sub gmtime {
    my $time = shift;
    $time = time if (!defined $time);
    _mktime($time, 0);
}

sub _mktime {
    my ($time, $islocal) = @_;
    if (ref($time)) {
	$time->[c_epoch] = undef;
	return wantarray ? @$time : bless [@$time, $islocal],
                                          'Time::Piece';
    }
    my @time = $islocal ?
            CORE::localtime($time)
                :
            CORE::gmtime($time);
    wantarray ? @time : bless [@time, $time, $islocal], 'Time::Piece';
}