Compress data from pugixml

Question

I'm trying to compress data from a pugi::xml_document. This is what I tried :

template<class T> void save(const T &object, const QString &path)
{
    pugi::xml_document doc;
    object.exportXML(doc);

    std::ostringstream stream;
    doc.save(stream);

    QByteArray data = qCompress(stream.c_str(), 9);

    QFile outfile(path);
    outfile.write(data);
    outfile.close();
}

But it doesn't work because doc.save() takes a ostream and not a ostringstream. How can I get the tree formated to a string from the xml_document and compress it using qCompress?

p-a-o-l-o · Answer 1 · 2018-03-03T16:44:28.013

1

Be sure the no-stl define is commented in pugiconfig.hpp file:

// Uncomment this to disable STL
// #define PUGIXML_NO_STL

The stringstream header include is required:

 #include <sstream>

That said, watch out: you're calling a non existing method c_str() directly on the std::ostringstream object, and not on its underlying string, returned by str() (and your compiler output should be something like: no member named 'c_str' in 'std::basic_ostringstream').

Your code should be like this:

QByteArray data = qCompress(stream.str().c_str(), 9);

edited Mar 03 '18 at 16:44

answered Mar 03 '18 at 15:27

p-a-o-l-o

9,807
2
22
35

As I said the method `save()` takes an `ostream` object no an `ostringstream` which gives me an error. – Louis Etienne Mar 03 '18 at 15:39
ostream is a direct base of ostringstream, please post your compiler output – p-a-o-l-o Mar 03 '18 at 15:42
`error: no matching function for call to 'pugi::xml_document::save(std::ostringstream&)'` For the doc : https://pugixml.org/docs/manual.html#saving.stream – Louis Etienne Mar 03 '18 at 15:43
It's commented. :/ – Louis Etienne Mar 03 '18 at 16:36
I also have these errors: `error: 'std::ostringstream stream' has incomplete type` and `error: invalid use of incomplete type 'std::ostringstream {aka class std::__cxx11::basic_ostringstream}'` – Louis Etienne Mar 03 '18 at 16:42
Edited again. Check your includes. – p-a-o-l-o Mar 03 '18 at 16:50

Compress data from pugixml

1 Answers1