function _get_record($key)
	{
		$this->_io_times = 1;
		$index = ($this->hash_prime > 1 ? $this->_get_index($key) : 0);
		$poff = $index * 8 + 32;
		fseek($this->fd, $poff, SEEK_SET);
		$buf = fread($this->fd, 8);

		if (strlen($buf) == 8) $tmp = unpack('Ioff/Ilen', $buf);
		else $tmp = array('off' => 0, 'len' => 0);
		return $this->_tree_get_record($tmp['off'], $tmp['len'], $poff, $key);
	}