+++ /dev/null
-/* -*-c-*-
- *
- * $Id: lcrand.h,v 1.3 2004/04/08 01:36:15 mdw Exp $
- *
- * Simple linear congruential generator
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Notes on the linear congruential generator ------------------------*
- *
- * This pseudorandom number generator is simple, but has absolutely no
- * cryptographic strength whatever. It may be used whenever random numbers
- * are required but cryptographic strength is not, for example when
- * generating numbers for use in primality tests. To be honest, it's not
- * even particularly fast, although a certain amount of effort has been
- * expended on making it better than awfully slow. To put things in
- * perspective, it can't quite spit bytes out as fast as OFB DES. (Then
- * again, bytes aren't its natural output format.) Its main use is probably
- * seeding a Fibonacci generator.
- *
- * There exists a fixed-point input @LCRAND_FIXEDPT@ -- when fed to the
- * generator it comes straight back out again. All other inputs less than
- * the modulus are part of the same sequence of period %$p - 1$%.
- *
- * The generator has been tested for its statistical properties. George
- * Marsaglia's Diehard tests give it a reasonably clean bill of health.
- *
- * The modulus %$p$% is chosen as the largest prime number less than
- * %$2^{32}$%. The multiplier %$a$% and additive constant %$c$% are based on
- * the decimal expansions of %$\pi$% and %$e$%, with the additional
- * restriction that the multiplier must be a primitive element modulo %$p$%.
- * The fixed point value is determined as %$c / (1 - a) \bmod p$%.
- */
-
-#ifndef CATACOMB_LCRAND_H
-#define CATACOMB_LCRAND_H
-
-#ifdef __cplusplus
- extern "C" {
-#endif
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <mLib/bits.h>
-
-#ifndef CATACOMB_GRAND_H
-# include "grand.h"
-#endif
-
-/*----- Constants ---------------------------------------------------------*/
-
-#define LCRAND_P 4294967291u /* Modulus for the generator */
-#define LCRAND_A 314159265u /* Multiplier (primitive mod @p@) */
-#define LCRAND_C 271828183u /* Additive constant */
-
-#define LCRAND_FIXEDPT 3223959250u /* Fixed point (only bad input) */
-
-/*----- Functions provided ------------------------------------------------*/
-
-/* --- @lcrand@ --- *
- *
- * Arguments: @uint32 x@ = seed value
- *
- * Returns: New state of the generator.
- *
- * Use: Steps the generator. Returns %$ax + c \bmod p$%.
- */
-
-extern uint32 lcrand(uint32 /*x*/);
-
-/* --- @lcrand_range@ --- *
- *
- * Arguments: @uint32 *x@ = pointer to seed value (updated)
- * @uint32 m@ = limit allowable
- *
- * Returns: A uniformly distributed pseudorandom integer in the interval
- * %$[0, m)$%.
- */
-
-extern uint32 lcrand_range(uint32 */*x*/, uint32 /*m*/);
-
-/* --- @lcrand_create@ --- *
- *
- * Arguments: @uint32 x@ = initial seed
- *
- * Returns: Pointer to a generic generator.
- *
- * Use: Constructs a generic generator interface over a linear
- * congruential generator.
- */
-
-extern grand *lcrand_create(uint32 /*x*/);
-
-/*----- That's all, folks -------------------------------------------------*/
-
-#ifdef __cplusplus
- }
-#endif
-
-#endif
projects / u / mdw / catacomb / blobdiff