/*
 * The mrouted program is covered by the license in the accompanying file
 * named "LICENSE.mrouted". Use of the mrouted program represents acceptance
 * of the terms and conditions listed in that file.
 *
 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
 * Leland Stanford Junior University.
 *
 *
 * callout.c,v 3.8.4.5 1997/05/16 20:18:25 fenner Exp
 */
/*
 *  Questions concerning this software should be directed to
 *  Mickael Hoerdt (hoerdt@clarinet.u-strasbg.fr) LSIIT Strasbourg.
 *
 */
/*
 * This program has been derived from pim6dd.
 * The pim6dd program is covered by the license in the accompanying file
 * named "LICENSE.pim6dd".
 */
/*
 * This program has been derived from pimd.
 * The pimd program is covered by the license in the accompanying file
 * named "LICENSE.pimd".
 *
 * $FreeBSD$
 */


#include <stdio.h>
#include <syslog.h>
#include <stdlib.h>
#include "debug.h"
#include "defs.h"

/* the code below implements a callout queue */

static int      	id = 0;
static struct timeout_q *Q = 0;	/* pointer to the beginning of timeout queue */

struct timeout_q
{
    struct timeout_q *next;	/* next event */
    int             id;
    cfunc_t         func;	/* function to call */
    void           *data;	/* func's data */
    int             time;	/* time offset to next event */
};

#if 0
#define CALLOUT_DEBUG 1
#define CALLOUT_DEBUG2 1
#endif				/* 0 */

#ifdef CALLOUT_DEBUG2
static void print_Q __P((void));
#else
#define	print_Q()
#endif

void
callout_init()
{
    Q = (struct timeout_q *) 0;
}

void
free_all_callouts()
{
    struct timeout_q *p;

    while (Q)
    {
	p = Q;
	Q = Q->next;
	free(p);
    }
}


/*
 * elapsed_time seconds have passed; perform all the events that should
 * happen.
 */
void
age_callout_queue(elapsed_time)
    int             elapsed_time;
{
    struct timeout_q *ptr,
                   *expQ;

#ifdef CALLOUT_DEBUG
    IF_DEBUG(DEBUG_TIMEOUT)
	log(LOG_DEBUG, 0, "aging queue (elapsed time %d):", elapsed_time);
    print_Q();
#endif

    expQ = Q;
    ptr = NULL;

    while (Q)
    {
	if (Q->time > elapsed_time)
	{
	    Q->time -= elapsed_time;
	    if (ptr)
	    {
		ptr->next = NULL;
		break;
	    }
	    return;
	}
	else
	{
	    elapsed_time -= Q->time;
	    ptr = Q;
	    Q = Q->next;
	}
    }

    /* handle queue of expired timers */
    while (expQ)
    {
	ptr = expQ;
	if (ptr->func)
	    ptr->func(ptr->data);
	expQ = expQ->next;
	free(ptr);
    }
}

/*
 * Return in how many seconds age_callout_queue() would like to be called.
 * Return -1 if there are no events pending.
 */

int
timer_nextTimer()
{
    if (Q)
    {
	if (Q->time < 0)
	{
	    log(LOG_WARNING, 0, "timer_nextTimer top of queue says %d",
		Q->time);
	    return 0;
	}
	return Q->time;
    }
    return -1;
}

/*
 * sets the timer
 */

int
timer_setTimer(delay, action, data)
    int             delay;	/* number of units for timeout */
    cfunc_t         action;	/* function to be called on timeout */
    void           *data;	/* what to call the timeout function with */
{
    struct timeout_q *ptr,
                   *node,
                   *prev;

#ifdef CALLOUT_DEBUG
    IF_DEBUG(DEBUG_TIMEOUT)
	log(LOG_DEBUG, 0, "setting timer:");
    print_Q();
#endif

    /* create a node */

    node = (struct timeout_q *) malloc(sizeof(struct timeout_q));
    if (node == 0)
    {
	log(LOG_WARNING, 0, "Malloc Failed in timer_settimer\n");
	return -1;
    }
    node->func = action;
    node->data = data;
    node->time = delay;
    node->next = 0;
    node->id = ++id;

    prev = ptr = Q;

    /* insert node in the queue */

    /* if the queue is empty, insert the node and return */

    if (!Q)
	Q = node;
    else
    {
	/* chase the pointer looking for the right place */

	while (ptr)
	{

	    if (delay < ptr->time)
	    {
		/* right place */

		node->next = ptr;
		if (ptr == Q)
		    Q = node;
		else
		    prev->next = node;
		ptr->time -= node->time;
		print_Q();
		return node->id;
	    }
	    else
	    {
		/* keep moving */

		delay -= ptr->time;
		node->time = delay;
		prev = ptr;
		ptr = ptr->next;
	    }
	}
	prev->next = node;
    }
    print_Q();
    return node->id;
}

/* returns the time until the timer is scheduled */

int
timer_leftTimer(timer_id)
    int             timer_id;
{
    struct timeout_q *ptr;
    int             left = 0;

    if (!timer_id)
	return -1;

    for (ptr = Q; ptr; ptr = ptr->next)
    {
	left += ptr->time;
	if (ptr->id == timer_id)
	    return left;
    }
    return -1;
}

/* clears the associated timer */

void
timer_clearTimer(timer_id)
    int             timer_id;
{
    struct timeout_q *ptr,
                   *prev;

    if (!timer_id)
	return;

    prev = ptr = Q;

    /*
     * find the right node, delete it. the subsequent node's time gets bumped
     * up
     */

    print_Q();
    while (ptr)
    {
	if (ptr->id == timer_id)
	{
	    /* got the right node */

	    /* unlink it from the queue */

	    if (ptr == Q)
		Q = Q->next;
	    else
		prev->next = ptr->next;

	    /* increment next node if any */
	    if (ptr->next != 0)
		(ptr->next)->time += ptr->time;

	    if (ptr->data)
		free(ptr->data);
	    free(ptr);
	    print_Q();
	    return;
	}
	prev = ptr;
	ptr = ptr->next;
    }
    print_Q();
}

#ifdef CALLOUT_DEBUG2
/*
 * debugging utility
 */

static void
print_Q()
{
    struct timeout_q *ptr;

    IF_DEBUG(DEBUG_TIMEOUT)
	for (ptr = Q; ptr; ptr = ptr->next)
	log(LOG_DEBUG, 0, "(%d,%d) ", ptr->id, ptr->time);
}
#endif				/* CALLOUT_DEBUG2 */