Re: [Boost-bugs] [Boost C++ Libraries] #5215: regex_match is giving a performance hit.

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #5215: regex_match is giving a performance hit.
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-03-01 09:32:47

#5215: regex_match is giving a performance hit.
---------------------------------+------------------------------------------
  Reporter:  arjun_m@…           |       Owner:  johnmaddock 
      Type:  Bugs                |      Status:  new         
 Milestone:  To Be Determined    |   Component:  regex       
   Version:  Boost 1.46.0        |    Severity:  Optimization
Resolution:                      |    Keywords:              
---------------------------------+------------------------------------------

Comment (by anonymous):

 Replying to [comment:2 anonymous]:
 > Can you please provide some example code that illustrates the problem?
 >
 > Please also bare in mind that matching a regular expression is in the
 general case NP-complete.  Assuming it doesn't change the semantics of
 your program then something like:
 >
 > {{{/Volumes/[^/]*/Backups.backupdb/.*}}}
 >
 > Should be more efficient.  Otherwise try something like:
 >
 > {{{/Volumes(?:/[^/]*)+?/Backups.backupdb/.*}}}



 Thanks for the reply.

 After I posted this issue, I was trying out different alternatives and
 found something.
 The back drop for this issue is that,
 I am getting exclusion list from the User, based on which I am performing
 some operations. So I convert the exclusion list to an 'expression' and
 pass it to regex_match().
 The more I add exclusion's , more time is taken by regex_match().  As
 suggested by I would provide an example code that would illustrate the
 problem.

 Thanks.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5215#comment:3>
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