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

[egallager at gcc dot gnu.org]

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

--- Comment #9 from Eric Gallager <egallager at gcc dot gnu.org> ---
(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?