/*
 * Sieve of Eratosthenes
 *
 * This test exercises the scheduler's core directly.
 *
 * Original version by Gary Lindstrom.
 */
#include <stdlib.h>
#include <stdio.h>
#include "scheduler.h"

struct filter {
    struct process super;
    struct process *higher;
    struct process *lower;
    int p;
};

int val;

static struct process * filter_create(struct scheduler *sched, const char *s, int p_);

static void 
filter_body(struct process *p)
{
    struct filter *self = (struct filter *)p;
    struct scheduler *sched = p->scheduler;
    while (val != 0) { /* not shut down yet */
        if (val % self->p != 0) { 
            /* val is not a multiple of this filter stage's p */
            if (self->higher == NULL) {
                /* next stage needs to be created */
                self->higher = filter_create(sched, "filter", val);
            } else
                sched_pass_baton(sched, self->higher);
        }
        /* get next val */
        sched_pass_baton(sched, self->lower);
    }

    /* do shut down */
    printf("%d is prime.\n", self->p);
    if (self->higher != NULL) {
        sched_pass_baton(sched, self->higher);
    }
    sched_pass_baton_and_die(sched, self->lower);
}

static struct process *
filter_create(struct scheduler *sched, const char *s, int p_)
{
    struct filter *self = calloc(1, sizeof(*self));
    self->p = p_;
    self->lower = sched->current;
    process_init(&self->super, s, sched, filter_body);
    return &self->super;
}

static void 
filter_base_body(struct process *p)
{
    struct filter *self = (struct filter *)p;
    self->higher = filter_create(p->scheduler, "filter_2", 2);

    for (int i = 3; i <= 1000; i++) {
        val = i;
        sched_pass_baton(p->scheduler, self->higher); 
    }

    /* signal shut down */
    val = 0;
    sched_pass_baton(p->scheduler, self->higher);
}

int
main()
{
    struct scheduler *sched = sched_create();
    struct filter sieve = { .lower = NULL, .higher = NULL };
    process_init(&sieve.super, "filter base", sched, filter_base_body);
    sched_pass_baton(sched, &sieve.super);
    process_terminate(&sieve.super);
}