realloc.c

void * realloc(void * ptr, size_t size) //size_t in bytes
{
  // printf("in realloc %d",size);
  if (ptr != NULL && size == 0) {
    free(ptr);
    return;
  } else if (ptr == NULL) {
    return malloc(size);
  } else {
    pthread_mutex_lock( & arrThread - > arrlock);
    void * newptr = NULL;
    struct MyNode * n = malloc_search_node(ptr);
    pthread_mutex_unlock( & arrThread - > arrlock);
    if (n != NULL) {
      if (n - > occupied < size) {
        //pthread_mutex_lock(&mutex);
        newptr = malloc(size);
        //pthread_mutex_unlock(&mutex);
        newptr = memcpy(newptr, ptr, n - > occupied);
        // pthread_mutex_unlock(&mutex);
        free(ptr);
        //pthread_mutex_unlock(&mutex);
        return newptr;
      } else {
        return ptr;
      }
    } else {
      return malloc(size);
    }
  }
  //printf("I m here 2:");
  return NULL;
}

int malloc_search_node(void * sbt_pointer) {
  struct MyNode * n;
  n = arrThread - > ghead;
  while (n != NULL) {
    if (n - > sb_pointer == sbt_pointer) {
      return n;
      break;
    }
    n = n - > next;
  }
  return NULL;
}