FreeRTOS/Common/ethernet/FreeRTOS-uIP/timer.c

   1 /**
   2  * \addtogroup timer
   3  * @{
   4  */
   5
   6 /**
   7  * \file
   8  * Timer library implementation.
   9  * \author
  10  * Adam Dunkels <adam@sics.se>
  11  */
  12
  13 /*
  14  * Copyright (c) 2004, Swedish Institute of Computer Science.
  15  * All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  * 3. Neither the name of the Institute nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40  *
  41  * This file is part of the uIP TCP/IP stack
  42  *
  43  * Author: Adam Dunkels <adam@sics.se>
  44  *
  45  * $Id: timer.c,v 1.2 2006/06/12 08:00:30 adam Exp $
  46  */
  47 #include "clock.h"
  48 #include "uip_timer.h"
  49
  50 /*---------------------------------------------------------------------------*/
  51
  52 /**
  53  * Set a timer.
  54  *
  55  * This function is used to set a timer for a time sometime in the
  56  * future. The function timer_expired() will evaluate to true after
  57  * the timer has expired.
  58  *
  59  * \param t A pointer to the timer
  60  * \param interval The interval before the timer expires.
  61  *
  62  */
  63 void timer_set( struct timer *t, clock_time_t interval )
  64 {
  65         t->interval = interval;
  66         t->start = clock_time();
  67 }
  68
  69 /*---------------------------------------------------------------------------*/
  70
  71 /**
  72  * Reset the timer with the same interval.
  73  *
  74  * This function resets the timer with the same interval that was
  75  * given to the timer_set() function. The start point of the interval
  76  * is the exact time that the timer last expired. Therefore, this
  77  * function will cause the timer to be stable over time, unlike the
  78  * timer_rester() function.
  79  *
  80  * \param t A pointer to the timer.
  81  *
  82  * \sa timer_restart()
  83  */
  84 void timer_reset( struct timer *t )
  85 {
  86         t->start += t->interval;
  87 }
  88
  89 /*---------------------------------------------------------------------------*/
  90
  91 /**
  92  * Restart the timer from the current point in time
  93  *
  94  * This function restarts a timer with the same interval that was
  95  * given to the timer_set() function. The timer will start at the
  96  * current time.
  97  *
  98  * \note A periodic timer will drift if this function is used to reset
  99  * it. For preioric timers, use the timer_reset() function instead.
 100  *
 101  * \param t A pointer to the timer.
 102  *
 103  * \sa timer_reset()
 104  */
 105 void timer_restart( struct timer *t )
 106 {
 107         t->start = clock_time();
 108 }
 109
 110 /*---------------------------------------------------------------------------*/
 111
 112 /**
 113  * Check if a timer has expired.
 114  *
 115  * This function tests if a timer has expired and returns true or
 116  * false depending on its status.
 117  *
 118  * \param t A pointer to the timer
 119  *
 120  * \return Non-zero if the timer has expired, zero otherwise.
 121  *
 122  */
 123 int timer_expired( struct timer *t )
 124 {
 125         return( clock_time_t ) ( clock_time() - t->start ) >= ( clock_time_t ) t->interval;
 126 }
 127
 128 /*---------------------------------------------------------------------------*/
 129
 130 /** @} */