+++ /dev/null
-/*
- * wrbufcore.c
- *
- * Core of algorithm for writing output to devices which don't like
- * constant stopping and starting, such as tape drives. This is:
- * Copyright (C) 1997-1998,2000-2001 Ian Jackson <ian@chiark.greenend.org.uk>
- *
- * writebuffer is part of chiark backup, a system for backing up GNU/Linux
- * and other UN*X-compatible machines, as used on chiark.greenend.org.uk.
- * chiark backup is:
- * Copyright (C) 1997-1998,2000-2001 Ian Jackson <ian@chiark.greenend.org.uk>
- * Copyright (C) 1999 Peter Maydell <pmaydell@chiark.greenend.org.uk>
- *
- * This is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2,
- * or (at your option) any later version.
- *
- * This is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this file; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- */
-
-static size_t waitfill;
-static int writing;
-
-void wrbufcore_startup(void) {
- waitfill= (buffersize*3)/4;
- writing=0;
-}
-
-void wrbufcore_mainloop(void) {
- int r;
-
- while (!seeneof || used) {
-
- FD_ZERO(&readfds); if (!seeneof && used+1<buffersize) FD_SET(0,&readfds);
- FD_ZERO(&writefds); if (writing) FD_SET(1,&writefds);
-
- callselect();
-
- if (FD_ISSET(1,&writefds) && !FD_ISSET(0,&readfds) && !used) {
- writing= 0;
- FD_CLR(1,&writefds);
- }
-
- if (FD_ISSET(0,&readfds)) {
- r= read(0,rp,min(buffersize-1-used,buf+buffersize-rp));
- if (!r) {
- seeneof=1; writing=1;
- } else if (r<0) {
- if (!(errno == EAGAIN || errno == EINTR)) { perror("read"); exit(1); }
- } else {
- used+= r;
- rp+= r;
- if (rp == buf+buffersize) rp=buf;
- }
- if (used > waitfill) writing=1;
- }
-
- if (FD_ISSET(1,&writefds) && used) {
- r= write(1,wp,min(used,buf+buffersize-wp));
- if (r<=0) {
- if (!(errno == EAGAIN || errno == EINTR)) { perror("write"); exit(1); }
- } else {
- used-= r;
- wp+= r;
- if (wp == buf+buffersize) wp=buf;
- }
- }
- }
-}