void save_index::write_save_index()
{
        log_scope("write_save_index()");
        try {
                scoped_ostream stream = ostream_file(get_save_index_file());
                if (preferences::compress_saves()) {
                  write_gz(*stream, load());
                } else {
                  write(*stream, load());
                }
        } catch(io_exception& e) {
                ERR_SAVE << "error writing to save index file: '" << e.what() << "'\n";
        }
}