ldap_escape() function

ldap_escape.php

/**
 * function ldap_escape
 * @source http://stackoverflow.com/questions/8560874/php-ldap-add-function-to-escape-ldap-special-characters-in-dn-syntax#answer-8561604
 * @author Chris Wright
 * @version 2.0
 * @param string $subject The subject string
 * @param bool $dn Treat subject as a DN if TRUE
 * @param string|array $ignore Set of characters to leave untouched
 * @return string The escaped string
 */
public static function ldap_escape($subject, $dn = FALSE, $ignore = NULL)
{
        // The base array of characters to escape
        // Flip to keys for easy use of unset()
        $search = array_flip($dn ? array('\\', ',', '=', '+', '<', '>', ';', '"', '#') : array('\\', '*', '(', ')', "\x00"));

        // Process characters to ignore
        if (is_array($ignore)) {
                $ignore = array_values($ignore);
        }
        for ($char = 0; isset($ignore[$char]); $char++) {
                unset($search[$ignore[$char]]);
        }

        // Flip $search back to values and build $replace array
        $search = array_keys($search); 
        $replace = array();
        foreach ($search as $char) {
                $replace[] = sprintf('\\%02x', ord($char));
        }

        // Do the main replacement
        $result = str_replace($search, $replace, $subject);

        // Encode leading/trailing spaces in DN values
        if ($dn) {
                if ($result[0] == ' ') {
                        $result = '\\20'.substr($result, 1);
                }
                if ($result[strlen($result) - 1] == ' ') {
                        $result = substr($result, 0, -1).'\\20';
                }
        }

        return $result;
}