blob: 819ebbc04ad6a4098362e6f3de70ea7d248a9a1e [file] [log] [blame]
/* gmp_randinit_lc_2exp_size -- initialize a random state with a linear
congruential generator of a requested size.
Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The GNU MP Library 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
#include <stdio.h> /* for NULL */
#include "gmp.h"
#include "gmp-impl.h"
/* Array of LC-schemes, ordered in increasing order of the first
member (the 'm2exp' value). The end of the array is indicated with
an entry containing all zeros. */
/* All multipliers are in the range 0.01*m and 0.99*m, and are
congruent to 5 (mod 8).
They all pass the spectral test with Vt >= 2^(30/t) and merit >= 1.
(Up to and including 196 bits, merit is >= 3.) */
struct __gmp_rand_lc_scheme_struct
{
unsigned long int m2exp; /* Modulus is 2 ^ m2exp. */
const char *astr; /* Multiplier in string form. */
unsigned long int c; /* Addend. */
};
static const struct __gmp_rand_lc_scheme_struct __gmp_rand_lc_scheme[] =
{
{32, "29CF535", 1},
{33, "51F666D", 1},
{34, "A3D73AD", 1},
{35, "147E5B85", 1},
{36, "28F725C5", 1},
{37, "51EE3105", 1},
{38, "A3DD5CDD", 1},
{39, "147AF833D", 1},
{40, "28F5DA175", 1},
{56, "AA7D735234C0DD", 1},
{64, "BAECD515DAF0B49D", 1},
{100, "292787EBD3329AD7E7575E2FD", 1},
{128, "48A74F367FA7B5C8ACBB36901308FA85", 1},
{156, "78A7FDDDC43611B527C3F1D760F36E5D7FC7C45", 1},
{196, "41BA2E104EE34C66B3520CE706A56498DE6D44721E5E24F5", 1},
{200, "4E5A24C38B981EAFE84CD9D0BEC48E83911362C114F30072C5", 1},
{256, "AF66BA932AAF58A071FD8F0742A99A0C76982D648509973DB802303128A14CB5", 1},
{0, NULL, 0} /* End of array. */
};
int
gmp_randinit_lc_2exp_size (gmp_randstate_t rstate, unsigned long size)
{
const struct __gmp_rand_lc_scheme_struct *sp;
mpz_t a;
/* Pick a scheme. */
for (sp = __gmp_rand_lc_scheme; sp->m2exp != 0; sp++)
if (sp->m2exp / 2 >= size)
goto found;
return 0;
found:
/* Install scheme. */
mpz_init_set_str (a, sp->astr, 16);
gmp_randinit_lc_2exp (rstate, a, sp->c, sp->m2exp);
mpz_clear (a);
return 1;
}