Re: [Boost-users] Boost.Regex hangs with large pattern

From: Brian Crowder (crowder_at_[hidden])
Date: 2006-10-29 11:38:06

Is it possible that the expression you're using explodes  
exponentially on failed matches (regex is NP-Hard, at least)?  Can  
you share the pattern?

On Oct 28, 2006, at 11:03 PM, Dave Druelinger wrote:

> I'm using Boost.Regex to match a long, complicated pattern to  
> between 30 and 50 long strings.  I loop through and call  
> regex_search until it doesn't find any more matches in the current  
> string and then it moves on to the next string.  The problem is  
> that when it has looped through about 40 of the strings,  
> Boost.Regex will hang on the regex_search() function, and it will  
> just sit there processing forever.  If I reduce the number of  
> strings I match against there is no problem;  20-30 iterations  
> works like a charm.  It also seems to help if I reduce the size of  
> the regex pattern.
>
> Frankly I have no clue what could be causing the problem, and any  
> help would be greatly appreciated.
>
> Thanks
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users