handle first_block calculation when file size is 0
handle first_block calculation when file size is 0

iychoi/syndicate,jcnelson/syndicate,jcnelson/syndicate,jcnelson/syndicate,iychoi/syndicate,iychoi/syndicate,jcnelson/syndicate,jcnelson/syndicate,iychoi/syndicate,iychoi/syndicate,jcnelson/syndicate,jcnelson/syndicate,iychoi/syndicate,jcnelson/syndicate,iychoi/syndicate,iychoi/syndicate