Re: [lisp-snmp] Memory usage of ASN.1 library

[John F. <jf...@ms...>]

"Chun Tian (binghe)" <bin...@gm...> writes:

> Great!
>
> And, please use my more updated version of ASN.1:OID-< as a work base:

Sorry, I already made a new version, is it okay?

(defun oid-< (oid-1 oid-2)
  "test if oid-1 is oid-2's child"
  (let ((o-1 (oid-number-list oid-1))
        (o-2 (oid-number-list oid-2))
        (o-1-len (oid-length oid-1))
        (o-2-len (oid-length oid-2)))
    (unless (<= o-1-len o-2-len)
      (loop for x-1 in o-1
	    for x-2 in o-2
	    always (equal x-1 x-2)))))

In the old version with O(n) lengths this is suboptimal but in the new
version with O(1) lengths we are better off with checking the length first

>
> (defun oid-< (oid-1 oid-2)
>   "test if oid-1 is oid-2's child"
>   (let ((o-1-len (oid-length oid-1))
>         (o-2-len (oid-length oid-2)))
>     (if (<= o-1-len o-2-len) nil
>       (let ((o-1 (reverse (oid-number-list oid-1)))
>             (o-2 (reverse (oid-number-list oid-2))))
>         (equal o-2 (nthcdr (- o-1-len o-2-len) o-1))))))
>
> I believe it's more sufficient than before.

if test nil else === unless test else

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