/* foldl en C con hilos */

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#include <unistd.h>

#include <math.h>

#define MAXHILOS 8
#undef DEBUG

int n = 0;
int shift = 1;

int * from = NULL;
int * to = NULL;
int * tmp = NULL;

pthread_barrier_t * barrera;
pthread_t hilo[MAXHILOS];

void proc1(void * xp);

/* hace 'zipWith (+) xs (drop shift xs)' y guarda el resultado en ys */

void zipWithPlus(void){
    int i = 0;

    printf("init\n");

    pthread_barrier_init(barrera, NULL, (MAXHILOS - shift));

    printf("post barrera\n");

    for(i = 0; i < (MAXHILOS - shift); ++i){
        printf("en ciclo\n");
	pthread_create(&hilo[i],NULL,(void *)&proc1, (void *) i);
    }

    printf("pre destruir\n");

    pthread_barrier_destroy(barrera);

    printf("post destruir\n");

    /* siguiente vuelta */

    /*  swap */
    tmp = from;
    from = to;
    to = tmp;

    ++n;
    shift = pow (2,n);
}

void proc1(void * xp)  {
  int x = (int) xp;

  *(to+x+shift) = *(from+x) + *(from+x+shift);

  pthread_exit(0);
}


int main()  {

  int i;

  from =  malloc(sizeof(int) * MAXHILOS);
  to =  malloc(sizeof(int) * MAXHILOS);

  barrera = malloc(sizeof(pthread_barrier_t));

  for(i = 0; i < MAXHILOS; ++i){
    *(from+i) = *(to+i) = i;
  }

  zipWithPlus();
  zipWithPlus();
  zipWithPlus();

  for(i = 0; i < MAXHILOS; ++i){
    if(i < (MAXHILOS / 2)){
      printf(" %d", *(to+i));
    } else {
      printf(" %d", *(from+i));
    }
  }

  printf("\n");

  free(from);
  free(to);

  free(barrera);

  return 0;
}