Problem with the QTextCodec::toUnicode function (no difference between NULL string and EMPTY string)

Just a little exemple :

QTextCodec *_code = QTextCodec::codecForName(QString(QLatin1String("Windows-1252")).toLocal8Bit());
QString _t = _code->toUnicode("", 0);

the isNull() and the isEmpty() method of "_t" returns true or the isNull method must be return false.

Otherwise :

QString _t = QString::fromUtf8("", 0);

In this case isNull return false and isEmpty return true. (good result for me).

if we look into the code of qsimplecodec.cpp in the function convertToUnicode :

if (len <= 0 || chars == 0)
    return QString();

i think the problem is there and the code should be :

 if (len < 0 ||chars == 0)
     return QString();
 if (len == 0) 
     return QString("");

This bug is very problematic for the database drivers