Queue.h

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

Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  

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

In addition, the Doom 3 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 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

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

#define idQueue( type, next )           idQueueTemplate<type, (int)&(((type*)NULL)->next)>

template< class type, int nextOffset >
class idQueueTemplate {
public:
                                                        idQueueTemplate( void );

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

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

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

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

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

#endif /* !__QUEUE_H__ */