使用Qt中的QUdpSocket将并集转换为QByteArray，反之亦然

Question

我有一个类似的Union

#define no_of_bits 240
#define word_size 16
struct bits
{
unsigned short int bit1:1;
unsigned short int bit2:1;
unsigned short int bit3:1;
unsigned short int bit4:1;
unsigned short int bit5:1;
unsigned short int bit6:1;
unsigned short int bit7:1;
unsigned short int bit8:1;
unsigned short int bit9:1;
unsigned short int bit10:1;
unsigned short int bit11:1;
unsigned short int bit12:1;
unsigned short int bit13:1;
unsigned short int bit14:1;
unsigned short int bit15:1;
unsigned short int bit16:1;
};
union myData
{
unsigned short int data[no_of_bits/word_size];
struct bits word[no_of_bits/word_size];
};

我想将myData并集转换为QByteArray，这样我就可以使用QUdpSocket和writeDatagram()函数通过套接字发送它。首先告诉我如何将其转换为QByteArray。

接下来的问题是，在接收方，我如何将QByteArray再次转换为该联合myData。

Answer 1

使用QByteArray构造函数或QByteArray::fromRawData。

参见将转换为QByteArray的示例：

#include <QCoreApplication>
#include <QByteArray>

#define no_of_bits 240
#define word_size 16
struct bits
{
unsigned short int bit1:1;
unsigned short int bit2:1;
unsigned short int bit3:1;
unsigned short int bit4:1;
unsigned short int bit5:1;
unsigned short int bit6:1;
unsigned short int bit7:1;
unsigned short int bit8:1;
unsigned short int bit9:1;
unsigned short int bit10:1;
unsigned short int bit11:1;
unsigned short int bit12:1;
unsigned short int bit13:1;
unsigned short int bit14:1;
unsigned short int bit15:1;
unsigned short int bit16:1;
};
union myData
{
unsigned short int data[no_of_bits/word_size];
struct bits word[no_of_bits/word_size];
};

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
myData data;
// Variant 1  (no copy data)
auto byteArray = QByteArray::fromRawData(reinterpret_cast<const char*>(&data), sizeof(data));
// Variant 2  (copy data)
QByteArray byteArray2(reinterpret_cast<const char*>(&data), sizeof(data));
return a.exec();
}

从QByteArray转换：

assert(byteArray.size() == sizeof(data));
memcpy(&data, byteArray.data(), sizeof(data)); // Copy
// OR
assert(byteArray.size() == sizeof(data));
myData* data2 = reinterpret_cast<myData*>(byteArray.data()); // No copy

实际上，您可以直接调用writeDatagram：

QUdpSocket socket;
socket.writeDatagram(reinterpret_cast<const char*>(&data), sizeof(data), QHostAddress("127.0.0.1"), 1234);