stl_queue.h
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// Queue implementation -*- C++ -*-
// Copyright (C) 2001-2018 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 __cplusplus >= 201103L
template<typename _Alloc>
using _Uses = typename
enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
#endif
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.
*/
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
};
/**
* @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 __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;
#endif
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) { }
template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
priority_queue(const _Compare& __x, const _Sequence& __c,
const _Alloc& __a)
: c(__c, __a), comp(__x) { }
template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
priority_queue(const _Compare& __x, _Sequence&& __c, const _Alloc& __a)
: c(std::move(__c), __a), comp(__x) { }
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.
*/
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
};
// 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 */
std::enable_if
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:1987
std::priority_queue::size
size_type size() const
Definition: stl_queue.h:572
std::priority_queue::pop
void pop()
Removes first element.
Definition: stl_queue.h:630
std::push_heap
void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
Push an element onto a heap using comparison functor.
Definition: stl_heap.h:189
std::priority_queue::priority_queue
priority_queue()
Default constructor creates no elements.
Definition: stl_queue.h:473
std::priority_queue::empty
bool empty() const
Definition: stl_queue.h:567
std::queue::front
reference front()
Definition: stl_queue.h:202
std::queue::size
size_type size() const
Definition: stl_queue.h:194
debug.h
std::is_default_constructible
is_default_constructible
Definition: type_traits:926
std::make_heap
void make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
Construct a heap over a range using comparison functor.
Definition: stl_heap.h:386
std::queue::front
const_reference front() const
Definition: stl_queue.h:213
std::queue::back
const_reference back() const
Definition: stl_queue.h:235
std::queue::pop
void pop()
Removes first element.
Definition: stl_queue.h:284
std::priority_queue::priority_queue
priority_queue(_InputIterator __first, _InputIterator __last, const _Compare &__x, const _Sequence &__s)
Builds a queue from a range.
Definition: stl_queue.h:541
std
ISO C++ entities toplevel namespace is std.
std::queue
A standard container giving FIFO behavior.
Definition: stl_queue.h:96
std::queue::c
_Sequence c
c is the underlying container.
Definition: stl_queue.h:139
std::priority_queue::push
void push(const value_type &__x)
Add data to the queue.
Definition: stl_queue.h:595
std::queue::queue
queue()
Default constructor creates no elements.
Definition: stl_queue.h:152
std::queue::empty
bool empty() const
Definition: stl_queue.h:189
std::pop_heap
void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
Pop an element off a heap using comparison functor.
Definition: stl_heap.h:304
std::uses_allocator
Declare uses_allocator so it can be specialized in <queue> etc.
Definition: memoryfwd.h:71
std::queue::push
void push(const value_type &__x)
Add data to the end of the queue.
Definition: stl_queue.h:251
concept_check.h
std::priority_queue
A standard container automatically sorting its contents.
Definition: stl_queue.h:423
std::priority_queue::top
const_reference top() const
Definition: stl_queue.h:580
std::queue::back
reference back()
Definition: stl_queue.h:224