How do you convert a base64 value to a hex value using Qt /KDE?

Question

I am working a software that uses Qt and has existing methods to encrypt/decrypt checksum values in hex. Currently, I've encountered some checksum values that are in base 64. Instead of reinventing the wheel to do the same stuff for base64 checksum, I was wondering if there is a way to convert a base64 value to a hex value using Qt or KDE libs . This way I'd save myself from writing semi duplicate code to do the almost similar task.

Here is how it should work:

Input: VO2S9pgCq1lqgTFTKssVj6amn0npNdagtjI8ziDtiRQ=
Output: 54ed92f69802ab596a8131532acb158fa6a69f49e935d6a0b6323cce20ed8914

The input is contained in a QString. Also in case there is no built in support in Qt/KDE can you suggest me a method in C++ ?

Answer 1

This is what I tried right now:

 QString b64("VO2S9pgCq1lqgTFTKssVj6amn0npNdagtjI8ziDtiRQ=");
 QByteArray ba = QByteArray::fromBase64(b64.toAscii());

 QString res(ba.toHex());

 qDebug() << res;

Probably there's a more correct way to do it, but I'm too sleepy right now, sorry.

As a function:

 /// untested
 QString base64ToHex(const QString& b64){
     QByteArray ba = QByteArray::fromBase64(b64.toAscii());
     QString res(ba.toHex());

     return res;      
 }

or simply..

 QString base64ToHex(const QString& b64){
     return QString(QByteArray::fromBase64(b64.toAscii()).toHex());
 }

Edit 1: with Qt5 you should use QString::toLatin1() instead of QString::toAscii().