[Bug libstdc++/61601] C++11 regex resource exhaustion

[timshen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61601

--- Comment #10 from Tim Shen <timshen at gcc dot gnu.org> ---
(In reply to Eric Gallager from comment #9)
> (In reply to Tim Shen from comment #7)
> > (In reply to Maksymilian Arciemowicz from comment #6)
> > > > Do you have any other testcases?
> > > 
> > > for trunk? maybe you have to use ::regex_match
> > 
> > std::regex_match("findme", std::regex("(.*{100}{200}findme)"));
> > 
> > there's no memory problem, it just takes exponentially long time to run
> > (which is expected when using backtracking).
> > 
> > To avoid it, you can use Thompson NFA:
> > 
> > #define _GLIBCXX_REGEX_USE_THOMPSON_NFA
> > #include <regex>
> > 
> > int main (int argc, char *argv[])
> > {
> >   std::regex_match("findme", std::regex("(.*{100}{200}findme)",
> > std::regex_constants::extended));
> > 
> >   return 0;
> > 
> > }
> > 
> > Notice that for now Thompson NFA doesn't support ECMAScript.
> 
> Are you still working on this?

No, I'm not actively working on this.