10 #define BUFFER 16*1024*1024
11 #define WAITFILL ((BUFFER*3)/4)
13 static inline int min(int a, int b) { return a<=b ? a : b; }
15 static void nonblock(int fd) {
17 r= fcntl(fd,F_GETFL,0); if (r == -1) { perror("fcntl getfl"); exit(1); }
19 if (fcntl(fd,F_SETFL,r) == -1) { perror("fcntl setfl"); exit(1); }
23 static unsigned char buf[BUFFER];
25 unsigned char *wp, *rp;
26 int used,r,writing,seeneof;
30 used=0; wp=rp=buf; writing=0; seeneof=0;
31 nonblock(0); nonblock(1);
32 while (!seeneof || used) {
33 FD_ZERO(&readfds); if (!seeneof && used+1<BUFFER) FD_SET(0,&readfds);
34 FD_ZERO(&writefds); if (writing) FD_SET(1,&writefds);
35 /*fprintf(stderr,"used %6d writing %d seeneof %d wp %8lx rp %8lx read %d write %d\n",
36 used,writing,seeneof,(unsigned long)(wp-buf),(unsigned long)(rp-buf),
37 FD_ISSET(0,&readfds),FD_ISSET(1,&writefds));*/
38 r= select(2,&readfds,&writefds,0,0);
39 /*fprintf(stderr,"\t readable %d writeable %d\n",
40 FD_ISSET(0,&readfds),FD_ISSET(1,&writefds));*/
42 if (errno == EINTR) continue;
43 perror("select"); exit(1);
45 if (FD_ISSET(1,&writefds) && !FD_ISSET(0,&readfds) && !used) {
48 /*fprintf(stderr,"\t buffers empty - stopping\n");*/
50 if (FD_ISSET(0,&readfds)) {
51 r= read(0,rp,min(BUFFER-1-used,buf+BUFFER-rp));
53 /*fprintf(stderr,"\t eof detected\n");*/
56 if (!(errno == EAGAIN || errno == EINTR)) { perror("read"); exit(1); }
57 fprintf(stderr,"\t read transient error\n");
59 /*fprintf(stderr,"\t read %d\n",r);*/
62 if (rp == buf+BUFFER) rp=buf;
63 /*fprintf(stderr,"\t starting writes\n");*/
65 if (used > WAITFILL) writing=1;
67 if (FD_ISSET(1,&writefds) && used) {
68 r= write(1,wp,min(used,buf+BUFFER-wp));
70 if (!(errno == EAGAIN || errno == EINTR)) { perror("write"); exit(1); }
71 /*fprintf(stderr,"\t write transient error\n");*/
73 /*fprintf(stderr,"\t wrote %d\n",r);*/
76 if (wp == buf+BUFFER) wp=buf;