| 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 | * The length @b@ may be zero; but %$\texttt{or} \ge 2^b$% is |
| 63 | * not permitted. |
| 64 | */ |
| 65 | |
| 66 | extern mp *mprand(mp */*d*/, unsigned /*b*/, grand */*r*/, mpw /*or*/); |
| 67 | |
| 68 | /* --- @mprand_range@ --- * |
| 69 | * |
| 70 | * Arguments: @mp *d@ = destination integer |
| 71 | * @mp *l@ = limit for random number |
| 72 | * @grand *r@ = random number source |
| 73 | * @mpw or@ = mask for low-order bits |
| 74 | * |
| 75 | * Returns: A pseudorandom integer, unformly distributed over the |
| 76 | * interval %$[0, l)$%. |
| 77 | * |
| 78 | * Use: Generates a uniformly-distributed pseudorandom number in the |
| 79 | * appropriate range. We must have %$l > 0$%. |
| 80 | */ |
| 81 | |
| 82 | extern mp *mprand_range(mp */*d*/, mp */*l*/, grand */*r*/, mpw /*or*/); |
| 83 | |
| 84 | /*----- That's all, folks -------------------------------------------------*/ |
| 85 | |
| 86 | #ifdef __cplusplus |
| 87 | } |
| 88 | #endif |
| 89 | |
| 90 | #endif |