[boost] Doubt about regex speed.

From: Renato Tegon Forti (re.tf_at_[hidden])
Date: 2005-11-22 11:06:35

Hi All,

 

I have one system that receive many messages (TCP/IP transport) on one
second, and I validate these messages whit a sequence of if,s and switch’s,
see exemple of message:

19092;1;12345678;1111222233334444;123;0512;10000;1;0

 

I would like know if I use regex to do this I will have improvement in
performance of my system, or I will have delay in my system?

 

My regex to validate this message is:
"\\d{1,5};1;\\d{1,8};\\d{16};\\d{3};\\d{4};\\d{1,8};([0-9]|10|11|12);[012]"

 

My code sample (in old version I need same about 300 lines to do the same):

 

class CParser

{

public:

 

      CParser(const std::string& toparser, const RWDBDatabase &database)

      {

 
if(validate("\\d{1,5};1;\\d{1,8};\\d{16};\\d{3};\\d{4};\\d{1,8};([0-9]|10|11
|12);[012]", toparser))

            {

                  CContext<CProcessMessage1> process;

            }

            else if(validate("\\d{1,5};3;\\d{16};\\d{11};[01]", toparser))

            {

…

            }

            else if(validate("\\d{1,5};5;\\d{16};\\d{11}", toparser))

            {

…

            }

            else if(validate("\\d{1,5};7;\\d{16};\\d{11}", toparser))

            {

…

            }

            else

            {

                  throw CParserException("bad_message");

            }

      }

 

protected:  

      

      bool validate(const std::string& regex, const std::string&
to_validate)

      {

            try

            {

                  const boost::regex e(regex);

                  return regex_match(to_validate.c_str(), e);

            }

            catch (...) 

            {

                  throw CParserException("bad_regex_syntax");

            }

      }

 

};

 

Thanks to help

 

  _____  

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