/* -*-	Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (c) 1994 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the Computer Systems
 *	Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /usr/src/mash/repository/vint/ns-2/drop-tail.cc,v 1.9 1998/06/27 01:23:44 gnguyen Exp $ (LBL)";
#endif

#include "drop-tail.h"

static class DropTailClass : public TclClass {
 public:
	DropTailClass() : TclClass("Queue/DropTail") {}
	TclObject* create(int, const char*const*) {
		return (new DropTail);
	}
} class_drop_tail;

int 
DropTail::command(int argc, const char*const* argv) {

	if (argc == 3) {
		if (!strcmp(argv[1], "packetqueue-attach")) {
			delete q_;
			if (!(q_ = (PacketQueue*) TclObject::lookup(argv[2])))
				return (TCL_ERROR);
			else {
				pq_ = q_;
				return (TCL_OK);
			}
		}
	}
	return Queue::command(argc, argv);
}
/*
 * drop-tail
 */
void DropTail::enque(Packet* p)
{
	q_->enque(p);
	if (q_->length() >= qlim_) {
		if (drop_front_) { /* remove from head of queue */
			Packet *pp = q_->deque();
			drop(pp);
		} else {
			q_->remove(p);
			drop(p);
		}
	}
}

Packet* DropTail::deque()
{
	return q_->deque();
}