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					129 lines
				
				4.0 KiB
			|   
											8 years ago
										 | /**
 | ||
|  |  * \addtogroup timer | ||
|  |  * @{ | ||
|  |  */ | ||
|  | 
 | ||
|  | /**
 | ||
|  |  * \file | ||
|  |  * Timer library implementation. | ||
|  |  * \author | ||
|  |  * Adam Dunkels <adam@sics.se> | ||
|  |  */ | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Copyright (c) 2004, Swedish Institute of Computer Science. | ||
|  |  * 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 | ||
|  |  *    notice, this list of conditions and the following disclaimer. | ||
|  |  * 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. Neither the name of the Institute nor the names of its contributors | ||
|  |  *    may be used to endorse or promote products derived from this software | ||
|  |  *    without specific prior written permission. | ||
|  |  * | ||
|  |  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND | ||
|  |  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
|  |  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
|  |  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE | ||
|  |  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
|  |  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
|  |  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
|  |  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
|  |  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | ||
|  |  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | ||
|  |  * SUCH DAMAGE. | ||
|  |  * | ||
|  |  * This file is part of the uIP TCP/IP stack | ||
|  |  * | ||
|  |  * Author: Adam Dunkels <adam@sics.se> | ||
|  |  * | ||
|  |  * $Id: timer.c,v 1.2 2006/06/12 08:00:30 adam Exp $ | ||
|  |  */ | ||
|  | 
 | ||
|  | #include "clock.h"
 | ||
|  | #include "timer.h"
 | ||
|  | 
 | ||
|  | /*---------------------------------------------------------------------------*/ | ||
|  | /**
 | ||
|  |  * Set a timer. | ||
|  |  * | ||
|  |  * This function is used to set a timer for a time sometime in the | ||
|  |  * future. The function timer_expired() will evaluate to true after | ||
|  |  * the timer has expired. | ||
|  |  * | ||
|  |  * \param t A pointer to the timer | ||
|  |  * \param interval The interval before the timer expires. | ||
|  |  * | ||
|  |  */ | ||
|  | void | ||
|  | timer_set(struct timer *t, clock_time_t interval) | ||
|  | { | ||
|  |   t->interval = interval; | ||
|  |   t->start = clock_time(); | ||
|  | } | ||
|  | /*---------------------------------------------------------------------------*/ | ||
|  | /**
 | ||
|  |  * Reset the timer with the same interval. | ||
|  |  * | ||
|  |  * This function resets the timer with the same interval that was | ||
|  |  * given to the timer_set() function. The start point of the interval | ||
|  |  * is the exact time that the timer last expired. Therefore, this | ||
|  |  * function will cause the timer to be stable over time, unlike the | ||
|  |  * timer_restart() function. | ||
|  |  * | ||
|  |  * \param t A pointer to the timer. | ||
|  |  * | ||
|  |  * \sa timer_restart() | ||
|  |  */ | ||
|  | void | ||
|  | timer_reset(struct timer *t) | ||
|  | { | ||
|  |   t->start += t->interval; | ||
|  | } | ||
|  | /*---------------------------------------------------------------------------*/ | ||
|  | /**
 | ||
|  |  * Restart the timer from the current point in time | ||
|  |  * | ||
|  |  * This function restarts a timer with the same interval that was | ||
|  |  * given to the timer_set() function. The timer will start at the | ||
|  |  * current time. | ||
|  |  * | ||
|  |  * \note A periodic timer will drift if this function is used to reset | ||
|  |  * it. For periodic timers, use the timer_reset() function instead. | ||
|  |  * | ||
|  |  * \param t A pointer to the timer. | ||
|  |  * | ||
|  |  * \sa timer_reset() | ||
|  |  */ | ||
|  | void | ||
|  | timer_restart(struct timer *t) | ||
|  | { | ||
|  |   t->start = clock_time(); | ||
|  | } | ||
|  | /*---------------------------------------------------------------------------*/ | ||
|  | /**
 | ||
|  |  * Check if a timer has expired. | ||
|  |  * | ||
|  |  * This function tests if a timer has expired and returns true or | ||
|  |  * false depending on its status. | ||
|  |  * | ||
|  |  * \param t A pointer to the timer | ||
|  |  * | ||
|  |  * \return Non-zero if the timer has expired, zero otherwise. | ||
|  |  * | ||
|  |  */ | ||
|  | int | ||
|  | timer_expired(struct timer *t) | ||
|  | { | ||
|  |   return (clock_time_t)(clock_time() - t->start) >= (clock_time_t)t->interval; | ||
|  | } | ||
|  | /*---------------------------------------------------------------------------*/ | ||
|  | 
 | ||
|  | /** @} */ | ||
|  | 
 |