Fast text file downloading. Fast searching in the text file.
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The problem with download speeds of a text file and the problem with the speed of search in a text file.
I have a program generates a text file - "Generator"
This file must be read simultaneously and displayed on the screen by
another program - "Reader".I ran into a situation where reading a file by "Reader" program ends
some time after the end of "Generator". After the long time.File size is ~10Kb - 100MB
Delay is of 3 seconds to 10 minutes
Letter 'e' searching in the file size of 2 MB takes about 80 seconds.I use the following code to download the file and search for it :
@QTextEdit *textEdit ;QTextStream in( file );
textEdit -> append( in.readAll() );
.........................QTextDocument *tmpDoc = textEdit -> document( ) ->clone( this ) ;
QTextCursor cursor ( tmpDoc ) ;
cursor = tmpDoc -> find ( regexp , cursor );@So I want to speed up text loading and searching in it.
Could you please advise something. ?
Thanks. -
Depending what it is you are searching for (just simple words or really complex RegExp), you could just read a line at a time and search that line for the text and append it to the TextDocment á la:
@
QTextDocument *document = textEdit->document();
QTextCursor cursor(document);
cursor.beginEditBlock();
while(!in.atEnd())
{
QString data = in.readLine();
int index = data.indexOf(regexp);
//do something with that
cursor.insertText(data);
}
cursor.endEditBlock();
@But as I said this will only work if you're looking for simple expressions that don't span multiple lines (if that's what you want)
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[quote author="koahnig" date="1307107463"]
... If you can avoid the clone, it should be faster.
[/quote]
Frankly I did not notice much difference with clone() and without.[quote author="loladiro" date="1307123109"]Depending what it is you are searching for (just simple words or really complex RegExp), you could just read a line at a time and search that line for the text and append it to the TextDocment ....)[/quote]
I do both - looking for simple words and complex RegExp
I experimented with reading line by line like this :
QtextStream in ;
QString line = in . readLine() ;
.........
processing( line ) ;
.........
textEdit -> append( line ) ;I believe that the append function works very slowly.
textEdit -> append( in.readAll() );
works faster than
textEdit -> append( line ) ;
but still too slow.I would like to achieve the speed of reading and finding comparable with gvim.
There is also insertPlainText(). But after insertPlainText() needed to re-format all textA search for likely have to rewrite by myself :)
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Maybe you shouldn't always append to the textEdit, just try out "this":http://doc.qt.nokia.com/4.6/qstring.html#more-efficient-string-construction method, and in the and this way you have to call the setText() function only once.