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/**
* \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;
}
/*---------------------------------------------------------------------------*/
/** @} */
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