DOOM-3-BFG/neo/idlib/containers/Queue.h

/*
===========================================================================

Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").  

Doom 3 BFG Edition Source Code 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 of the License, or
(at your option) any later version.

Doom 3 BFG Edition Source Code 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 Doom 3 BFG Edition Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 BFG Edition Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 BFG Edition Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/
#ifndef __QUEUE_H__
#define __QUEUE_H__

/*
===============================================================================

	Queue template

===============================================================================
*/
template< class type, int nextOffset >
class idQueueTemplate {
public:
							idQueueTemplate();

	void					Add( type *element );
	type *					Get();

private:
	type *					first;
	type *					last;
};

#define QUEUE_NEXT_PTR( element )		(*((type**)(((byte*)element)+nextOffset)))

template< class type, int nextOffset >
idQueueTemplate<type,nextOffset>::idQueueTemplate() {
	first = last = NULL;
}

template< class type, int nextOffset >
void idQueueTemplate<type,nextOffset>::Add( type *element ) {
	QUEUE_NEXT_PTR(element) = NULL;
	if ( last ) {
		QUEUE_NEXT_PTR(last) = element;
	} else {
		first = element;
	}
	last = element;
}

template< class type, int nextOffset >
type *idQueueTemplate<type,nextOffset>::Get() {
	type *element;

	element = first;
	if ( element ) {
		first = QUEUE_NEXT_PTR(first);
		if ( last == element ) {
			last = NULL;
		}
		QUEUE_NEXT_PTR(element) = NULL;
	}
	return element;
}

/*
================================================
A node of a Queue
================================================
*/
template< typename type >
class idQueueNode {
public:
				idQueueNode() { next = NULL; }

	type *		GetNext() const { return next; }
	void		SetNext( type *next ) { this->next = next; }

private:
	type *		next;
};

/*
================================================
A Queue, idQueue, is a template Container class implementing the Queue abstract data 
type.
================================================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
class idQueue {
public:
				idQueue();

	void		Add( type *element );
	type *		RemoveFirst();
	type *		Peek() const;
	bool		IsEmpty();

	static void	Test();

private:
	type *		first;
	type *		last;
};

/*
========================
idQueue<type,nodePtr>::idQueue
========================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
idQueue<type,nodePtr>::idQueue() {
	first = last = NULL;
}

/*
========================
idQueue<type,nodePtr>::Add
========================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
void idQueue<type,nodePtr>::Add( type *element ) {
	(element->*nodePtr).SetNext( NULL );
	if ( last ) {
		(last->*nodePtr).SetNext( element );
	} else {
		first = element;
	}
	last = element;
}

/*
========================
idQueue<type,nodePtr>::RemoveFirst
========================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
type *idQueue<type,nodePtr>::RemoveFirst() {
	type *element;

	element = first;
	if ( element ) {
		first = (first->*nodePtr).GetNext();
		if ( last == element ) {
			last = NULL;
		}
		(element->*nodePtr).SetNext( NULL );
	}
	return element;
}

/*
========================
idQueue<type,nodePtr>::Peek
========================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
type *idQueue<type,nodePtr>::Peek() const {
	return first;
}

/*
========================
idQueue<type,nodePtr>::IsEmpty
========================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
bool idQueue<type,nodePtr>::IsEmpty() {
	return ( first == NULL );
}

/*
========================
idQueue<type,nodePtr>::Test
========================
*/
template< typename type, idQueueNode<type> type::*nodePtr >
void idQueue<type,nodePtr>::Test() {

	class idMyType {
	public:
		idQueueNode<idMyType> queueNode;
	};

	idQueue<idMyType,&idMyType::queueNode> myQueue;

	idMyType *element = new (TAG_IDLIB) idMyType;
	myQueue.Add( element );
	element = myQueue.RemoveFirst();
	delete element;
}

#endif // !__QUEUE_H__