function Draw($i = -1)
	{
		if ($i < 0 || $i >= $this->hash_prime)
		{
			$i = 0;
			$j = $this->hash_prime;
		}
		else
		{
			$j = $i + 1;
		}

		echo "Draw the XDB data [$i ~ $j]. (" . trim($this->Version()) . ")\n\n";
		while ($i < $j)
		{
			$poff = $i * 8 + 32;
			fseek($this->fd, $poff, SEEK_SET);
			$buf = fread($this->fd, 8);
			if (strlen($buf) != 8) break;
			$ptr = unpack('Ioff/Ilen', $buf);
			
			$this->_cur_depth = 0;
			$this->_node_num = 0;
			$this->_draw_node($ptr['off'], $ptr['len']);
			echo "-------------------------------------------\n";
			echo "Tree(xdb) [$i] max_depth: {$this->_cur_depth} nodes_num: {$this->_node_num}\n";			
			$i++;
		}
	}