Line data Source code
1 : // Pair implementation -*- C++ -*-
2 :
3 : // Copyright (C) 2001-2019 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 : _GLIBCXX17_INLINE constexpr piecewise_construct_t piecewise_construct =
80 : piecewise_construct_t();
81 :
82 : // Forward declarations.
83 : template<typename...>
84 : class tuple;
85 :
86 : template<std::size_t...>
87 : struct _Index_tuple;
88 :
89 : // Concept utility functions, reused in conditionally-explicit
90 : // constructors.
91 : // See PR 70437, don't look at is_constructible or
92 : // is_convertible if the types are the same to
93 : // avoid querying those properties for incomplete types.
94 : template <bool, typename _T1, typename _T2>
95 : struct _PCC
96 : {
97 : template <typename _U1, typename _U2>
98 : static constexpr bool _ConstructiblePair()
99 : {
100 : return __and_<is_constructible<_T1, const _U1&>,
101 : is_constructible<_T2, const _U2&>>::value;
102 : }
103 :
104 : template <typename _U1, typename _U2>
105 : static constexpr bool _ImplicitlyConvertiblePair()
106 : {
107 : return __and_<is_convertible<const _U1&, _T1>,
108 : is_convertible<const _U2&, _T2>>::value;
109 : }
110 :
111 : template <typename _U1, typename _U2>
112 : static constexpr bool _MoveConstructiblePair()
113 : {
114 : return __and_<is_constructible<_T1, _U1&&>,
115 : is_constructible<_T2, _U2&&>>::value;
116 : }
117 :
118 : template <typename _U1, typename _U2>
119 : static constexpr bool _ImplicitlyMoveConvertiblePair()
120 : {
121 : return __and_<is_convertible<_U1&&, _T1>,
122 : is_convertible<_U2&&, _T2>>::value;
123 : }
124 :
125 : template <bool __implicit, typename _U1, typename _U2>
126 : static constexpr bool _CopyMovePair()
127 : {
128 : using __do_converts = __and_<is_convertible<const _U1&, _T1>,
129 : is_convertible<_U2&&, _T2>>;
130 : using __converts = typename conditional<__implicit,
131 : __do_converts,
132 : __not_<__do_converts>>::type;
133 : return __and_<is_constructible<_T1, const _U1&>,
134 : is_constructible<_T2, _U2&&>,
135 : __converts
136 : >::value;
137 : }
138 :
139 : template <bool __implicit, typename _U1, typename _U2>
140 : static constexpr bool _MoveCopyPair()
141 : {
142 : using __do_converts = __and_<is_convertible<_U1&&, _T1>,
143 : is_convertible<const _U2&, _T2>>;
144 : using __converts = typename conditional<__implicit,
145 : __do_converts,
146 : __not_<__do_converts>>::type;
147 : return __and_<is_constructible<_T1, _U1&&>,
148 : is_constructible<_T2, const _U2&&>,
149 : __converts
150 : >::value;
151 : }
152 : };
153 :
154 : template <typename _T1, typename _T2>
155 : struct _PCC<false, _T1, _T2>
156 : {
157 : template <typename _U1, typename _U2>
158 : static constexpr bool _ConstructiblePair()
159 : {
160 : return false;
161 : }
162 :
163 : template <typename _U1, typename _U2>
164 : static constexpr bool _ImplicitlyConvertiblePair()
165 : {
166 : return false;
167 : }
168 :
169 : template <typename _U1, typename _U2>
170 : static constexpr bool _MoveConstructiblePair()
171 : {
172 : return false;
173 : }
174 :
175 : template <typename _U1, typename _U2>
176 : static constexpr bool _ImplicitlyMoveConvertiblePair()
177 : {
178 : return false;
179 : }
180 : };
181 :
182 : // PR libstdc++/79141, a utility type for preventing
183 : // initialization of an argument of a disabled assignment
184 : // operator from a pair of empty braces.
185 : struct __nonesuch_no_braces : std::__nonesuch {
186 : explicit __nonesuch_no_braces(const __nonesuch&) = delete;
187 : };
188 : #endif // C++11
189 :
190 : template<typename _U1, typename _U2> class __pair_base
191 : {
192 : #if __cplusplus >= 201103L
193 : template<typename _T1, typename _T2> friend struct pair;
194 : __pair_base() = default;
195 : ~__pair_base() = default;
196 : __pair_base(const __pair_base&) = default;
197 : __pair_base& operator=(const __pair_base&) = delete;
198 : #endif // C++11
199 : };
200 :
201 : /**
202 : * @brief Struct holding two objects of arbitrary type.
203 : *
204 : * @tparam _T1 Type of first object.
205 : * @tparam _T2 Type of second object.
206 : */
207 : template<typename _T1, typename _T2>
208 2057962663 : struct pair
209 : : private __pair_base<_T1, _T2>
210 : {
211 : typedef _T1 first_type; /// @c first_type is the first bound type
212 : typedef _T2 second_type; /// @c second_type is the second bound type
213 :
214 : _T1 first; /// @c first is a copy of the first object
215 : _T2 second; /// @c second is a copy of the second object
216 :
217 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
218 : // 265. std::pair::pair() effects overly restrictive
219 : /** The default constructor creates @c first and @c second using their
220 : * respective default constructors. */
221 : #if __cplusplus >= 201103L
222 : template <typename _U1 = _T1,
223 : typename _U2 = _T2,
224 : typename enable_if<__and_<
225 : __is_implicitly_default_constructible<_U1>,
226 : __is_implicitly_default_constructible<_U2>>
227 : ::value, bool>::type = true>
228 : #endif
229 29516 : _GLIBCXX_CONSTEXPR pair()
230 29516 : : first(), second() { }
231 :
232 : #if __cplusplus >= 201103L
233 : template <typename _U1 = _T1,
234 : typename _U2 = _T2,
235 : typename enable_if<__and_<
236 : is_default_constructible<_U1>,
237 : is_default_constructible<_U2>,
238 : __not_<
239 : __and_<__is_implicitly_default_constructible<_U1>,
240 : __is_implicitly_default_constructible<_U2>>>>
241 : ::value, bool>::type = false>
242 : explicit constexpr pair()
243 : : first(), second() { }
244 : #endif
245 :
246 : /** Two objects may be passed to a @c pair constructor to be copied. */
247 : #if __cplusplus < 201103L
248 : pair(const _T1& __a, const _T2& __b)
249 : : first(__a), second(__b) { }
250 : #else
251 : // Shortcut for constraining the templates that don't take pairs.
252 : using _PCCP = _PCC<true, _T1, _T2>;
253 :
254 : template<typename _U1 = _T1, typename _U2=_T2, typename
255 : enable_if<_PCCP::template
256 : _ConstructiblePair<_U1, _U2>()
257 : && _PCCP::template
258 : _ImplicitlyConvertiblePair<_U1, _U2>(),
259 : bool>::type=true>
260 6782 : constexpr pair(const _T1& __a, const _T2& __b)
261 13564 : : first(__a), second(__b) { }
262 :
263 : template<typename _U1 = _T1, typename _U2=_T2, typename
264 : enable_if<_PCCP::template
265 : _ConstructiblePair<_U1, _U2>()
266 : && !_PCCP::template
267 : _ImplicitlyConvertiblePair<_U1, _U2>(),
268 : bool>::type=false>
269 : explicit constexpr pair(const _T1& __a, const _T2& __b)
270 : : first(__a), second(__b) { }
271 : #endif
272 :
273 : /** There is also a templated copy ctor for the @c pair class itself. */
274 : #if __cplusplus < 201103L
275 : template<typename _U1, typename _U2>
276 : pair(const pair<_U1, _U2>& __p)
277 : : first(__p.first), second(__p.second) { }
278 : #else
279 : // Shortcut for constraining the templates that take pairs.
280 : template <typename _U1, typename _U2>
281 : using _PCCFP = _PCC<!is_same<_T1, _U1>::value
282 : || !is_same<_T2, _U2>::value,
283 : _T1, _T2>;
284 :
285 : template<typename _U1, typename _U2, typename
286 : enable_if<_PCCFP<_U1, _U2>::template
287 : _ConstructiblePair<_U1, _U2>()
288 : && _PCCFP<_U1, _U2>::template
289 : _ImplicitlyConvertiblePair<_U1, _U2>(),
290 : bool>::type=true>
291 3260 : constexpr pair(const pair<_U1, _U2>& __p)
292 3260 : : first(__p.first), second(__p.second) { }
293 :
294 : template<typename _U1, typename _U2, typename
295 : enable_if<_PCCFP<_U1, _U2>::template
296 : _ConstructiblePair<_U1, _U2>()
297 : && !_PCCFP<_U1, _U2>::template
298 : _ImplicitlyConvertiblePair<_U1, _U2>(),
299 : bool>::type=false>
300 : explicit constexpr pair(const pair<_U1, _U2>& __p)
301 : : first(__p.first), second(__p.second) { }
302 :
303 4441943 : constexpr pair(const pair&) = default;
304 2580544006 : constexpr pair(pair&&) = default;
305 :
306 : // DR 811.
307 : template<typename _U1, typename
308 : enable_if<_PCCP::template
309 : _MoveCopyPair<true, _U1, _T2>(),
310 : bool>::type=true>
311 40563709 : constexpr pair(_U1&& __x, const _T2& __y)
312 40566965 : : first(std::forward<_U1>(__x)), second(__y) { }
313 :
314 : template<typename _U1, typename
315 : enable_if<_PCCP::template
316 : _MoveCopyPair<false, _U1, _T2>(),
317 : bool>::type=false>
318 : explicit constexpr pair(_U1&& __x, const _T2& __y)
319 : : first(std::forward<_U1>(__x)), second(__y) { }
320 :
321 : template<typename _U2, typename
322 : enable_if<_PCCP::template
323 : _CopyMovePair<true, _T1, _U2>(),
324 : bool>::type=true>
325 101515149 : constexpr pair(const _T1& __x, _U2&& __y)
326 97478392 : : first(__x), second(std::forward<_U2>(__y)) { }
327 :
328 : template<typename _U2, typename
329 : enable_if<_PCCP::template
330 : _CopyMovePair<false, _T1, _U2>(),
331 : bool>::type=false>
332 : explicit pair(const _T1& __x, _U2&& __y)
333 : : first(__x), second(std::forward<_U2>(__y)) { }
334 :
335 : template<typename _U1, typename _U2, typename
336 : enable_if<_PCCP::template
337 : _MoveConstructiblePair<_U1, _U2>()
338 : && _PCCP::template
339 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
340 : bool>::type=true>
341 748745067 : constexpr pair(_U1&& __x, _U2&& __y)
342 878337996 : : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
343 :
344 : template<typename _U1, typename _U2, typename
345 : enable_if<_PCCP::template
346 : _MoveConstructiblePair<_U1, _U2>()
347 : && !_PCCP::template
348 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
349 : bool>::type=false>
350 : explicit constexpr pair(_U1&& __x, _U2&& __y)
351 : : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
352 :
353 :
354 : template<typename _U1, typename _U2, typename
355 : enable_if<_PCCFP<_U1, _U2>::template
356 : _MoveConstructiblePair<_U1, _U2>()
357 : && _PCCFP<_U1, _U2>::template
358 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
359 : bool>::type=true>
360 3237820 : constexpr pair(pair<_U1, _U2>&& __p)
361 3237167 : : first(std::forward<_U1>(__p.first)),
362 3266289 : second(std::forward<_U2>(__p.second)) { }
363 :
364 : template<typename _U1, typename _U2, typename
365 : enable_if<_PCCFP<_U1, _U2>::template
366 : _MoveConstructiblePair<_U1, _U2>()
367 : && !_PCCFP<_U1, _U2>::template
368 : _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
369 : bool>::type=false>
370 : explicit constexpr pair(pair<_U1, _U2>&& __p)
371 : : first(std::forward<_U1>(__p.first)),
372 : second(std::forward<_U2>(__p.second)) { }
373 :
374 : template<typename... _Args1, typename... _Args2>
375 : pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
376 :
377 : pair&
378 3500981 : operator=(typename conditional<
379 : __and_<is_copy_assignable<_T1>,
380 : is_copy_assignable<_T2>>::value,
381 : const pair&, const __nonesuch_no_braces&>::type __p)
382 : {
383 3500981 : first = __p.first;
384 3500867 : second = __p.second;
385 0 : return *this;
386 : }
387 :
388 : pair&
389 20611 : operator=(typename conditional<
390 : __and_<is_move_assignable<_T1>,
391 : is_move_assignable<_T2>>::value,
392 : pair&&, __nonesuch_no_braces&&>::type __p)
393 : noexcept(__and_<is_nothrow_move_assignable<_T1>,
394 : is_nothrow_move_assignable<_T2>>::value)
395 : {
396 20611 : first = std::forward<first_type>(__p.first);
397 20611 : second = std::forward<second_type>(__p.second);
398 0 : return *this;
399 : }
400 :
401 : template<typename _U1, typename _U2>
402 : typename enable_if<__and_<is_assignable<_T1&, const _U1&>,
403 : is_assignable<_T2&, const _U2&>>::value,
404 : pair&>::type
405 0 : operator=(const pair<_U1, _U2>& __p)
406 : {
407 0 : first = __p.first;
408 0 : second = __p.second;
409 0 : return *this;
410 : }
411 :
412 : template<typename _U1, typename _U2>
413 : typename enable_if<__and_<is_assignable<_T1&, _U1&&>,
414 : is_assignable<_T2&, _U2&&>>::value,
415 : pair&>::type
416 0 : operator=(pair<_U1, _U2>&& __p)
417 : {
418 0 : first = std::forward<_U1>(__p.first);
419 0 : second = std::forward<_U2>(__p.second);
420 : return *this;
421 : }
422 :
423 : void
424 0 : swap(pair& __p)
425 : noexcept(__and_<__is_nothrow_swappable<_T1>,
426 : __is_nothrow_swappable<_T2>>::value)
427 : {
428 : using std::swap;
429 0 : swap(first, __p.first);
430 0 : swap(second, __p.second);
431 0 : }
432 :
433 : private:
434 : template<typename... _Args1, std::size_t... _Indexes1,
435 : typename... _Args2, std::size_t... _Indexes2>
436 : pair(tuple<_Args1...>&, tuple<_Args2...>&,
437 : _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>);
438 : #endif
439 : };
440 :
441 : #if __cpp_deduction_guides >= 201606
442 : template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>;
443 : #endif
444 :
445 : /// Two pairs of the same type are equal iff their members are equal.
446 : template<typename _T1, typename _T2>
447 : inline _GLIBCXX_CONSTEXPR bool
448 405 : operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
449 309 : { return __x.first == __y.first && __x.second == __y.second; }
450 :
451 : /// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
452 : template<typename _T1, typename _T2>
453 : inline _GLIBCXX_CONSTEXPR bool
454 9589 : operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
455 0 : { return __x.first < __y.first
456 9589 : || (!(__y.first < __x.first) && __x.second < __y.second); }
457 :
458 : /// Uses @c operator== to find the result.
459 : template<typename _T1, typename _T2>
460 : inline _GLIBCXX_CONSTEXPR bool
461 0 : operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
462 0 : { return !(__x == __y); }
463 :
464 : /// Uses @c operator< to find the result.
465 : template<typename _T1, typename _T2>
466 : inline _GLIBCXX_CONSTEXPR bool
467 : operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
468 : { return __y < __x; }
469 :
470 : /// Uses @c operator< to find the result.
471 : template<typename _T1, typename _T2>
472 : inline _GLIBCXX_CONSTEXPR bool
473 : operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
474 : { return !(__y < __x); }
475 :
476 : /// Uses @c operator< to find the result.
477 : template<typename _T1, typename _T2>
478 : inline _GLIBCXX_CONSTEXPR bool
479 : operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
480 : { return !(__x < __y); }
481 :
482 : #if __cplusplus >= 201103L
483 : /// See std::pair::swap().
484 : // Note: no std::swap overloads in C++03 mode, this has performance
485 : // implications, see, eg, libstdc++/38466.
486 : template<typename _T1, typename _T2>
487 : inline
488 : #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
489 : // Constrained free swap overload, see p0185r1
490 : typename enable_if<__and_<__is_swappable<_T1>,
491 : __is_swappable<_T2>>::value>::type
492 : #else
493 : void
494 : #endif
495 0 : swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
496 : noexcept(noexcept(__x.swap(__y)))
497 0 : { __x.swap(__y); }
498 :
499 : #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
500 : template<typename _T1, typename _T2>
501 : typename enable_if<!__and_<__is_swappable<_T1>,
502 : __is_swappable<_T2>>::value>::type
503 : swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete;
504 : #endif
505 : #endif // __cplusplus >= 201103L
506 :
507 : /**
508 : * @brief A convenience wrapper for creating a pair from two objects.
509 : * @param __x The first object.
510 : * @param __y The second object.
511 : * @return A newly-constructed pair<> object of the appropriate type.
512 : *
513 : * The standard requires that the objects be passed by reference-to-const,
514 : * but LWG issue #181 says they should be passed by const value. We follow
515 : * the LWG by default.
516 : */
517 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
518 : // 181. make_pair() unintended behavior
519 : #if __cplusplus >= 201103L
520 : // NB: DR 706.
521 : template<typename _T1, typename _T2>
522 : constexpr pair<typename __decay_and_strip<_T1>::__type,
523 : typename __decay_and_strip<_T2>::__type>
524 4097308 : make_pair(_T1&& __x, _T2&& __y)
525 : {
526 : typedef typename __decay_and_strip<_T1>::__type __ds_type1;
527 : typedef typename __decay_and_strip<_T2>::__type __ds_type2;
528 : typedef pair<__ds_type1, __ds_type2> __pair_type;
529 6098682 : return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
530 : }
531 : #else
532 : template<typename _T1, typename _T2>
533 : inline pair<_T1, _T2>
534 : make_pair(_T1 __x, _T2 __y)
535 : { return pair<_T1, _T2>(__x, __y); }
536 : #endif
537 :
538 : /// @}
539 :
540 : _GLIBCXX_END_NAMESPACE_VERSION
541 : } // namespace std
542 :
543 : #endif /* _STL_PAIR_H */
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