barrier/lib/base/CPriorityQueue.h

/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2003 Chris Schoeneman
 * 
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file COPYING that should have accompanied this file.
 * 
 * This package 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.
 */

#ifndef CPRIORITYQUEUE_H
#define CPRIORITYQUEUE_H

#include "stdvector.h"
#include <algorithm>
#include <functional>

//! A priority queue with an iterator
/*!
This priority queue is the same as a standard priority queue except:
it sorts by std::greater, it has a forward iterator through the elements
(which can appear in any order), and its contents can be swapped.
*/
template <class T, class Container = std::vector<T>,
			class Compare = std::greater<typename Container::value_type> >
class CPriorityQueue {
public:
	typedef typename Container::value_type value_type;
	typedef typename Container::size_type size_type;
	typedef typename Container::iterator iterator;
	typedef typename Container::const_iterator const_iterator;
	typedef Container container_type;

	CPriorityQueue() { }
	CPriorityQueue(Container& swappedIn) { swap(swappedIn); }
	~CPriorityQueue() { }

	//! @name manipulators
	//@{

	//! Add element
	void				push(const value_type& v)
	{
		c.push_back(v);
		std::push_heap(c.begin(), c.end(), comp);
	}

	//! Remove head element
	void				pop()
	{
		std::pop_heap(c.begin(), c.end(), comp);
		c.pop_back();
	}

	//! Erase element
	void				erase(iterator i)
	{
		c.erase(i);
		std::make_heap(c.begin(), c.end(), comp);
	}

	//! Get start iterator
	iterator			begin()
	{
		return c.begin();
	}

	//! Get end iterator
	iterator			end()
	{
		return c.end();
	}

	//! Swap contents with another priority queue
	void				swap(CPriorityQueue<T, Container, Compare>& q)
	{
		c.swap(q.c);
	}

	//! Swap contents with another container
	void				swap(Container& c2)
	{
		c.swap(c2);
		std::make_heap(c.begin(), c.end(), comp);
	}

	//@}
	//! @name accessors
	//@{

	//! Returns true if there are no elements
	bool				empty() const
	{
		return c.empty();
	}

	//! Returns the number of elements
	size_type			size() const
	{
		return c.size();
	}

	//! Returns the head element
	const value_type&	top() const
	{
		return c.front();
	}

	//! Get start iterator
	const_iterator		begin() const
	{
		return c.begin();
	}

	//! Get end iterator
	const_iterator		end() const
	{
		return c.end();
	}

	//@}

private:
	Container			c;
	Compare				comp;
};

#endif