X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=utils%2Fyarandom.c;h=cc38895e5130bc2a7a625def971bd6e98cd8c338;hb=de460e831dc8578acfa8b72251ab9346c99c1f96;hp=63958e24700b35bdff62cda8af9a7f34d50cdb26;hpb=f3e0240915ed9f9b3a61781f5c7002d587563fe0;p=xscreensaver diff --git a/utils/yarandom.c b/utils/yarandom.c index 63958e24..cc38895e 100644 --- a/utils/yarandom.c +++ b/utils/yarandom.c @@ -1,13 +1,23 @@ /* yarandom.c -- Yet Another Random Number Generator. + * Copyright (c) 1997, 1998, 2003 by Jamie Zawinski + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that + * copyright notice and this permission notice appear in supporting + * documentation. No representations are made about the suitability of this + * software for any purpose. It is provided "as is" without express or + * implied warranty. + */ - The unportable mess that is rand(), random(), drand48() and friends led me +/* The unportable mess that is rand(), random(), drand48() and friends led me to ask Phil Karlton what the Right Thing to Do was. He responded with this. It is non-cryptographically secure, reasonably random (more so than anything that is in any C library), and very fast. I don't understand how it works at all, but he says "look at Knuth, Vol. 2 (original edition), page 26, Algorithm A. In this case n=55, - k=20 and m=2^32." + k=24 and m=2^32." So there you have it. @@ -51,6 +61,7 @@ #include /* for gettimeofday() */ #include "yarandom.h" +# undef ya_rand_init /* The following 'random' numbers are taken from CRC, 18th Edition, page 622. @@ -110,5 +121,5 @@ ya_rand_init(unsigned int seed) } i1 = a[0] % VectorSize; - i2 = (i1 + 024) % VectorSize; + i2 = (i1 + 24) % VectorSize; }