Restructure: Move timer from common code to 'libtimer'

libtimer/Makefile.am

@@ -0,0 +1,6 @@
+AM_CPPFLAGS = -Wall -Wextra -g $(all_includes)
+
+noinst_LIBRARIES = libtimer.a
+
+libtimer_a_SOURCES = \
+	timer.c

libtimer/timer.c

@@ -0,0 +1,121 @@
+/* Timer handling
+ *
+ * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
+ * All Rights Reserved
+ *
+ * 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include "timer.h"
+
+static struct timer *timer_head = NULL;
+static struct timer **timer_tail_p = &timer_head;
+
+double get_time(void)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+
+	return (double)tv.tv_sec + (double)tv.tv_usec / 1000000.0;
+}
+
+void timer_init(struct timer *timer, void (*fn)(struct timer *timer), void *priv)
+{
+	if (timer->linked) {
+		fprintf(stderr, "Timer is already initialized, aborting!\n");
+		abort();
+	}
+
+	timer->timeout = 0;
+	timer->fn = fn;
+	timer->priv = priv;
+	timer->next = NULL;
+	*timer_tail_p = timer;
+	timer_tail_p = &timer->next;
+	timer->linked = 1;
+}
+
+void timer_exit(struct timer *timer)
+{
+	timer_tail_p = &timer_head;
+	while (*timer_tail_p) {
+		if (timer == *timer_tail_p)
+			*timer_tail_p = (*timer_tail_p)->next;
+		else
+			timer_tail_p = &((*timer_tail_p)->next);
+	}
+	timer->linked = 0;
+}
+
+void timer_start(struct timer *timer, double duration)
+{
+	struct timeval tv;
+
+	if (!timer->linked) {
+		fprintf(stderr, "Timer is not initialized, aborting!\n");
+		abort();
+	}
+
+	gettimeofday(&tv, NULL);
+
+	timer->duration = duration;
+	timer->timeout = get_time() + duration;
+}
+
+void timer_stop(struct timer *timer)
+{
+	if (!timer->linked) {
+		fprintf(stderr, "Timer is not initialized, aborting!\n");
+		abort();
+	}
+
+	timer->timeout = 0;
+}
+
+int timer_running(struct timer *timer)
+{
+	if (!timer->linked) {
+		fprintf(stderr, "Timer is not initialized, aborting!\n");
+		abort();
+	}
+
+	return (timer->timeout != 0);
+}
+
+void process_timer(void)
+{
+	struct timer *timer;
+	double now;
+
+	now = get_time();
+
+again:
+	timer = timer_head;
+
+	while (timer) {
+		if (timer->linked && timer->timeout > 0 && now >= timer->timeout) {
+			timer->timeout = 0;
+			timer->fn(timer);
+			goto again;
+		}
+		timer = timer->next;
+	}
+}
+

libtimer/timer.h

@@ -0,0 +1,18 @@
+
+struct timer {
+	struct timer *next;
+	int linked; /* set is timer is initialized and linked */
+	double duration;
+	double timeout;
+	void (*fn)(struct timer *timer);
+	void *priv;
+};
+
+double get_time(void);
+void timer_init(struct timer *timer, void (*fn)(struct timer *timer), void *priv);
+void timer_exit(struct timer *timer);
+void timer_start(struct timer *timer, double duration);
+void timer_stop(struct timer *timer);
+int timer_running(struct timer *timer);
+void process_timer(void);
+