open/write gzipped file

[niko]

Hello,

I have gziped xml-files that are gziped. I can unzip then with gunzip on the commandline.
how can I open such a file in Qt?

there exists qCompress/qUncompress but this doesn't seem to work on .gz files.

I also found this: http://quazip.sourceforge.net/

... is there a simpler way that doens't need an extra dependendency?
(i don't need to write full zip-archives with multiple files etc.)

thanks,
niko

[tzioboro]

Maybe http://osdab.sourceforge.net/ will be more helpful ??

[niko]

thanks,

but it looks like another full-blown-zip-archive library - I need only gzipping one file (something more lightweight)

niko

[tzioboro]

So maybe using QProcess and gzip would be more suitable?

[niko]

that would be the easiest i guess...
but would work only on unix

or does something comparable exist on win32?

[tzioboro]

Yes, you might use gzip from Cygwin ... I guess ..

[niko]

sure, that will work

but the users of my application won't be happy about that

[Brandybuck]

zlib is fairly lightweight, you may want to try it. http://www.zlib.net/. This is the same compression library that Qt uses, but it doesn't expose the gzip functionality.

[niko]

i was thinking about that too.
but where to start?
could you give me some hints?

(i have almost no c++ experience)

thanks
niko

[Brandybuck]

zlib is C, not C++. I have never used it directly. My first step would be to read its documentation and look at any example programs. You may also want to look at the qCompress sources to see how Trolltech uses it.

[niko]

hooray, it works

this is how I did it:

gzFile file;
file = gzopen (fileName.toUtf8().data(), "rb");
if(!file) {
	QMessageBox::critical(0, tr("import"), tr("Can't open file"));
	return;
}
QByteArray input;
char buffer[1024];
QByteArray inputData;
while(int readBytes =  gzread (file, buffer, 1024))
 {
	input.append(QByteArray(buffer, readBytes));
}
gzclose(file);

gzFile file;
file = gzopen (fileName.toUtf8().data(), "rb");
if(!file) {
	QMessageBox::critical(0, tr("import"), tr("Can't open file"));
	return;
}
QByteArray input;
char buffer[1024];
QByteArray inputData;
while(int readBytes =  gzread (file, buffer, 1024))
 {
	input.append(QByteArray(buffer, readBytes));
}
gzclose(file);

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thanks for the help....

niko