require_once($CFG->libdir.'/umnlib.php'); 

            $tablename = "sitequota";
            $coursequota = getquotadetails($COURSE->id);
            if ($coursequota == NULL) {
                $coursequota = getquotadetails(0);
            }

            $coursesize = get_directory_size("{$CFG->dataroot}/$COURSE->id"); // in bytes - may overflow for large directories
            // this switch is for the size of the course directory in a the same unit as the quota unit is defined in
            switch ($coursequota->unit) {
                case "B":
                        break;
                case "K":
                        $coursesize /= 1024;
                        break;
                case "M":
                        $coursesize /= 1048576;
                        break;
                case "G":
                        $coursesize /= 1073741824;
                        break;
                case "T":
                        $coursesize /= 1099511627776;
                        break;
                case "P":
                        $coursesize /= 1125899906842624;
                        break;
                case "E":
                        $coursesize /= 1152921504606846976;
                        break;
            }

            if ($coursesize > (int) $coursequota->quota && isteacher()) {
                error("Unable to upload files: Total site size is $coursesize $coursequota->unit and quota is $coursequota->quota $coursequota->unit", "{$CFG->wwwroot}/files/index.php?id=$COURSE->id");
            }

                print_simple_box_start();
                echo "Using $coursesize " . readablestorageunit($coursequota->unit) . " out of $coursequota->quota " . readablestorageunit($coursequota->unit) . " allowed";
                print_simple_box_end();