#include <pthread.h>
#include <stdio.h>
#define MAX_THREADS 8
void *barrier_test(void *s);

typedef struct {
        pthread_mutex_t count_lock;
        pthread_cond_t ok_to_proceed;
        int count;
} mylib_barrier_t;

void mylib_init_barrier(mylib_barrier_t *b)
{
        b -> count = 0;
        pthread_mutex_init(&(b -> count_lock), NULL);
        pthread_cond_init(&(b -> ok_to_proceed), NULL);
}

void mylib_barrier (mylib_barrier_t *b, int num_threads)
{
        pthread_mutex_lock(&(b -> count_lock));
        b -> count ++;
        if (b -> count == num_threads) {
                b -> count = 0;
                pthread_cond_broadcast(&(b -> ok_to_proceed));
        }
        else
                while (pthread_cond_wait(&(b -> ok_to_proceed),
                        &(b -> count_lock)) != 0);
        pthread_mutex_unlock(&(b -> count_lock));
}


typedef struct barrier_node mylob_logbarrier_t[MAX_THREADS];
pthread_t p_threads[MAX_THREADS];
pthread_attr_t attr;

mylib_barrier_t barr;

main()
{
/* barrier tester */
        int i, hits[MAX_THREADS];

        pthread_attr_init (&attr);
        pthread_attr_setscope (&attr,PTHREAD_SCOPE_SYSTEM);

        mylib_init_barrier (&barr);

        for (i=0; i< MAX_THREADS; i++)
	{
		hits[i] = i;
                pthread_create(&p_threads[i], &attr, barrier_test,
                        (void *) &hits[i]);
        }
        for (i=0; i< MAX_THREADS; i++)
                pthread_join(p_threads[i], NULL);

/*
	for (i=0; i< MAX_THREADS; i++)
		printf("%d ", barr[i].count);
*/
}

void *barrier_test(void *s)
{
        int thread_id, i, j;
        thread_id = *((int *) s);
        for (i=0; i < 100; i++)
      		mylib_barrier(&barr, MAX_THREADS);
}