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comparison network/timer.c @ 107:56d09a0969b5 avr-http

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Import uIP and the PPP implementation from https://code.google.com/p/avrusbmodem/
author Matt Johnston <matt@ucc.asn.au>
date Fri, 07 Sep 2012 23:53:53 +0800
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106:5c8404549cc0 107:56d09a0969b5
1 /**
2 * \addtogroup timer
3 * @{
4 */
5
6 /**
7 * \file
8 * Timer library implementation.
9 * \author
10 * Adam Dunkels <[email protected]>
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 <[email protected]>
44 *
45 * $Id: timer.c,v 1.2 2006/06/12 08:00:30 adam Exp $
46 */
47
48 #include "clock.h"
49 #include "timer.h"
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
64 timer_set(struct timer *t, clock_time_t interval)
65 {
66 t->interval = interval;
67 t->start = clock_time();
68 }
69 /*---------------------------------------------------------------------------*/
70 /**
71 * Reset the timer with the same interval.
72 *
73 * This function resets the timer with the same interval that was
74 * given to the timer_set() function. The start point of the interval
75 * is the exact time that the timer last expired. Therefore, this
76 * function will cause the timer to be stable over time, unlike the
77 * timer_rester() function.
78 *
79 * \param t A pointer to the timer.
80 *
81 * \sa timer_restart()
82 */
83 void
84 timer_reset(struct timer *t)
85 {
86 t->start += t->interval;
87 }
88 /*---------------------------------------------------------------------------*/
89 /**
90 * Restart the timer from the current point in time
91 *
92 * This function restarts a timer with the same interval that was
93 * given to the timer_set() function. The timer will start at the
94 * current time.
95 *
96 * \note A periodic timer will drift if this function is used to reset
97 * it. For preioric timers, use the timer_reset() function instead.
98 *
99 * \param t A pointer to the timer.
100 *
101 * \sa timer_reset()
102 */
103 void
104 timer_restart(struct timer *t)
105 {
106 t->start = clock_time();
107 }
108 /*---------------------------------------------------------------------------*/
109 /**
110 * Check if a timer has expired.
111 *
112 * This function tests if a timer has expired and returns true or
113 * false depending on its status.
114 *
115 * \param t A pointer to the timer
116 *
117 * \return Non-zero if the timer has expired, zero otherwise.
118 *
119 */
120 int
121 timer_expired(struct timer *t)
122 {
123 return (clock_time_t)(clock_time() - t->start) >= (clock_time_t)t->interval;
124 }
125 /*---------------------------------------------------------------------------*/
126
127 /** @} */