// Queue implementation -*- C++ -*- // Copyright (C) 2001-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996,1997 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Silicon Graphics makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. */ /** @file bits/stl_queue.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{queue} */ #ifndef _STL_QUEUE_H #define _STL_QUEUE_H 1 #include <bits/concept_check.h> #include <debug/debug.h> #if __cplusplus >= 201103L # include <bits/uses_allocator.h> #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @brief A standard container giving FIFO behavior. * * @ingroup sequences * * @tparam _Tp Type of element. * @tparam _Sequence Type of underlying sequence, defaults to deque<_Tp>. * * Meets many of the requirements of a * <a href="tables.html#65">container</a>, * but does not define anything to do with iterators. Very few of the * other standard container interfaces are defined. * * This is not a true container, but an @e adaptor. It holds another * container, and provides a wrapper interface to that container. The * wrapper is what enforces strict first-in-first-out %queue behavior. * * The second template parameter defines the type of the underlying * sequence/container. It defaults to std::deque, but it can be any type * that supports @c front, @c back, @c push_back, and @c pop_front, * such as std::list or an appropriate user-defined type. * * Members not found in @a normal containers are @c container_type, * which is a typedef for the second Sequence parameter, and @c push and * @c pop, which are standard %queue/FIFO operations. */ template<typename _Tp, typename _Sequence = deque<_Tp> > class queue { #ifdef _GLIBCXX_CONCEPT_CHECKS // concept requirements typedef typename _Sequence::value_type _Sequence_value_type; # if __cplusplus < 201103L __glibcxx_class_requires(_Tp, _SGIAssignableConcept) # endif __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept) __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept) __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept) #endif template<typename _Tp1, typename _Seq1> friend bool operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&); template<typename _Tp1, typename _Seq1> friend bool operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&); #if __cpp_lib_three_way_comparison template<typename _Tp1, three_way_comparable _Seq1> friend compare_three_way_result_t<_Seq1> operator<=>(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&); #endif #if __cplusplus >= 201103L template<typename _Alloc> using _Uses = typename enable_if<uses_allocator<_Sequence, _Alloc>::value>::type; #if __cplusplus >= 201703L // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2566. Requirements on the first template parameter of container // adaptors static_assert(is_same<_Tp, typename _Sequence::value_type>::value, "value_type must be the same as the underlying container"); #endif // C++17 #endif // C++11 public: typedef typename _Sequence::value_type value_type; typedef typename _Sequence::reference reference; typedef typename _Sequence::const_reference const_reference; typedef typename _Sequence::size_type size_type; typedef _Sequence container_type; protected: /* Maintainers wondering why this isn't uglified as per style * guidelines should note that this name is specified in the standard, * C++98 [23.2.3.1]. * (Why? Presumably for the same reason that it's protected instead * of private: to allow derivation. But none of the other * containers allow for derivation. Odd.) */ /// @c c is the underlying container. _Sequence c; public: /** * @brief Default constructor creates no elements. */ #if __cplusplus < 201103L explicit queue(const _Sequence& __c = _Sequence()) : c(__c) { } #else template<typename _Seq = _Sequence, typename _Requires = typename enable_if<is_default_constructible<_Seq>::value>::type> queue() : c() { } explicit queue(const _Sequence& __c) : c(__c) { } explicit queue(_Sequence&& __c) : c(std::move(__c)) { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> explicit queue(const _Alloc& __a) : c(__a) { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> queue(const _Sequence& __c, const _Alloc& __a) : c(__c, __a) { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> queue(_Sequence&& __c, const _Alloc& __a) : c(std::move(__c), __a) { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> queue(const queue& __q, const _Alloc& __a) : c(__q.c, __a) { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> queue(queue&& __q, const _Alloc& __a) : c(std::move(__q.c), __a) { } #endif /** * Returns true if the %queue is empty. */ _GLIBCXX_NODISCARD bool empty() const { return c.empty(); } /** Returns the number of elements in the %queue. */ size_type size() const { return c.size(); } /** * Returns a read/write reference to the data at the first * element of the %queue. */ reference front() { __glibcxx_requires_nonempty(); return c.front(); } /** * Returns a read-only (constant) reference to the data at the first * element of the %queue. */ const_reference front() const { __glibcxx_requires_nonempty(); return c.front(); } /** * Returns a read/write reference to the data at the last * element of the %queue. */ reference back() { __glibcxx_requires_nonempty(); return c.back(); } /** * Returns a read-only (constant) reference to the data at the last * element of the %queue. */ const_reference back() const { __glibcxx_requires_nonempty(); return c.back(); } /** * @brief Add data to the end of the %queue. * @param __x Data to be added. * * This is a typical %queue operation. The function creates an * element at the end of the %queue and assigns the given data * to it. The time complexity of the operation depends on the * underlying sequence. */ void push(const value_type& __x) { c.push_back(__x); } #if __cplusplus >= 201103L void push(value_type&& __x) { c.push_back(std::move(__x)); } #if __cplusplus > 201402L template<typename... _Args> decltype(auto) emplace(_Args&&... __args) { return c.emplace_back(std::forward<_Args>(__args)...); } #else template<typename... _Args> void emplace(_Args&&... __args) { c.emplace_back(std::forward<_Args>(__args)...); } #endif #endif /** * @brief Removes first element. * * This is a typical %queue operation. It shrinks the %queue by one. * The time complexity of the operation depends on the underlying * sequence. * * Note that no data is returned, and if the first element's * data is needed, it should be retrieved before pop() is * called. */ void pop() { __glibcxx_requires_nonempty(); c.pop_front(); } #if __cplusplus >= 201103L void swap(queue& __q) #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 noexcept(__is_nothrow_swappable<_Sequence>::value) #else noexcept(__is_nothrow_swappable<_Tp>::value) #endif { using std::swap; swap(c, __q.c); } #endif // __cplusplus >= 201103L }; #if __cpp_deduction_guides >= 201606 template<typename _Container, typename = _RequireNotAllocator<_Container>> queue(_Container) -> queue<typename _Container::value_type, _Container>; template<typename _Container, typename _Allocator, typename = _RequireNotAllocator<_Container>, typename = _RequireAllocator<_Allocator>> queue(_Container, _Allocator) -> queue<typename _Container::value_type, _Container>; #endif /** * @brief Queue equality comparison. * @param __x A %queue. * @param __y A %queue of the same type as @a __x. * @return True iff the size and elements of the queues are equal. * * This is an equivalence relation. Complexity and semantics depend on the * underlying sequence type, but the expected rules are: this relation is * linear in the size of the sequences, and queues are considered equivalent * if their sequences compare equal. */ template<typename _Tp, typename _Seq> inline bool operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return __x.c == __y.c; } /** * @brief Queue ordering relation. * @param __x A %queue. * @param __y A %queue of the same type as @a x. * @return True iff @a __x is lexicographically less than @a __y. * * This is an total ordering relation. Complexity and semantics * depend on the underlying sequence type, but the expected rules * are: this relation is linear in the size of the sequences, the * elements must be comparable with @c <, and * std::lexicographical_compare() is usually used to make the * determination. */ template<typename _Tp, typename _Seq> inline bool operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return __x.c < __y.c; } /// Based on operator== template<typename _Tp, typename _Seq> inline bool operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return !(__x == __y); } /// Based on operator< template<typename _Tp, typename _Seq> inline bool operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return __y < __x; } /// Based on operator< template<typename _Tp, typename _Seq> inline bool operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return !(__y < __x); } /// Based on operator< template<typename _Tp, typename _Seq> inline bool operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return !(__x < __y); } #if __cpp_lib_three_way_comparison template<typename _Tp, three_way_comparable _Seq> inline compare_three_way_result_t<_Seq> operator<=>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) { return __x.c <=> __y.c; } #endif #if __cplusplus >= 201103L template<typename _Tp, typename _Seq> inline #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 // Constrained free swap overload, see p0185r1 typename enable_if<__is_swappable<_Seq>::value>::type #else void #endif swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y) noexcept(noexcept(__x.swap(__y))) { __x.swap(__y); } template<typename _Tp, typename _Seq, typename _Alloc> struct uses_allocator<queue<_Tp, _Seq>, _Alloc> : public uses_allocator<_Seq, _Alloc>::type { }; #endif // __cplusplus >= 201103L /** * @brief A standard container automatically sorting its contents. * * @ingroup sequences * * @tparam _Tp Type of element. * @tparam _Sequence Type of underlying sequence, defaults to vector<_Tp>. * @tparam _Compare Comparison function object type, defaults to * less<_Sequence::value_type>. * * This is not a true container, but an @e adaptor. It holds * another container, and provides a wrapper interface to that * container. The wrapper is what enforces priority-based sorting * and %queue behavior. Very few of the standard container/sequence * interface requirements are met (e.g., iterators). * * The second template parameter defines the type of the underlying * sequence/container. It defaults to std::vector, but it can be * any type that supports @c front(), @c push_back, @c pop_back, * and random-access iterators, such as std::deque or an * appropriate user-defined type. * * The third template parameter supplies the means of making * priority comparisons. It defaults to @c less<value_type> but * can be anything defining a strict weak ordering. * * Members not found in @a normal containers are @c container_type, * which is a typedef for the second Sequence parameter, and @c * push, @c pop, and @c top, which are standard %queue operations. * * @note No equality/comparison operators are provided for * %priority_queue. * * @note Sorting of the elements takes place as they are added to, * and removed from, the %priority_queue using the * %priority_queue's member functions. If you access the elements * by other means, and change their data such that the sorting * order would be different, the %priority_queue will not re-sort * the elements for you. (How could it know to do so?) */ template<typename _Tp, typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type> > class priority_queue { #ifdef _GLIBCXX_CONCEPT_CHECKS // concept requirements typedef typename _Sequence::value_type _Sequence_value_type; # if __cplusplus < 201103L __glibcxx_class_requires(_Tp, _SGIAssignableConcept) # endif __glibcxx_class_requires(_Sequence, _SequenceConcept) __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept) __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept) __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp, _BinaryFunctionConcept) #endif #if __cplusplus >= 201103L template<typename _Alloc> using _Uses = typename enable_if<uses_allocator<_Sequence, _Alloc>::value>::type; #if __cplusplus >= 201703L // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2566. Requirements on the first template parameter of container // adaptors static_assert(is_same<_Tp, typename _Sequence::value_type>::value, "value_type must be the same as the underlying container"); #endif // C++17 #endif // C++11 public: typedef typename _Sequence::value_type value_type; typedef typename _Sequence::reference reference; typedef typename _Sequence::const_reference const_reference; typedef typename _Sequence::size_type size_type; typedef _Sequence container_type; // _GLIBCXX_RESOLVE_LIB_DEFECTS // DR 2684. priority_queue lacking comparator typedef typedef _Compare value_compare; protected: // See queue::c for notes on these names. _Sequence c; _Compare comp; public: /** * @brief Default constructor creates no elements. */ #if __cplusplus < 201103L explicit priority_queue(const _Compare& __x = _Compare(), const _Sequence& __s = _Sequence()) : c(__s), comp(__x) { std::make_heap(c.begin(), c.end(), comp); } #else template<typename _Seq = _Sequence, typename _Requires = typename enable_if<__and_<is_default_constructible<_Compare>, is_default_constructible<_Seq>>::value>::type> priority_queue() : c(), comp() { } explicit priority_queue(const _Compare& __x, const _Sequence& __s) : c(__s), comp(__x) { std::make_heap(c.begin(), c.end(), comp); } explicit priority_queue(const _Compare& __x, _Sequence&& __s = _Sequence()) : c(std::move(__s)), comp(__x) { std::make_heap(c.begin(), c.end(), comp); } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> explicit priority_queue(const _Alloc& __a) : c(__a), comp() { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> priority_queue(const _Compare& __x, const _Alloc& __a) : c(__a), comp(__x) { } // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2537. Constructors [...] taking allocators should call make_heap template<typename _Alloc, typename _Requires = _Uses<_Alloc>> priority_queue(const _Compare& __x, const _Sequence& __c, const _Alloc& __a) : c(__c, __a), comp(__x) { std::make_heap(c.begin(), c.end(), comp); } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> priority_queue(const _Compare& __x, _Sequence&& __c, const _Alloc& __a) : c(std::move(__c), __a), comp(__x) { std::make_heap(c.begin(), c.end(), comp); } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> priority_queue(const priority_queue& __q, const _Alloc& __a) : c(__q.c, __a), comp(__q.comp) { } template<typename _Alloc, typename _Requires = _Uses<_Alloc>> priority_queue(priority_queue&& __q, const _Alloc& __a) : c(std::move(__q.c), __a), comp(std::move(__q.comp)) { } #endif /** * @brief Builds a %queue from a range. * @param __first An input iterator. * @param __last An input iterator. * @param __x A comparison functor describing a strict weak ordering. * @param __s An initial sequence with which to start. * * Begins by copying @a __s, inserting a copy of the elements * from @a [first,last) into the copy of @a __s, then ordering * the copy according to @a __x. * * For more information on function objects, see the * documentation on @link functors functor base * classes@endlink. */ #if __cplusplus < 201103L template<typename _InputIterator> priority_queue(_InputIterator __first, _InputIterator __last, const _Compare& __x = _Compare(), const _Sequence& __s = _Sequence()) : c(__s), comp(__x) { __glibcxx_requires_valid_range(__first, __last); c.insert(c.end(), __first, __last); std::make_heap(c.begin(), c.end(), comp); } #else template<typename _InputIterator> priority_queue(_InputIterator __first, _InputIterator __last, const _Compare& __x, const _Sequence& __s) : c(__s), comp(__x) { __glibcxx_requires_valid_range(__first, __last); c.insert(c.end(), __first, __last); std::make_heap(c.begin(), c.end(), comp); } template<typename _InputIterator> priority_queue(_InputIterator __first, _InputIterator __last, const _Compare& __x = _Compare(), _Sequence&& __s = _Sequence()) : c(std::move(__s)), comp(__x) { __glibcxx_requires_valid_range(__first, __last); c.insert(c.end(), __first, __last); std::make_heap(c.begin(), c.end(), comp); } #endif /** * Returns true if the %queue is empty. */ _GLIBCXX_NODISCARD bool empty() const { return c.empty(); } /** Returns the number of elements in the %queue. */ size_type size() const { return c.size(); } /** * Returns a read-only (constant) reference to the data at the first * element of the %queue. */ const_reference top() const { __glibcxx_requires_nonempty(); return c.front(); } /** * @brief Add data to the %queue. * @param __x Data to be added. * * This is a typical %queue operation. * The time complexity of the operation depends on the underlying * sequence. */ void push(const value_type& __x) { c.push_back(__x); std::push_heap(c.begin(), c.end(), comp); } #if __cplusplus >= 201103L void push(value_type&& __x) { c.push_back(std::move(__x)); std::push_heap(c.begin(), c.end(), comp); } template<typename... _Args> void emplace(_Args&&... __args) { c.emplace_back(std::forward<_Args>(__args)...); std::push_heap(c.begin(), c.end(), comp); } #endif /** * @brief Removes first element. * * This is a typical %queue operation. It shrinks the %queue * by one. The time complexity of the operation depends on the * underlying sequence. * * Note that no data is returned, and if the first element's * data is needed, it should be retrieved before pop() is * called. */ void pop() { __glibcxx_requires_nonempty(); std::pop_heap(c.begin(), c.end(), comp); c.pop_back(); } #if __cplusplus >= 201103L void swap(priority_queue& __pq) noexcept(__and_< #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 __is_nothrow_swappable<_Sequence>, #else __is_nothrow_swappable<_Tp>, #endif __is_nothrow_swappable<_Compare> >::value) { using std::swap; swap(c, __pq.c); swap(comp, __pq.comp); } #endif // __cplusplus >= 201103L }; #if __cpp_deduction_guides >= 201606 template<typename _Compare, typename _Container, typename = _RequireNotAllocator<_Compare>, typename = _RequireNotAllocator<_Container>> priority_queue(_Compare, _Container) -> priority_queue<typename _Container::value_type, _Container, _Compare>; template<typename _InputIterator, typename _ValT = typename iterator_traits<_InputIterator>::value_type, typename _Compare = less<_ValT>, typename _Container = vector<_ValT>, typename = _RequireInputIter<_InputIterator>, typename = _RequireNotAllocator<_Compare>, typename = _RequireNotAllocator<_Container>> priority_queue(_InputIterator, _InputIterator, _Compare = _Compare(), _Container = _Container()) -> priority_queue<_ValT, _Container, _Compare>; template<typename _Compare, typename _Container, typename _Allocator, typename = _RequireNotAllocator<_Compare>, typename = _RequireNotAllocator<_Container>, typename = _RequireAllocator<_Allocator>> priority_queue(_Compare, _Container, _Allocator) -> priority_queue<typename _Container::value_type, _Container, _Compare>; #endif // No equality/comparison operators are provided for priority_queue. #if __cplusplus >= 201103L template<typename _Tp, typename _Sequence, typename _Compare> inline #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 // Constrained free swap overload, see p0185r1 typename enable_if<__and_<__is_swappable<_Sequence>, __is_swappable<_Compare>>::value>::type #else void #endif swap(priority_queue<_Tp, _Sequence, _Compare>& __x, priority_queue<_Tp, _Sequence, _Compare>& __y) noexcept(noexcept(__x.swap(__y))) { __x.swap(__y); } template<typename _Tp, typename _Sequence, typename _Compare, typename _Alloc> struct uses_allocator<priority_queue<_Tp, _Sequence, _Compare>, _Alloc> : public uses_allocator<_Sequence, _Alloc>::type { }; #endif // __cplusplus >= 201103L _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif /* _STL_QUEUE_H */