--- ray/src/common/readoct.c	1989/03/22 09:53:46	1.4
+++ ray/src/common/readoct.c	1989/09/19 13:40:48	1.6
@@ -59,7 +59,7 @@ char  *ofn[];
 		getheader(infp, NULL);
 					/* check format */
 	if (getint(2) != OCTMAGIC)
-		octerror(USER, "bad octree");
+		octerror(USER, "invalid octree format");
 					/* get boundaries */
 	if (load & IO_BOUNDS) {
 		for (i = 0; i < 3; i++)
@@ -139,16 +139,18 @@ register int  siz;
 	register int  c;
 	register long  r;
 
-	c = getc(infp);
-	r = c&0x80 ? -1L : 0L;		/* sign extend */
-	ungetc(c, infp);
-	while (siz--) {
+	if ((c = getc(infp)) == EOF)
+		goto end_file;
+	r = 0x80&c ? -1<<8|c : c;		/* sign extend */
+	while (--siz > 0) {
 		if ((c = getc(infp)) == EOF)
-			octerror(USER, "truncated octree");
+			goto end_file;
 		r <<= 8;
 		r |= c;
 	}
 	return(r);
+end_file:
+	octerror(USER, "truncated octree");
 }