我正在编写一个C程序，以在连接到公共网络（只是一个实验室项目）的两台计算机（运行Windows OS）之间共享文件。当我读取非.txt文件（如.docx或.gif）时，无法获取整个文件。在大多数情况下，服务器程序向客户端发送了一些空（或某些未知字符），但客户端从未收到过。这是我的服务器程序：
#include<io.h>
#include<stdio.h>
#include<winsock2.h>
#include<string.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s , new_socket;
struct sockaddr_in server , client;
int c;
char message[10240];
char filename[100];
char response[50];
int k = 0;
printf("Enter filename :");
scanf("%s",&filename);
FILE *f = fopen(filename, "rb");
fseek(f, 0, SEEK_END);
long fsize = ftell(f);
fseek(f, 0, SEEK_SET); /* same as rewind(f); */
char *string = malloc(fsize + 1);
int count = 0;
while(count < fsize){
string[count++] = getc(f);
if(getc(f) == EOF)
fseek(f, 0, count+1);
}
fclose(f);
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
//Bind
if( bind(s ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
{
printf("Bind failed with error code : %d" , WSAGetLastError());
}
puts("Bind done");
//Listen to incoming connections
listen(s , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
new_socket = accept(s , (struct sockaddr *)&client, &c);
if (new_socket == INVALID_SOCKET)
{
printf("accept failed with error code : %d" , WSAGetLastError());
}
puts("Connection accepted");
//Reply to client
// message = "Hello Client , I have received your connection. But I have to go now, bye\n";
send(new_socket , filename , strlen(filename) , 0);
int len = recv(new_socket, response, 50, 0);
response[len] = '\0';
if(strcmp(response, "OKAY") == 0) printf("SUCCESS");
else printf("ERROR");
int i = 0;
char cn = 'a';
// getchar();
int j = 0;
int ssize = strlen(string);
printf("FIle size is : %d",ssize);
getchar(); getchar();
while(j < ssize){
while(i < 1024){
message[i++] = string[j++];
if(j == ssize) break;
}
printf("sent :%s\n",message);
send(new_socket, message, strlen(message), 0);
printf("%d\n",k); k++;
i = 0;
}
send(new_socket, "...END...CONNECTION...", strlen("...END...CONNECTION..."), 0);
printf("sent end connection");
recv(new_socket, response, strlen(response), 0);
if(strcmp(response, "...END...CONNECTION...") != 0)
send(new_socket, "...END...CONNECTION...", strlen("...END...CONNECTION..."), 0);
printf("SUCCESS");
closesocket(s);
WSACleanup();
return 0;
}
这是我的客户程序：
#include<stdio.h>;
#include<winsock2.h>;
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char *message , server_reply[1024];
int recv_size;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf(";Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(s , (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
if((recv_size = recv(s , server_reply , 1024 , 0)) == SOCKET_ERROR)
{
puts("recv failed");
}
puts("filename : ");
server_reply[recv_size] = '\0';
puts(server_reply);
FILE* fptr = fopen(server_reply, "wb");
send(s , "OKAY" , strlen("OKAY") , 0);
int i = 0;
while(1){
if((recv_size = recv(s , server_reply , 1024, 0)) == SOCKET_ERROR)
{
puts("recv failed"); break;
}
if(strcmp(server_reply, "...END...CONNECTION...") == 0) {
printf("recieved end connection"); break;
}
fputs(server_reply, fptr);
server_reply[recv_size] = '\0';
printf("%s\n", server_reply);
printf("%d,\n",i++);
}
send(s, "...END...CONNECTION...", strlen("...END...CONNECTION..."), 0);
printf("sent : end connection");
fclose(fptr);
puts("File received\n");
return 0;
}
然后，我想知道我的程序实际读取多少字节。因此，我编写了一个简单的程序来读取文件，但是这次，我将使用fseek函数找到EOF并进行打印，读取文件，然后打印读取的缓冲区的长度。这是我使用的代码：
#include <stdio.h>
#include <stdlib.h>
void main(){
printf("Enter file : ");
char filename[50];
scanf("%s",&filename);
FILE *f = fopen(filename, "rb");
fseek(f, 0, SEEK_END);
long fsize = ftell(f);
fseek(f, 0, SEEK_SET); /* same as rewind(f); */
printf("File size is : %ld bytes (according to SEEK_END)\n", fsize);
char *string = malloc(fsize + 1);
fread(string, 1, fsize, f);
long len = strlen(string);
printf("File size is : %ld bytes (according to freed)\n", len);
fclose(f);
string[fsize] = 0;
puts(string);
}
我得到的输出是这个：
Enter file : 1.docx
File size is : 12920 bytes (according to SEEK_END)
File size is : 5 bytes (according to freed)
PK
有人可以帮我吗:(我真的不知道为什么这两个值不同。他们应该相等，对吧？
因此，我尝试使用fsanf，fgets，read读取.docx文件。所以我了解到，Fscanf和fgets在文件中搜索ascii字符，因此不适合读取二进制文件。fread读取二进制文件，但您无法将其存储在char数组中，相反，我们可以使用uint8_t。在进行这些更改后，现在效果很好。
因此结论是，所有函数都读取到EOF为止，但是我们用来存储它们的数据类型不能容纳所有值。这就是为什么当我使用strlen（）时得到不同的值的原因。