--- ray/src/util/rpiece.c	1993/01/29 11:56:09	2.16
+++ ray/src/util/rpiece.c	1993/04/17 13:13:58	2.19
@@ -1,4 +1,4 @@
-/* Copyright (c) 1992 Regents of the University of California */
+/* Copyright (c) 1993 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -39,7 +39,15 @@ char *argv[];
 #define  MAXFORK		0
 #endif
 #endif
-
+					/* protection from SYSV signals(!) */
+#if defined(sgi) || defined(hpux)
+#define guard_io()	sighold(SIGALRM)
+#define unguard()	sigrelse(SIGALRM)
+#endif
+#ifndef guard_io
+#define guard_io()	0
+#define unguard()	0
+#endif
 				/* rpict command */
 char  *rpargv[128] = {"rpict", "-S", "1", "-x", "512", "-y", "512", "-pa", "1"};
 int  rpargc = 9;
@@ -258,7 +266,7 @@ int  *xp, *yp;
 				return(0);
 			}
 		}
-		sprintf(buf, "%d %d\n%d %d\n", hmult, vmult, *xp, *yp);
+		sprintf(buf, "%4d %4d\n%4d %4d\n", hmult, vmult, *xp, *yp);
 		lseek(syncfd, 0L, 0);		/* write new position */
 		write(syncfd, buf, strlen(buf));
 		fls.l_type = F_UNLCK;		/* release sync file */
@@ -351,19 +359,24 @@ int  xpos, ypos;
 		exit(cleanup(1));
 	}
 				/* check header from rpict */
+	guard_io();
 	getheader(fromrp, NULL, NULL);
 	if (!fscnresolu(&hr, &vr, fromrp) || hr != hres | vr != vres) {
 		fprintf(stderr, "%s: resolution mismatch from %s\n",
 				progname, rpargv[0]);
 		exit(cleanup(1));
 	}
+	unguard();
 				/* load new piece into buffer */
-	for (y = 0; y < vr; y++)
+	for (y = 0; y < vr; y++) {
+		guard_io();
 		if (freadcolrs(pbuf+y*hr, hr, fromrp) < 0) {
 			fprintf(stderr, "%s: read error from %s\n",
 					progname, rpargv[0]);
 			exit(cleanup(1));
 		}
+		unguard();
+	}
 #if MAXFORK
 				/* fork so we don't slow rpict down */
 	if ((pid = fork()) > 0) {
@@ -378,16 +391,17 @@ int  xpos, ypos;
 #else
 	pid = -1;		/* no forking */
 #endif
-	fls.l_len = (long)vres*hmult*hres*sizeof(COLR);
-	fls.l_start = scanorig + (vmult-1-ypos)*fls.l_len;
+	fls.l_start = scanorig +
+		((long)(vmult-1-ypos)*vres*hmult+xpos)*hres*sizeof(COLR);
 #if NFS
+	fls.l_len = ((long)(vres-1)*hmult+1)*hres*sizeof(COLR);
 				/* lock file section so NFS doesn't mess up */
 	fls.l_whence = 0;
 	fls.l_type = F_WRLCK;
 	fcntl(outfd, F_SETLKW, &fls);
 #endif
 				/* write new piece to file */
-	if (lseek(outfd, fls.l_start+(long)xpos*hres*sizeof(COLR), 0) == -1)
+	if (lseek(outfd, fls.l_start, 0) == -1)
 		goto seekerr;
 	if (hmult == 1) {
 		if (writebuf(outfd, (char *)pbuf,