aboutsummaryrefslogtreecommitdiffstats
path: root/timer.c
blob: 5ac2965d31b88860128834d4db72155a8bb2c30a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/* $Id$
 * $URL$
 *
 * generic timer handling
 *
 * Copyright (C) 2003, 2004 Michael Reinelt <michael@reinelt.co.at>
 * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/* 
 * exported functions:
 *
 * int timer_add (void(*callback)(void *data), void *data, int interval, int one_shot);
 *   adds a timer to the queue
 *
 * int timer_process (struct timespec *delay);
 *   process timer queue
 *
 * int timer_remove(void (*callback) (void *data), void *data);
 *   remove a timer with given callback and data
 *
 * int timer_add_late(void (*callback) (void *data), void *data, const int interval, const int one_shot)
 *   same as timer_add, but the one shot does not fire now (useful for scheduling things)
 *
 * void timer_exit();
 *   release all timers
 *
 */


#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#include <time.h>

#include "debug.h"
#include "cfg.h"
#include "timer.h"

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif

#define CLOCK_SKEW_DETECT_TIME_IN_S 1

typedef struct TIMER {
    void (*callback) (void *data);
    void *data;
    struct timeval when;
    int interval;
    int one_shot;
    int active;
} TIMER;


TIMER *Timers = NULL;
int nTimers = 0;


static void timer_inc(struct timeval *tv, const int msec)
{
    tv->tv_sec += msec / 1000;
    tv->tv_usec += (msec - 1000 * (msec / 1000)) * 1000;

    if (tv->tv_usec >= 1000000) {
	tv->tv_usec -= 1000000;
	tv->tv_sec++;
    }
}

int timer_remove(void (*callback) (void *data), void *data)
{
    int i;
    for (i = 0; i < nTimers; i++) {
	if (Timers[i].callback == callback && Timers[i].data == data && Timers[i].active) {
	    Timers[i].active = 0;
	    return 0;
	}
    }
    return -1;
}

int timer_add_late(void (*callback) (void *data), void *data, const int interval, const int one_shot)
{
    if (!timer_add(callback, data, interval, 1)) {
	return -1;
    }
    if (one_shot) {
	return 0;
    }
    int i;
    for (i = 0; i < nTimers; i++) {
	if (Timers[i].callback == callback && Timers[i].data == data && Timers[i].active
	    && Timers[i].interval == interval && Timers[i].one_shot) {
	    //we forced it to one_shot when adding to make it late (which gives us the alternate behavior)
	    Timers[i].one_shot = one_shot;
	    return 0;
	}
    }

    return -1;
}

int timer_add(void (*callback) (void *data), void *data, const int interval, const int one_shot)
{
    int i;
    struct timeval now;

    /* find a free slot */
    for (i = 0; i < nTimers; i++) {
	if (Timers[i].active == 0)
	    break;
    }

    /* none found, allocate a new slot */
    if (i >= nTimers) {
	nTimers++;
	Timers = realloc(Timers, nTimers * sizeof(*Timers));
    }

    gettimeofday(&now, NULL);

    /* fill slot */
    Timers[i].callback = callback;
    Timers[i].data = data;
    Timers[i].when = now;
    Timers[i].interval = interval;
    Timers[i].one_shot = one_shot;
    Timers[i].active = 1;

    /* if one-shot timer, don't fire now */
    if (one_shot) {
	timer_inc(&Timers[i].when, interval);
    }

    return 0;
}


int timer_process(struct timespec *delay)
{
    int i, flag, min;
    struct timeval now;

    /* the current moment */
    gettimeofday(&now, NULL);

    /* sanity check */
    if (nTimers == 0) {
	error("huh? not one single timer to process? dazed and confused...");
	return -1;
    }

    /* process expired timers */
    flag = 0;
    for (i = 0; i < nTimers; i++) {
	if (Timers[i].active == 0)
	    continue;
	if (timercmp(&Timers[i].when, &now, <=)) {
	    flag = 1;
	    /* callback */
	    if (Timers[i].callback != NULL) {
		Timers[i].callback(Timers[i].data);
	    }
	    /* respawn or delete timer */
	    if (Timers[i].one_shot) {
		Timers[i].active = 0;
	    } else {
		Timers[i].when = now;
		timer_inc(&Timers[i].when, Timers[i].interval);
	    }
	}
    }

    /* find next timer */
    flag = 1;
    min = -1;
    for (i = 0; i < nTimers; i++) {
	if (Timers[i].active == 0)
	    continue;
	if (flag || timercmp(&Timers[i].when, &Timers[min].when, <)) {
	    flag = 0;
	    min = i;
	}
    }

    if (min < 0) {
	error("huh? not one single timer left? dazed and confused...");
	return -1;
    }

    /* delay until next timer event */
    delay->tv_sec = Timers[min].when.tv_sec - now.tv_sec;
    delay->tv_nsec = Timers[min].when.tv_usec - now.tv_usec;
    if (delay->tv_nsec < 0) {
	delay->tv_sec--;
	delay->tv_nsec += 1000000;
    }
    /* nanoseconds!! */
    delay->tv_nsec *= 1000;

    /* check if date changed */
    if ((delay->tv_sec) > CLOCK_SKEW_DETECT_TIME_IN_S) {
	delay->tv_sec = 0;
	delay->tv_nsec = 0;
	info("Oops, clock skewed, update timestamp");
	gettimeofday(&now, NULL);
	Timers[min].when = now;
    }

    return 0;

}


void timer_exit(void)
{
    nTimers = 0;

    if (Timers != NULL) {
	free(Timers);;
	Timers = NULL;
    }
}