scheduler.h

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/* -*-  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
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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 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.
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 *
 * @(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/common/scheduler.h,v 1.26 2002/08/02 01:35:20 yuri Exp $ (LBL)
 */

#ifndef ns_scheduler_h
#define ns_scheduler_h

#include "config.h"

// Make use of 64 bit integers if available.
#ifdef HAVE_INT64
typedef int64_t scheduler_uid_t;
#define UID_PRINTF_FORMAT STRTOI64_FMTSTR
#define STRTOUID(S) STRTOI64((S), NULL, 0)
#else
typedef int scheduler_uid_t;
#define UID_PRINTF_FORMAT "%d"
#define STRTOUID(S) atoi((S))
#endif


class Handler;

class Event {
public:
        Event* next_;           /* event list */
        Event* prev_;
        Handler* handler_;      /* handler to call when event ready */
        double time_;           /* time at which event is ready */
        scheduler_uid_t uid_;   /* unique ID */
        Event() : time_(0), uid_(0) {}
};

/*
 * The base class for all event handlers.  When an event's scheduled
 * time arrives, it is passed to handle which must consume it.
 * i.e., if it needs to be freed it, it must be freed by the handler.
 */
class Handler {
 public:
        virtual void handle(Event* event) = 0;
};

#define SCHED_START     0.0     /* start time (secs) */

class Scheduler : public TclObject {
public:
        static Scheduler& instance() {
                return (*instance_);            // general access to scheduler
        }
        void schedule(Handler*, Event*, double delay);  // sched later event
        virtual void run();                     // execute the simulator
        virtual void cancel(Event*) = 0;        // cancel event
        virtual void insert(Event*) = 0;        // schedule event
        virtual Event* lookup(scheduler_uid_t uid) = 0; // look for event
        virtual Event* deque() = 0;             // next event (removes from q)
        virtual const Event* head() = 0;        // next event (not removed from q)
        double clock() const {                  // simulator virtual time
                return (clock_);
        }
        virtual void sync() {};
        virtual double start() {                // start time
                return SCHED_START;
        }
        virtual void reset();
protected:
        void dumpq();   // for debug: remove + print remaining events
        void dispatch(Event*);  // execute an event
        void dispatch(Event*, double);  // exec event, set clock_
        Scheduler();
        virtual ~Scheduler();
        int command(int argc, const char*const* argv);
        double clock_;
        int halted_;
        static Scheduler* instance_;
        static scheduler_uid_t uid_;
};

class ListScheduler : public Scheduler {
public:
        ListScheduler() : queue_(0) {}
        void cancel(Event*);
        void insert(Event*);
        Event* deque();
        const Event* head() { return queue_; }
        Event* lookup(scheduler_uid_t uid);

protected:
        Event* queue_;
};

#include "heap.h"

class HeapScheduler : public Scheduler {
public:
        HeapScheduler() { hp_ = new Heap; } 
        void cancel(Event* e) {
                if (e->uid_ <= 0)
                        return;
                e->uid_ = - e->uid_;
                hp_->heap_delete((void*) e);
        }
        void insert(Event* e) {
                hp_->heap_insert(e->time_, (void*) e);
        }
        Event* lookup(scheduler_uid_t uid);
        Event* deque();
        const Event* head() { return (const Event *)hp_->heap_min(); }
protected:
        Heap* hp_;
};

class CalendarScheduler : public Scheduler {
public:
        CalendarScheduler();
        ~CalendarScheduler();
        void cancel(Event*);
        void insert(Event*);
        Event* lookup(scheduler_uid_t uid);
        Event* deque();
        const Event* head();

protected:
        double width_;
        double diff0_, diff1_, diff2_; /* wrap-around checks */

        int stat_qsize_;                /* # of distinct priorities in queue*/
        int nbuckets_;
        int lastbucket_;
        int top_threshold_;
        int bot_threshold_;

        struct Bucket {
                Event *list_;
                int    count_;
        } *buckets_;
                
        int qsize_;

        virtual void reinit(int nbuck, double bwidth, double start);
        virtual void resize(int newsize, double start);
        virtual double newwidth(int newsize);

private:
        virtual void insert2(Event*);
        double cal_clock_;  // same as clock in sims, may be different in RT-scheduling.

};

class SplayScheduler : public Scheduler 
{
public:
        SplayScheduler() : root_(0), qsize_(0) {}
        void insert(Event *);
        Event *deque();
        const Event *head();
        void cancel(Event *);
        Event *lookup(scheduler_uid_t);

        //void validate() { assert(validate(root_) == qsize_); };
    
protected:
        /* XXX even if debug is enabled, we want these inlined, so
           XXX they are defined as macros in splay-scheduler.cc
           Event *&LEFT(Event *e)  { return e->prev_; }
           Event *&RIGHT(Event *e) { return e->next_; }
        */
        Event *uid_lookup(Event *);

        Event                   *root_;
        scheduler_uid_t         lookup_uid_;
        int                     qsize_;
private:
        int validate(Event *);
};


#endif

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