--- ray/src/common/urand.c	1991/05/17 12:55:27	1.1
+++ ray/src/common/urand.c	2003/02/25 02:47:22	2.6
@@ -1,35 +1,41 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: urand.c,v 2.6 2003/02/25 02:47:22 greg Exp $";
 #endif
-
 /*
- * Uncorrelated (anticorrelated) random function
+ * Anticorrelated random function due to Christophe Schlick
  */
 
+#include "copyright.h"
+
+#include  <stdlib.h>
 #include  "random.h"
 
-#define  NULL		0
+#undef initurand
 
-extern char  *malloc();
+#define  MAXORDER	(8*sizeof(unsigned short))
 
-short  *urperm;		/* urand() permutation */
+unsigned short  *urperm = NULL;	/* urand() permutation */
 int  urmask;		/* bits used in permutation */
 
-
+int
 initurand(size)		/* initialize urand() for size entries */
 int  size;
 {
 	int  order, n;
 	register int  i, offset;
 
-	size--;
+	if (urperm != NULL)
+		free((void *)urperm);
+	if (--size <= 0) {
+		urperm = NULL;
+		urmask = 0;
+		return(0);
+	}
 	for (i = 1; size >>= 1; i++)
 		;
-	order = i;
+	order = i>MAXORDER ? MAXORDER : i;
 	urmask = (1<<i) - 1;
-	urperm = (short *)malloc((urmask+1)*sizeof(short));
+	urperm = (unsigned short *)malloc((urmask+1)*sizeof(unsigned short));
 	if (urperm == NULL) {
 		eputs("out of memory in initurand\n");
 		quit(1);
@@ -44,4 +50,20 @@ int  size;
 			else
 				urperm[i+offset]++;
 		}
+	return(1<<order);
+}
+
+
+int
+ilhash(d, n)			/* hash a set of integer values */
+register int  *d;
+register int  n;
+{
+	static int  tab[8] = {13623,353,1637,5831,2314,3887,5832,8737};
+	register int  hval;
+
+	hval = 0;
+	while (n-- > 0)
+		hval += *d++ * tab[n&7];
+	return(hval);
 }