c++ socket 分包传输mat示例代码

以下是一个简单的示例代码，展示了如何在 C++ 中使用 socket 分包传输 mat：

发送方代码：

#include <iostream>
#include <opencv2/opencv.hpp>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

// 将 mat 转换为字节数组
std::vector<unsigned char> mat_to_bytes(cv::Mat& mat)
{
    std::vector<unsigned char> bytes;
    if (mat.isContinuous()) {
        bytes.assign(mat.datastart, mat.dataend);
    } else {
        for (int i = 0; i < mat.rows; ++i) {
            bytes.insert(bytes.end(), mat.ptr<unsigned char>(i), mat.ptr<unsigned char>(i) + mat.cols * mat.channels());
        }
    }
    return bytes;
}

int main()
{
    // 加载图像
    cv::Mat img = cv::imread("test.jpg");

    // 创建 socket 对象
    WSADATA wsaData = {};
    WSAStartup(MAKEWORD(2, 2), &wsaData);
    SOCKET client_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    // 连接服务器
    struct sockaddr_in server_address = {};
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = inet_addr("127.0.0.1");
    server_address.sin_port = htons(8888);
    connect(client_socket, (struct sockaddr*)&server_address, sizeof(server_address));

    // 将图像转换为 mat 对象
    cv::Mat mat = img.clone();

    // 将 mat 转换为字节数组
    std::vector<unsigned char> data = mat_to_bytes(mat);

    // 发送包头
    int data_size = data.size();
    char header[4] = {};
    memcpy(header, &data_size, 4);
    send(client_socket, header, 4, 0);

    // 分包发送数据
    int buffer_size = 1024;
    int offset = 0;
    while (offset < data_size) {
        int size = std::min(buffer_size, data_size - offset);
        send(client_socket, (char*)&data[offset], size, 0);
        offset += size;
    }

    // 关闭连接
    closesocket(client_socket);
    WSACleanup();

    return 0;
}

接收方代码：

#include <iostream>
#include <opencv2/opencv.hpp>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

// 将字节数组转换为 mat
cv::Mat bytes_to_mat(std::vector<unsigned char>& bytes, int height, int width)
{
    cv::Mat mat(height, width, CV_8UC3, bytes.data());
    return mat.clone();
}

int main()
{
    // 创建 socket 对象
    WSADATA wsaData = {};
    WSAStartup(MAKEWORD(2, 2), &wsaData);
    SOCKET server_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    // 绑定地址和端口号
    struct sockaddr_in server_address = {};
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = htonl(INADDR_ANY);
    server_address.sin_port = htons(8888);
    bind(server_socket, (struct sockaddr*)&server_address, sizeof(server_address));

    // 开始监听
    listen(server_socket, 1);

    // 等待客户端连接
    SOCKET client_socket = accept(server_socket, NULL, NULL);

    // 接收包头
    char header[4] = {};
    recv(client_socket, header, 4, 0);
    int data_size = *(int*)header;

    // 接收数据
    std::vector<unsigned char> data(data_size);
    int buffer_size = 1024;
    int offset = 0;
    while (offset < data_size) {
        int size = std::min(buffer_size, data_size - offset);
        recv(client_socket, (char*)&data[offset], size, 0);
        offset += size;
    }

    // 将字节数组转换为 mat 对象
    int height = 480, width = 640;
    cv::Mat img = bytes_to_mat(data, height, width);

    // 显示图像
    cv::imshow("image", img);
    cv::waitKey(0);

    // 关闭连接
    closesocket(client_socket);
    closesocket(server_socket);
    WSACleanup();

    return 0;
}

需要注意的是，由于网络传输的不确定性，可能会出现粘包或者丢包的情况，因此在接收数据时需要进行相应的处理，保证数据的完整性和正确性。