473 lines
16 KiB
C++
473 lines
16 KiB
C++
// Queue implementation -*- C++ -*-
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// Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996,1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file stl_queue.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*/
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#ifndef _QUEUE_H
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#define _QUEUE_H 1
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#include <bits/concept_check.h>
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#include <debug/debug.h>
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namespace std
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{
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// Forward declarations of operators < and ==, needed for friend declaration.
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template<typename _Tp, typename _Sequence = deque<_Tp> >
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class queue;
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template<typename _Tp, typename _Seq>
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inline bool
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operator==(const queue<_Tp,_Seq>&, const queue<_Tp,_Seq>&);
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template<typename _Tp, typename _Seq>
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inline bool
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operator<(const queue<_Tp,_Seq>&, const queue<_Tp,_Seq>&);
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/**
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* @brief A standard container giving FIFO behavior.
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*
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* @ingroup Containers
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* @ingroup Sequences
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*
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* Meets many of the requirements of a
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* <a href="tables.html#65">container</a>,
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* but does not define anything to do with iterators. Very few of the
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* other standard container interfaces are defined.
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*
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* This is not a true container, but an @e adaptor. It holds another
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* container, and provides a wrapper interface to that container. The
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* wrapper is what enforces strict first-in-first-out %queue behavior.
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*
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* The second template parameter defines the type of the underlying
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* sequence/container. It defaults to std::deque, but it can be any type
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* that supports @c front, @c back, @c push_back, and @c pop_front,
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* such as std::list or an appropriate user-defined type.
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*
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* Members not found in "normal" containers are @c container_type,
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* which is a typedef for the second Sequence parameter, and @c push and
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* @c pop, which are standard %queue/FIFO operations.
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*/
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template<typename _Tp, typename _Sequence>
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class queue
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{
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// concept requirements
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typedef typename _Sequence::value_type _Sequence_value_type;
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__glibcxx_class_requires(_Tp, _SGIAssignableConcept)
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__glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
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__glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
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__glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
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template<typename _Tp1, typename _Seq1>
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friend bool
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operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
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template<typename _Tp1, typename _Seq1>
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friend bool
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operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
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public:
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typedef typename _Sequence::value_type value_type;
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typedef typename _Sequence::reference reference;
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typedef typename _Sequence::const_reference const_reference;
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typedef typename _Sequence::size_type size_type;
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typedef _Sequence container_type;
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protected:
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/**
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* 'c' is the underlying container. Maintainers wondering why
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* this isn't uglified as per style guidelines should note that
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* this name is specified in the standard, [23.2.3.1]. (Why?
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* Presumably for the same reason that it's protected instead
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* of private: to allow derivation. But none of the other
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* containers allow for derivation. Odd.)
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*/
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_Sequence c;
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public:
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/**
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* @brief Default constructor creates no elements.
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*/
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explicit
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queue(const _Sequence& __c = _Sequence()) : c(__c) {}
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/**
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* Returns true if the %queue is empty.
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*/
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bool
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empty() const
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{ return c.empty(); }
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/** Returns the number of elements in the %queue. */
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size_type
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size() const
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{ return c.size(); }
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/**
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* Returns a read/write reference to the data at the first
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* element of the %queue.
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*/
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reference
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front()
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{
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__glibcxx_requires_nonempty();
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return c.front();
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}
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/**
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* Returns a read-only (constant) reference to the data at the first
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* element of the %queue.
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*/
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const_reference
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front() const
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{
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__glibcxx_requires_nonempty();
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return c.front();
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}
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/**
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* Returns a read/write reference to the data at the last
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* element of the %queue.
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*/
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reference
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back()
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{
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__glibcxx_requires_nonempty();
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return c.back();
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}
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/**
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* Returns a read-only (constant) reference to the data at the last
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* element of the %queue.
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*/
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const_reference
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back() const
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{
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__glibcxx_requires_nonempty();
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return c.back();
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}
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/**
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* @brief Add data to the end of the %queue.
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* @param x Data to be added.
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*
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* This is a typical %queue operation. The function creates an
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* element at the end of the %queue and assigns the given data
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* to it. The time complexity of the operation depends on the
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* underlying sequence.
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*/
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void
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push(const value_type& __x)
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{ c.push_back(__x); }
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/**
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* @brief Removes first element.
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*
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* This is a typical %queue operation. It shrinks the %queue by one.
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* The time complexity of the operation depends on the underlying
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* sequence.
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*
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* Note that no data is returned, and if the first element's
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* data is needed, it should be retrieved before pop() is
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* called.
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*/
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void
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pop()
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{
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__glibcxx_requires_nonempty();
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c.pop_front();
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}
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};
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/**
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* @brief Queue equality comparison.
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* @param x A %queue.
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* @param y A %queue of the same type as @a x.
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* @return True iff the size and elements of the queues are equal.
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*
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* This is an equivalence relation. Complexity and semantics depend on the
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* underlying sequence type, but the expected rules are: this relation is
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* linear in the size of the sequences, and queues are considered equivalent
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* if their sequences compare equal.
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*/
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template<typename _Tp, typename _Sequence>
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inline bool
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operator==(const queue<_Tp,_Sequence>& __x,
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const queue<_Tp,_Sequence>& __y)
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{ return __x.c == __y.c; }
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/**
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* @brief Queue ordering relation.
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* @param x A %queue.
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* @param y A %queue of the same type as @a x.
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* @return True iff @a x is lexicographically less than @a y.
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*
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* This is an total ordering relation. Complexity and semantics
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* depend on the underlying sequence type, but the expected rules
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* are: this relation is linear in the size of the sequences, the
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* elements must be comparable with @c <, and
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* std::lexicographical_compare() is usually used to make the
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* determination.
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*/
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template<typename _Tp, typename _Sequence>
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inline bool
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operator<(const queue<_Tp,_Sequence>& __x, const queue<_Tp,_Sequence>& __y)
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{ return __x.c < __y.c; }
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/// Based on operator==
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template<typename _Tp, typename _Sequence>
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inline bool
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operator!=(const queue<_Tp,_Sequence>& __x,
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const queue<_Tp,_Sequence>& __y)
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{ return !(__x == __y); }
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/// Based on operator<
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template<typename _Tp, typename _Sequence>
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inline bool
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operator>(const queue<_Tp,_Sequence>& __x, const queue<_Tp,_Sequence>& __y)
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{ return __y < __x; }
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/// Based on operator<
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template<typename _Tp, typename _Sequence>
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inline bool
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operator<=(const queue<_Tp,_Sequence>& __x,
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const queue<_Tp,_Sequence>& __y)
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{ return !(__y < __x); }
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/// Based on operator<
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template<typename _Tp, typename _Sequence>
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inline bool
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operator>=(const queue<_Tp,_Sequence>& __x,
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const queue<_Tp,_Sequence>& __y)
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{ return !(__x < __y); }
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/**
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* @brief A standard container automatically sorting its contents.
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*
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* @ingroup Containers
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* @ingroup Sequences
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*
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* This is not a true container, but an @e adaptor. It holds
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* another container, and provides a wrapper interface to that
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* container. The wrapper is what enforces sorting and
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* first-in-first-out %queue behavior. Very few of the standard
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* container/sequence interface requirements are met (e.g.,
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* iterators).
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*
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* The second template parameter defines the type of the underlying
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* sequence/container. It defaults to std::vector, but it can be
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* any type that supports @c front(), @c push_back, @c pop_back,
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* and random-access iterators, such as std::deque or an
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* appropriate user-defined type.
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*
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* The third template parameter supplies the means of making
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* priority comparisons. It defaults to @c less<value_type> but
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* can be anything defining a strict weak ordering.
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*
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* Members not found in "normal" containers are @c container_type,
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* which is a typedef for the second Sequence parameter, and @c
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* push, @c pop, and @c top, which are standard %queue/FIFO
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* operations.
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*
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* @note No equality/comparison operators are provided for
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* %priority_queue.
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*
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* @note Sorting of the elements takes place as they are added to,
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* and removed from, the %priority_queue using the
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* %priority_queue's member functions. If you access the elements
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* by other means, and change their data such that the sorting
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* order would be different, the %priority_queue will not re-sort
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* the elements for you. (How could it know to do so?)
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*/
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template<typename _Tp, typename _Sequence = vector<_Tp>,
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typename _Compare = less<typename _Sequence::value_type> >
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class priority_queue
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{
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// concept requirements
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typedef typename _Sequence::value_type _Sequence_value_type;
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__glibcxx_class_requires(_Tp, _SGIAssignableConcept)
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__glibcxx_class_requires(_Sequence, _SequenceConcept)
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__glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
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__glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
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__glibcxx_class_requires4(_Compare, bool, _Tp,_Tp,_BinaryFunctionConcept)
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public:
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typedef typename _Sequence::value_type value_type;
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typedef typename _Sequence::reference reference;
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typedef typename _Sequence::const_reference const_reference;
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typedef typename _Sequence::size_type size_type;
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typedef _Sequence container_type;
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protected:
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// See queue::c for notes on these names.
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_Sequence c;
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_Compare comp;
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public:
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/**
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* @brief Default constructor creates no elements.
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*/
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explicit
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priority_queue(const _Compare& __x = _Compare(),
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const _Sequence& __s = _Sequence())
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: c(__s), comp(__x)
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{ std::make_heap(c.begin(), c.end(), comp); }
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/**
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* @brief Builds a %queue from a range.
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* @param first An input iterator.
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* @param last An input iterator.
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* @param x A comparison functor describing a strict weak ordering.
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* @param s An initial sequence with which to start.
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*
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* Begins by copying @a s, inserting a copy of the elements
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* from @a [first,last) into the copy of @a s, then ordering
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* the copy according to @a x.
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*
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* For more information on function objects, see the
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* documentation on @link s20_3_1_base functor base
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* classes@endlink.
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*/
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template<typename _InputIterator>
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priority_queue(_InputIterator __first, _InputIterator __last,
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const _Compare& __x = _Compare(),
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const _Sequence& __s = _Sequence())
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: c(__s), comp(__x)
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{
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__glibcxx_requires_valid_range(__first, __last);
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c.insert(c.end(), __first, __last);
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std::make_heap(c.begin(), c.end(), comp);
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}
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/**
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* Returns true if the %queue is empty.
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*/
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bool
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empty() const { return c.empty(); }
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/** Returns the number of elements in the %queue. */
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size_type
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size() const { return c.size(); }
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/**
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* Returns a read-only (constant) reference to the data at the first
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* element of the %queue.
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*/
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const_reference
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top() const
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{
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__glibcxx_requires_nonempty();
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return c.front();
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}
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/**
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* @brief Add data to the %queue.
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* @param x Data to be added.
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*
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* This is a typical %queue operation.
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* The time complexity of the operation depends on the underlying
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* sequence.
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*/
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void
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push(const value_type& __x)
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{
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try
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{
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c.push_back(__x);
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std::push_heap(c.begin(), c.end(), comp);
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}
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catch(...)
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{
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c.clear();
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__throw_exception_again;
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}
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}
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/**
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* @brief Removes first element.
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*
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* This is a typical %queue operation. It shrinks the %queue
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* by one. The time complexity of the operation depends on the
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* underlying sequence.
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*
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* Note that no data is returned, and if the first element's
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* data is needed, it should be retrieved before pop() is
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* called.
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*/
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void
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pop()
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{
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__glibcxx_requires_nonempty();
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try
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{
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std::pop_heap(c.begin(), c.end(), comp);
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c.pop_back();
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}
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catch(...)
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{
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c.clear();
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__throw_exception_again;
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}
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}
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};
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// No equality/comparison operators are provided for priority_queue.
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} // namespace std
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#endif /* _QUEUE_H */
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