gcab_folder_get_ndatablocks (GCabFolder *self)
{
    gsize total_size = 0;

    for (GSList *l = self->files; l != NULL; l = l->next) {
        GCabFile *file = GCAB_FILE (l->data);
        total_size += gcab_file_get_usize (file);
    }

    return total_size / DATABLOCKSIZE + 1 ;
}
gcab_folder_get_ndatablocks (GCabFolder *self)
{
    gsize total_size = 0;

    for (GSList *l = self->files; l != NULL; l = l->next) {
        GCabFile *file = GCAB_FILE (l->data);
        total_size += gcab_file_get_usize (file);
    }

    return total_size / DATABLOCKSIZE + 1 ;
}