duplicate data on TCPSocket

[tbscope]

One problem is this line:

this->write(authq, 40);

this->write(authq, 40);

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This makes an implicite conversion from QByteArray to const char*
For some reason this works, but I'm sure it won't give you what you want.

This might not be the problem why you get things double though.


Another thing that's not 100% correct is the initialisation of your random number generators.

[tbscope]

And the probable reason why you get a double auth code is because you don't flush the stream.
You do clear the bytearray though.

Note that this is a pure guess though!

In short: this is what happens

create bytearray authq
create datastream dsauthq which writes and reads on bytearray authq

by default (in the constructor) already write (quint16)65502 via the data stream to the bytearray.
clear the bytearray
The stream still contains the code
Now write the code again with the random numbers and operator.

In effect, you write the code twice.

The fun thing is, QDatastream doesn't have a flush() function.
Delete the stream and create a new one on the go. That will definatly solve stream buffer problems.

I would do this very differently though but I assume you can not change the requirements of (quint16)65502 ?

[tbscope]

Confirmation:

#include <QtCore/QCoreApplication>
 
#include <QDebug>
#include <QByteArray>
#include <QDataStream>
 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
 
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
 
    qint32 random1;
    qint32 random2;
    qint32 oper;
 
    //generate random numbers
    srand(time(NULL));
    random1=rand()%256;
    //sleep(3);
    srand(time(NULL));
    random2=rand()%256;
    srand((time(NULL)+5));
    oper=rand()%5;
 
    qDebug() << "Test hex";
    qDebug() << "";
 
    QByteArray array;
    QDataStream stream(&array,QIODevice::ReadWrite);
 
    stream << (quint16)65502;
    array.clear();
    stream << (quint16)65502 << (quint8)random1 << (quint8)random2 << (quint8)oper;
 
    qDebug() << "Hex =" << array.toHex();
 
    QDataStream stream1(&array, QIODevice::ReadWrite);
    QDataStream stream2(&array, QIODevice::ReadWrite);
 
    array.clear();
    stream1 << (quint16)65502;
    array.clear();
    stream2 << (quint16)65502 << (quint8)random1 << (quint8)random2 << (quint8)oper;
 
    qDebug() << "Hex =" << array.toHex();
 
    return a.exec();
}

#include <QtCore/QCoreApplication>

#include <QDebug>
#include <QByteArray>
#include <QDataStream>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    qint32 random1;
    qint32 random2;
    qint32 oper;

    //generate random numbers
    srand(time(NULL));
    random1=rand()%256;
    //sleep(3);
    srand(time(NULL));
    random2=rand()%256;
    srand((time(NULL)+5));
    oper=rand()%5;

    qDebug() << "Test hex";
    qDebug() << "";

    QByteArray array;
    QDataStream stream(&array,QIODevice::ReadWrite);

    stream << (quint16)65502;
    array.clear();
    stream << (quint16)65502 << (quint8)random1 << (quint8)random2 << (quint8)oper;

    qDebug() << "Hex =" << array.toHex();

    QDataStream stream1(&array, QIODevice::ReadWrite);
    QDataStream stream2(&array, QIODevice::ReadWrite);

    array.clear();
    stream1 << (quint16)65502;
    array.clear();
    stream2 << (quint16)65502 << (quint8)random1 << (quint8)random2 << (quint8)oper;

    qDebug() << "Hex =" << array.toHex();

    return a.exec();
}

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Results:

Test hex
 
Hex = "ffdeffde5d5d01"
Hex = "ffde5d5d01"

Test hex

Hex = "ffdeffde5d5d01"
Hex = "ffde5d5d01"

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Edit: All I can say is that QDataStream is not meant to be used like this.

[daemonna]

thanks for all your replies...

Edit: All I can say is that QDataStream is not meant to be used like this.

what else do you suggest if i need to work with 'raw data', not a text???

[daemonna]

yeah, you were exactly right.. i had to use separate qbytearray to send thru socket, and mentioned bytearrays use only for comparison (sockdata.startsWith(auth)) + i have to use .device()->seek(0) all the time to make sure nothing left in bytearray, coz i've noticed packet was several times OK, but suddenly i found extra zeros in beginning of array..

THANKS