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关于socket 传送文件的问题 [困惑]
这几天一直被这个问题困扰着
编写了一个socket 传送BMP 图像的程序
client 向 server 传送client.bmp
但是在server 端接受到的图像不能打开
用 UltraEdit 打开client发送的 client.bmp图像和server接受的图像 server.bmp 对比,
server.bmp文件的前面 1448个字节 与 client.bmp的前1448个字节一样
但是server.bmp文件第1448个字节后的全部字节都为 0x00了
所以 server.bmp 所显示出来的几乎就是黑色的图片了
我的问题是 ---》 传送的是非0值,为什么收了一部分后就全变为0了呢?
请大虾们指点一下,我参考了资料+百度这个问题,还是百思不得其解。
我把我的代码附上
- ----------server-----------
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <errno.h>
- #include <string.h>
- #include <unistd.h>
- #include <netinet/in.h>
- #define SERVPORT 3333
- #define BACKLOG 10
- #define MAX_CONNECTED_NO 10
- #define MAXDATASIZE 100*100*3+54
- int main()
- {
- struct sockaddr_in server_sockaddr,client_sockaddr;
- int sin_size,recvbytes;
- int sockfd,client_fd;
- char buf[MAXDATASIZE];
- int nwrite,i;
-
- FILE *fbmp;
- char bmpdata[100*100*3+54];
-
- if (( fbmp = fopen("server.bmp", "w+")) == NULL)
- {
- printf("Open server bmp error !\n");
- exit(-1);
- }
-
-
- if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
- perror("socket");
- exit(1);
- }
- printf("socket success!,sockfd = %d\n",sockfd);
-
- server_sockaddr.sin_family = AF_INET;
- server_sockaddr.sin_port = htons(SERVPORT);
- server_sockaddr.sin_addr.s_addr = INADDR_ANY;
-
- bzero(&(server_sockaddr.sin_zero), 8);
-
- if(bind(sockfd, (struct sockaddr *)&server_sockaddr, sizeof(struct sockaddr)) == -1 ){
- perror("bind");
- exit(1);
- }
-
- printf("bind success!\n");
-
- if(listen(sockfd, BACKLOG) == -1){
- perror("listen");
- exit(1);
- }
-
- printf("listening - - - \n");
-
- if( (client_fd = accept(sockfd, (struct sockaddr *)&client_sockaddr, &sin_size)) == -1 ){
- perror("accept");
- exit(1);
- }
-
- if(( recvbytes = recv(client_fd, bmpdata, MAXDATASIZE, 0)) == -1){
- perror("recv");
- exit(1);
- }
- for( i = 0 ; i< MAXDATASIZE ; i++ )
- {
- printf("%x - ",bmpdata[i] ) ;
- }
- if ( nwrite = fwrite (bmpdata,MAXDATASIZE,1, fbmp ) < 0)
- {
- printf("Write BMP error !\n");
- exit(-1);
- }
- fclose(fbmp);
- close(sockfd);
- }
- ---------------client---------------------
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <errno.h>
- #include <string.h>
- #include <unistd.h>
- #include <netinet/in.h>
- #include <netdb.h>
- #define SERVPORT 3333
- #define MAXDATASIZE 100*100*3+54
- main( int argc , char *argv[] )
- {
- struct hostent *host;
- struct sockaddr_in serv_addr;
- int sockfd,sendbytes;
- char buf[MAXDATASIZE];
- int bmpsize = 0,
- i,
- headersize = 0,
- pixelsize = 0;
-
- FILE *fbmp;
- char bmpdata[100*100*3+54];
-
- if (( fbmp = fopen("client.bmp", "r")) == NULL)
- {
- printf("Open client bmp error !\n");
- exit(-1);
- }
-
-
- fseek(fbmp,0,SEEK_SET);
- fread(bmpdata,MAXDATASIZE,1,fbmp);
-
- if( argc < 2) {
- fprintf(stderr, "Please enter the server's hostname!\n");
- exit(1);
- }
-
- if( (host = gethostbyname(argv[1])) == NULL ){
- perror("gethostbyname");
- exit(1);
- }
-
- if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
- perror("socket");
- exit(1);
- }
- printf("socket success!,socket = %d\n",sockfd);
-
- serv_addr.sin_family = AF_INET;
- serv_addr.sin_port = htons(SERVPORT);
- serv_addr.sin_addr = *( (struct in_addr *)host->h_addr );
-
- bzero(&(serv_addr.sin_zero), 8);
-
- if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)) == -1 ){
- perror("connect");
- exit(1);
- }
-
- printf("connect success!\n");
-
- if(( sendbytes = send(sockfd, bmpdata ,bmpsize, 0)) == -1){
- perror("send");
- exit(1);
- }
- for( i = 0 ; i< MAXDATASIZE ; i++ )
- {
- printf("%x - ",bmpdata[i] ) ;
- }
-
- printf("send over!\n");
-
- fclose(fbmp);
- close(sockfd);
- }
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