--- ray/src/common/urand.c	1991/11/12 16:55:47	2.1
+++ ray/src/common/urand.c	2004/05/16 14:49:42	2.9
@@ -1,35 +1,44 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: urand.c,v 2.9 2004/05/16 14:49:42 greg Exp $";
 #endif
-
 /*
  * Anticorrelated random function due to Christophe Schlick
  */
 
+#include "copyright.h"
+
+#include  <stdlib.h>
+
+#include  "standard.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--;
-	for (i = 1; size >>= 1; i++)
-		;
+	if (urperm != NULL)
+		free((void *)urperm);
+	if (--size <= 0) {
+		urperm = NULL;
+		urmask = 0;
+		return(0);
+	}
+	for (i = 1; (size >>= 1); i++)
+		if (i == MAXORDER)
+			break;
 	order = i;
-	urmask = (1<<i) - 1;
-	urperm = (short *)malloc((urmask+1)*sizeof(short));
+	urmask = (1<<order) - 1;
+	urperm = (unsigned short *)malloc((urmask+1)*sizeof(unsigned short));
 	if (urperm == NULL) {
 		eputs("out of memory in initurand\n");
 		quit(1);
@@ -37,13 +46,13 @@ int  size;
 	urperm[0] = 0;
 	for (n = 1, offset = 1; n <= order; n++, offset <<= 1)
 		for (i = offset; i--; ) {
-			urperm[i] =
-			urperm[i+offset] = 2*urperm[i];
+			urperm[i+offset] = urperm[i] <<= 1;
 			if (random() & 0x4000)
 				urperm[i]++;
 			else
 				urperm[i+offset]++;
 		}
+	return(urmask+1);
 }