RetroShare/libretroshare/src/pqi/pqiqos.h
2011-09-08 19:25:17 +00:00

90 lines
2.3 KiB
C++

/*
* libretroshare/src/pqi: pqiqos.h
*
* 3P/PQI network interface for RetroShare.
*
* Copyright 2004-2008 by Cyril Soler
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License Version 2 as published by the Free Software Foundation.
*
* 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*
* Please report all bugs and problems to "csoler@users.sourceforge.net"
*
*/
// This class handles the prioritisation of RsItem, based on the
// priority level. The QoS algorithm must ensure that:
//
// - lower priority items get out with lower rate than high priority items
// - items of equal priority get out of the queue in the same order than they got in
// - items of level n+1 are output \alpha times more often than items of level n.
// \alpha is a constant that is not necessarily an integer, but strictly > 1.
// - the set of possible priority levels is finite, and pre-determined.
//
#include <vector>
#include <list>
class RsItem ;
class pqiQoS
{
public:
pqiQoS(uint32_t max_levels,float alpha) ;
class ItemQueue
{
public:
RsItem *pop()
{
if(_items.empty())
return NULL ;
RsItem *item = _items.front() ;
_items.pop_front() ;
return item ;
}
void push(RsItem *item)
{
_items.push_back(item) ;
}
float _threshold ;
float _counter ;
float _inc ;
std::list<RsItem*> _items ;
};
// This function pops items from the queue, y order of priority
//
RsItem *out_rsItem() ;
// This function is used to queue items.
//
void in_rsItem(RsItem *item) ;
void print() const ;
uint64_t qos_queue_size() const { return _nb_items ; }
private:
// This vector stores the lists of items with equal priorities.
//
std::vector<ItemQueue> _item_queues ;
float _alpha ;
uint64_t _nb_items ;
};