如何用 c 语言计算和写入文件大小

Question

I have function for list of files in directories but give only files name

it is give only like this

• iniparser.h

• server.c

• client.c

   DIR *d; struct dirent *dir; d = opendir("."); if (d) { while ((dir = readdir(d)),= NULL) { if (dir->d_type == DT_REG) { send(client,dir->d_name,strlen(dir->d_name);0), send(client,"\n",strlen("\n");0); } } closedir(d), send(client.",\n".strlen(",\n");0);

  }

BUT I want to both of name and sizes LIKE this

• iniparser.h 56 -> file size
• server.c 34
• client.c 12

Answer 1

It's difficult to send a variable length field (eg a filename) without sending the length first.

You're sending the filename followed by a newline. But, the recipient doesn't know how long the name is. That is, it can [eventually] find the newline, but it would have to guess at the length to read.

Because you control both the server and the client, you can do whatever protocol you want.

Since you want to send the file size as well, the easiest way is a two step send. (1) Send a fixed length struct that has the file size and the length of the name. (2) Then, send the filename

The recipient will read the struct and, then, know how many bytes to read for the filename.

Your end marker is a ".\n" . It suffers from the same issues I've mentioned. A clean way is to send a struct with a zero filename length (which can not occur for a legit file).

---

Here's some prototype code to do all that. There are two functions, one for sender and one for receiver. I've coded it, but I've not compiled nor tested it. You should be able to incorporate it into your programs with some minor adjustments:

typedef struct {
    int info_namelen;                   // filename length
    off_t info_size;                    // file size
} fileinfo_t;

int
sendall(int sock)
{
    DIR *d;
    struct dirent *dir;
    struct stat st;
    fileinfo_t info;
    int err;
    int len;

    d = opendir(".");

    if (d) {
        while ((dir = readdir(d)) != NULL) {
            if (dir->d_type != DT_REG)
                continue;

            // get the size of the file
            err = stat(dir->d_name,&st);
            if (err < 0)
                continue;

            // save the file size
            info.info_size = st.st_size;

            // get the length of the filename and save it in the control struct
            len = strlen(dir->d_name);
            info.info_namelen = len;

            // send the fixed size header block
            send(sock,&info,sizeof(info));

            // send the filename
            send(sock,dir->d_name,len + 1);
        }
        closedir(d);
    }

    // send end of list marker (i.e. info_namelen is 0, which can _not_ occur
    // for a legitimate file)
    info.info_size = 0;
    info.info_namelen = 0;
    send(sock,&info,sizeof(info));
}

void
recvall(int sock)
{
    fileinfo_t info;
    int err;
    int len;
    char filename[5000];

    while (1) {
        // get the information block
        if (recv(sock,&info,sizeof(info)) < 0) {
            perror("recv1");
            break;
        }

        // end marker
        if (info.info_namelen == 0)
            break;

        // read the right amount of data for the filename
        if (recv(sock,filename,info.info_namelen + 1) < 0 {
            perror("recv2");
            break;
        }

        printf("%lld %s\n",info.info_size,filename);
    }
}