constexpr pair(_U1&& __x, const _T2& __y)
236 : first(std::forward<_U1>(__x)), second(__y) { }
237
238 template<typename _U1, typename
239 enable_if<_ConstructiblePair<_T2, _T2, _T2, _T2>()
240 && _MoveConstructiblePair<_T1, _T2, _U1, _T2>()
241 && (!_ImplicitlyConvertiblePair<_T2, _T2, _T2, _T2>()
242 || !_ImplicitlyMoveConvertiblePair<_T1, _T2,
243 _U1, _T2>()),
244 bool>::type=false>
245 explicit constexpr pair(_U1&& __x, const _T2& __y)
246 : first(std::forward<_U1>(__x)), second(__y) { }
247
248 template<typename _U2, typename
249 enable_if<_ConstructiblePair<_T1, _T1, _T1, _T1>()
250 && _MoveConstructiblePair<_T1, _T2, _T1, _U2>()
251 && _ImplicitlyConvertiblePair<_T1, _T1, _T1, _T1>()
252 && _ImplicitlyMoveConvertiblePair<_T1, _T2,
253 _T1, _U2>(),
254 bool>::type=true>
255 constexpr pair(const _T1& __x, _U2&& __y)
256 : first(__x), second(std::forward<_U2>(__y)) { }
257
258 template<typename _U2, typename
259 enable_if<_ConstructiblePair<_T1, _T1, _T1, _T1>()
260 && _MoveConstructiblePair<_T1, _T2, _T1, _U2>()
261 && (!_ImplicitlyConvertiblePair<_T1, _T1, _T1, _T1>()
262 || !_ImplicitlyMoveConvertiblePair<_T1, _T2,
263 _T1, _U2>()),
264 bool>::type=false>
265 explicit pair(const _T1& __x, _U2&& __y)
266 : first(__x), second(std::forward<_U2>(__y)) { }
267
268 template<typename _U1, typename _U2, typename
269 enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
270 && _ImplicitlyMoveConvertiblePair<_T1, _T2,
271 _U1, _U2>(),
272 bool>::type=true>
273 constexpr pair(_U1&& __x, _U2&& __y)
274 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
275
276 template<typename _U1, typename _U2, typename
277 enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
278 && !_ImplicitlyMoveConvertiblePair<_T1, _T2,
279 _U1, _U2>(),
280 bool>::type=false>
281 explicit constexpr pair(_U1&& __x, _U2&& __y)
282 : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
283
284
285 template<typename _U1, typename _U2, typename
286 enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
287 && _ImplicitlyMoveConvertiblePair<_T1, _T2,
288 _U1, _U2>(),
289 bool>::type=true>
290 constexpr pair(pair<_U1, _U2>&& __p)
291 : first(std::forward<_U1>(__p.first)),
292 second(std::forward<_U2>(__p.second)) { }
293
294 template<typename _U1, typename _U2, typename
295 enable_if<_MoveConstructiblePair<_T1, _T2, _U1, _U2>()
296 && !_ImplicitlyMoveConvertiblePair<_T1, _T2,
297 _U1, _U2>(),
298 bool>::type=false>
299 explicit constexpr pair(pair<_U1, _U2>&& __p)
300 : first(std::forward<_U1>(__p.first)),
301 second(std::forward<_U2>(__p.second)) { }
302
303 template<typename... _Args1, typename... _Args2>
304 pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
305
306 pair&
307 operator=(const pair& __p)
308 {
309 first = __p.first;
310 second = __p.second;
311 return *this;
312 }
313
314 pair&
315 operator=(pair&& __p)
316 noexcept(__and_<is_nothrow_move_assignable<_T1>,
317 is_nothrow_move_assignable<_T2>>::value)
318 {
319 first = std::forward<first_type>(__p.first);
320 second = std::forward<second_type>(__p.second);
321 return *this;
322 }
323
324 template<typename _U1, typename _U2>
325 pair&
326 operator=(const pair<_U1, _U2>& __p)
327 {
328 first = __p.first;
329 second = __p.second;
330 return *this;
331 }
332
333 template<typename _U1, typename _U2>
334 pair&
335 operator=(pair<_U1, _U2>&& __p)
336 {
337 first = std::forward<_U1>(__p.first);
338 second = std::forward<_U2>(__p.second);
339 return *this;
340 }
341
342 void
343 swap(pair& __p)
344 noexcept(__is_nothrow_swappable<_T1>::value
345 && __is_nothrow_swappable<_T2>::value)
346 {
347 using std::swap;
348 swap(first, __p.first);
349 swap(second, __p.second);
350 }
351
352 private:
353 template<typename... _Args1, std::size_t... _Indexes1,
354 typename... _Args2, std::size_t... _Indexes2>
355 pair(tuple<_Args1...>&, tuple<_Args2...>&,
356 _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>);
357#endif
358 };
359
360 /// Two pairs of the same type are equal iff their members are equal.
361 template<typename _T1, typename _T2>
362 inline _GLIBCXX_CONSTEXPR bool
363 operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
364 { return __x.first == __y.first && __x.second == __y.second; }
365
366 /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
367 template<typename _T1, typename _T2>
368 inline _GLIBCXX_CONSTEXPR bool
369 operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
370 { return __x.first < __y.first
371 || (!(__y.first < __x.first) && __x.second < __y.second); }
372
373 /// Uses @c operator== to find the result.
374 template<typename _T1, typename _T2>
375 inline _GLIBCXX_CONSTEXPR bool
376 operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
377 { return !(__x == __y); }
378
379 /// Uses @c operator< to find the result.
380 template<typename _T1, typename _T2>
381 inline _GLIBCXX_CONSTEXPR bool
382 operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
383 { return __y < __x; }
384
385 /// Uses @c operator< to find the result.
386 template<typename _T1, typename _T2>
387 inline _GLIBCXX_CONSTEXPR bool
388 operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
389 { return !(__y < __x); }
390
391 /// Uses @c operator< to find the result.
392 template<typename _T1, typename _T2>
393 inline _GLIBCXX_CONSTEXPR bool
394 operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
395 { return !(__x < __y); }
396
397#if __cplusplus >= 201103L
398 /// See std::pair::swap().
399 // Note: no std::swap overloads in C++03 mode, this has performance
400 // implications, see, eg, libstdc++/38466.
401 template<typename _T1, typename _T2>
402 inline void
403 swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
404 noexcept(noexcept(__x.swap(__y)))
405 { __x.swap(__y); }
406#endif
407
408 /**
409 * @brief A convenience wrapper for creating a pair from two objects.
410 * @param __x The first object.
411 * @param __y The second object.
412 * @return A newly-constructed pair<> object of the appropriate type.
413 *
414 * The standard requires that the objects be passed by reference-to-const,
415 * but LWG issue #181 says they should be passed by const value. We follow
416 * the LWG by default.
417 */
418 // _GLIBCXX_RESOLVE_LIB_DEFECTS
419 // 181. make_pair() unintended behavior
420#if __cplusplus >= 201103L
421 // NB: DR 706.
422 template<typename _T1, typename _T2>
423 constexpr pair<typename __decay_and_strip<_T1>::__type,
424 typename __decay_and_strip<_T2>::__type>
425 make_pair(_T1&& __x, _T2&& __y)
426 {
427 typedef typename __decay_and_strip<_T1>::__type __ds_type1;
428 typedef typename __decay_and_strip<_T2>::__type __ds_type2;
429 typedef pair<__ds_type1, __ds_type2> __pair_type;
430 return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
431 }
432#else
433 template<typename _T1, typename _T2>
434 inline pair<_T1, _T2>
435 make_pair(_T1 __x, _T2 __y)
436 { return pair<_T1, _T2>(__x, __y); }
437#endif
438
439 /// @}
440
441_GLIBCXX_END_NAMESPACE_VERSION
442} // namespace std
443
444#endif /* _STL_PAIR_H */
445