http://splen.sakura.ne.jp/project/trac.cgi/ticket/9#comment:222
http://splen.sakura.ne.jp/project/trac.cgi/ticket/9#comment:223
http://splen.sakura.ne.jp/project/trac.cgi/ticket/9#comment:222
http://splen.sakura.ne.jp/project/trac.cgi/ticket/9#comment:223