> > > I take it back, it is regular (kinda) but you can't to it with a > deterministic finite atomaton. If there is a cycle in pattern1, off of > which pattern2 has a branch, then you would need to count how many times > you have gone around the cycle to know where to jump to in pattern2 if > it fails to match pattern1 (which you can't do, pumping lemma and all > that.) If you use a non-determistic FA, you should be able to just go > through each pattern until both crash or one matches and declare that > the winner. Strange way of reasoning... what if pattern1 is "(subpat1|subpat2)" ? regexp is a regular language so it is equivalent to a DFA. For every NDFA, there exist a DFA that recognize the same language. So, it is possible. The question is : will we have enough memory to store a DFA that recognize a big regexp ? The answer is : let loose some speed and use NDFA. > If your lib did that, it would work quite well for the layer-7 filter. Anyone here interested by doing a regexp compiler ? I can help for details or libqsearch internals, but I won't find enough time to do all that quickly enough. -- Philippe Biondi <biondi@ cartel-securite.fr> Cartel Sécurité Security Consultant/R&D http://www.cartel-securite.fr Phone: +33 1 44 06 97 94 Fax: +33 1 44 06 97 99 PGP KeyID:3D9A43E2 FingerPrint:C40A772533730E39330DC0985EE8FF5F3D9A43E2 - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
