RE: Infinite Loop or Just taking too long ?

"Kumar, Vasanth" <[email protected]> Tue, 25 Feb 2003 17:06:56 -0500

Newsgroups	gmane.comp.jakarta.oro.user
Message-ID	<F500BDA6D2EAD311AD5B00508BCF2DF304CB1A4A@iwexchange1.na.interworld.com>

Sorry, it seems that my attachment didn't make it through in my prior email.

And here is how I ran it:

java TestRegex ^[A-Za-z0-9#_!'\(\)\-]+([A-Za-z0-9#_!'\(\)\.\-]+)*@[A-Za-z0-9#_!'\(\)\-]+[\.]+([AZa-z0-9#_!'\(\)\.\-]+)+$ abcdefghijklmnopqrstuvwxyz1234567890@yahoo.



-----Original Message-----
From: Kumar, Vasanth 
Sent: Tuesday, February 25, 2003 4:56 PM
To: [email protected]
Subject: Infinite Loop or Just taking too long ?


Hi,

We use ORO in our application for to provide regular expression capability.  One of our users had created an email validation expression as follows:
^[A-Za-z0-9#_!'\(\)\-]+([A-Za-z0-9#_!'\(\)\.\-]+)*@[A-Za-z0-9#_!'\(\)\-]+[\.]+([AZa-z0-9#_!'\(\)\.\-]+)+$

As you can see, this is inefficient and can be simplified to (at least) the following:
^[A-Za-z0-9#_!'\(\)\-]+[A-Za-z0-9#_!'\(\)\.\-]*@[A-Za-z0-9#_!'\(\)\-]+[\.]+[AZa-z0-9#_!'\(\)\.\-]+$

However, the original expression seems to hang ORO when given a long, invalid, email.
(Though I must admit I don't know whether it is hanging or just taking a really long time.)

An example of an email that seems to slow it down/hang is:
abcdefghijklmnopqrstuvwxyz1234567890@yahoo.

Note that valid emails are evaluated successfully (i.e. [email protected] doesn't hang ORO).

I am enclosing my test case as well.

This seems to be an issue in the latest version - 2.0.7.

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TestRegex.java.txt (text/plain, 1.6 KB)

import java.util.*;
import org.apache.oro.text.regex.PatternMatcher;
import org.apache.oro.text.regex.PatternCompiler;
import org.apache.oro.text.regex.Pattern;
import org.apache.oro.text.regex.PatternMatcherInput;
import org.apache.oro.text.regex.MatchResult;
import org.apache.oro.text.regex.Util;
import org.apache.oro.text.regex.Perl5Compiler;
import org.apache.oro.text.regex.StringSubstitution;
import org.apache.oro.text.regex.Perl5Matcher;
import org.apache.oro.text.regex.MalformedPatternException;

public class TestRegex
{
  public static void main(String[] args)
  {
    try
    {
      PatternMatcher oroMatcher;
      PatternCompiler oroCompiler;
      Pattern oroPattern;
      PatternMatcherInput oroInput;
      
      String sExpr = args[0];
      String sData = args[1];
      
      oroCompiler = new Perl5Compiler();
      oroMatcher  = new Perl5Matcher();
      oroPattern = oroCompiler.compile(sExpr, Perl5Compiler.CASE_INSENSITIVE_MASK);
      
      MatchResult oroResult;
      oroInput = new PatternMatcherInput(sData);

      if (oroMatcher.contains(oroInput, oroPattern))
      {
        System.out.println("Match");

        oroResult = oroMatcher.getMatch();

        int totalGroups = oroResult.groups();
        for(int groupNum = 0; groupNum < totalGroups; groupNum++)
        {
          System.out.println("match: " + oroResult.group(groupNum));
        }
      }
      else
      {
        System.out.println("No match");
      }
    }
    catch (Exception e)
    {
      e.printStackTrace();
      System.out.println(e);
    }
  }
}