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Qt-interest Archive, September 2007
Re: QByteArray comparsion in Qt 4.3.0 (1.fc6)

Message 1 in thread

Hi,

> But when I used data with zero character inside thats showed some 
> interesting thing
> 
> inline bool operator<(const QByteArray &a1, const QByteArray &a2)
> { return strcmp(a1, a2) < 0; }
> 
> inline bool operator==(const QByteArray &a1, const QByteArray &a2)
> { return (a1.size () == a2.size()) && (memcmp(a1, a2, a1.size())==0); }
> [...]
> But this things causes:
> 
> a == b = 0
> a > b = 0
> b > a = 0

You're right. This can be reproduced with the following test case:
	#include <QByteArray>
	#include <QDebug>
	int main() {
	    const char ca[3] = { '@', '\0', 'A' };
	    QByteArray a(ca, 3);
	    const char cb[3] = { '@', '\0', 'B' };
	    QByteArray b(cb, 3);
	    qDebug() << (a == b);
	    qDebug() << (a < b);
	    qDebug() << (a > b);
	}

I suggest you report this to Trolltech:
	http://trolltech.com/bugreport-form

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Message 2 in thread

Dimitri wrote:
>Hi,
>
>> But when I used data with zero character inside thats showed some
>> interesting thing
>>
>> inline bool operator<(const QByteArray &a1, const QByteArray &a2)
>> { return strcmp(a1, a2) < 0; }
>>
>> inline bool operator==(const QByteArray &a1, const QByteArray &a2)
>> { return (a1.size () == a2.size()) && (memcmp(a1, a2, a1.size())==0);
>> } [...]
>> But this things causes:
>>
>> a == b = 0
>> a > b = 0
>> b > a = 0
>
>You're right. This can be reproduced with the following test case:
>	#include <QByteArray>
>	#include <QDebug>
>	int main() {
>	    const char ca[3] = { '@', '\0', 'A' };
>	    QByteArray a(ca, 3);
>	    const char cb[3] = { '@', '\0', 'B' };
>	    QByteArray b(cb, 3);
>	    qDebug() << (a == b);
>	    qDebug() << (a < b);
>	    qDebug() << (a > b);
>	}
>
>I suggest you report this to Trolltech:
>	http://trolltech.com/bugreport-form

No need. I've already fixed the problem.

Be careful if you were depending on the broken behaviour.

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