private function inBounds() {
        $in = true;
        if ($this->from !== null) {
            $in = $this->current >= $this->from;
            if ($in && $this->length !== null) {
                $in = $this->current < $this->from + $this->length;
                if (!$in && $this->outOfBounds) {
                    die("Process stopped in TcTable Debug Plugin, because " .
                        "\$outOfBounds is set to TRUE in setBounds().");
                }
            }
        }
        if ($in && is_callable($this->boundsFn)) {
            return $this->boundsFn($this, $this->current);
        }
        return $in;
    }