sub from_to($$$;$) {
    my ( $string, $from, $to, $check ) = @_;
    return undef unless defined $string;
    $check ||= 0;
    my $f = find_encoding($from);
    unless ( defined $f ) {
        require Carp;
        Carp::croak("Unknown encoding '$from'");
    }
    my $t = find_encoding($to);
    unless ( defined $t ) {
        require Carp;
        Carp::croak("Unknown encoding '$to'");
    }
    my $uni = $f->decode($string);
    $_[0] = $string = $t->encode( $uni, $check );
    return undef if ( $check && length($uni) );
    return defined( $_[0] ) ? length($string) : undef;
}

##</code><code>##

my $uni = $f->decode($string);