1/* gmp_randinit_lc_2exp_size -- initialize a random state with a linear 2 congruential generator of a requested size. 3 4Copyright 1999, 2000, 2001 Free Software Foundation, Inc. 5 6This file is part of the GNU MP Library. 7 8The GNU MP Library is free software; you can redistribute it and/or modify 9it under the terms of the GNU Lesser General Public License as published by 10the Free Software Foundation; either version 3 of the License, or (at your 11option) any later version. 12 13The GNU MP Library is distributed in the hope that it will be useful, but 14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 16License for more details. 17 18You should have received a copy of the GNU Lesser General Public License 19along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 20 21#include <stdio.h> /* for NULL */ 22#include "gmp.h" 23#include "gmp-impl.h" 24 25 26/* Array of LC-schemes, ordered in increasing order of the first 27 member (the 'm2exp' value). The end of the array is indicated with 28 an entry containing all zeros. */ 29 30/* All multipliers are in the range 0.01*m and 0.99*m, and are 31congruent to 5 (mod 8). 32They all pass the spectral test with Vt >= 2^(30/t) and merit >= 1. 33(Up to and including 196 bits, merit is >= 3.) */ 34 35struct __gmp_rand_lc_scheme_struct 36{ 37 unsigned long int m2exp; /* Modulus is 2 ^ m2exp. */ 38 const char *astr; /* Multiplier in string form. */ 39 unsigned long int c; /* Addend. */ 40}; 41 42static const struct __gmp_rand_lc_scheme_struct __gmp_rand_lc_scheme[] = 43{ 44 {32, "29CF535", 1}, 45 {33, "51F666D", 1}, 46 {34, "A3D73AD", 1}, 47 {35, "147E5B85", 1}, 48 {36, "28F725C5", 1}, 49 {37, "51EE3105", 1}, 50 {38, "A3DD5CDD", 1}, 51 {39, "147AF833D", 1}, 52 {40, "28F5DA175", 1}, 53 {56, "AA7D735234C0DD", 1}, 54 {64, "BAECD515DAF0B49D", 1}, 55 {100, "292787EBD3329AD7E7575E2FD", 1}, 56 {128, "48A74F367FA7B5C8ACBB36901308FA85", 1}, 57 {156, "78A7FDDDC43611B527C3F1D760F36E5D7FC7C45", 1}, 58 {196, "41BA2E104EE34C66B3520CE706A56498DE6D44721E5E24F5", 1}, 59 {200, "4E5A24C38B981EAFE84CD9D0BEC48E83911362C114F30072C5", 1}, 60 {256, "AF66BA932AAF58A071FD8F0742A99A0C76982D648509973DB802303128A14CB5", 1}, 61 {0, NULL, 0} /* End of array. */ 62}; 63 64int 65gmp_randinit_lc_2exp_size (gmp_randstate_t rstate, mp_bitcnt_t size) 66{ 67 const struct __gmp_rand_lc_scheme_struct *sp; 68 mpz_t a; 69 70 /* Pick a scheme. */ 71 for (sp = __gmp_rand_lc_scheme; sp->m2exp != 0; sp++) 72 if (sp->m2exp / 2 >= size) 73 goto found; 74 return 0; 75 76 found: 77 /* Install scheme. */ 78 mpz_init_set_str (a, sp->astr, 16); 79 gmp_randinit_lc_2exp (rstate, a, sp->c, sp->m2exp); 80 mpz_clear (a); 81 return 1; 82} 83