(QByteArray::fromHex("a").toHex() == QByteArray("a")) false?!

MichelS

Would you expect the above to be true?

I tried the following and the results are puzzling me.

@
qDebug() << (QByteArray::fromHex("a").toHex() == QByteArray("a")); // false
qDebug() << QByteArray::fromHex("a").toHex(); // 0a
qDebug() << QByteArray::fromHex("aa").toHex(); // aa
qDebug() << QByteArray::fromHex("aaa").toHex(); // 0aaa
@

I'm a bit confused... What do you think?

sierdzio

Looks ok to me.

When you call toHex(), QBA translates the symbol into a hex value (1 byte, hence the '0a' you get in line 2 and 4).

Line 1 is fine because you are comparing a value converted into hex with a string "a". Remember: "a" != 'a' != 0xa

MichelS

So how do I convert a hex string into Hex BA without the leading zero?

SGaist

Hi,

Did you try "fromHex":http://qt-project.org/doc/qt-4.8/qbytearray.html#fromHex ?

volnei

Hi,

QByteArray ba = "BA";
qDebug() << ba.toHex();

"4241"

Is this you want?

MichelS

fromHex/toHex works quite well with a even number of hex-digits.
But with odd numbers there's always the leading zero.

I think I understand the problem now.
One character takes only half a byte. So if there is an odd number of characters there must be 4 bits padded. These are the first 4 bits.