273 lines
7.1 KiB
C
273 lines
7.1 KiB
C
/*
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* Copyright (c) 2004, Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* Author: Adam Dunkels <adam@sics.se>
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*
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*/
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/**
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* \addtogroup etimer
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* @{
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*/
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/**
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* \file
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* Event timer library implementation.
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* \author
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* Adam Dunkels <adam@sics.se>
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*/
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#include "contiki-conf.h"
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#include "sys/etimer.h"
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#include "sys/process.h"
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static struct etimer *timerlist;
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static clock_time_t next_expiration;
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PROCESS(etimer_process, "Event timer");
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/*---------------------------------------------------------------------------*/
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static void
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update_time(void)
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{
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clock_time_t tdist;
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clock_time_t now;
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struct etimer *t;
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if (timerlist == NULL) {
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next_expiration = 0;
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} else {
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now = clock_time();
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t = timerlist;
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/* Must calculate distance to next time into account due to wraps */
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tdist = t->timer.start + t->timer.interval - now;
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for(t = t->next; t != NULL; t = t->next) {
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if(t->timer.start + t->timer.interval - now < tdist) {
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tdist = t->timer.start + t->timer.interval - now;
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}
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}
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next_expiration = now + tdist;
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}
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}
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/*---------------------------------------------------------------------------*/
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PROCESS_THREAD(etimer_process, ev, data)
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{
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struct etimer *t, *u;
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PROCESS_BEGIN();
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timerlist = NULL;
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while(1) {
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PROCESS_YIELD();
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if(ev == PROCESS_EVENT_EXITED) {
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struct process *p = data;
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while(timerlist != NULL && timerlist->p == p) {
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timerlist = timerlist->next;
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}
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if(timerlist != NULL) {
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t = timerlist;
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while(t->next != NULL) {
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if(t->next->p == p) {
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t->next = t->next->next;
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} else
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t = t->next;
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}
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}
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continue;
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} else if(ev != PROCESS_EVENT_POLL) {
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continue;
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}
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again:
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u = NULL;
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for(t = timerlist; t != NULL; t = t->next) {
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if(timer_expired(&t->timer)) {
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if(process_post(t->p, PROCESS_EVENT_TIMER, t) == PROCESS_ERR_OK) {
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/* Reset the process ID of the event timer, to signal that the
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etimer has expired. This is later checked in the
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etimer_expired() function. */
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t->p = PROCESS_NONE;
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if(u != NULL) {
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u->next = t->next;
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} else {
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timerlist = t->next;
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}
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t->next = NULL;
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update_time();
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goto again;
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} else {
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etimer_request_poll();
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}
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}
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u = t;
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}
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}
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PROCESS_END();
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_request_poll(void)
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{
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process_poll(&etimer_process);
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}
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/*---------------------------------------------------------------------------*/
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static void
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add_timer(struct etimer *timer)
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{
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struct etimer *t;
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etimer_request_poll();
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if(timer->p != PROCESS_NONE) {
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for(t = timerlist; t != NULL; t = t->next) {
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if(t == timer) {
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/* Timer already on list, bail out. */
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timer->p = PROCESS_CURRENT();
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update_time();
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return;
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}
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}
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}
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/* Timer not on list. */
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timer->p = PROCESS_CURRENT();
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timer->next = timerlist;
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timerlist = timer;
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update_time();
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_set(struct etimer *et, clock_time_t interval)
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{
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timer_set(&et->timer, interval);
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add_timer(et);
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_reset_with_new_interval(struct etimer *et, clock_time_t interval)
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{
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timer_reset(&et->timer);
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et->timer.interval = interval;
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add_timer(et);
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_reset(struct etimer *et)
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{
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timer_reset(&et->timer);
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add_timer(et);
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_restart(struct etimer *et)
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{
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timer_restart(&et->timer);
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add_timer(et);
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_adjust(struct etimer *et, int timediff)
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{
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et->timer.start += timediff;
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update_time();
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}
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/*---------------------------------------------------------------------------*/
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int
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etimer_expired(struct etimer *et)
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{
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return et->p == PROCESS_NONE;
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}
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/*---------------------------------------------------------------------------*/
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clock_time_t
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etimer_expiration_time(struct etimer *et)
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{
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return et->timer.start + et->timer.interval;
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}
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/*---------------------------------------------------------------------------*/
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clock_time_t
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etimer_start_time(struct etimer *et)
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{
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return et->timer.start;
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}
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/*---------------------------------------------------------------------------*/
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int
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etimer_pending(void)
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{
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return timerlist != NULL;
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}
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/*---------------------------------------------------------------------------*/
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clock_time_t
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etimer_next_expiration_time(void)
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{
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return etimer_pending() ? next_expiration : 0;
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}
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/*---------------------------------------------------------------------------*/
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void
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etimer_stop(struct etimer *et)
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{
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struct etimer *t;
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/* First check if et is the first event timer on the list. */
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if(et == timerlist) {
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timerlist = timerlist->next;
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update_time();
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} else {
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/* Else walk through the list and try to find the item before the
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et timer. */
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for(t = timerlist; t != NULL && t->next != et; t = t->next);
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if(t != NULL) {
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/* We've found the item before the event timer that we are about
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to remove. We point the items next pointer to the event after
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the removed item. */
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t->next = et->next;
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update_time();
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}
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}
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/* Remove the next pointer from the item to be removed. */
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et->next = NULL;
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/* Set the timer as expired */
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et->p = PROCESS_NONE;
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}
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/*---------------------------------------------------------------------------*/
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/** @} */
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