util.c

一个C编写网络广播的程序

/* util.c -- miscelanneous common code
 *  
 * This file is part of 'netcast' program, released under BSD License. 
 * (c) 2001-2002 Stanis砤w Pa秌o <[e-mail]>. All rights reserved.   
 */

#include <arpa/inet.h>
#include <sys/types.h>
#include <fcntl.h>

#include "mdist.h"
#include "util.h"

int code;

/* Create sockaddr_in from address. Now supports only IPs, may 
   be easily extended (since all addresses are resolved here) */
struct sockaddr_in make_addr(char *addr, unsigned short port) {
  struct sockaddr_in sin;
  sin.sin_family=AF_INET;
  if (!addr) 
    sin.sin_addr.s_addr=htonl(INADDR_ANY);
  else { 
    if (!inet_aton(addr,&sin.sin_addr)) 
      crit("cant resolve address: %s",addr);
  } 
  sin.sin_port=htons(port);
  return sin;  
}

/* Better than using a macro */
void set_nonblock(int s) {
  if (fcntl(s,F_SETFL,O_NONBLOCK)<0) 
    crit("fcntl() failed, can't set O_NONBLOCK");
}

size_t read_all(int fd, void *buf, size_t count) {
  size_t t=0,r=0;
  while (count>0) {
    r=read(fd,buf+t,count);
    if (r<=0) return t?t:r;
    t+=r;count-=r;   
  }
  return t;
}