sub dfind {
    my ($dref, $top) = @_;
    hidden( $top )
      and return;
    if (-d $top) {
        for my $file (glob( "$top/*" )) {
            dfind( $dref, $file );
        }
    }
    else {
        register( $dref, $top ); # add to HoA
    }
}

sub hidden {
    my $file = shift;
    my $attribs;
    Win32::File::GetAttributes($file,  $attribs);
    return $attribs & HIDDEN;
}