Method truncate

/**
 * Truncates text blocks over the specified character limit and closes
 * all open HTML tags. The method will optionally not truncate an individual
 * word, it will find the first space that is within the limit and
 * truncate at that point. This method is UTF-8 safe.
 *
 * @param   string   $text       The text to truncate.
 * @param   integer  $length     The maximum length of the text.
 * @param   boolean  $noSplit    Don't split a word if that is where the cutoff occurs (default: true).
 * @param   boolean  $allowHtml  Allow HTML tags in the output, and close any open tags (default: true).
 *
 * @return  string   The truncated text.
 *
 * @since   1.6
 */
public static function truncate($text, $length = 0, $noSplit = true, $allowHtml = true)
{
    // Assume a lone open tag is invalid HTML.
    if ($length === 1 && $text[0] === '<') {
        return '...';
    }
    // Check if HTML tags are allowed.
    if (!$allowHtml) {
        // Deal with spacing issues in the input.
        $text = str_replace('>', '> ', $text);
        $text = str_replace(array(' ', ' '), ' ', $text);
        $text = FrameworkStringHelper::trim(preg_replace('#\\s+#mui', ' ', $text));
        // Strip the tags from the input and decode entities.
        $text = strip_tags($text);
        $text = html_entity_decode($text, ENT_QUOTES, 'UTF-8');
        // Remove remaining extra spaces.
        $text = str_replace(' ', ' ', $text);
        $text = FrameworkStringHelper::trim(preg_replace('#\\s+#mui', ' ', $text));
    }
    // Whether or not allowing HTML, truncate the item text if it is too long.
    if ($length > 0 && FrameworkStringHelper::strlen($text) > $length) {
        $tmp = trim(FrameworkStringHelper::substr($text, 0, $length));
        if ($tmp[0] === '<' && strpos($tmp, '>') === false) {
            return '...';
        }
        // $noSplit true means that we do not allow splitting of words.
        if ($noSplit) {
            // Find the position of the last space within the allowed length.
            $offset = FrameworkStringHelper::strrpos($tmp, ' ');
            $tmp = FrameworkStringHelper::substr($tmp, 0, $offset + 1);
            // If there are no spaces and the string is longer than the maximum
            // we need to just use the ellipsis. In that case we are done.
            if ($offset === false && strlen($text) > $length) {
                return '...';
            }
            if (FrameworkStringHelper::strlen($tmp) > $length - 3) {
                $tmp = trim(FrameworkStringHelper::substr($tmp, 0, FrameworkStringHelper::strrpos($tmp, ' ')));
            }
        }
        if ($allowHtml) {
            // Put all opened tags into an array
            preg_match_all("#<([a-z][a-z0-9]*)\\b.*?(?!/)>#i", $tmp, $result);
            $openedTags = $result[1];
            // Some tags self close so they do not need a separate close tag.
            $openedTags = array_diff($openedTags, array('img', 'hr', 'br'));
            $openedTags = array_values($openedTags);
            // Put all closed tags into an array
            preg_match_all("#</([a-z][a-z0-9]*)\\b(?:[^>]*?)>#iU", $tmp, $result);
            $closedTags = $result[1];
            $numOpened = count($openedTags);
            // Not all tags are closed so trim the text and finish.
            if (count($closedTags) !== $numOpened) {
                // Closing tags need to be in the reverse order of opening tags.
                $openedTags = array_reverse($openedTags);
                // Close tags
                for ($i = 0; $i < $numOpened; $i++) {
                    if (!in_array($openedTags[$i], $closedTags)) {
                        $tmp .= '</' . $openedTags[$i] . '>';
                    } else {
                        unset($closedTags[array_search($openedTags[$i], $closedTags)]);
                    }
                }
            }
            // Check if we are within a tag
            if (FrameworkStringHelper::strrpos($tmp, '<') > FrameworkStringHelper::strrpos($tmp, '>')) {
                $offset = FrameworkStringHelper::strrpos($tmp, '<');
                $tmp = FrameworkStringHelper::trim(FrameworkStringHelper::substr($tmp, 0, $offset));
            }
        }
        if ($tmp === false || strlen($text) > strlen($tmp)) {
            $text = trim($tmp) . '...';
        }
    }
    // Clean up any internal spaces created by the processing.
    $text = str_replace(' </', '</', $text);
    $text = str_replace(' ...', '...', $text);
    return $text;
}