[Qt-interest] Parsing input and performance of QRegExp

[Jens Saathoff]

Hi!

I need to parse some input. The input is a poker handhistory-file.
You can view an example here: "http://pastebin.com/rzhccyfK":
http://pastebin.com/rzhccyfK

I need the following informations:
- All Playernames
- Gamenumber
- All costs (and of each player)

Let's say i  have to get all information to put in a database and to examine
the data.

My first try was "use regular expressions" and use boost::spirit.

I find out that regular expressions are much slower than parsing with
boost::spirit. The problem with spirit is that it takes a long time to
compile. Very long, but it's fast as hell!

What would you suggest? Use another parser? QLALR?

Can i parse the following with QLALR?
Input1: Player raises $1 to $2 (Name: Player, amount $2)
Input2: Player raises raises $1 to $2 (Name: Player raises, amount $2)

And...another thing? Is it fast?

What's with other parsers? Any experience with Ragel, Bison or something
else?


Nex thing: Performance of QRegExp!

I did a test with the following code:

void MainWindow::on_btnTest_clicked()
> {
>     int i = TestRegex();
>     qDebug() << "Dauerte: " << i << "\n";
> }
> int MainWindow::TestRegex()
> {
>     list.clear();
>     qDebug() << "Start\n";
>     tgone.start();
>     regex.setCaseSensitivity(Qt::CaseInsensitive);
>     regex.setPatternSyntax(QRegExp::RegExp2);
>     regex.setPattern("^(\\d{2,2})\\.(\\d{2,2})\\.(\\d{4,4})$");
>
>     if(regex.isValid())
>     {
>         int i=0;
>         i++;
>         for(i=0; i<5000; i++)
>         {
>             if (regex.indexIn("12.03.2011") != -1)
>             {
>                  list.append(regex.cap(0));
>                  list.append(regex.cap(1));
>                  list.append(regex.cap(2));
>             }
>         }
>     }
>     qDebug() << "Elemente: " << list.count() << "\n";
>     return tgone.elapsed();
> }


If i run the code for the first time the used time is 71 ms, on second run
400, on third 501. It grows!! But why?

I know that other frameworks need to compile a regexe, why is there no need
for QRegExp?

Thank you very much! Im really interested in your answers!!!
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