Torrent::decode_dictionary PHP Method

    private static function decode_dictionary(&$data)
    {
        $dictionary = array();
        $previous = null;
        while (($char = self::char($data)) != 'e') {
            if ($char === false) {
                return self::set_error(new Exception('Unterminated dictionary'));
            }
            if (!ctype_digit($char)) {
                return self::set_error(new Exception('Invalid dictionary key'));
            }
            $key = self::decode_string($data);
            if (isset($dictionary[$key])) {
                return self::set_error(new Exception('Duplicate dictionary key'));
            }
            if ($key < $previous) {
                self::set_error(new Exception('Missorted dictionary key'));
            }
            $dictionary[$key] = self::decode_data($data);
            $previous = $key;
        }
        $data = substr($data, 1);
        return $dictionary;
    }