server和client之间进行Socket通信，进行数据切片

参考链接

• send函数和recv函数 – gudako's memo

注意事项

• 代码很low，主要看封装的Send函数所体现的切片思想即可

server代码

//udp服务端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>
#include <string>
#include <iostream>

#define SLICE_SIZE 5

bool Send(int sock_fd, char* buffer, int length)
{
    int once;            //一次发送的返回值
    int total = 0;        //目前发送了多少数据
    int thislen = 0;    //本次要发送的数据长度
    do
    {
        if (length - total > SLICE_SIZE)
            thislen = SLICE_SIZE;
        else
            thislen = length - total;
        once = send(sock_fd, buffer + total, thislen, 0);
        if (once <= 0)                        //如果once < 0则表示发送失败，用break跳出循环，返回FALSE
        {
            break;
        }
        total += once;
    } while (total < length);                //如果total < length说明数据还未完全发送，继续循环
    if (total == length)                    //当total == length时，说明已完全发送，返回TRUE
        return true;
    return false;
}

int main(int argc, char const *argv[])
{
    //1.创建socket
    int cfd = socket(AF_INET,SOCK_DGRAM,0);
    if(cfd<0){
        perror("socket error");
        return -1;
    }

    //绑定
    struct sockaddr_in serv;
    struct sockaddr_in client;
    bzero(&serv,sizeof(serv));
    serv.sin_family = AF_INET;
    serv.sin_port = htons(7777);
    serv.sin_addr.s_addr = htonl(INADDR_ANY);
    bind(cfd,(struct sockaddr *)&serv,sizeof(serv));

    //3.循环读取读取客户端消息和给客户端回复消息
    int i;
    int n;
    socklen_t len;
    char buf[1024];
    std::string merge;
    while(1){
        //4.读取数据
        memset(buf,0x00,sizeof(buf));
        len = sizeof(client);
        n = recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&client,&len);
        merge += buf;
        printf("serv端口号=[%d]:本次发送字节数=[%d],buf=[%s]\n",ntohs(client.sin_port),n,buf);
        //        printf("serv端口号=[%d]:本次发送字节数=[%d],bufer=[%s]\n",ntohs(serv.sin_port),once,tmp);
        std::cout << "merge= " << merge << ";" << "merge size is " << merge.size() <<  std::endl;
        //5.给客户端回复消息
        sendto(cfd,buf,n,0,(struct sockaddr*)&client,len);

    }
    //关闭套接字
    close(cfd);

    return 0;
}

client代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>

#define SLICE_SIZE 5

char* buffer = {"Helloworld\n"};
char* tmp[1024] ={0};
struct sockaddr_in serv;
bool Send(int sock_fd, char* buffer, int length)
{
    int once;            //一次发送的返回值
    int total = 0;        //目前发送了多少数据
    int thislen = 0;    //本次要发送的数据长度
    do
    {
        if (length - total > SLICE_SIZE)
            thislen = SLICE_SIZE;
        else
            thislen = length - total;
        once = send(sock_fd, buffer + total, thislen, 0);
//        printf("serv端口号=[%d]:本次发送字节数=[%d],bufer=[%s]\n",ntohs(serv.sin_port),once,tmp);
        //        sendto(cfd,buf,n,0,(struct sockaddr*)&serv,sizeof(serv));
        if (once <= 0)                        //如果once < 0则表示发送失败，用break跳出循环，返回FALSE
        {
            break;
        }
        total += once;
    } while (total < length);                //如果total < length说明数据还未完全发送，继续循环
    if (total == length)                    //当total == length时，说明已完全发送，返回TRUE
        return true;
    return false;
}

int main(){
    //1.创建socket
    int cfd = socket(AF_INET,SOCK_DGRAM,0);
    if(cfd<0){
        perror("socket error");
        return -1;
    }

    int n ;

    serv.sin_family = AF_INET;
    serv.sin_port = htons(7777);
    inet_pton(AF_INET,"127.0.0.1",&serv.sin_addr.s_addr);

    struct sockaddr_in client;
    client.sin_family = AF_INET;
    client.sin_port = htons(3333);

    bind(cfd, (struct sockaddr*)&client, sizeof(client));
    connect(cfd, (struct sockaddr*)&serv, sizeof(serv));
    char buf[1024] = {'\0'};
//    while(1){
        //读取标准输入数据
//        memset(buf,0x00,sizeof(buf));
//        n = read(STDIN_FILENO,buf, sizeof(buf));
//        buf[n-1] = 0x00;
//        n -= 1;
        Send(cfd,buffer, strlen(buffer));
        //发送数据
//        sendto(cfd,buf,n,0,(struct sockaddr*)&serv,sizeof(serv));
        //读取数据
        memset(buf,0x00,sizeof(buf));
        n = recvfrom(cfd,buf,sizeof(buf),0,NULL,NULL);
//        printf("[%d]:n=[%d],buf=[%s]\n",ntohs(serv.sin_port),n,buf);
//    }
    //关闭套接字
    close(cfd);

    return 0;
}