#include <sys/time.h>
#include <time.h>
#include <stdint.h>
#include <stdio.h>

static struct timespec r;
static int period;

#define NSEC_PER_SEC 1000000000ULL
static inline void timespec_add_us(struct timespec *t, uint64_t d)
{
    d *= 1000;
    d += t->tv_nsec;
    while (d >= NSEC_PER_SEC) {
        d -= NSEC_PER_SEC;
	t->tv_sec += 1;
    }
    t->tv_nsec = d;
}

static void wait_next_activation(void)
{
    clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &r, NULL);
    timespec_add_us(&r, period);
}

static int start_periodic_timer(uint64_t offs, int t)
{
    clock_gettime(CLOCK_REALTIME, &r);
    timespec_add_us(&r, offs);
    period = t;

    return 0;
}

int main(int argc, char *argv[])
{
    int res;

    res = start_periodic_timer(1000000, 50000);
    if (res < 0) {
        perror("Start Periodic Timer");

        return -1;
    }

    while(1) {
        wait_next_activation();
	/* Begin of the Major cycle */
	task1();
	task2();
	task3();
        wait_next_activation();
	/* 50 */
	task1();
        wait_next_activation();
	/* 100 */
	task1();
	task2();
        wait_next_activation();
	/* 150 */
	task1();
	task3();
        wait_next_activation();
	/* 200 */
	task1();
	task2();
        wait_next_activation();
	/* 250 */
	task1();
    }

    return 0;
}