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// Queue implementation -*- C++ -*-
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
// 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 2, 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.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING. If not, write to the Free
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
// USA.
// As a special exception, you may use this file as part of a free software
// library without restriction. Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License. This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.
/*
*
* 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 stl_queue.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*/
#ifndef _QUEUE_H
#define _QUEUE_H 1
#include <bits/concept_check.h>
#include <debug/debug.h>
_GLIBCXX_BEGIN_NAMESPACE(std)
/**
* @brief A standard container giving FIFO behavior.
*
* @ingroup Containers
* @ingroup Sequences
*
* 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 "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
{
// concept requirements
typedef typename _Sequence::value_type _Sequence_value_type;
__glibcxx_class_requires(_Tp, _SGIAssignableConcept)
__glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
__glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
__glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
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>&);
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:
/**
* 'c' is the underlying container. Maintainers wondering why
* this isn't uglified as per style guidelines should note that
* this name is specified in the standard, [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.)
*/
_Sequence c;
public:
/**
* @brief Default constructor creates no elements.
*/
explicit
queue(const _Sequence& __c = _Sequence()) : c(__c) {}
/**
* 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); }
/**
* @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();
}
};
/**
* @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); }
/**
* @brief A standard container automatically sorting its contents.
*
* @ingroup Containers
* @ingroup Sequences
*
* 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 "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
{
// concept requirements
typedef typename _Sequence::value_type _Sequence_value_type;
__glibcxx_class_requires(_Tp, _SGIAssignableConcept)
__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)
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:
// See queue::c for notes on these names.
_Sequence c;
_Compare comp;
public:
/**
* @brief Default constructor creates no elements.
*/
explicit
priority_queue(const _Compare& __x = _Compare(),
const _Sequence& __s = _Sequence())
: c(__s), comp(__x)
{ std::make_heap(c.begin(), c.end(), comp); }
/**
* @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 s20_3_1_base functor base
* classes@endlink.
*/
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);
}
/**
* 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);
}
/**
* @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();
}
};
// No equality/comparison operators are provided for priority_queue.
_GLIBCXX_END_NAMESPACE
#endif /* _QUEUE_H */
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