Line data Source code
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 :
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 { 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 types are the same to
92 : // avoid querying those properties for incomplete types.
93 : template <bool, typename _T1, typename _T2>
94 : struct _PCC
95 : {
96 : template <typename _U1, typename _U2>
97 : static constexpr bool _ConstructiblePair()
98 : {
99 : return __and_<is_constructible<_T1, const _U1&>,
100 : is_constructible<_T2, const _U2&>>::value;
101 : }
102 :
103 : template <typename _U1, typename _U2>
104 : static constexpr bool _ImplicitlyConvertiblePair()
105 : {
106 : return __and_<is_convertible<const _U1&, _T1>,
107 : is_convertible<const _U2&, _T2>>::value;
108 : }
109 :
110 : template <typename _U1, typename _U2>
111 : static constexpr bool _MoveConstructiblePair()
112 : {
113 : return __and_<is_constructible<_T1, _U1&&>,
114 : is_constructible<_T2, _U2&&>>::value;
115 : }
116 :
117 : template <typename _U1, typename _U2>
118 : static constexpr bool _ImplicitlyMoveConvertiblePair()
119 : {
120 : return __and_<is_convertible<_U1&&, _T1>,
121 : is_convertible<_U2&&, _T2>>::value;
122 : }
123 :
124 : template <bool __implicit, typename _U1, typename _U2>
125 : static constexpr bool _CopyMovePair()
126 : {
127 : using __do_converts = __and_<is_convertible<const _U1&, _T1>,
128 : is_convertible<_U2&&, _T2>>;
129 : using __converts = typename conditional<__implicit,
130 : __do_converts,
131 : __not_<__do_converts>>::type;
132 : return __and_<is_constructible<_T1, const _U1&>,
133 : is_constructible<_T2, _U2&&>,
134 : __converts
135 : >::value;
136 : }
137 :
138 : template <bool __implicit, typename _U1, typename _U2>
139 : static constexpr bool _MoveCopyPair()
140 : {
141 : using __do_converts = __and_<is_convertible<_U1&&, _T1>,
142 : is_convertible<const _U2&, _T2>>;
143 : using __converts = typename conditional<__implicit,
144 : __do_converts,
145 : __not_<__do_converts>>::type;
146 : return __and_<is_constructible<_T1, _U1&&>,
147 : is_constructible<_T2, const _U2&&>,
148 : __converts
149 : >::value;
150 : }
151 : };
152 :
153 : template <typename _T1, typename _T2>
154 : struct _PCC<false, _T1, _T2>
155 : {
156 : template <typename _U1, typename _U2>
157 : static constexpr bool _ConstructiblePair()
158 : {
159 : return false;
160 : }
161 :
162 : template <typename _U1, typename _U2>
163 : static constexpr bool _ImplicitlyConvertiblePair()
164 : {
165 : return false;
166 : }
167 :
168 : template <typename _U1, typename _U2>
169 : static constexpr bool _MoveConstructiblePair()
170 : {
171 : return false;
172 : }
173 :
174 : template <typename _U1, typename _U2>
175 : static constexpr bool _ImplicitlyMoveConvertiblePair()
176 : {
177 : return false;
178 : }
179 : };
180 :
181 : #endif
182 :
183 : /**
184 : * @brief Struct holding two objects of arbitrary type.
185 : *
186 : * @tparam _T1 Type of first object.
187 : * @tparam _T2 Type of second object.
188 : */
189 : template<typename _T1, typename _T2>
190 0 : struct pair
191 : {
192 : typedef _T1 first_type; /// @c first_type is the first bound type
193 : typedef _T2 second_type; /// @c second_type is the second bound type
194 :
195 : _T1 first; /// @c first is a copy of the first object
196 : _T2 second; /// @c second is a copy of the second object
197 :
198 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
199 : // 265. std::pair::pair() effects overly restrictive
200 : /** The default constructor creates @c first and @c second using their
201 : * respective default constructors. */
202 : #if __cplusplus >= 201103L
203 : template <typename _U1 = _T1,
204 : typename _U2 = _T2,
205 : typename enable_if<__and_<
206 : __is_implicitly_default_constructible<_U1>,
207 : __is_implicitly_default_constructible<_U2>>
208 : ::value, bool>::type = true>
209 : #endif
210 0 : _GLIBCXX_CONSTEXPR pair()
211 0 : : first(), second() { }
212 :
213 : #if __cplusplus >= 201103L
214 : template <typename _U1 = _T1,
215 : typename _U2 = _T2,
216 : typename enable_if<__and_<
217 : is_default_constructible<_U1>,
218 : is_default_constructible<_U2>,
219 : __not_<
220 : __and_<__is_implicitly_default_constructible<_U1>,
221 : __is_implicitly_default_constructible<_U2>>>>
222 : ::value, bool>::type = false>
223 : explicit constexpr pair()
224 : : first(), second() { }
225 : #endif
226 :
227 : /** Two objects may be passed to a @c pair constructor to be copied. */
228 : #if __cplusplus < 201103L
229 : pair(const _T1& __a, const _T2& __b)
230 : : first(__a), second(__b) { }
231 : #else
232 : // Shortcut for constraining the templates that don't take pairs.
233 : using _PCCP = _PCC<true, _T1, _T2>;
234 :
235 : template<typename _U1 = _T1, typename _U2=_T2, typename
236 : enable_if<_PCCP::template
237 : _ConstructiblePair<_U1, _U2>()
238 : && _PCCP::template
239 : _ImplicitlyConvertiblePair<_U1, _U2>(),
240 : bool>::type=true>
241 0 : constexpr pair(const _T1& __a, const _T2& __b)
242 0 : : first(__a), second(__b) { }
243 :
244 : template<typename _U1 = _T1, typename _U2=_T2, typename
245 : enable_if<_PCCP::template
246 : _ConstructiblePair<_U1, _U2>()
247 : && !_PCCP::template
248 : _ImplicitlyConvertiblePair<_U1, _U2>(),
249 : bool>::type=false>
250 : explicit constexpr pair(const _T1& __a, const _T2& __b)
251 : : first(__a), second(__b) { }
252 : #endif
253 :
254 : /** There is also a templated copy ctor for the @c pair class itself. */
255 : #if __cplusplus < 201103L
256 : template<typename _U1, typename _U2>
257 : pair(const pair<_U1, _U2>& __p)
258 : : first(__p.first), second(__p.second) { }
259 : #else
260 : // Shortcut for constraining the templates that take pairs.
261 : template <typename _U1, typename _U2>
262 : using _PCCFP = _PCC<!is_same<_T1, _U1>::value
263 : || !is_same<_T2, _U2>::value,
264 : _T1, _T2>;
265 :
266 : template<typename _U1, typename _U2, typename
267 : enable_if<_PCCFP<_U1, _U2>::template
268 : _ConstructiblePair<_U1, _U2>()
269 : && _PCCFP<_U1, _U2>::template
270 : _ImplicitlyConvertiblePair<_U1, _U2>(),
271 : bool>::type=true>
272 : constexpr pair(const pair<_U1, _U2>& __p)
273 : : first(__p.first), second(__p.second) { }
274 :
275 : template<typename _U1, typename _U2, typename
276 : enable_if<_PCCFP<_U1, _U2>::template
277 : _ConstructiblePair<_U1, _U2>()
278 : && !_PCCFP<_U1, _U2>::template
279 : _ImplicitlyConvertiblePair<_U1, _U2>(),
280 : bool>::type=false>
281 : explicit constexpr pair(const pair<_U1, _U2>& __p)
282 : : first(__p.first), second(__p.second) { }
283 :
284 0 : constexpr pair(const pair&) = default;
285 0 : constexpr pair(pair&&) = default;
286 :
287 : // DR 811.
288 : template<typename _U1, typename
289 : enable_if<_PCCP::template
290 : _MoveCopyPair<true, _U1, _T2>(),
291 : bool>::type=true>
292 0 : constexpr pair(_U1&& __x, const _T2& __y)
293 0 : : first(std::forward<_U1>(__x)), second(__y) { }
294 :
295 : template<typename _U1, typename
296 : enable_if<_PCCP::template
297 : _MoveCopyPair<false, _U1, _T2>(),
298 : bool>::type=false>
299 : explicit constexpr pair(_U1&& __x, const _T2& __y)
300 : : first(std::forward<_U1>(__x)), second(__y) { }
301 :
302 : template<typename _U2, typename
303 : enable_if<_PCCP::template
304 : _CopyMovePair<true, _T1, _U2>(),
305 : bool>::type=true>
306 0 : constexpr pair(const _T1& __x, _U2&& __y)
307 0 : : first(__x), second(std::forward<_U2>(__y)) { }
308 :
309 : template<typename _U2, typename
310 : enable_if<_PCCP::template
311 : _CopyMovePair<false, _T1, _U2>(),
312 : bool>::type=false>
313 : explicit pair(const _T1& __x, _U2&& __y)
314 : : first(__x), second(std::forward<_U2>(__y)) { }
315 :
316 : template<typename _U1, typename _U2, typename
317 : enable_if<_PCCP::template
318 : _MoveConstructiblePair<_U1, _U2>()
319 : && _PCCP::template
320 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
321 : bool>::type=true>
322 0 : constexpr pair(_U1&& __x, _U2&& __y)
323 0 : : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
324 :
325 : template<typename _U1, typename _U2, typename
326 : enable_if<_PCCP::template
327 : _MoveConstructiblePair<_U1, _U2>()
328 : && !_PCCP::template
329 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
330 : bool>::type=false>
331 : explicit constexpr pair(_U1&& __x, _U2&& __y)
332 : : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
333 :
334 :
335 : template<typename _U1, typename _U2, typename
336 : enable_if<_PCCFP<_U1, _U2>::template
337 : _MoveConstructiblePair<_U1, _U2>()
338 : && _PCCFP<_U1, _U2>::template
339 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
340 : bool>::type=true>
341 : constexpr pair(pair<_U1, _U2>&& __p)
342 : : first(std::forward<_U1>(__p.first)),
343 : second(std::forward<_U2>(__p.second)) { }
344 :
345 : template<typename _U1, typename _U2, typename
346 : enable_if<_PCCFP<_U1, _U2>::template
347 : _MoveConstructiblePair<_U1, _U2>()
348 : && !_PCCFP<_U1, _U2>::template
349 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
350 : bool>::type=false>
351 : explicit constexpr pair(pair<_U1, _U2>&& __p)
352 : : first(std::forward<_U1>(__p.first)),
353 : second(std::forward<_U2>(__p.second)) { }
354 :
355 : template<typename... _Args1, typename... _Args2>
356 : pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
357 :
358 : pair&
359 : operator=(typename conditional<
360 : __and_<is_copy_assignable<_T1>,
361 : is_copy_assignable<_T2>>::value,
362 : const pair&, const __nonesuch&>::type __p)
363 : {
364 : first = __p.first;
365 : second = __p.second;
366 : return *this;
367 : }
368 :
369 : pair&
370 : operator=(typename conditional<
371 : __not_<__and_<is_copy_assignable<_T1>,
372 : is_copy_assignable<_T2>>>::value,
373 : const pair&, const __nonesuch&>::type __p) = delete;
374 :
375 : pair&
376 0 : operator=(typename conditional<
377 : __and_<is_move_assignable<_T1>,
378 : is_move_assignable<_T2>>::value,
379 : pair&&, __nonesuch&&>::type __p)
380 : noexcept(__and_<is_nothrow_move_assignable<_T1>,
381 : is_nothrow_move_assignable<_T2>>::value)
382 : {
383 0 : first = std::forward<first_type>(__p.first);
384 0 : second = std::forward<second_type>(__p.second);
385 0 : return *this;
386 : }
387 :
388 : template<typename _U1, typename _U2>
389 : typename enable_if<__and_<is_assignable<_T1&, const _U1&>,
390 : is_assignable<_T2&, const _U2&>>::value,
391 : pair&>::type
392 : operator=(const pair<_U1, _U2>& __p)
393 : {
394 : first = __p.first;
395 : second = __p.second;
396 : return *this;
397 : }
398 :
399 : template<typename _U1, typename _U2>
400 : typename enable_if<__and_<is_assignable<_T1&, _U1&&>,
401 : is_assignable<_T2&, _U2&&>>::value,
402 : pair&>::type
403 : operator=(pair<_U1, _U2>&& __p)
404 : {
405 : first = std::forward<_U1>(__p.first);
406 : second = std::forward<_U2>(__p.second);
407 : return *this;
408 : }
409 :
410 : void
411 : swap(pair& __p)
412 : noexcept(__is_nothrow_swappable<_T1>::value
413 : && __is_nothrow_swappable<_T2>::value)
414 : {
415 : using std::swap;
416 : swap(first, __p.first);
417 : swap(second, __p.second);
418 : }
419 :
420 : private:
421 : template<typename... _Args1, std::size_t... _Indexes1,
422 : typename... _Args2, std::size_t... _Indexes2>
423 : pair(tuple<_Args1...>&, tuple<_Args2...>&,
424 : _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>);
425 : #endif
426 : };
427 :
428 : /// Two pairs of the same type are equal iff their members are equal.
429 : template<typename _T1, typename _T2>
430 : inline _GLIBCXX_CONSTEXPR bool
431 : operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
432 : { return __x.first == __y.first && __x.second == __y.second; }
433 :
434 : /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
435 : template<typename _T1, typename _T2>
436 : inline _GLIBCXX_CONSTEXPR bool
437 : operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
438 : { return __x.first < __y.first
439 : || (!(__y.first < __x.first) && __x.second < __y.second); }
440 :
441 : /// Uses @c operator== to find the result.
442 : template<typename _T1, typename _T2>
443 : inline _GLIBCXX_CONSTEXPR bool
444 : operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
445 : { return !(__x == __y); }
446 :
447 : /// Uses @c operator< to find the result.
448 : template<typename _T1, typename _T2>
449 : inline _GLIBCXX_CONSTEXPR bool
450 : operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
451 : { return __y < __x; }
452 :
453 : /// Uses @c operator< to find the result.
454 : template<typename _T1, typename _T2>
455 : inline _GLIBCXX_CONSTEXPR bool
456 : operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
457 : { return !(__y < __x); }
458 :
459 : /// Uses @c operator< to find the result.
460 : template<typename _T1, typename _T2>
461 : inline _GLIBCXX_CONSTEXPR bool
462 : operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
463 : { return !(__x < __y); }
464 :
465 : #if __cplusplus >= 201103L
466 : /// See std::pair::swap().
467 : // Note: no std::swap overloads in C++03 mode, this has performance
468 : // implications, see, eg, libstdc++/38466.
469 : template<typename _T1, typename _T2>
470 : inline void
471 : swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
472 : noexcept(noexcept(__x.swap(__y)))
473 : { __x.swap(__y); }
474 : #endif
475 :
476 : /**
477 : * @brief A convenience wrapper for creating a pair from two objects.
478 : * @param __x The first object.
479 : * @param __y The second object.
480 : * @return A newly-constructed pair<> object of the appropriate type.
481 : *
482 : * The standard requires that the objects be passed by reference-to-const,
483 : * but LWG issue #181 says they should be passed by const value. We follow
484 : * the LWG by default.
485 : */
486 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
487 : // 181. make_pair() unintended behavior
488 : #if __cplusplus >= 201103L
489 : // NB: DR 706.
490 : template<typename _T1, typename _T2>
491 : constexpr pair<typename __decay_and_strip<_T1>::__type,
492 : typename __decay_and_strip<_T2>::__type>
493 0 : make_pair(_T1&& __x, _T2&& __y)
494 : {
495 : typedef typename __decay_and_strip<_T1>::__type __ds_type1;
496 : typedef typename __decay_and_strip<_T2>::__type __ds_type2;
497 : typedef pair<__ds_type1, __ds_type2> __pair_type;
498 0 : return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
499 : }
500 : #else
501 : template<typename _T1, typename _T2>
502 : inline pair<_T1, _T2>
503 : make_pair(_T1 __x, _T2 __y)
504 : { return pair<_T1, _T2>(__x, __y); }
505 : #endif
506 :
507 : /// @}
508 :
509 : _GLIBCXX_END_NAMESPACE_VERSION
510 : } // namespace std
511 :
512 : #endif /* _STL_PAIR_H */
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