That was more than exponentially

    private function readInteger(string $delimiter)

    {

        $pos = ftell($this->stream);

        $readLength = 64;

        $readLength = 32; // More than enough for 64 bit int (19 digits + minus + delimiter)

        do {

            fseek($this->stream, $pos, SEEK_SET);

            }

            fread($this->stream, 1); // trigger feof

            $readLength *= $readLength; // grow exponentially

            $readLength *= 32; // grow exponentially

        } while (!feof($this->stream) && $readLength < PHP_INT_MAX);

        return false;