#include <stdio.h>
#include <semaphore.h>
#include <sys/mman.h>
#include <sys/stat.h>        /* For mode constants */
#include <fcntl.h>           /* For O_* constants */
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include "stencil.h"


double *cur_step;
double *next_step;

struct shared_memory_t *p_shm = NULL;


/* initialize matrixes */
void init() {
  int shm_id = shm_open(KEY, O_RDWR, 0666);
  assert(shm_id>=0);

  /* set the size of the shared memory segment */
  assert(ftruncate(shm_id, SHM_SIZE) >= 0);

  /* map the shared memory segment in the current address space */
  p_shm = mmap(NULL, SHM_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, shm_id, 0);
  assert(p_shm>=0);

  cur_step = p_shm->cur_step;
  next_step = p_shm->next_step;

}

void do_print() {
  int i;

  for(i=0;i<NB_STEPS +1; i++) {
    sem_wait(&p_shm->step_produced);

    print_matrix(cur_step);

    sem_post(&p_shm->step_consumed);

    sleep(1);
    double *tmp = cur_step;
    cur_step = next_step;
    next_step = tmp;
  }
}

int main(int argc, char** argv) {

  init();
  do_print();
  return 0;

}