Re: [Cppcms-users] Moving from boost::regex to re2 and ability to go without regex checks

[Lee E. <le...@el...>]

shouldn't the condition in your sample should be:
if((sequenceLen<=simplifiedPatternLength)||(sequence[simplifiedPatternLength]!='/'))

about your point - using regEx is great for ease of configuration & building
i like the ability to change the regex implementation being used (not just
for performance)
but using your own functions - or preferably function objects will be the
best in my opinion

and then just provide a default function object (or lambda) that uses the
boost::regex engine


On Mon, Sep 30, 2013 at 1:28 AM, Arsen Zahray <me...@gm...> wrote:

> Hey. I'd like to discuss a possibility of changing the way the app handles
> regex evaluations.
>
> Some time ago, I heavily used regex. That was before I found out, that it
> was killing  my app's performance. After I got rid of it, my app's speed
> improved by at least 10 times.
>
> So, here are few suggestions I'd like to discuss implementing:
>
> 1. Move from boost::regex (the app seems to be using that if I'm not
> mistaken) to re2 (it was developed by google for performance critical apps,
> and it seems to do the job well enough). re2 doesn't compile for windows,
> but the vast majority of cppcms users will use framework under linux (me
> included)
>
> 2. Give the users ability to go without regex altogether. Let us just pass
> along function pointers instead of regex strings. Performance wise, there
> is nothing that beats a function pointer.
>
> I've set up some benchmarks to demonstrate what I mean. Build commands:
>
> g++ -std=c++11 -Wall -fexceptions  -g  -c main.cpp -o main.o
> g++  -o regex-tests main.o  -lre2 -lbooster -lboost_regex
>
> I'm attaching the source, and here are the test results:
>
> RE2:                   326069
> boost::regex:      2164850
> function pointers;   27878
>
> Because cppcms is going to be used by those, who want top performance for
> the apps, I think that this is a way forward for the library.
>
> What do you guys think?
>
>
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