/**
     * Construct a SID from it's textual representation such as
     * <tt>S-1-5-21-1496946806-2192648263-3843101252-1029</tt>.
     */
    public SID(String textual) throws SmbException {
        StringTokenizer st = new StringTokenizer(textual, "-");
        if (st.countTokens() < 3 || !st.nextToken().equals("S"))
            // need S-N-M
            throw new SmbException("Bad textual SID format: " + textual);