Added a simple checking for the validity of user-supplied SDF file
Added a simple checking for the validity of user-supplied SDF file

HongjianLi/usr,HongjianLi/USR-VS,HongjianLi/USR-VS,HongjianLi/USR-VS,HongjianLi/USR-VS,HongjianLi/usr,HongjianLi/usr,HongjianLi/usr