Receive data with UDP protocol

[swansorter]

@KroMignon
1.i want to receive 2014080 bytes
2.Receiving it bunch by bunch
3.problem is each time i receive data the datagram1(bytearry )updated with new bunch of data and qstring also,so at last i only get last bunch of data.
4. i tried using global variable qstring it receives all the data but giving (SEGMENTATION FAULT).
is there any other way to do it .

this is my udp receive program
void MainWindow::readPendingDatagrams()
{
while(mSocket->hasPendingDatagrams())
{
QString received_data_x;
QByteArray datagram1;
datagram1.resize(mSocket->pendingDatagramSize());
mSocket->readDatagram(datagram1.data(),datagram1.size() );
received_data_x.append(datagram1.toHex());

}

}

[swansorter]

@swansorter if i use class member global variable it gives me a segmentation fault

void MainWindow::on_pushButton_2_pressed()
{
//if iuse class member or global variable;
QString test= received_data//class member;
int width = 2098, height = 240;
int bufpo0 = 0, bufpo1 = 1, bufpo2 = 2, bufpo3 = 3;
QImage img(width, height, QImage::Format_RGB888);
QByteArray cmd= QByteArray::fromHex(test.replace("\r\n","").toLatin1());

   for (int packet = 0; packet < cmd.length(); packet++)
   {

//in this loop am getting segmentation fault*///
Auto_image_RGBdata[packet] = static_cast<quint8>(cmd.data()[bufpo0]) | static_cast<quint8>(cmd.data()[bufpo1]) << 8 | static_cast<quint8>(cmd.data()[bufpo2]) << 16 | static_cast<quint8>(cmd.data()[bufpo3])<< 24;

       bufpo0 = bufpo0 + 4;
       bufpo1 = bufpo1 + 4;
       bufpo2 = bufpo2 + 4;
       bufpo3 = bufpo3 + 4;
   }



   for (int y = 0; y < height; y++)
   {
       for (int x = 0; x < width; x++)
       {
            QRgb value = qRgb((Auto_image_RGBdata[x] >> 22 & 0x000000ff),   Auto_image_RGBdata[x] >> 12 & 0x000000ff), (Auto_image_RGBdata[x]>>2  & 0x000003ff));
           img.setPixel(x,y,value);
       }
   }
   ui->port->setPixmap(QPixmap::fromImage(img.scaled(541,301,Qt::KeepAspectRatio)));

ui->port->setScaledContents(true); QPixmap::fromImage(img.scaled(width/4,height*2,Qt::KeepAspectRatio)).save("image2.jpg","JPG");

}

[KroMignon]

@swansorter said in Receive data with UDP protocol:

this is my udp receive program
void MainWindow::readPendingDatagrams()
{
while(mSocket->hasPendingDatagrams())
{
QString received_data_x;
QByteArray datagram1;
datagram1.resize(mSocket->pendingDatagramSize());
mSocket->readDatagram(datagram1.data(),datagram1.size() );
received_data_x.append(datagram1.toHex());
}
}

once again received_data_x is a local variable not a class member!

[swansorter]

@KroMignon if i use received_data_x as class member i am getting segmentation fault

[swansorter]

@KroMignon
28621 [1] {
0x55555562d82c 55 push %rbp
0x55555562d82d <+0x0001> 48 89 e5 mov %rsp,%rbp
0x55555562d830 <+0x0004> 53 push %rbx
0x55555562d831 <+0x0005> 48 81 ec d8 00 00 00 sub $0xd8,%rsp
0x55555562d838 <+0x000c> 48 89 bd 28 ff ff ff mov %rdi,-0xd8(%rbp)
0x55555562d83f <+0x0013> 64 48 8b 04 25 28 00 00 00 mov %fs:0x28,%rax
0x55555562d848 <+0x001c> 48 89 45 e8 mov %rax,-0x18(%rbp)
0x55555562d84c <+0x0020> 31 c0 xor %eax,%eax
28635 [1] QString test= x_member;
0x55555562d84e <+0x0022> 48 8b 85 28 ff ff ff mov -0xd8(%rbp),%rax
0x55555562d855 <+0x0029> 48 8d 90 88 02 00 00 lea 0x288(%rax),%rdx
0x55555562d85c <+0x0030> 48 8d 85 68 ff ff ff lea -0x98(%rbp),%rax
0x55555562d863 <+0x0037> 48 89 d6 mov %rdx,%rsi
0x55555562d866 <+0x003a> 48 89 c7 mov %rax,%rdi
0x55555562d869 <+0x003d> e8 26 52 00 00 callq 0x555555632a94 <QString::QString(QString const&)>
28636 [1] int width = 2098, height = 240;
0x55555562d86e <+0x0042> c7 85 5c ff ff ff 32 08 00 00 movl $0x832,-0xa4(%rbp)
0x55555562d878 <+0x004c> c7 85 60 ff ff ff f0 00 00 00 movl $0xf0,-0xa0(%rbp)
28637 [1] int bufpo0 = 0, bufpo1 = 1, bufpo2 = 2, bufpo3 = 3;
0x55555562d882 <+0x0056> c7 85 40 ff ff ff 00 00 00 00 movl $0x0,-0xc0(%rbp)
0x55555562d88c <+0x0060> c7 85 44 ff ff ff 01 00 00 00 movl $0x1,-0xbc(%rbp)
0x55555562d896 <+0x006a> c7 85 48 ff ff ff 02 00 00 00 movl $0x2,-0xb8(%rbp)
0x55555562d8a0 <+0x0074> c7 85 4c ff ff ff 03 00 00 00 movl $0x3,-0xb4(%rbp)
28638 [1] QImage img(width, height, QImage::Format_RGB888);
0x55555562d8aa <+0x007e> 8b 95 60 ff ff ff mov -0xa0(%rbp),%edx
0x55555562d8b0 <+0x0084> 8b b5 5c ff ff ff mov -0xa4(%rbp),%esi
0x55555562d8b6 <+0x008a> 48 8d 45 80 lea -0x80(%rbp),%rax
0x55555562d8ba <+0x008e> b9 0d 00 00 00 mov $0xd,%ecx
0x55555562d8bf <+0x0093> 48 89 c7 mov %rax,%rdi
0x55555562d8c2 <+0x0096> e8 19 f4 f2 ff callq 0x55555555cce0 _ZN6QImageC1EiiNS_6FormatE@plt
28639 [1] QByteArray cmd= QByteArray::fromHex(test.replace("\r\n","").toLatin1());
0x55555562d8c7 <+0x009b> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562d8cb <+0x009f> 48 8d 35 06 05 0d 00 lea 0xd0506(%rip),%rsi # 0x5555556fddd8
0x55555562d8d2 <+0x00a6> 48 89 c7 mov %rax,%rdi
0x55555562d8d5 <+0x00a9> e8 be 4e 00 00 callq 0x555555632798 <QString::QString(char const*)>
0x55555562d8da <+0x00ae> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562d8e1 <+0x00b5> 48 8d 35 c8 7e 0d 00 lea 0xd7ec8(%rip),%rsi # 0x5555557057b0
0x55555562d8e8 <+0x00bc> 48 89 c7 mov %rax,%rdi
0x55555562d8eb <+0x00bf> e8 a8 4e 00 00 callq 0x555555632798 <QString::QString(char const*)>
0x55555562d8f0 <+0x00c4> 48 8d 55 a0 lea -0x60(%rbp),%rdx
0x55555562d8f4 <+0x00c8> 48 8d b5 78 ff ff ff lea -0x88(%rbp),%rsi
0x55555562d8fb <+0x00cf> 48 8d 85 68 ff ff ff lea -0x98(%rbp),%rax
0x55555562d902 <+0x00d6> b9 01 00 00 00 mov $0x1,%ecx
0x55555562d907 <+0x00db> 48 89 c7 mov %rax,%rdi
0x55555562d90a <+0x00de> e8 b1 fc f2 ff callq 0x55555555d5c0 _ZN7QString7replaceERKS_S1_N2Qt15CaseSensitivityE@plt
0x55555562d90f <+0x00e3> 48 89 c2 mov %rax,%rdx
0x55555562d912 <+0x00e6> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562d916 <+0x00ea> 48 89 d6 mov %rdx,%rsi
0x55555562d919 <+0x00ed> 48 89 c7 mov %rax,%rdi
0x55555562d91c <+0x00f0> e8 83 4c 00 00 callq 0x5555556325a4 <QString::toLatin1() const &>
0x55555562d921 <+0x00f5> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562d928 <+0x00fc> 48 8d 55 c0 lea -0x40(%rbp),%rdx
0x55555562d92c <+0x0100> 48 89 d6 mov %rdx,%rsi
0x55555562d92f <+0x0103> 48 89 c7 mov %rax,%rdi
0x55555562d932 <+0x0106> e8 39 f4 f2 ff callq 0x55555555cd70 _ZN10QByteArray7fromHexERKS_@plt
0x55555562d937 <+0x010b> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562d93b <+0x010f> 48 89 c7 mov %rax,%rdi
0x55555562d93e <+0x0112> e8 11 00 f3 ff callq 0x55555555d954 QByteArray::~QByteArray()
0x55555562d943 <+0x0117> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562d94a <+0x011e> 48 89 c7 mov %rax,%rdi
0x55555562d94d <+0x0121> e8 b8 51 00 00 callq 0x555555632b0a QString::~QString()
0x55555562d952 <+0x0126> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562d956 <+0x012a> 48 89 c7 mov %rax,%rdi
0x55555562d959 <+0x012d> e8 ac 51 00 00 callq 0x555555632b0a QString::~QString()
28643 [1] for (int packet = 0; packet < cmd.length(); packet++)//2098100(lines)=540000packets
0x55555562d95e <+0x0132> c7 85 50 ff ff ff 00 00 00 00 movl $0x0,-0xb0(%rbp)
0x55555562d968 <+0x013c> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562d96f <+0x0143> 48 89 c7 mov %rax,%rdi
0x55555562d972 <+0x0146> e8 71 49 00 00 callq 0x5555556322e8 <QByteArray::length() const>
0x55555562d977 <+0x014b> 39 85 50 ff ff ff cmp %eax,-0xb0(%rbp)
0x55555562d97d <+0x0151> 0f 9c c0 setl %al
0x55555562d980 <+0x0154> 84 c0 test %al,%al
0x55555562d982 <+0x0156> 0f 84 d8 00 00 00 je 0x55555562da60 MainWindow::on_pushButton_2_pressed()+564
28648 [1] Auto_image_RGBdata[packet] = static_cast<quint8>(cmd.data()[bufpo0]) | static_cast<quint8>(cmd.data()[bufpo1]) << 8 | static_cast<quint8>(cmd.data()[bufpo2]) << 16 | static_cast<quint8>(cmd.data()[bufpo3])<< 24;
0x55555562d988 <+0x015c> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562d98f <+0x0163> 48 89 c7 mov %rax,%rdi
0x55555562d992 <+0x0166> e8 97 49 00 00 callq 0x55555563232e QByteArray::data()
0x55555562d997 <+0x016b> 48 89 c2 mov %rax,%rdx
0x55555562d99a <+0x016e> 8b 85 40 ff ff ff mov -0xc0(%rbp),%eax
0x55555562d9a0 <+0x0174> 48 98 cltq
0x55555562d9a2 <+0x0176> 48 01 d0 add %rdx,%rax
0x55555562d9a5 <+0x0179> 0f b6 00 movzbl (%rax),%eax
0x55555562d9a8 <+0x017c> 0f b6 d8 movzbl %al,%ebx
0x55555562d9ab <+0x017f> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562d9b2 <+0x0186> 48 89 c7 mov %rax,%rdi
0x55555562d9b5 <+0x0189> e8 74 49 00 00 callq 0x55555563232e QByteArray::data()
0x55555562d9ba <+0x018e> 48 89 c2 mov %rax,%rdx
0x55555562d9bd <+0x0191> 8b 85 44 ff ff ff mov -0xbc(%rbp),%eax
0x55555562d9c3 <+0x0197> 48 98 cltq
0x55555562d9c5 <+0x0199> 48 01 d0 add %rdx,%rax
0x55555562d9c8 <+0x019c> 0f b6 00 movzbl (%rax),%eax
0x55555562d9cb <+0x019f> 0f b6 c0 movzbl %al,%eax
0x55555562d9ce <+0x01a2> c1 e0 08 shl $0x8,%eax
0x55555562d9d1 <+0x01a5> 09 c3 or %eax,%ebx
0x55555562d9d3 <+0x01a7> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562d9da <+0x01ae> 48 89 c7 mov %rax,%rdi
0x55555562d9dd <+0x01b1> e8 4c 49 00 00 callq 0x55555563232e QByteArray::data()
0x55555562d9e2 <+0x01b6> 48 89 c2 mov %rax,%rdx
0x55555562d9e5 <+0x01b9> 8b 85 48 ff ff ff mov -0xb8(%rbp),%eax
0x55555562d9eb <+0x01bf> 48 98 cltq
0x55555562d9ed <+0x01c1> 48 01 d0 add %rdx,%rax
0x55555562d9f0 <+0x01c4> 0f b6 00 movzbl (%rax),%eax
0x55555562d9f3 <+0x01c7> 0f b6 c0 movzbl %al,%eax
0x55555562d9f6 <+0x01ca> c1 e0 10 shl $0x10,%eax
0x55555562d9f9 <+0x01cd> 09 c3 or %eax,%ebx
0x55555562d9fb <+0x01cf> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562da02 <+0x01d6> 48 89 c7 mov %rax,%rdi
0x55555562da05 <+0x01d9> e8 24 49 00 00 callq 0x55555563232e QByteArray::data()
0x55555562da0a <+0x01de> 48 89 c2 mov %rax,%rdx
0x55555562da0d <+0x01e1> 8b 85 4c ff ff ff mov -0xb4(%rbp),%eax
0x55555562da13 <+0x01e7> 48 98 cltq
0x55555562da15 <+0x01e9> 48 01 d0 add %rdx,%rax
0x55555562da18 <+0x01ec> 0f b6 00 movzbl (%rax),%eax
0x55555562da1b <+0x01ef> 0f b6 c0 movzbl %al,%eax
0x55555562da1e <+0x01f2> c1 e0 18 shl $0x18,%eax
0x55555562da21 <+0x01f5> 89 d9 mov %ebx,%ecx
0x55555562da23 <+0x01f7> 09 c1 or %eax,%ecx
0x55555562da25 <+0x01f9> 48 8d 05 74 a5 3a 00 lea 0x3aa574(%rip),%rax # 0x5555559d7fa0 <Auto_image_RGBdata>
0x55555562da2c <+0x0200> 8b 95 50 ff ff ff mov -0xb0(%rbp),%edx
0x55555562da32 <+0x0206> 48 63 d2 movslq %edx,%rdx
0x55555562da35 <+0x0209> 89 0c 90 mov %ecx,(%rax,%rdx,4)
28658 [1] bufpo0 = bufpo0 + 4;
0x55555562da38 <+0x020c> 83 85 40 ff ff ff 04 addl $0x4,-0xc0(%rbp)
28659 [1] bufpo1 = bufpo1 + 4;
0x55555562da3f <+0x0213> 83 85 44 ff ff ff 04 addl $0x4,-0xbc(%rbp)
28660 [1] bufpo2 = bufpo2 + 4;
0x55555562da46 <+0x021a> 83 85 48 ff ff ff 04 addl $0x4,-0xb8(%rbp)
28661 [1] bufpo3 = bufpo3 + 4;
0x55555562da4d <+0x0221> 83 85 4c ff ff ff 04 addl $0x4,-0xb4(%rbp)
28643 [2] for (int packet = 0; packet < cmd.length(); packet++)//2098100(lines)=540000packets
0x55555562da54 <+0x0228> 83 85 50 ff ff ff 01 addl $0x1,-0xb0(%rbp)
0x55555562da5b <+0x022f> e9 08 ff ff ff jmpq 0x55555562d968 MainWindow::on_pushButton_2_pressed()+316
28666 [1] for (int y = 0; y < height; y++)
0x55555562da60 <+0x0234> c7 85 54 ff ff ff 00 00 00 00 movl $0x0,-0xac(%rbp)
0x55555562da6a <+0x023e> 8b 85 54 ff ff ff mov -0xac(%rbp),%eax
0x55555562da70 <+0x0244> 3b 85 60 ff ff ff cmp -0xa0(%rbp),%eax
0x55555562da76 <+0x024a> 0f 8d b2 00 00 00 jge 0x55555562db2e MainWindow::on_pushButton_2_pressed()+770
28669 [1] for (int x = 0; x < width; x++)
0x55555562da7c <+0x0250> c7 85 58 ff ff ff 00 00 00 00 movl $0x0,-0xa8(%rbp)
0x55555562da86 <+0x025a> 8b 85 58 ff ff ff mov -0xa8(%rbp),%eax
0x55555562da8c <+0x0260> 3b 85 5c ff ff ff cmp -0xa4(%rbp),%eax
0x55555562da92 <+0x0266> 0f 8d 8a 00 00 00 jge 0x55555562db22 MainWindow::on_pushButton_2_pressed()+758

>> 22 & 0x000000ff),(Auto_image_RGBdata[x] >> 12 & 0x000000ff), (Auto_image_RGBdata[x]>>2 & 0x000003ff));

0x55555562da98 <+0x026c> 48 8d 05 01 a5 3a 00 lea 0x3aa501(%rip),%rax # 0x5555559d7fa0 <Auto_image_RGBdata>
0x55555562da9f <+0x0273> 8b 95 58 ff ff ff mov -0xa8(%rbp),%edx
0x55555562daa5 <+0x0279> 48 63 d2 movslq %edx,%rdx
0x55555562daa8 <+0x027c> 8b 04 90 mov (%rax,%rdx,4),%eax
0x55555562daab <+0x027f> c1 f8 02 sar $0x2,%eax
0x55555562daae <+0x0282> 25 ff 03 00 00 and $0x3ff,%eax
0x55555562dab3 <+0x0287> 89 c6 mov %eax,%esi
0x55555562dab5 <+0x0289> 48 8d 05 e4 a4 3a 00 lea 0x3aa4e4(%rip),%rax # 0x5555559d7fa0 <Auto_image_RGBdata>
0x55555562dabc <+0x0290> 8b 95 58 ff ff ff mov -0xa8(%rbp),%edx
0x55555562dac2 <+0x0296> 48 63 d2 movslq %edx,%rdx
0x55555562dac5 <+0x0299> 8b 04 90 mov (%rax,%rdx,4),%eax
0x55555562dac8 <+0x029c> c1 f8 0c sar $0xc,%eax
0x55555562dacb <+0x029f> 0f b6 c8 movzbl %al,%ecx
0x55555562dace <+0x02a2> 48 8d 05 cb a4 3a 00 lea 0x3aa4cb(%rip),%rax # 0x5555559d7fa0 <Auto_image_RGBdata>
0x55555562dad5 <+0x02a9> 8b 95 58 ff ff ff mov -0xa8(%rbp),%edx
0x55555562dadb <+0x02af> 48 63 d2 movslq %edx,%rdx
0x55555562dade <+0x02b2> 8b 04 90 mov (%rax,%rdx,4),%eax
0x55555562dae1 <+0x02b5> c1 f8 16 sar $0x16,%eax
0x55555562dae4 <+0x02b8> 0f b6 c0 movzbl %al,%eax
0x55555562dae7 <+0x02bb> 89 f2 mov %esi,%edx
0x55555562dae9 <+0x02bd> 89 ce mov %ecx,%esi
0x55555562daeb <+0x02bf> 89 c7 mov %eax,%edi
0x55555562daed <+0x02c1> e8 ff 56 00 00 callq 0x5555556331f1 <qRgb(int, int, int)>
0x55555562daf2 <+0x02c6> 89 85 64 ff ff ff mov %eax,-0x9c(%rbp)
28672 [1] img.setPixel(x,y,value);
0x55555562daf8 <+0x02cc> 8b 8d 64 ff ff ff mov -0x9c(%rbp),%ecx
0x55555562dafe <+0x02d2> 8b 95 54 ff ff ff mov -0xac(%rbp),%edx
0x55555562db04 <+0x02d8> 8b b5 58 ff ff ff mov -0xa8(%rbp),%esi
0x55555562db0a <+0x02de> 48 8d 45 80 lea -0x80(%rbp),%rax
0x55555562db0e <+0x02e2> 48 89 c7 mov %rax,%rdi
0x55555562db11 <+0x02e5> e8 aa f0 f2 ff callq 0x55555555cbc0 _ZN6QImage8setPixelEiij@plt
28669 [2] for (int x = 0; x < width; x++)
0x55555562db16 <+0x02ea> 83 85 58 ff ff ff 01 addl $0x1,-0xa8(%rbp)
0x55555562db1d <+0x02f1> e9 64 ff ff ff jmpq 0x55555562da86 MainWindow::on_pushButton_2_pressed()+602
28666 [2] for (int y = 0; y < height; y++)
0x55555562db22 <+0x02f6> 83 85 54 ff ff ff 01 addl $0x1,-0xac(%rbp)
0x55555562db29 <+0x02fd> e9 3c ff ff ff jmpq 0x55555562da6a MainWindow::on_pushButton_2_pressed()+574
28676 [1] ui->port->setPixmap(QPixmap::fromImage(img.scaled(541,301,Qt::KeepAspectRatio)));
0x55555562db2e <+0x0302> 48 8b 85 28 ff ff ff mov -0xd8(%rbp),%rax
0x55555562db35 <+0x0309> 48 8b 80 20 02 00 00 mov 0x220(%rax),%rax
0x55555562db3c <+0x0310> 48 8b 98 90 00 00 00 mov 0x90(%rax),%rbx
0x55555562db43 <+0x0317> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562db4a <+0x031e> be 00 00 00 00 mov $0x0,%esi
0x55555562db4f <+0x0323> 48 89 c7 mov %rax,%rdi
0x55555562db52 <+0x0326> e8 8d 44 00 00 callq 0x555555631fe4 <QFlagsQt::ImageConversionFlag::QFlags(Qt::ImageConversionFlag)>
0x55555562db57 <+0x032b> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562db5b <+0x032f> 48 8d 75 80 lea -0x80(%rbp),%rsi
0x55555562db5f <+0x0333> 41 b9 00 00 00 00 mov $0x0,%r9d
0x55555562db65 <+0x0339> 41 b8 01 00 00 00 mov $0x1,%r8d
0x55555562db6b <+0x033f> b9 2d 01 00 00 mov $0x12d,%ecx
0x55555562db70 <+0x0344> ba 1d 02 00 00 mov $0x21d,%edx
0x55555562db75 <+0x0349> 48 89 c7 mov %rax,%rdi
0x55555562db78 <+0x034c> e8 9d 57 00 00 callq 0x55555563331a <QImage::scaled(int, int, Qt::AspectRatioMode, Qt::TransformationMode) const>
0x55555562db7d <+0x0351> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562db81 <+0x0355> 8b 95 78 ff ff ff mov -0x88(%rbp),%edx
0x55555562db87 <+0x035b> 48 8d 4d a0 lea -0x60(%rbp),%rcx
0x55555562db8b <+0x035f> 48 89 ce mov %rcx,%rsi
0x55555562db8e <+0x0362> 48 89 c7 mov %rax,%rdi
0x55555562db91 <+0x0365> e8 fc 57 00 00 callq 0x555555633392 <QPixmap::fromImage(QImage&&, QFlagsQt::ImageConversionFlag)>
0x55555562db96 <+0x036a> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562db9a <+0x036e> 48 89 c6 mov %rax,%rsi
0x55555562db9d <+0x0371> 48 89 df mov %rbx,%rdi
0x55555562dba0 <+0x0374> e8 6b f3 f2 ff callq 0x55555555cf10 _ZN6QLabel9setPixmapERK7QPixmap@plt
0x55555562dba5 <+0x0379> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dba9 <+0x037d> 48 89 c7 mov %rax,%rdi
0x55555562dbac <+0x0380> e8 3f ec f2 ff callq 0x55555555c7f0 _ZN7QPixmapD1Ev@plt
0x55555562dbb1 <+0x0385> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562dbb5 <+0x0389> 48 89 c7 mov %rax,%rdi
0x55555562dbb8 <+0x038c> e8 33 f1 f2 ff callq 0x55555555ccf0 _ZN6QImageD1Ev@plt
28677 [1] ui->port->setScaledContents(true);
0x55555562dbbd <+0x0391> 48 8b 85 28 ff ff ff mov -0xd8(%rbp),%rax
0x55555562dbc4 <+0x0398> 48 8b 80 20 02 00 00 mov 0x220(%rax),%rax
0x55555562dbcb <+0x039f> 48 8b 80 90 00 00 00 mov 0x90(%rax),%rax
0x55555562dbd2 <+0x03a6> be 01 00 00 00 mov $0x1,%esi
0x55555562dbd7 <+0x03ab> 48 89 c7 mov %rax,%rdi
0x55555562dbda <+0x03ae> e8 41 f1 f2 ff callq 0x55555555cd20 _ZN6QLabel17setScaledContentsEb@plt
28679 [1] QPixmap::fromImage(img.scaled(width/4,height2,Qt::KeepAspectRatio)).save("image2.jpg","JPG");
0x55555562dbdf <+0x03b3> 48 8d 85 3c ff ff ff lea -0xc4(%rbp),%rax
0x55555562dbe6 <+0x03ba> be 00 00 00 00 mov $0x0,%esi
0x55555562dbeb <+0x03bf> 48 89 c7 mov %rax,%rdi
0x55555562dbee <+0x03c2> e8 f1 43 00 00 callq 0x555555631fe4 <QFlagsQt::ImageConversionFlag::QFlags(Qt::ImageConversionFlag)>
0x55555562dbf3 <+0x03c7> 8b 85 60 ff ff ff mov -0xa0(%rbp),%eax
0x55555562dbf9 <+0x03cd> 8d 14 00 lea (%rax,%rax,1),%edx
0x55555562dbfc <+0x03d0> 8b 85 5c ff ff ff mov -0xa4(%rbp),%eax
0x55555562dc02 <+0x03d6> 8d 48 03 lea 0x3(%rax),%ecx
0x55555562dc05 <+0x03d9> 85 c0 test %eax,%eax
0x55555562dc07 <+0x03db> 0f 48 c1 cmovs %ecx,%eax
0x55555562dc0a <+0x03de> c1 f8 02 sar $0x2,%eax
0x55555562dc0d <+0x03e1> 89 c7 mov %eax,%edi
0x55555562dc0f <+0x03e3> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562dc13 <+0x03e7> 48 8d 75 80 lea -0x80(%rbp),%rsi
0x55555562dc17 <+0x03eb> 41 b9 00 00 00 00 mov $0x0,%r9d
0x55555562dc1d <+0x03f1> 41 b8 01 00 00 00 mov $0x1,%r8d
0x55555562dc23 <+0x03f7> 89 d1 mov %edx,%ecx
0x55555562dc25 <+0x03f9> 89 fa mov %edi,%edx
0x55555562dc27 <+0x03fb> 48 89 c7 mov %rax,%rdi
0x55555562dc2a <+0x03fe> e8 eb 56 00 00 callq 0x55555563331a <QImage::scaled(int, int, Qt::AspectRatioMode, Qt::TransformationMode) const>
0x55555562dc2f <+0x0403> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dc33 <+0x0407> 8b 95 3c ff ff ff mov -0xc4(%rbp),%edx
0x55555562dc39 <+0x040d> 48 8d 4d a0 lea -0x60(%rbp),%rcx
0x55555562dc3d <+0x0411> 48 89 ce mov %rcx,%rsi
0x55555562dc40 <+0x0414> 48 89 c7 mov %rax,%rdi
0x55555562dc43 <+0x0417> e8 4a 57 00 00 callq 0x555555633392 <QPixmap::fromImage(QImage&&, QFlagsQt::ImageConversionFlag)>
0x55555562dc48 <+0x041c> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562dc4f <+0x0423> 48 8d 35 5d 7b 0d 00 lea 0xd7b5d(%rip),%rsi # 0x5555557057b3
0x55555562dc56 <+0x042a> 48 89 c7 mov %rax,%rdi
0x55555562dc59 <+0x042d> e8 3a 4b 00 00 callq 0x555555632798 <QString::QString(char const)>
0x55555562dc5e <+0x0432> 48 8d b5 78 ff ff ff lea -0x88(%rbp),%rsi
0x55555562dc65 <+0x0439> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dc69 <+0x043d> b9 ff ff ff ff mov $0xffffffff,%ecx
0x55555562dc6e <+0x0442> 48 8d 15 49 7b 0d 00 lea 0xd7b49(%rip),%rdx # 0x5555557057be
0x55555562dc75 <+0x0449> 48 89 c7 mov %rax,%rdi
0x55555562dc78 <+0x044c> e8 43 f6 f2 ff callq 0x55555555d2c0 _ZNK7QPixmap4saveERK7QStringPKci@plt
0x55555562dc7d <+0x0451> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562dc84 <+0x0458> 48 89 c7 mov %rax,%rdi
0x55555562dc87 <+0x045b> e8 7e 4e 00 00 callq 0x555555632b0a QString::~QString()
0x55555562dc8c <+0x0460> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dc90 <+0x0464> 48 89 c7 mov %rax,%rdi
0x55555562dc93 <+0x0467> e8 58 eb f2 ff callq 0x55555555c7f0 _ZN7QPixmapD1Ev@plt
0x55555562dc98 <+0x046c> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562dc9c <+0x0470> 48 89 c7 mov %rax,%rdi
0x55555562dc9f <+0x0473> e8 4c f0 f2 ff callq 0x55555555ccf0 _ZN6QImageD1Ev@plt
28639 [2] QByteArray cmd= QByteArray::fromHex(test.replace("\r\n","").toLatin1());
0x55555562dca4 <+0x0478> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562dcab <+0x047f> 48 89 c7 mov %rax,%rdi
0x55555562dcae <+0x0482> e8 a1 fc f2 ff callq 0x55555555d954 QByteArray::~QByteArray()
28638 [2] QImage img(width, height, QImage::Format_RGB888);
0x55555562dcb3 <+0x0487> 48 8d 45 80 lea -0x80(%rbp),%rax
0x55555562dcb7 <+0x048b> 48 89 c7 mov %rax,%rdi
0x55555562dcba <+0x048e> e8 31 f0 f2 ff callq 0x55555555ccf0 _ZN6QImageD1Ev@plt
28635 [2] QString test= x_member;
0x55555562dcbf <+0x0493> 48 8d 85 68 ff ff ff lea -0x98(%rbp),%rax
0x55555562dcc6 <+0x049a> 48 89 c7 mov %rax,%rdi
0x55555562dcc9 <+0x049d> e8 3c 4e 00 00 callq 0x555555632b0a QString::~QString()
28683 [1] }
0x55555562dcce <+0x04a2> 90 nop
0x55555562dccf <+0x04a3> 48 8b 45 e8 mov -0x18(%rbp),%rax
0x55555562dcd3 <+0x04a7> 64 48 33 04 25 28 00 00 00 xor %fs:0x28,%rax
0x55555562dcdc <+0x04b0> 0f 84 da 00 00 00 je 0x55555562ddbc MainWindow::on_pushButton_2_pressed()+1424
0x55555562dce2 <+0x04b6> e9 d0 00 00 00 jmpq 0x55555562ddb7 MainWindow::on_pushButton_2_pressed()+1419
0x55555562dce7 <+0x04bb> 48 89 c3 mov %rax,%rbx
0x55555562dcea <+0x04be> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dcee <+0x04c2> 48 89 c7 mov %rax,%rdi
0x55555562dcf1 <+0x04c5> e8 5e fc f2 ff callq 0x55555555d954 QByteArray::~QByteArray()
0x55555562dcf6 <+0x04ca> eb 03 jmp 0x55555562dcfb MainWindow::on_pushButton_2_pressed()+1231
0x55555562dcf8 <+0x04cc> 48 89 c3 mov %rax,%rbx
0x55555562dcfb <+0x04cf> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562dd02 <+0x04d6> 48 89 c7 mov %rax,%rdi
0x55555562dd05 <+0x04d9> e8 00 4e 00 00 callq 0x555555632b0a QString::~QString()
0x55555562dd0a <+0x04de> eb 03 jmp 0x55555562dd0f MainWindow::on_pushButton_2_pressed()+1251
0x55555562dd0c <+0x04e0> 48 89 c3 mov %rax,%rbx
0x55555562dd0f <+0x04e3> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562dd13 <+0x04e7> 48 89 c7 mov %rax,%rdi
0x55555562dd16 <+0x04ea> e8 ef 4d 00 00 callq 0x555555632b0a QString::~QString()
0x55555562dd1b <+0x04ef> eb 6f jmp 0x55555562dd8c MainWindow::on_pushButton_2_pressed()+1376
0x55555562dd1d <+0x04f1> 48 89 c3 mov %rax,%rbx
28676 [2] ui->port->setPixmap(QPixmap::fromImage(img.scaled(541,301,Qt::KeepAspectRatio)));
0x55555562dd20 <+0x04f4> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dd24 <+0x04f8> 48 89 c7 mov %rax,%rdi
0x55555562dd27 <+0x04fb> e8 c4 ea f2 ff callq 0x55555555c7f0 _ZN7QPixmapD1Ev@plt
0x55555562dd2c <+0x0500> eb 03 jmp 0x55555562dd31 MainWindow::on_pushButton_2_pressed()+1285
0x55555562dd2e <+0x0502> 48 89 c3 mov %rax,%rbx
0x55555562dd31 <+0x0505> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562dd35 <+0x0509> 48 89 c7 mov %rax,%rdi
0x55555562dd38 <+0x050c> e8 b3 ef f2 ff callq 0x55555555ccf0 _ZN6QImageD1Ev@plt
0x55555562dd3d <+0x0511> eb 39 jmp 0x55555562dd78 MainWindow::on_pushButton_2_pressed()+1356
0x55555562dd3f <+0x0513> 48 89 c3 mov %rax,%rbx
28679 [2] QPixmap::fromImage(img.scaled(width/4,height*2,Qt::KeepAspectRatio)).save("image2.jpg","JPG");
0x55555562dd42 <+0x0516> 48 8d 85 78 ff ff ff lea -0x88(%rbp),%rax
0x55555562dd49 <+0x051d> 48 89 c7 mov %rax,%rdi
0x55555562dd4c <+0x0520> e8 b9 4d 00 00 callq 0x555555632b0a QString::~QString()
0x55555562dd51 <+0x0525> eb 03 jmp 0x55555562dd56 MainWindow::on_pushButton_2_pressed()+1322
0x55555562dd53 <+0x0527> 48 89 c3 mov %rax,%rbx
0x55555562dd56 <+0x052a> 48 8d 45 c0 lea -0x40(%rbp),%rax
0x55555562dd5a <+0x052e> 48 89 c7 mov %rax,%rdi
0x55555562dd5d <+0x0531> e8 8e ea f2 ff callq 0x55555555c7f0 _ZN7QPixmapD1Ev@plt
0x55555562dd62 <+0x0536> eb 03 jmp 0x55555562dd67 MainWindow::on_pushButton_2_pressed()+1339
0x55555562dd64 <+0x0538> 48 89 c3 mov %rax,%rbx
0x55555562dd67 <+0x053b> 48 8d 45 a0 lea -0x60(%rbp),%rax
0x55555562dd6b <+0x053f> 48 89 c7 mov %rax,%rdi
0x55555562dd6e <+0x0542> e8 7d ef f2 ff callq 0x55555555ccf0 _ZN6QImageD1Ev@plt
0x55555562dd73 <+0x0547> eb 03 jmp 0x55555562dd78 MainWindow::on_pushButton_2_pressed()+1356
0x55555562dd75 <+0x0549> 48 89 c3 mov %rax,%rbx
28639 [3] QByteArray cmd= QByteArray::fromHex(test.replace("\r\n","").toLatin1());
0x55555562dd78 <+0x054c> 48 8d 85 70 ff ff ff lea -0x90(%rbp),%rax
0x55555562dd7f <+0x0553> 48 89 c7 mov %rax,%rdi
0x55555562dd82 <+0x0556> e8 cd fb f2 ff callq 0x55555555d954 QByteArray::~QByteArray()
0x55555562dd87 <+0x055b> eb 03 jmp 0x55555562dd8c MainWindow::on_pushButton_2_pressed()+1376
0x55555562dd89 <+0x055d> 48 89 c3 mov %rax,%rbx
28638 [3] QImage img(width, height, QImage::Format_RGB888);
0x55555562dd8c <+0x0560> 48 8d 45 80 lea -0x80(%rbp),%rax
0x55555562dd90 <+0x0564> 48 89 c7 mov %rax,%rdi
0x55555562dd93 <+0x0567> e8 58 ef f2 ff callq 0x55555555ccf0 _ZN6QImageD1Ev@plt
0x55555562dd98 <+0x056c> eb 03 jmp 0x55555562dd9d MainWindow::on_pushButton_2_pressed()+1393
0x55555562dd9a <+0x056e> 48 89 c3 mov %rax,%rbx
28635 [3] QString test= x_member;
0x55555562dd9d <+0x0571> 48 8d 85 68 ff ff ff lea -0x98(%rbp),%rax
0x55555562dda4 <+0x0578> 48 89 c7 mov %rax,%rdi
0x55555562dda7 <+0x057b> e8 5e 4d 00 00 callq 0x555555632b0a QString::~QString()
0x55555562ddac <+0x0580> 48 89 d8 mov %rbx,%rax
0x55555562ddaf <+0x0583> 48 89 c7 mov %rax,%rdi
0x55555562ddb2 <+0x0586> e8 39 ee f2 ff callq 0x55555555cbf0 _Unwind_Resume@plt
28683 [2] }
0x55555562ddb7 <+0x058b> e8 14 ec f2 ff callq 0x55555555c9d0 __stack_chk_fail@plt
0x55555562ddbc <+0x0590> 48 81 c4 d8 00 00 00 add $0xd8,%rsp
0x55555562ddc3 <+0x0597> 5b pop %rbx
0x55555562ddc4 <+0x0598> 5d pop %rbp
0x55555562ddc5 <+0x0599> c3 retq

[KroMignon]

@swansorter said in Receive data with UDP protocol:

if i use received_data_x as class member i am getting segmentation fault

I don't understand this, I do this in many application running on Windows, Linux and Android and I never got a segmentation fault!

class MainWindow : public QMainWindow
{
    Q_OBJECT

...
   QUdpSoccket *mSocket;
   QByteArray mPayload;
...

private slots:
    void readPendingDatagrams();
}

and then

void MainWindow::readPendingDatagrams()
{
    while(mSocket->hasPendingDatagrams())
    {
        QByteArray datagram1;
        datagram1.resize(mSocket->pendingDatagramSize());
        mSocket->readDatagram(datagram1.data(),datagram1.size() );
        mPayload.append(datagram1.toHex());
    }
}

And this works fine.

[swansorter]

@KroMignon
void MainWindow::on_pushButton_2_pressed()
{
//if iuse class member or global variable;
QString test= mPayLoad//class member;
int bufpo0 = 0, bufpo1 = 1, bufpo2 = 2, bufpo3 = 3;
QByteArray cmd= QByteArray::fromHex(test.replace("\r\n","").toLatin1());

for (int packet = 0; packet < cmd.length(); packet++)
{
//in this loop am getting segmentation fault*///
Auto_image_RGBdata[packet] = static_cast<quint8>(cmd.data()[bufpo0]) | static_cast<quint8>(cmd.data()[bufpo1]) << 8 | static_cast<quint8>(cmd.data()[bufpo2]) << 16 | static_cast<quint8>(cmd.data()[bufpo3])<< 24;

   bufpo0 = bufpo0 + 4;
   bufpo1 = bufpo1 + 4;
   bufpo2 = bufpo2 + 4;
   bufpo3 = bufpo3 + 4;

}

[swansorter]

@swansorter in the above code i am getting segmentation fault

[KroMignon]

@swansorter said in Receive data with UDP protocol:

in the above code i am getting segmentation fault

First, if you are expecting QByteArray, then store it as QByteArray in the readPendingDatagrams() slot, so don't have to convert from QByteArray to hexstring and back:

void MainWindow::readPendingDatagrams()
{
    while(mSocket->hasPendingDatagrams())
    {
        QByteArray datagram1;
        datagram1.resize(mSocket->pendingDatagramSize());
        mSocket->readDatagram(datagram1.data(),datagram1.size() );
        mPayload.append(datagram1);
    }
}

Then how did you declare Auto_image_RGBdata?

[swansorter]

@KroMignon
class MainWindow : public QMainWindow
{
Q_OBJECT
QByteArray mPayload;
QUdpSocket *mSocket;
QUdpSocket *socket;
qint32 Auto_image_RGBdata[2014080]={0};
private slots:
void readPendingDatagrams();
}

[KroMignon]

@swansorter Your code is not very clear to understand, I do my best.

I suppose you want to read 32 bit words from the stream, in big endian byte order.

So I would to it with QDataStream, like this:

QByteArray data = mPayLoad; // made local copy to avoid changes by slot
QDataStream stream(&data, QIODevice::ReadOnly);
// default byte order for QDataStream is big endian
///stream.setByteOrder(QDataStream::LittleEndian); // if you want to change byte order

// to be sure we are not trying to read more than possible!!
int maxCount = qMin(data.size() / 4, sizeof(Auto_image_RGBdata)/sizeof(Auto_image_RGBdata[0]));

for(int i = 0; i < maxCount; ++i)
   stream >> Auto_image_RGBdata[i];

That's it.

[swansorter]

@KroMignon
sir

1. i wan to receive 2014080 bytes (from udp)
   2.then i have to re arrange received data

for (int packet = 0; packet < cmd.length(); packet++)
{
//in this loop am getting segmentation fault*///
Auto_image_RGBdata[packet] = static_cast<quint8>(mPayload.data()[bufpo0]) | static_cast<quint8>(mPayload.data()[bufpo1]) << 8 | static_cast<quint8>(mPayload.data()[bufpo2]) << 16 | static_cast<quint8>(mPayload.data()[bufpo3])<< 24;

bufpo0 = bufpo0 + 4;
bufpo1 = bufpo1 + 4;
bufpo2 = bufpo2 + 4;
bufpo3 = bufpo3 + 4;

}
3.then ill convert Auto_image_RGBdata to image using pix map

[KroMignon]

@swansorter said in Receive data with UDP protocol:

1.i wan to receive 2014080 bytes (from udp)

How do you know which is the first datagram?

2.then i have to re arrange received data

Have you tried out the code in my previous post?

3.then ill convert Auto_image_RGBdata to image using pix map

To convert your image to QPixmap, if you receive a pixel buffer, you could do it like this:

// be careful, (image_width*image_height*4) must be lower or equal to mPayLoad.size()
QPixmap pixmap = QPixmap::fromImage(
    QImage(
     mPayLoad.constData(), 
     image_width,
     image_height,
     QImage::Format_ARGB32// take a look a QImage documentation to choose the right format
    ) 
); 

[swansorter]

@KroMignon solved thank you very much