// ....
        FilePath fp;
        FileConduit datFile;
        BzipOutput bzOut;
        try
        {
            fp = new FilePath("data/maps/" ~ filename ~ ".dat");
            datFile = new FileConduit(fp, FileConduit.WriteCreate);
            bzOut = new BzipOutput(datFile.output);
            Writer write = new Writer(bzOut);
            write.put(sig)(m_name)(m_tileTableID)
                (m_leftMap)(m_topMap)(m_rightMap)(m_bottomMap)
                (m_width)(m_height)(cast(ushort[])m_tiles)();
            bzOut.close();
            // ....