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/************************************************************************
*
* Utility functions to use with sockets
*
************************************************************************
/************************************************************************
*
* Read "n" bytes from a descriptor.
* Use in place of read() when fd is a stream socket.
*/
#include <iostream>
using namespace std;
int readn(int fd, char* ptr, int nbytes)
{
int nleft, nread;
nleft = nbytes;
while (nleft > 0) {
nread = read(fd, ptr, nleft);
if (nread < 0)
return(nread); /* error, return < 0 */
else if (nread == 0)
break; /* EOF */
nleft -= nread;
ptr += nread;
}
return(nbytes - nleft); /* return >= 0 */
}
/************************************************************************
/************************************************************************
*
* Read a line from a descriptor. Read the line one byte at a time,
* looking for the newline. We store the newline in the buffer,
* then follow it with a null (the same as fgets(3)).
* We return the number of characters up to, but not including,
* the null (the same as strlen(3)).
*/
int readline(int fd,char* ptr, int maxlen)
{
int n, rc;
char c;
for (n = 1; n < maxlen; n++) {
if ( (rc = read(fd, &c, 1)) == 1) {
*ptr++ = c;
if (c == '\n')
break;
} else if (rc == 0) {
if (n == 1)
return(0); /* EOF, no data read */
else
break; /* EOF, some data was read */
} else
return(-1); /* error */
}
*ptr = 0;
return(n);
}
/************************************************************************
/************************************************************************
*
* Write "n" bytes to a descriptor.
* Use in place of write() when fd is a stream socket.
*/
int writen(int fd, char* ptr, int nbytes)
{
int nleft, nwritten;
nleft = nbytes;
while (nleft > 0) {
nwritten = write(fd, ptr, nleft);
if (nwritten <= 0)
return(nwritten); /* error */
nleft -= nwritten;
ptr += nwritten;
}
return(nbytes - nleft);
}
/************************************************************************/
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