public function encodeQ($str, $position = 'text')
    {
        // There should not be any EOL in the string
        $pattern = '';
        $encoded = str_replace(array("\r", "\n"), '', $str);
        switch (strtolower($position)) {
            case 'phrase':
                // RFC 2047 section 5.3
                $pattern = '^A-Za-z0-9!*+\/ -';
                break;
            /** @noinspection PhpMissingBreakStatementInspection */
            case 'comment':
                // RFC 2047 section 5.2
                $pattern = '\(\)"';
                // intentional fall-through
                // for this reason we build the $pattern without including delimiters and []
            case 'text':
            default:
                // RFC 2047 section 5.1
                // Replace every high ascii, control, =, ? and _ characters
                $pattern = '\000-\011\013\014\016-\037\075\077\137\177-\377' . $pattern;
                break;
        }
        $matches = array();
        if (preg_match_all("/[{$pattern}]/", $encoded, $matches)) {
            // If the string contains an '=', make sure it's the first thing we replace
            // so as to avoid double-encoding
            $eqkey = array_search('=', $matches[0]);
            if ($eqkey !== false) {
                unset($matches[0][$eqkey]);
                array_unshift($matches[0], '=');
            }
            foreach (array_unique($matches[0]) as $char) {
                $encoded = str_replace($char, '=' . sprintf('%02X', ord($char)), $encoded);
            }
        }
        // Replace every spaces to _ (more readable than =20)
        return str_replace(' ', '_', $encoded);
    }