From: Paolo Bonzini <paolo.bonzini@gmail.com>
To: demerphq <demerphq@gmail.com>
Cc: Jeff King <peff@peff.net>, Paolo Bonzini <bonzini@gnu.org>,
git@vger.kernel.org, gitster@pobox.com
Subject: Re: [PATCH] avoid exponential regex match for java and objc function names
Date: Wed, 17 Jun 2009 18:04:57 +0200 [thread overview]
Message-ID: <4A391429.4010706@gmail.com> (raw)
In-Reply-To: <9b18b3110906170900g778b3c8aie627fb45a4967eb2@mail.gmail.com>
> Ah ok. Im not familiar with the finer points of the POSIX engine, but
> PCRE and Perl's engine, and most similar engines are not true regular
> expression engines and thus benefit *greatly* from atomic matching if
> it is available.
>
> Like the difference between heat-death performance (or stack
> overflow), and running instantly.
You can almost always fix the regex to avoid this, by ensuring that
whenever you have (...)+ (or *) a suffix of the subexpression cannot be
a prefix of the subexpression too. This is what my patch did --
changing a bad regex to a nicely behaving one.
Paolo
next prev parent reply other threads:[~2009-06-17 16:05 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 1:37 git diff looping? John Bito
2009-06-16 2:44 ` Jeff Epler
2009-06-16 2:53 ` John Bito
2009-06-16 11:47 ` Jeff King
2009-06-16 12:07 ` Jeff King
2009-06-16 12:11 ` [PATCH 1/2] Makefile: refactor regex compat support Jeff King
2009-06-16 18:47 ` Johannes Sixt
2009-06-16 19:05 ` Jeff King
2009-06-16 19:07 ` [PATCH v2 " Jeff King
2009-06-16 19:08 ` [PATCH v2 2/2] Makefile: use compat regex on Solaris Jeff King
2009-06-16 20:07 ` Brandon Casey
2009-06-17 13:15 ` Mike Ralphson
2009-06-17 13:55 ` Mike Ralphson
2009-06-16 12:14 ` [PATCH " Jeff King
2009-06-16 15:48 ` git diff looping? John Bito
2009-06-16 16:51 ` Junio C Hamano
2009-06-16 17:15 ` Jeff King
2009-06-16 17:35 ` Brandon Casey
2009-06-16 17:39 ` John Bito
2009-06-16 17:41 ` Jeff King
2009-06-16 20:22 ` Brandon Casey
2009-06-17 8:46 ` Paolo Bonzini
2009-06-17 10:23 ` Jeff King
2009-06-17 11:02 ` Paolo Bonzini
2009-06-17 11:31 ` Andreas Ericsson
2009-06-17 13:08 ` Paolo Bonzini
2009-06-17 13:16 ` Andreas Ericsson
2009-06-17 13:58 ` Paolo Bonzini
2009-06-17 14:26 ` [PATCH] avoid exponential regex match for java and objc function names Paolo Bonzini
2009-06-17 15:46 ` demerphq
2009-06-17 15:56 ` Jeff King
2009-06-17 16:00 ` demerphq
2009-06-17 16:04 ` Paolo Bonzini [this message]
2009-06-17 16:42 ` Junio C Hamano
2009-06-18 6:45 ` Paolo Bonzini
2009-06-16 17:16 ` git diff looping? John Bito
2009-06-16 17:24 ` Jeff King
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