writing binary data to a file using c++ , after receiving from socket - c++

Question

I am trying to write a c++ code which read from a file (any type) and write the file data (binary data) on the socket , so the receiver must take this data and create a file , i should see the same data with the same format , the problem is the data is still binary and written to the file as binary data !
if a tested the code without sending on a network , it will work well !
any idea ?
thanks in advance .
note , i am using Ubuntu 11.10 if it affects this issue ..
Here is the code, on the client side:
filer=fopen("a.doc","rb");
fseek (filer , 0 , SEEK_END);
long size;
size = ftell (filer);
rewind (filer);
buffer = (char*) malloc (sizeof(char)*size);
numr=fread(buffer,1,size,filer);
fclose(filer); //some socket code
char buffer2[size];
strcpy(buffer2 , buffer);
n = write(sockfd,buffer2,size);
and for the server side :
n = read(sock,buffer,length);
FILE * filew;
int numw;
filew=fopen("acopy.doc","wb");
numw=fwrite(buffer,1,len,filew);
fclose(filew);

Answer 1

First thing is that you'll need to loop. The calls to read and write will not always be the full buffer. Disclaimer that I couldn't test this here
Ex:
numr=fread(buffer,1,size,filer);
fclose(filer); //some socket code
char buffer2[size];
strcpy(buffer2 , buffer);
n = write(sockfd,buffer2,size);
to
char buffer2[size];
while ((numr=fread(buffer,1,size,filer)) != 0)
{
strcpy(buffer2 , buffer);
n = 0;
while ((n = write(sockfd,buffer2+n,numr-n)) != 0)
;
}
fclose(filer); //some socket code
filer = NULL;
Likewise on the server side
n = read(sock,buffer,length);
FILE * filew;
int numw;
filew=fopen("acopy.doc","wb");
numw=fwrite(buffer,1,len,filew);
fclose(filew);
to
FILE * filew;
filew=fopen("acopy.doc","wb");
int numw = 0;
while ((n = read(sock,buffer,length)) != 0)
{
while ((numw=fwrite(buffer+numw,1,n-numw,filew) != 0)
;
}
fclose(filew);