1 // Set implementation -*- C++ -*-
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51 /** @file bits/stl_set.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{set}
59 #include <bits/concept_check.h>
60 #if __cplusplus >= 201103L
61 #include <initializer_list>
64 namespace std _GLIBCXX_VISIBILITY(default)
66 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
69 * @brief A standard container made up of unique keys, which can be
70 * retrieved in logarithmic time.
72 * @ingroup associative_containers
74 * @tparam _Key Type of key objects.
75 * @tparam _Compare Comparison function object type, defaults to less<_Key>.
76 * @tparam _Alloc Allocator type, defaults to allocator<_Key>.
78 * Meets the requirements of a <a href="tables.html#65">container</a>, a
79 * <a href="tables.html#66">reversible container</a>, and an
80 * <a href="tables.html#69">associative container</a> (using unique keys).
82 * Sets support bidirectional iterators.
84 * The private tree data is declared exactly the same way for set and
85 * multiset; the distinction is made entirely in how the tree functions are
86 * called (*_unique versus *_equal, same as the standard).
88 template<typename _Key, typename _Compare = std::less<_Key>,
89 typename _Alloc = std::allocator<_Key> >
92 // concept requirements
93 typedef typename _Alloc::value_type _Alloc_value_type;
94 __glibcxx_class_requires(_Key, _SGIAssignableConcept)
95 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
96 _BinaryFunctionConcept)
97 __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
103 typedef _Key key_type;
104 typedef _Key value_type;
105 typedef _Compare key_compare;
106 typedef _Compare value_compare;
107 typedef _Alloc allocator_type;
111 typedef typename _Alloc::template rebind<_Key>::other _Key_alloc_type;
113 typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
114 key_compare, _Key_alloc_type> _Rep_type;
115 _Rep_type _M_t; // Red-black tree representing set.
119 /// Iterator-related typedefs.
120 typedef typename _Key_alloc_type::pointer pointer;
121 typedef typename _Key_alloc_type::const_pointer const_pointer;
122 typedef typename _Key_alloc_type::reference reference;
123 typedef typename _Key_alloc_type::const_reference const_reference;
124 // _GLIBCXX_RESOLVE_LIB_DEFECTS
125 // DR 103. set::iterator is required to be modifiable,
126 // but this allows modification of keys.
127 typedef typename _Rep_type::const_iterator iterator;
128 typedef typename _Rep_type::const_iterator const_iterator;
129 typedef typename _Rep_type::const_reverse_iterator reverse_iterator;
130 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
131 typedef typename _Rep_type::size_type size_type;
132 typedef typename _Rep_type::difference_type difference_type;
135 // allocation/deallocation
137 * @brief Default constructor creates no elements.
143 * @brief Creates a %set with no elements.
144 * @param __comp Comparator to use.
145 * @param __a An allocator object.
148 set(const _Compare& __comp,
149 const allocator_type& __a = allocator_type())
150 : _M_t(__comp, _Key_alloc_type(__a)) { }
153 * @brief Builds a %set from a range.
154 * @param __first An input iterator.
155 * @param __last An input iterator.
157 * Create a %set consisting of copies of the elements from
158 * [__first,__last). This is linear in N if the range is
159 * already sorted, and NlogN otherwise (where N is
160 * distance(__first,__last)).
162 template<typename _InputIterator>
163 set(_InputIterator __first, _InputIterator __last)
165 { _M_t._M_insert_unique(__first, __last); }
168 * @brief Builds a %set from a range.
169 * @param __first An input iterator.
170 * @param __last An input iterator.
171 * @param __comp A comparison functor.
172 * @param __a An allocator object.
174 * Create a %set consisting of copies of the elements from
175 * [__first,__last). This is linear in N if the range is
176 * already sorted, and NlogN otherwise (where N is
177 * distance(__first,__last)).
179 template<typename _InputIterator>
180 set(_InputIterator __first, _InputIterator __last,
181 const _Compare& __comp,
182 const allocator_type& __a = allocator_type())
183 : _M_t(__comp, _Key_alloc_type(__a))
184 { _M_t._M_insert_unique(__first, __last); }
187 * @brief %Set copy constructor.
188 * @param __x A %set of identical element and allocator types.
190 * The newly-created %set uses a copy of the allocation object used
196 #if __cplusplus >= 201103L
198 * @brief %Set move constructor
199 * @param __x A %set of identical element and allocator types.
201 * The newly-created %set contains the exact contents of @a x.
202 * The contents of @a x are a valid, but unspecified %set.
205 noexcept(is_nothrow_copy_constructible<_Compare>::value)
206 : _M_t(std::move(__x._M_t)) { }
209 * @brief Builds a %set from an initializer_list.
210 * @param __l An initializer_list.
211 * @param __comp A comparison functor.
212 * @param __a An allocator object.
214 * Create a %set consisting of copies of the elements in the list.
215 * This is linear in N if the list is already sorted, and NlogN
216 * otherwise (where N is @a __l.size()).
218 set(initializer_list<value_type> __l,
219 const _Compare& __comp = _Compare(),
220 const allocator_type& __a = allocator_type())
221 : _M_t(__comp, _Key_alloc_type(__a))
222 { _M_t._M_insert_unique(__l.begin(), __l.end()); }
226 * @brief %Set assignment operator.
227 * @param __x A %set of identical element and allocator types.
229 * All the elements of @a __x are copied, but unlike the copy
230 * constructor, the allocator object is not copied.
233 operator=(const set& __x)
239 #if __cplusplus >= 201103L
241 * @brief %Set move assignment operator.
242 * @param __x A %set of identical element and allocator types.
244 * The contents of @a __x are moved into this %set (without copying).
245 * @a __x is a valid, but unspecified %set.
258 * @brief %Set list assignment operator.
259 * @param __l An initializer_list.
261 * This function fills a %set with copies of the elements in the
262 * initializer list @a __l.
264 * Note that the assignment completely changes the %set and
265 * that the resulting %set's size is the same as the number
266 * of elements assigned. Old data may be lost.
269 operator=(initializer_list<value_type> __l)
272 this->insert(__l.begin(), __l.end());
279 /// Returns the comparison object with which the %set was constructed.
282 { return _M_t.key_comp(); }
283 /// Returns the comparison object with which the %set was constructed.
286 { return _M_t.key_comp(); }
287 /// Returns the allocator object with which the %set was constructed.
289 get_allocator() const _GLIBCXX_NOEXCEPT
290 { return allocator_type(_M_t.get_allocator()); }
293 * Returns a read-only (constant) iterator that points to the first
294 * element in the %set. Iteration is done in ascending order according
298 begin() const _GLIBCXX_NOEXCEPT
299 { return _M_t.begin(); }
302 * Returns a read-only (constant) iterator that points one past the last
303 * element in the %set. Iteration is done in ascending order according
307 end() const _GLIBCXX_NOEXCEPT
308 { return _M_t.end(); }
311 * Returns a read-only (constant) iterator that points to the last
312 * element in the %set. Iteration is done in descending order according
316 rbegin() const _GLIBCXX_NOEXCEPT
317 { return _M_t.rbegin(); }
320 * Returns a read-only (constant) reverse iterator that points to the
321 * last pair in the %set. Iteration is done in descending order
322 * according to the keys.
325 rend() const _GLIBCXX_NOEXCEPT
326 { return _M_t.rend(); }
328 #if __cplusplus >= 201103L
330 * Returns a read-only (constant) iterator that points to the first
331 * element in the %set. Iteration is done in ascending order according
335 cbegin() const noexcept
336 { return _M_t.begin(); }
339 * Returns a read-only (constant) iterator that points one past the last
340 * element in the %set. Iteration is done in ascending order according
344 cend() const noexcept
345 { return _M_t.end(); }
348 * Returns a read-only (constant) iterator that points to the last
349 * element in the %set. Iteration is done in descending order according
353 crbegin() const noexcept
354 { return _M_t.rbegin(); }
357 * Returns a read-only (constant) reverse iterator that points to the
358 * last pair in the %set. Iteration is done in descending order
359 * according to the keys.
362 crend() const noexcept
363 { return _M_t.rend(); }
366 /// Returns true if the %set is empty.
368 empty() const _GLIBCXX_NOEXCEPT
369 { return _M_t.empty(); }
371 /// Returns the size of the %set.
373 size() const _GLIBCXX_NOEXCEPT
374 { return _M_t.size(); }
376 /// Returns the maximum size of the %set.
378 max_size() const _GLIBCXX_NOEXCEPT
379 { return _M_t.max_size(); }
382 * @brief Swaps data with another %set.
383 * @param __x A %set of the same element and allocator types.
385 * This exchanges the elements between two sets in constant
386 * time. (It is only swapping a pointer, an integer, and an
387 * instance of the @c Compare type (which itself is often
388 * stateless and empty), so it should be quite fast.) Note
389 * that the global std::swap() function is specialized such
390 * that std::swap(s1,s2) will feed to this function.
394 { _M_t.swap(__x._M_t); }
397 #if __cplusplus >= 201103L
399 * @brief Attempts to build and insert an element into the %set.
400 * @param __args Arguments used to generate an element.
401 * @return A pair, of which the first element is an iterator that points
402 * to the possibly inserted element, and the second is a bool
403 * that is true if the element was actually inserted.
405 * This function attempts to build and insert an element into the %set.
406 * A %set relies on unique keys and thus an element is only inserted if
407 * it is not already present in the %set.
409 * Insertion requires logarithmic time.
411 template<typename... _Args>
412 std::pair<iterator, bool>
413 emplace(_Args&&... __args)
414 { return _M_t._M_emplace_unique(std::forward<_Args>(__args)...); }
417 * @brief Attempts to insert an element into the %set.
418 * @param __pos An iterator that serves as a hint as to where the
419 * element should be inserted.
420 * @param __args Arguments used to generate the element to be
422 * @return An iterator that points to the element with key equivalent to
423 * the one generated from @a __args (may or may not be the
426 * This function is not concerned about whether the insertion took place,
427 * and thus does not return a boolean like the single-argument emplace()
428 * does. Note that the first parameter is only a hint and can
429 * potentially improve the performance of the insertion process. A bad
430 * hint would cause no gains in efficiency.
432 * For more on @a hinting, see:
433 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
435 * Insertion requires logarithmic time (if the hint is not taken).
437 template<typename... _Args>
439 emplace_hint(const_iterator __pos, _Args&&... __args)
441 return _M_t._M_emplace_hint_unique(__pos,
442 std::forward<_Args>(__args)...);
447 * @brief Attempts to insert an element into the %set.
448 * @param __x Element to be inserted.
449 * @return A pair, of which the first element is an iterator that points
450 * to the possibly inserted element, and the second is a bool
451 * that is true if the element was actually inserted.
453 * This function attempts to insert an element into the %set. A %set
454 * relies on unique keys and thus an element is only inserted if it is
455 * not already present in the %set.
457 * Insertion requires logarithmic time.
459 std::pair<iterator, bool>
460 insert(const value_type& __x)
462 std::pair<typename _Rep_type::iterator, bool> __p =
463 _M_t._M_insert_unique(__x);
464 return std::pair<iterator, bool>(__p.first, __p.second);
467 #if __cplusplus >= 201103L
468 std::pair<iterator, bool>
469 insert(value_type&& __x)
471 std::pair<typename _Rep_type::iterator, bool> __p =
472 _M_t._M_insert_unique(std::move(__x));
473 return std::pair<iterator, bool>(__p.first, __p.second);
478 * @brief Attempts to insert an element into the %set.
479 * @param __position An iterator that serves as a hint as to where the
480 * element should be inserted.
481 * @param __x Element to be inserted.
482 * @return An iterator that points to the element with key of
483 * @a __x (may or may not be the element passed in).
485 * This function is not concerned about whether the insertion took place,
486 * and thus does not return a boolean like the single-argument insert()
487 * does. Note that the first parameter is only a hint and can
488 * potentially improve the performance of the insertion process. A bad
489 * hint would cause no gains in efficiency.
491 * For more on @a hinting, see:
492 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
494 * Insertion requires logarithmic time (if the hint is not taken).
497 insert(const_iterator __position, const value_type& __x)
498 { return _M_t._M_insert_unique_(__position, __x); }
500 #if __cplusplus >= 201103L
502 insert(const_iterator __position, value_type&& __x)
503 { return _M_t._M_insert_unique_(__position, std::move(__x)); }
507 * @brief A template function that attempts to insert a range
509 * @param __first Iterator pointing to the start of the range to be
511 * @param __last Iterator pointing to the end of the range.
513 * Complexity similar to that of the range constructor.
515 template<typename _InputIterator>
517 insert(_InputIterator __first, _InputIterator __last)
518 { _M_t._M_insert_unique(__first, __last); }
520 #if __cplusplus >= 201103L
522 * @brief Attempts to insert a list of elements into the %set.
523 * @param __l A std::initializer_list<value_type> of elements
526 * Complexity similar to that of the range constructor.
529 insert(initializer_list<value_type> __l)
530 { this->insert(__l.begin(), __l.end()); }
533 #if __cplusplus >= 201103L
534 // _GLIBCXX_RESOLVE_LIB_DEFECTS
535 // DR 130. Associative erase should return an iterator.
537 * @brief Erases an element from a %set.
538 * @param __position An iterator pointing to the element to be erased.
539 * @return An iterator pointing to the element immediately following
540 * @a __position prior to the element being erased. If no such
541 * element exists, end() is returned.
543 * This function erases an element, pointed to by the given iterator,
544 * from a %set. Note that this function only erases the element, and
545 * that if the element is itself a pointer, the pointed-to memory is not
546 * touched in any way. Managing the pointer is the user's
549 _GLIBCXX_ABI_TAG_CXX11
551 erase(const_iterator __position)
552 { return _M_t.erase(__position); }
555 * @brief Erases an element from a %set.
556 * @param position An iterator pointing to the element to be erased.
558 * This function erases an element, pointed to by the given iterator,
559 * from a %set. Note that this function only erases the element, and
560 * that if the element is itself a pointer, the pointed-to memory is not
561 * touched in any way. Managing the pointer is the user's
565 erase(iterator __position)
566 { _M_t.erase(__position); }
570 * @brief Erases elements according to the provided key.
571 * @param __x Key of element to be erased.
572 * @return The number of elements erased.
574 * This function erases all the elements located by the given key from
576 * Note that this function only erases the element, and that if
577 * the element is itself a pointer, the pointed-to memory is not touched
578 * in any way. Managing the pointer is the user's responsibility.
581 erase(const key_type& __x)
582 { return _M_t.erase(__x); }
584 #if __cplusplus >= 201103L
585 // _GLIBCXX_RESOLVE_LIB_DEFECTS
586 // DR 130. Associative erase should return an iterator.
588 * @brief Erases a [__first,__last) range of elements from a %set.
589 * @param __first Iterator pointing to the start of the range to be
592 * @param __last Iterator pointing to the end of the range to
594 * @return The iterator @a __last.
596 * This function erases a sequence of elements from a %set.
597 * Note that this function only erases the element, and that if
598 * the element is itself a pointer, the pointed-to memory is not touched
599 * in any way. Managing the pointer is the user's responsibility.
601 _GLIBCXX_ABI_TAG_CXX11
603 erase(const_iterator __first, const_iterator __last)
604 { return _M_t.erase(__first, __last); }
607 * @brief Erases a [first,last) range of elements from a %set.
608 * @param __first Iterator pointing to the start of the range to be
610 * @param __last Iterator pointing to the end of the range to
613 * This function erases a sequence of elements from a %set.
614 * Note that this function only erases the element, and that if
615 * the element is itself a pointer, the pointed-to memory is not touched
616 * in any way. Managing the pointer is the user's responsibility.
619 erase(iterator __first, iterator __last)
620 { _M_t.erase(__first, __last); }
624 * Erases all elements in a %set. Note that this function only erases
625 * the elements, and that if the elements themselves are pointers, the
626 * pointed-to memory is not touched in any way. Managing the pointer is
627 * the user's responsibility.
630 clear() _GLIBCXX_NOEXCEPT
636 * @brief Finds the number of elements.
637 * @param __x Element to located.
638 * @return Number of elements with specified key.
640 * This function only makes sense for multisets; for set the result will
641 * either be 0 (not present) or 1 (present).
644 count(const key_type& __x) const
645 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
647 // _GLIBCXX_RESOLVE_LIB_DEFECTS
648 // 214. set::find() missing const overload
651 * @brief Tries to locate an element in a %set.
652 * @param __x Element to be located.
653 * @return Iterator pointing to sought-after element, or end() if not
656 * This function takes a key and tries to locate the element with which
657 * the key matches. If successful the function returns an iterator
658 * pointing to the sought after element. If unsuccessful it returns the
659 * past-the-end ( @c end() ) iterator.
662 find(const key_type& __x)
663 { return _M_t.find(__x); }
666 find(const key_type& __x) const
667 { return _M_t.find(__x); }
672 * @brief Finds the beginning of a subsequence matching given key.
673 * @param __x Key to be located.
674 * @return Iterator pointing to first element equal to or greater
675 * than key, or end().
677 * This function returns the first element of a subsequence of elements
678 * that matches the given key. If unsuccessful it returns an iterator
679 * pointing to the first element that has a greater value than given key
680 * or end() if no such element exists.
683 lower_bound(const key_type& __x)
684 { return _M_t.lower_bound(__x); }
687 lower_bound(const key_type& __x) const
688 { return _M_t.lower_bound(__x); }
693 * @brief Finds the end of a subsequence matching given key.
694 * @param __x Key to be located.
695 * @return Iterator pointing to the first element
696 * greater than key, or end().
699 upper_bound(const key_type& __x)
700 { return _M_t.upper_bound(__x); }
703 upper_bound(const key_type& __x) const
704 { return _M_t.upper_bound(__x); }
709 * @brief Finds a subsequence matching given key.
710 * @param __x Key to be located.
711 * @return Pair of iterators that possibly points to the subsequence
712 * matching given key.
714 * This function is equivalent to
716 * std::make_pair(c.lower_bound(val),
717 * c.upper_bound(val))
719 * (but is faster than making the calls separately).
721 * This function probably only makes sense for multisets.
723 std::pair<iterator, iterator>
724 equal_range(const key_type& __x)
725 { return _M_t.equal_range(__x); }
727 std::pair<const_iterator, const_iterator>
728 equal_range(const key_type& __x) const
729 { return _M_t.equal_range(__x); }
732 template<typename _K1, typename _C1, typename _A1>
734 operator==(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
736 template<typename _K1, typename _C1, typename _A1>
738 operator<(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
743 * @brief Set equality comparison.
745 * @param __y A %set of the same type as @a x.
746 * @return True iff the size and elements of the sets are equal.
748 * This is an equivalence relation. It is linear in the size of the sets.
749 * Sets are considered equivalent if their sizes are equal, and if
750 * corresponding elements compare equal.
752 template<typename _Key, typename _Compare, typename _Alloc>
754 operator==(const set<_Key, _Compare, _Alloc>& __x,
755 const set<_Key, _Compare, _Alloc>& __y)
756 { return __x._M_t == __y._M_t; }
759 * @brief Set ordering relation.
761 * @param __y A %set of the same type as @a x.
762 * @return True iff @a __x is lexicographically less than @a __y.
764 * This is a total ordering relation. It is linear in the size of the
765 * maps. The elements must be comparable with @c <.
767 * See std::lexicographical_compare() for how the determination is made.
769 template<typename _Key, typename _Compare, typename _Alloc>
771 operator<(const set<_Key, _Compare, _Alloc>& __x,
772 const set<_Key, _Compare, _Alloc>& __y)
773 { return __x._M_t < __y._M_t; }
775 /// Returns !(x == y).
776 template<typename _Key, typename _Compare, typename _Alloc>
778 operator!=(const set<_Key, _Compare, _Alloc>& __x,
779 const set<_Key, _Compare, _Alloc>& __y)
780 { return !(__x == __y); }
783 template<typename _Key, typename _Compare, typename _Alloc>
785 operator>(const set<_Key, _Compare, _Alloc>& __x,
786 const set<_Key, _Compare, _Alloc>& __y)
787 { return __y < __x; }
790 template<typename _Key, typename _Compare, typename _Alloc>
792 operator<=(const set<_Key, _Compare, _Alloc>& __x,
793 const set<_Key, _Compare, _Alloc>& __y)
794 { return !(__y < __x); }
797 template<typename _Key, typename _Compare, typename _Alloc>
799 operator>=(const set<_Key, _Compare, _Alloc>& __x,
800 const set<_Key, _Compare, _Alloc>& __y)
801 { return !(__x < __y); }
803 /// See std::set::swap().
804 template<typename _Key, typename _Compare, typename _Alloc>
806 swap(set<_Key, _Compare, _Alloc>& __x, set<_Key, _Compare, _Alloc>& __y)
809 _GLIBCXX_END_NAMESPACE_CONTAINER
811 #endif /* _STL_SET_H */