Hi Didier, Thank you for trying the patch :) and all the good comments given.
I've attached a new patch to the wiki. Please see my detailed reply below. On Fri, Mar 20, 2009 at 6:30 AM, didier <dgauthe...@magic.fr> wrote: > Hi, > > Le mercredi 18 mars 2009 à 23:05 +0800, yami a écrit : > > Thanks, I've written a page in Wiki: > > http://wiki.wireshark.org/Development/FastFiltering > Nice work. > > - If compiled without NDEBUG defined I get a failed assert: > epan/dfilter/wslimmat.c :1680 : fix_variables: "v->assignment == v" > It seems like a 'bug' of gcc optimization. We can simply remove this assertion, see explanations below. The assertion fails, but the 'real' value of v->assignment and v are equal. I came to this conclusion by following experiments (is there any better way?): experiment 1. without NDEBUG defined, but using '-O0' to compile, not assertion failure occurs. experiment 2. no change to Makefile, simply add printf(v->assignment, v) to fix_pointer(), no assertion failure experiment 3. no change to Makefile, add following to fix_variables() after the assert line: if (v->assignment != v) printf("not hold v->assignment=%p, v=%p\n", v->assignment, v); else printf(" hold v->assignment=%p, v=%p\n", v->assignment, v); The assertion fails (simply print, no abort), however output is: hold v->assignment=0x8070508, v=0x8070508 which just says the opposite. > valgrind doesn't complain and it seems to work with NDEBUG but only for > simple stuff ie udp && dns, something like !(tcp.stream eq 1) > && !(tcp.stream eq 2) doesn't return the right result. > ie: > follow TCP stream, filter out this stream, follow TCP this stream, and > so on. > Does it work for you? This is a bug, I've fixed '!' (TEST_OP_NOT) part at least. I'll test the patch more. > > > - stupid but Limmat uses the original BSD license which is incompatible > with the GPL. > Really? I've thought BSD license is looser than GPL (can you give me more details?). On the other hand, I find Wireshark code has already contains similar licenses (am I right?), for example, Menu -> Help -> About Wireshark -> License -> Part III has metioned some. > > - On the other hand if expressions are made incrementally via popup > menus is a full SAT solver need? > Perhaps you are right, but I'm not sure. However using a SAT solver (even if it is a simple one) is the most generalized way, which requires no special handling. And it is also a good example of how math is applied in real life :) Cons are 1. SAT solvers are complicated. (But we may use a simple algorithm) 2. Public available SAT solvers are mainly wrote by researchers, which may not have time to maintain the software. > > eg: > Something like > tcp.stream eq 1 --> H1 > > !(tcp.stream eq 1) --> !H1 --> H2 > > tcp.stream eq 2 --> H3 > > !(tcp.stream eq 1) && !(tcp.stream eq 2) --> H2 && !H3 > > may be good enough. > > Didier > > > > ___________________________________________________________________________ > Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org> > Archives: http://www.wireshark.org/lists/wireshark-dev > Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev > mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe >
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