# return -1 if we've reached the end of the buffer.
    def _scan_name(self, i, declstartpos):
        rawdata = self.rawdata
        n = len(rawdata)
        if i == n:
            return None, -1
        m = _declname_match(rawdata, i)
        if m:
            s = m.group()
            name = s.strip()
            if (i + len(s)) == n:
                return None, -1  # end of buffer
            return name.lower(), m.end()
        else:
            self.updatepos(declstartpos, i)
            raise AssertionError(
                "expected name token at %r" % rawdata[declstartpos:declstartpos+20]
            )
    # To be overridden -- handlers for unknown objects
    def unknown_decl(self, data):
        pass