public static boolean isPubid(int c) {
        return c < 0x10000 && (CHARS[c] & MASK_PUBID) != 0;
    }
Returns true if the specified character is a valid Pubid
character as defined by production [13] in the XML 1.0
specification.

@param c The character to check.
stroom-util/src/main/java/stroom/util/xml/XMLChar.java