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flightgear/Time/event.c

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/**************************************************************************
* event.c -- Flight Gear periodic event scheduler
*
* Written by Curtis Olson, started December 1997.
*
* Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
* (Log is kept at end of this file)
**************************************************************************/
#include <string.h>
#include <stdio.h>
#ifdef USE_FTIME
# include <sys/timeb.h> /* for ftime() and struct timeb */
#else
# include <sys/time.h> /* for get/setitimer, gettimeofday, struct timeval */
#endif USE_FTIME
#include "event.h"
#define MAX_EVENTS 100 /* size of event table */
#define MAX_RUN_QUEUE 100 /* size of run queue */
struct fgEVENT {
char description[256];
void (*event)(); /* pointer to function */
int status; /* status flag */
long interval; /* interval in ms between each iteration of this event */
#ifdef USE_FTIME
struct timeb last_run; /* absolute time for last run */
struct timeb current; /* current time */
struct timeb next_run; /* absolute time for next run */
#else
struct timeval last_run; /* absolute time for last run */
struct timeval current; /* current time */
struct timeval next_run; /* absolute time for next run */
struct timezone tz;
#endif /* USE_FTIME */
long cum_time; /* cumulative processor time of this event */
long min_time; /* time of quickest execution */
long max_time; /* time of slowest execution */
long count; /* number of times executed */
};
/* Event table */
struct fgEVENT events[MAX_EVENTS];
int event_ptr;
/* Run Queue */
int queue[MAX_RUN_QUEUE];
int queue_front;
int queue_end;
/* initialize the run queue */
void initq() {
queue_front = queue_end = 0;
}
/* return queue empty status */
int emptyq() {
if ( queue_front == queue_end ) {
return(1);
} else {
return(0);
}
}
/* return queue full status */
int fullq() {
if ( (queue_end + 1) % MAX_RUN_QUEUE == queue_front ) {
return(1);
} else {
return(0);
}
}
/* add a member to the back of the queue */
void addq(int ptr) {
if ( !fullq() ) {
queue[queue_end] = ptr;
events[ptr].status = FG_EVENT_QUEUED;
queue_end = (queue_end + 1) % MAX_RUN_QUEUE;
} else {
printf("RUN QUEUE FULL!!!\n");
}
/* printf("Queued function %d (%d %d)\n", ptr, queue_front, queue_end); */
}
/* remove a member from the front of the queue */
int popq() {
int ptr;
if ( !emptyq() ) {
ptr = queue[queue_front];
/* printf("Popped position %d = %d\n", queue_front, ptr); */
queue_front = (queue_front + 1) % MAX_RUN_QUEUE;
return(ptr);
} else {
printf("PANIC: RUN QUEUE IS EMPTY!!!\n");
exit(0);
}
}
/* run a specified event */
void fgEventRun(int ptr) {
struct fgEVENT *e;
long duration;
e = &events[ptr];
printf("Running %s\n", e->description);
/* record starting time */
#ifdef USE_FTIME
ftime(&e->last_run);
#else
gettimeofday(&e->last_run, &e->tz);
#endif /* USE_FTIME */
/* run the event */
(*e->event)();
/* increment the counter for this event */
e->count++;
/* update the event status */
e->status = FG_EVENT_READY;
/* calculate duration and stats */
#ifdef USE_FTIME
ftime(&e->current);
duration = 1000 * (e->current.time - e->last_run.time) +
(e->current.millitm - e->last_run.millitm);
#else
gettimeofday(&e->current, &e->tz);
duration = 1000000 * (e->current.tv_sec - e->last_run.tv_sec) +
(e->current.tv_usec - e->last_run.tv_usec);
duration /= 1000; /* convert back to milleseconds */
#endif /* USE_FTIME */
e->cum_time += duration;
if ( duration < e->min_time ) {
e->min_time = duration;
}
if ( duration > e->max_time ) {
e->max_time = duration;
}
/* determine the next absolute run time */
#ifdef USE_FTIME
e->next_run.time = e->last_run.time +
(e->last_run.millitm + e->interval) / 1000;
e->next_run.millitm = (e->last_run.millitm + e->interval) % 1000;
#else
e->next_run.tv_sec = e->last_run.tv_sec +
(e->last_run.tv_usec + e->interval * 1000) / 1000000;
e->next_run.tv_usec = (e->last_run.tv_usec + e->interval * 1000) % 1000000;
#endif /* USE_FTIME */
}
/* Initialize the scheduling subsystem */
void fgEventInit() {
printf("Initializing event manager\n");
event_ptr = 0;
initq();
}
/* Register an event with the scheduler, returns a pointer into the
* event table */
int fgEventRegister(char *desc, void (*event)(), int status, int interval) {
struct fgEVENT *e;
e = &events[event_ptr];
printf("Registering event: %s\n", desc);
if ( strlen(desc) < 256 ) {
strcpy(e->description, desc);
} else {
strncpy(e->description, desc, 255);
e->description[255] = '\0';
}
e->event = event;
e->status = status;
e->interval = interval;
e->cum_time = 0;
e->min_time = 100000;
e->max_time = 0;
e->count = 0;
/* Actually run the event */
fgEventRun(event_ptr);
event_ptr++;
return(event_ptr - 1);
}
/* Update the scheduling parameters for an event */
void fgEventUpdate() {
}
/* Delete a scheduled event */
void fgEventDelete() {
}
/* Temporarily suspend scheduling of an event */
void fgEventSuspend() {
}
/* Resume scheduling and event */
void fgEventResume() {
}
/* Dump scheduling stats */
void fgEventPrintStats() {
int i;
if ( event_ptr > 0 ) {
printf("\n");
printf("Event Stats\n");
printf("----- -----\n");
for ( i = 0; i < event_ptr; i++ ) {
printf(" %s cum=%d min=%d max=%d count=%d ave=%.2f\n",
events[i].description, events[i].cum_time,
events[i].min_time, events[i].max_time, events[i].count,
events[i].cum_time / (double)events[i].count);
}
}
}
/* Add pending jobs to the run queue and run the job at the front of
* the queue */
void fgEventProcess() {
#ifdef USE_FTIME
struct timeb current;
#else
struct timeval current;
struct timezone tz;
#endif /* USE_FTIME */
int i;
printf("Processing events\n");
/* get the current time */
#ifdef USE_FTIME
ftime(&current);
#else
gettimeofday(&current, &tz);
#endif /* USE_FTIME */
/* printf("Checking if anything is ready to move to the run queue\n"); */
/* see if anything else is ready to be placed on the run queue */
for ( i = 0; i < event_ptr; i++ ) {
if ( events[i].status == FG_EVENT_READY ) {
#ifdef USE_FTIME
if ( current.time > events[i].next_run.time ) {
addq(i);
} else if ( (current.time == events[i].next_run.time) &&
(current.millitm >= events[i].next_run.millitm) ) {
addq(i);
}
#else
if ( current.tv_sec > events[i].next_run.tv_sec ) {
addq(i);
} else if ( (current.tv_sec == events[i].next_run.tv_sec) &&
(current.tv_usec >= events[i].next_run.tv_usec) ) {
addq(i);
}
#endif /* USE_FTIME */
}
}
/* Checking to see if there is anything on the run queue */
/* printf("Checking to see if there is anything on the run queue\n"); */
if ( !emptyq() ) {
/* printf("Yep, running it\n"); */
i = popq();
fgEventRun(i);
}
}
/* $Log$
/* Revision 1.2 1997/12/30 20:47:58 curt
/* Integrated new event manager with subsystem initializations.
/*
* Revision 1.1 1997/12/30 04:19:22 curt
* Initial revision.
*
*/
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