/* From Stevens */

int readn(int fd, void *buff, int nbytes)
{
	int nleft, nread;
	char *ptr;

	ptr = (char *)buff;
	nleft = nbytes;

	while(nleft > 0) {
		if( (nread = read(fd, ptr, nleft)) < 0) {
			if( errno == EINTR)
				nread = 0;
			else if(errno == EAGAIN)
				break;
			else
				return(-1);
		}
		else if(nread == 0)
			break;

		nleft -= nread;
		ptr   += nread;
	}
	
	return (nbytes-nleft);

}


int writen(int fd, const void *buff, int nbytes)
{
	int nleft, nwritten;
	const char *ptr;

	ptr = (char*)buff;
	nleft = nbytes;

	while(nleft > 0) {
		if((nwritten = write(fd, ptr, nleft)) <= 0) {
			if(errno == EINTR)
				nwritten = 0;
			else
				return(-1);
		}
		nleft -= nwritten;
		ptr   += nwritten;
	}

	return (nbytes);

}