/*
 * Implementação com bug de mutex locks e variáveis de condição
 * utilizando semáforos.
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include "mutex_bug.h"

int mutex_init(mutex_t *lock, mutexattr_t* attr) {
  return sem_init(&lock->sem, 0, 1);
}

int mutex_destroy(mutex_t *lock) {
  return sem_destroy(&lock->sem);
}

int mutex_lock(mutex_t *lock) {
  return sem_wait(&lock->sem);
}

int mutex_unlock(mutex_t *lock) {
  return sem_post(&lock->sem);
}


/*------------------------------------------------------*/

int cond_init(cond_t *cond, condattr_t* attr) {
  mutex_init(&cond->lock, NULL);
  sem_init(&cond->sem, 0, 0);
  cond->n_wait = 0;
  return 0;
}

int cond_destroy(cond_t *cond) {
  mutex_destroy(&cond->lock);
  sem_destroy(&cond->sem);
  return 0;
}

int v = 0;

int cond_wait(cond_t *cond, 
              mutex_t *mutex_externo) {
  mutex_lock(&cond->lock);              
  cond->n_wait++;
  mutex_unlock(&cond->lock);                
  mutex_unlock(mutex_externo);
  if (v == 0) 
    { v = 1; printf("Vai dormir\n"); sleep(3); }
  sem_wait(&cond->sem);
  mutex_lock(mutex_externo);
  return 0;
  
}

int cond_signal(cond_t *cond){
  mutex_lock(&cond->lock);
  if (cond->n_wait > 0) {
    cond->n_wait--;
    sem_post(&cond->sem);
  }
  mutex_unlock(&cond->lock);
  return 0;  
}

int cond_broadcast(cond_t *cond){
  mutex_lock(&cond->lock);
  while (cond->n_wait > 0) {
    cond->n_wait--;
    sem_post(&cond->sem);
  }
  mutex_unlock(&cond->lock);
  return 0;  
}