sub decode_base64 ($)
{
    local($^W) = 0; # unpack("u",...) gives bogus warning in 5.00[123]
    #use integer;

    my $str = shift;
    $str =~ tr|A-Za-z0-9+=/||cd;            # remove non-base64 chars
    if (length($str) % 4) {
	require Carp;
	Carp::carp("Length of base64 data not a multiple of 4")
    }
    $str =~ s/=+$//;                        # remove padding
    $str =~ tr|A-Za-z0-9+/| -_|;            # convert to uuencoded format
    return "" unless length $str;

    ## I guess this could be written as
    #return unpack("u", join('', map( chr(32 + length($_)*3/4) . $_,
    #			$str =~ /(.{1,60})/gs) ) );
    ## but I do not like that...
    my $uustr = '';
    my ($i, $l);
    $l = length($str) - 60;
    for ($i = 0; $i <= $l; $i += 60) {
	$uustr .= "M" . substr($str, $i, 60);
    }
    $str = substr($str, $i);
    # and any leftover chars
    if ($str ne "") {
	$uustr .= chr(32 + length($str)*3/4) . $str;
    }
    return unpack ("u", $uustr);
}