Added is_open to mmapper.
Added is_open to mmapper.

takei-yuya/pficommon,pfi/pficommon,pfi/pficommon,takei-yuya/pficommon,retrieva/pficommon,retrieva/pficommon,retrieva/pficommon,takei-yuya/pficommon,retrieva/pficommon,pfi/pficommon,retrieva/pficommon,takei-yuya/pficommon,pfi/pficommon