git.distorted.org.uk Git - u/mdw/catacomb/blob - math/mprand.h

   1 /* -*-c-*-
   2  *
   3  * Generate a random multiprecision integer
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef CATACOMB_MPRAND_H
  29 #define CATACOMB_MPRAND_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #ifndef CATACOMB_GRAND_H
  38 #  include "grand.h"
  39 #endif
  40
  41 #ifndef CATACOMB_MP_H
  42 #  include "mp.h"
  43 #endif
  44
  45 /*----- Functions provided ------------------------------------------------*/
  46
  47 /* --- @mprand@ --- *
  48  *
  49  * Arguments:   @mp *d@ = destination integer
  50  *              @unsigned b@ = number of bits
  51  *              @grand *r@ = pointer to random number source
  52  *              @mpw or@ = mask to OR with low-order bits
  53  *
  54  * Returns:     A random integer with the requested number of bits
  55  *
  56  * Use:         Constructs an arbitrarily large pseudorandom integer.
  57  *              Assuming that the generator @r@ is good, the result is
  58  *              uniformly distributed in the interval %$[2^{b - 1}, 2^b)$%.
  59  *              The result is then ORred with the given @or@ value.  This
  60  *              will often be 1, to make the result odd.
  61  */
  62
  63 extern mp *mprand(mp */*d*/, unsigned /*b*/, grand */*r*/, mpw /*or*/);
  64
  65 /* --- @mprand_range@ --- *
  66  *
  67  * Arguments:   @mp *d@ = destination integer
  68  *              @mp *l@ = limit for random number
  69  *              @grand *r@ = random number source
  70  *              @mpw or@ = mask for low-order bits
  71  *
  72  * Returns:     A pseudorandom integer, unformly distributed over the
  73  *              interval %$[0, l)$%.
  74  *
  75  * Use:         Generates a uniformly-distributed pseudorandom number in the
  76  *              appropriate range.
  77  */
  78
  79 extern mp *mprand_range(mp */*d*/, mp */*l*/, grand */*r*/, mpw /*or*/);
  80
  81 /*----- That's all, folks -------------------------------------------------*/
  82
  83 #ifdef __cplusplus
  84   }
  85 #endif
  86
  87 #endif