Function bitmap_init

mysys/my_bitmap.c:138–177

my_bool bitmap_init(MY_BITMAP *map, my_bitmap_map *buf, uint n_bits,
		    my_bool thread_safe __attribute__((unused)))
{
  DBUG_ENTER("bitmap_init");
  if (!buf)
  {
    uint size_in_bytes= bitmap_buffer_size(n_bits);
    uint extra= 0;

    if (thread_safe)
    {
      size_in_bytes= ALIGN_SIZE(size_in_bytes);
      extra= sizeof(mysql_mutex_t);
    }
    map->mutex= 0;

    if (!(buf= (my_bitmap_map*) my_malloc(size_in_bytes+extra, MYF(MY_WME))))
      DBUG_RETURN(1);

    if (thread_safe)
    {
      map->mutex= (mysql_mutex_t *) ((char*) buf + size_in_bytes);
      mysql_mutex_init(key_BITMAP_mutex, map->mutex, MY_MUTEX_INIT_FAST);
    }

  }

  else
  {
    DBUG_ASSERT(thread_safe == 0);
    map->mutex= NULL;
  }


  map->bitmap= buf;
  map->n_bits= n_bits;
  create_last_word_mask(map);
  bitmap_clear_all(map);
  DBUG_RETURN(0);
}


void bitmap_free(MY_BITMAP *map)