--- ray/src/common/urand.c 1991/07/11 16:25:58 1.6
+++ ray/src/common/urand.c 2003/02/22 02:07:22 2.5
@@ -1,35 +1,96 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
#ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char RCSid[] = "$Id: urand.c,v 2.5 2003/02/22 02:07:22 greg Exp $";
#endif
-
/*
* Anticorrelated random function due to Christophe Schlick
*/
+/* ====================================================================
+ * The Radiance Software License, Version 1.0
+ *
+ * Copyright (c) 1990 - 2002 The Regents of the University of California,
+ * through Lawrence Berkeley National Laboratory. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. The end-user documentation included with the redistribution,
+ * if any, must include the following acknowledgment:
+ * "This product includes Radiance software
+ * (http://radsite.lbl.gov/)
+ * developed by the Lawrence Berkeley National Laboratory
+ * (http://www.lbl.gov/)."
+ * Alternately, this acknowledgment may appear in the software itself,
+ * if and wherever such third-party acknowledgments normally appear.
+ *
+ * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
+ * and "The Regents of the University of California" must
+ * not be used to endorse or promote products derived from this
+ * software without prior written permission. For written
+ * permission, please contact radiance@radsite.lbl.gov.
+ *
+ * 5. Products derived from this software may not be called "Radiance",
+ * nor may "Radiance" appear in their name, without prior written
+ * permission of Lawrence Berkeley National Laboratory.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of Lawrence Berkeley National Laboratory. For more
+ * information on Lawrence Berkeley National Laboratory, please see
+ * .
+ */
+
+#include
#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< 0)
hval += *d++ * tab[n&7];
return(hval);
-}
-
-
-static char bctab[256] = {
- 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
- };
-
-
-#define NBITS 32
-
-#if NBITS==32
-#define bitcount(i) (bctab[(i)>>24&0xff]+bctab[(i)>>16&0xff]+ \
- bctab[(i)>>8&0xff]+bctab[(i)&0xff])
-#endif
-#if NBITS==16
-#define bitcount(i) (bctab[(i)>>8&0xff]+bctab[(i)&0xff])
-#endif
-
-
-int
-urind(s, i) /* compute i'th index from seed s */
-int s, i;
-{
- register int ss, k;
- int left;
-
- ss = s*1103515245 + 12345;
- left = 0;
- for (k = i/NBITS; k--; ) {
- left += bitcount(ss);
- ss = ss*1103515245 + 12345;
- }
- for (k = i&(NBITS-1); k--; ss >>= 1)
- left += ss & 1;
- if (ss & 1)
- return(s-left-1);
- return(s-left+i);
}