queue.h

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (c) 1996-1997 The 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
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 * 1. Redistributions of source code must retain the above copyright
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 * 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 Network Research
 *      Group at Lawrence Berkeley National 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
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * @(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/queue/queue.h,v 1.31 2002/12/18 03:36:37 sundarra Exp $ (LBL)
 */

#ifndef ns_queue_h
#define ns_queue_h

#include "connector.h"
#include "packet.h"
#include "ip.h"
class Packet;

class PacketQueue : public TclObject {
public:
        PacketQueue() : head_(0), tail_(0), len_(0), bytes_(0) {}
        virtual int length() const { return (len_); }
        virtual int byteLength() const { return (bytes_); }
        virtual Packet* enque(Packet* p) { // Returns previous tail
                Packet* pt = tail_;
                if (!tail_) head_= tail_= p;
                else {
                        tail_->next_= p;
                        tail_= p;
                }
                tail_->next_= 0;
                ++len_;
                bytes_ += hdr_cmn::access(p)->size();
                return pt;
        }
        virtual Packet* deque() {
                if (!head_) return 0;
                Packet* p = head_;
                head_= p->next_; // 0 if p == tail_
                if (p == tail_) head_= tail_= 0;
                --len_;
                bytes_ -= hdr_cmn::access(p)->size();
                return p;
        }
        Packet* lookup(int n) {
                for (Packet* p = head_; p != 0; p = p->next_) {
                        if (--n < 0)
                                return (p);
                }
                return (0);
        }
        /* remove a specific packet, which must be in the queue */
        virtual void remove(Packet*);
        /* Remove a packet, located after a given packet. Either could be 0. */
        void remove(Packet *, Packet *);
        Packet* head() { return head_; }
        Packet* tail() { return tail_; }
        // MONARCH EXTNS
        virtual inline void enqueHead(Packet* p) {
                if (!head_) tail_ = p;
                p->next_ = head_;
                head_ = p;
                ++len_;
                bytes_ += hdr_cmn::access(p)->size();
        }
        void resetIterator() {iter = head_;}
        Packet* getNext() { 
                if (!iter) return 0;
                Packet *tmp = iter; iter = iter->next_;
                return tmp;
        }

protected:
        Packet* head_;
        Packet* tail_;
        int len_;               // packet count
        int bytes_;             // queue size in bytes


// MONARCH EXTNS
private:
        Packet *iter;
};

class Queue;

class QueueHandler : public Handler {
public:
        inline QueueHandler(Queue& q) : queue_(q) {}
        void handle(Event*);
private:
        Queue& queue_;
};


class Queue : public Connector {
public:
        virtual void enque(Packet*) = 0;
        virtual Packet* deque() = 0;
        virtual void recv(Packet*, Handler*);
        virtual void updateStats(int queuesize); 
        void resume();
        int blocked() const { return (blocked_ == 1); }
        void unblock() { blocked_ = 0; }
        void block() { blocked_ = 1; }
        int limit() { return qlim_; }
        int length() { return pq_->length(); }  /* number of pkts currently in
                                                 * underlying packet queue */
        int byteLength() { return pq_->byteLength(); }  /* number of bytes *
                                                 * currently in packet queue */
        virtual double utilization (void);
protected:
        Queue();
        ~Queue();
        void reset();
        int qlim_;              /* maximum allowed pkts in queue */
        int blocked_;           /* blocked now? */
        int unblock_on_resume_; /* unblock q on idle? */
        QueueHandler qh_;
        PacketQueue *pq_;       /* pointer to actual packet queue 
                                 * (maintained by the individual disciplines
                                 * like DropTail and RED). */
        double true_ave_;       /* true long-term average queue size */
        double total_time_;     /* total time average queue size compute for */


        void utilUpdate(double int_begin, double int_end, int link_state);
        double last_change_;  /* time at which state changed/utilization measured */
        double old_util_;     /* current utilization */ 
        double util_weight_;  /* decay factor for measuring the link utilization */
};

#endif

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