private boolean isWhitespace(char c) {
        if (c > 0x20) {
            return false;
        }
        if ((c == 0x20) || (c == 0x0a) || (c == 0x09) || (c == 0x0d)) {
            return true;
        }
        return false; // illegal ...
    }
Test if a character is whitespace.

<pre>
  [3] S ::= (#x20 | #x9 | #xd | #xa)+
</pre>

@param c
           The character to test.
@return true if the character is whitespace.
src/nu/validator/gnu/xml/aelfred2/XmlParser.java