XOOPS / XoopsCore25

        return iconv_substr($s, $start, $length, $encoding).'';

    }

    public static function mb_stripos($haystack, $needle, $offset = 0, $encoding = null)

    {

        $haystack = self::mb_convert_case($haystack, self::MB_CASE_FOLD, $encoding);

        $needle = self::mb_convert_case($needle, self::MB_CASE_FOLD, $encoding);

        return self::mb_strpos($haystack, $needle, $offset, $encoding);

    }

    public static function mb_stristr($haystack, $needle, $part = false, $encoding = null)

    {

        return self::getSubpart($pos, $part, $haystack, $encoding);

    }

    public static function mb_strripos($haystack, $needle, $offset = 0, $encoding = null)

    {

        $haystack = self::mb_convert_case($haystack, self::MB_CASE_FOLD, $encoding);

        $needle = self::mb_convert_case($needle, self::MB_CASE_FOLD, $encoding);

        return self::mb_strrpos($haystack, $needle, $offset, $encoding);

    }

    public static function mb_strstr($haystack, $needle, $part = false, $encoding = null)

    {