public function parseInnerTree(array $elementMap = null)
    {
        $text = null;
        $elements = [];

        if (self::ELEMENT === $this->nodeType && $this->isEmptyElement) {
            // Easy!
            $this->next();

            return null;
        }

        if (!is_null($elementMap)) {
            $this->pushContext();
            $this->elementMap = $elementMap;
        }

        try {
            if (!$this->read()) {
                $errors = libxml_get_errors();
                libxml_clear_errors();
                if ($errors) {
                    throw new LibXMLException($errors);
                }
                throw new ParseException('This should never happen (famous last words)');
            }

            while (true) {
                if (!$this->isValid()) {
                    $errors = libxml_get_errors();

                    if ($errors) {
                        libxml_clear_errors();
                        throw new LibXMLException($errors);
                    }
                }

                switch ($this->nodeType) {
                    case self::ELEMENT:
                        $elements[] = $this->parseCurrentElement();
                        break;
                    case self::TEXT:
                    case self::CDATA:
                        $text .= $this->value;
                        $this->read();
                        break;
                    case self::END_ELEMENT:
                        // Ensuring we are moving the cursor after the end element.
                        $this->read();
                        break 2;
                    case self::NONE:
                        throw new ParseException('We hit the end of the document prematurely. This likely means that some parser "eats" too many elements. Do not attempt to continue parsing.');
                    default:
                        // Advance to the next element
                        $this->read();
                        break;
                }
            }
        } finally {
            if (!is_null($elementMap)) {
                $this->popContext();
            }
        }

        return $elements ? $elements : $text;
    }