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root/radiance/ray/src/common/urand.c
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Comparing ray/src/common/urand.c (file contents):
Revision 2.8 by greg, Fri May 14 20:49:13 2004 UTC vs.
Revision 2.11 by greg, Wed May 27 08:42:06 2015 UTC

# Line 7 | Line 7 | static const char      RCSid[] = "$Id$";
7  
8   #include "copyright.h"
9  
10 – #include  <stdlib.h>
11 –
10   #include  "standard.h"
11   #include  "random.h"
12  
# Line 16 | Line 14 | static const char      RCSid[] = "$Id$";
14  
15   #define  MAXORDER       (8*sizeof(unsigned short))
16  
17 < unsigned short  *urperm = NULL; /* urand() permutation */
20 < int  urmask;            /* bits used in permutation */
17 > static unsigned short  empty_tab = 0;
18  
19 + unsigned short  *urperm = &empty_tab;   /* urand() permutation */
20 + int  urmask = 0;                        /* bits used in permutation */
21 +
22 +
23   int
24 < initurand(size)         /* initialize urand() for size entries */
25 < int  size;
24 > initurand(                      /* initialize urand() for size entries */
25 >        int  size
26 > )
27   {
28          int  order, n;
29 <        register int  i, offset;
29 >        int  i, offset;
30  
31 <        if (urperm != NULL)
31 >        if ((urperm != NULL) & (urperm != &empty_tab))
32                  free((void *)urperm);
33          if (--size <= 0) {
34 <                urperm = NULL;
34 >                empty_tab = 0;
35 >                urperm = &empty_tab;
36                  urmask = 0;
37                  return(0);
38          }
# Line 43 | Line 46 | int  size;
46                  eputs("out of memory in initurand\n");
47                  quit(1);
48          }
49 <        urperm[0] = (random() & 0x4000) != 0;
49 >        urperm[0] = 0;
50          for (n = 1, offset = 1; n <= order; n++, offset <<= 1)
51                  for (i = offset; i--; ) {
52                          urperm[i+offset] = urperm[i] <<= 1;
# Line 57 | Line 60 | int  size;
60  
61  
62   int
63 < ilhash(d, n)                    /* hash a set of integer values */
64 < register int  *d;
65 < register int  n;
63 > ilhash(                         /* hash a set of integer values */
64 >        int  *d,
65 >        int  n
66 > )
67   {
68 <        static int  tab[8] = {13623,353,1637,5831,2314,3887,5832,8737};
69 <        register int  hval;
68 >        static int  tab[8] = {103699,96289,73771,65203,81119,87037,92051,98899};
69 >        int  hval;
70  
71          hval = 0;
72          while (n-- > 0)
73 <                hval += *d++ * tab[n&7];
74 <        return(hval);
73 >                hval ^= *d++ * tab[n&7];
74 >        return(hval & 0x7fffffff);
75   }

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