--- ray/src/common/urand.c	2004/05/14 20:49:13	2.8
+++ ray/src/common/urand.c	2022/04/21 15:22:30	2.14
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: urand.c,v 2.8 2004/05/14 20:49:13 greg Exp $";
+static const char	RCSid[] = "$Id: urand.c,v 2.14 2022/04/21 15:22:30 greg Exp $";
 #endif
 /*
  * Anticorrelated random function due to Christophe Schlick
@@ -7,29 +7,46 @@ static const char	RCSid[] = "$Id: urand.c,v 2.8 2004/0
 
 #include "copyright.h"
 
-#include  <stdlib.h>
-
-#include  "standard.h"
+#include  "rterror.h"
 #include  "random.h"
 
 #undef initurand
 
 #define  MAXORDER	(8*sizeof(unsigned short))
 
-unsigned short  *urperm = NULL;	/* urand() permutation */
-int  urmask;		/* bits used in permutation */
+static unsigned short  empty_tab = 0;
 
+unsigned short  *urperm = &empty_tab;	/* urand() permutation */
+int  urmask = 0;			/* bits used in permutation */
+
+
+long
+irandom(			/* better than using random() % modulus */
+	long modulus
+)
+{
+	if (sizeof(long) >= 8)
+		return((random()*modulus)>>31);
+
+	if (sizeof(long long) >= 8)
+		return((random()*(long long)modulus)>>31);
+
+	return(frandom()*modulus);
+}
+
 int
-initurand(size)		/* initialize urand() for size entries */
-int  size;
+initurand(			/* initialize urand() for size entries */
+	int  size
+)
 {
 	int  order, n;
-	register int  i, offset;
+	int  i, offset;
 
-	if (urperm != NULL)
+	if ((urperm != NULL) & (urperm != &empty_tab))
 		free((void *)urperm);
 	if (--size <= 0) {
-		urperm = NULL;
+		empty_tab = 0;
+		urperm = &empty_tab;
 		urmask = 0;
 		return(0);
 	}
@@ -43,7 +60,7 @@ int  size;
 		eputs("out of memory in initurand\n");
 		quit(1);
 	}
-	urperm[0] = (random() & 0x4000) != 0;
+	urperm[0] = 0;
 	for (n = 1, offset = 1; n <= order; n++, offset <<= 1)
 		for (i = offset; i--; ) {
 			urperm[i+offset] = urperm[i] <<= 1;
@@ -57,15 +74,16 @@ int  size;
 
 
 int
-ilhash(d, n)			/* hash a set of integer values */
-register int  *d;
-register int  n;
+ilhash(				/* hash a set of integer values */
+	int  *d,
+	int  n
+)
 {
-	static int  tab[8] = {13623,353,1637,5831,2314,3887,5832,8737};
-	register int  hval;
+	static int  tab[8] = {103699,96289,73771,65203,81119,87037,92051,98899};
+	int  hval;
 
 	hval = 0;
 	while (n-- > 0)
-		hval += *d++ * tab[n&7];
-	return(hval);
+		hval ^= *d++ * tab[n&7];
+	return(hval & 0x7fffffff);
 }