How to reverse a QByteArray

[Hollywood33]

Hi! I have this code:
QByteArray a = "Test Data"; QByteArray aBase64 = a.toBase64(); qDebug() << aBase64;

Upon executon, I get this: VGVzdCBEYXRh. How to reverse the resulting code?

[SGaist]

Hi,

Are you thinking about QByteArray::fromBase64 ?

[Hollywood33]

I want to get the resulting code written backwards: hRXY....

[VRonin]

QByteArray a = "Test Data";
QByteArray aBase64 = a.toBase64();
QByteArray b(aBase64.size(),0);
std::copy(aBase64.crbegin(),aBase64.crend(),b.begin());
qDebug() << aBase64;
qDebug() << b;

[Hollywood33]

@VRonin Thank you!

[Hollywood33]

@VRonin class QByteArray' has no member named 'crbegin

[VRonin]

@Hollywood33 that method was added ~2 years ago: http://doc.qt.io/qt-5/qbytearray.html#crbegin

What version of Qt are you using?

Workaround:

QByteArray a = "Test Data";
QByteArray aBase64 = a.toBase64();
QByteArray b;
b.reserve(aBase64.size());
for(int i= aBase64.size()-1;i>=0;--i)
b.append(aBase64.at(i));
qDebug() << aBase64;
qDebug() << b;

[Hollywood33]

@VRonin This works! Thanks!