if (!isDigits(s)) {
            return null;
        }

        try {
            long longValue = Long.parseLong(s);
            if (longValue > Integer.MAX_VALUE) {
                return null;
            }
            return (int) longValue;
        } catch (NumberFormatException e) {
            // should never happen since checked isDigits(s) before
            return null;

    public static boolean isDotQuadIP(final String hostname) {
        if (Character.isDigit(hostname.charAt(0))) {
            int i, len, dots;
            char[] data;

            i = dots = 0; /* quick IP address validation */
            len = hostname.length();
            data = hostname.toCharArray();
            while (i < len && Character.isDigit(data[i++])) {
                if (i == len && dots == 3) {

                    throw new IOException("no lmhosts alternate includes loaded");
                }
            } else if (Character.isDigit(line.charAt(0))) {
                final char[] data = line.toCharArray();
                int ip, i, j;
                Name name;
                NbtAddress addr;
                char c = '.';

                    alt--;
                    throw new IOException("no lmhosts alternate includes loaded");
                }
            } else if (Character.isDigit(line.charAt(0))) {
                final char[] data = line.toCharArray();
                int ip, i, j;
                Name name;
                NbtAddress addr;
                char c = '.';