c++ - fstream 正在向我的文件的每一行添加字符？

Question

我正在用 C++ 编写一个小型 DLL，它将从网络服务器下载文件。下载部分工作正常，但是当我将文件写入磁盘时，它在每一行都添加了额外的字符。

当我在 Notepad++ 中查看原始文件(复制到网络服务器的文件)时，我可以看到它在每一行的末尾都有 CR 和 LF(回车和换行)字符，就像它应该的那样.不过，在保存的版本中，不是

line of textCRLF

看起来像

line of textCR
CRLF
CR
CRLF
Another line of text...

我一直没能找到是什么原因造成的。 (o)fstream 是否存在某种问题？

extern "C" void TCP_get_file(char *server, char *path, char *filename){
ofstream logfile("Crashlog.txt");
WSAData wsadata;
if ((WSAStartup(MAKEWORD(2, 2), &wsadata)) != 0){
    logfile << "Error starting winsocks." << endl;
    WSACleanup();
    return;
}
int status, sock, received;
struct addrinfo hints, *servinfo;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
if ((status = getaddrinfo(server, "http", &hints, &servinfo)) != 0){
    logfile << "Error getting server info:  " << gai_strerror(status) << endl;
    WSACleanup();
    freeaddrinfo(servinfo);
    return;
}
sock = socket(servinfo->ai_family, servinfo->ai_socktype, servinfo->ai_protocol);
connect(sock, servinfo->ai_addr, servinfo->ai_addrlen);
string request = string("GET ") + path + " HTTP/1.0\nhost: " + server + "\r\n\r\n";
if (send(sock, request.c_str(), strlen(request.c_str()), 0) == -1){
    logfile << "Error sending request to server." << endl;
    freeaddrinfo(servinfo);
    closesocket(sock);
    WSACleanup();
    return;
}
char filebuffer[5000];
string full, file;
while ((received = recv(sock, filebuffer, 4999, 0)) > 0){
    full.append(filebuffer, received);
    ZeroMemory(filebuffer, 4999);
}
full.push_back("\0");
int offset = full.find("\r\n\r\n") + 4;
file.assign(full, offset, full.size());
ofstream savefile(filename);
savefile << file;
savefile.flush();
savefile.close();
freeaddrinfo(servinfo);
closesocket(sock);
WSACleanup();
return;

Answer 1

首先要做的是在 ofstream 对象上使用二进制模式:

ofstream savefile(filename, std::ofstream::binary);

它将阻止 ofstream 修改 weriten 数据，这是默认完成的(在文本模式下)。