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

#define MINOR_CYCLE 50
#define MAJOR_CYCLE 300
static uint8_t scheduling_table[] = {7, 1, 3, 5, 3, 1};

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;
    int t = 0;

    res = start_periodic_timer(1000000, MINOR_CYCLE * 1000);
    if (res < 0) {
        perror("Start Periodic Timer");

        return -1;
    }

    while(1) {
        uint8_t scheduled_tasks;

        wait_next_activation();
        scheduled_tasks = scheduling_table[t / MINOR_CYCLE];
        if (scheduled_tasks & 0x01) {
	    task1();
        }
        if (scheduled_tasks & 0x02) {
	    task2();
        }
        if (scheduled_tasks & 0x04) {
	    task3();
        }
        t = (t + MINOR_CYCLE) % MAJOR_CYCLE;
    }

    return 0;
}