Qt 发UDP广播 服务端及客户端

• Qt += network

数据结构

• data_geo.h

  #pragma pack(1)
  struct DataGeoLines
  {
      DataGeoLine data[4];
      uint32_t num_lines_valid;
          uint64_t timestamp_ms;		    //毫秒时间戳
          EnumLinesPattern type_pattern;  //导线的类型
  };
  #pragma pack()
  

• udp_data_wrap.h

  #pragma once  
  
  // 内存对齐
  #pragma pack(1)
  template<typename T>
  struct UDP_DATA_WRAP
  {
      UDP_DATA_WRAP():real_data_size(sizeof(T)){}
      uint16_t header{0xffee};
      uint64_t real_data_size{0};
      T real_data;
  };
  #pragma pack()
  

服务端

• udpserver.hpp

  #pragma once
  #include <QUdpSocket>
  #include <stdint.h>
  
  class UDPServer
  {
  public:    
      bool init(uint64_t port_in){
          port = port_in;
          p_udpSocket = new QUdpSocket();
          if(nullptr == p_udpSocket) return false;
          else return true;}
      uint64_t send(char* p_data, uint64_t len){
          return p_udpSocket->writeDatagram(p_data, len, QHostAddress::Broadcast, port);
      }
  private:
      uint64_t port;
      QUdpSocket* p_udpSocket{nullptr};
  };   
  

• 使用

  // send it, pass udp
  static UDPServer udp_server;
  static std::once_flag once_flag;
  std::call_once(once_flag, [&](){if(false == udp_server.init(9999)) printf("udp socket init failed \n");});
  uint64_t send_size =  udp_server.send((char*)&udp_data, sizeof(UDP_DATA_WRAP<DataGeoLines>));
  printf("send_size: %d \n", send_size);
  

客户端

• udp_client.h

  #pragma once
  #include <QUdpSocket>
  #include <QObject>
  class UDPClient : public QObject
  {
      Q_OBJECT
  public:
      void init(uint16_t port_in);
      void readPendingDatagrams();    
  
      QUdpSocket* p_qudp_socket{nullptr};
  private:
      uint8_t p_buf[1024];
      std::string ip{"192.168.0.255"};
      uint16_t port{9999};
  };
  

• udp_client.cpp

  #include "udp_client.h"
  #include <QNetworkDatagram>
  #include <QHostAddress>
  #include "data_geo.h"
  #include <iostream>
  #include <thread>
  
  void UDPClient::init(uint16_t port_in)
  {
      port = port_in;
      p_qudp_socket = new QUdpSocket(this);
      p_qudp_socket->bind(QHostAddress::Broadcast, port);
      connect(p_qudp_socket, &QUdpSocket::readyRead, this, &UDPClient::readPendingDatagrams);
  }
  
  void UDPClient::readPendingDatagrams()
  {
      while (p_qudp_socket->hasPendingDatagrams()) {
          int64_t len = p_qudp_socket->readDatagram((char*)p_buf, sizeof(p_buf), nullptr, &port);
          if(-1 == len)   continue;
          std::cout << "recive len: " << len << std::endl;
          uint16_t* p_header = (uint16_t*)&p_buf;
          if(*p_header == 0xffee)
          {
              DataGeoLines* p_data_geo_line =  (DataGeoLines*)&p_buf[10];
              printf("DataGeoLine num: %d \n", p_data_geo_line->num_lines_valid);
              printf("p_data_geo_line->data->height: %.2f \n", p_data_geo_line->data->height);
              printf("p_data_geo_line->data->stagger: %.2f \n", p_data_geo_line->data->stagger);
          }
      }
  }
  

• 使用

  #include <QCoreApplication>
  #include "udp_client.h"
  int main(int argc, char *argv[])
  {
      QCoreApplication a(argc, argv);
      UDPClient udp_client;
      const uint16_t port = 9999;
      udp_client.init(port);
      return a.exec();
  }