85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
/* gmp_randinit_lc_2exp_size -- initialize a random state with a linear
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congruential generator of a requested size.
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Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include <stdio.h> /* for NULL */
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#include "mpir.h"
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#include "gmp-impl.h"
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/* Array of LC-schemes, ordered in increasing order of the first
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member (the 'm2exp' value). The end of the array is indicated with
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an entry containing all zeros. */
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/* All multipliers are in the range 0.01*m and 0.99*m, and are
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congruent to 5 (mod 8).
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They all pass the spectral test with Vt >= 2^(30/t) and merit >= 1.
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(Up to and including 196 bits, merit is >= 3.) */
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struct __gmp_rand_lc_scheme_struct
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{
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unsigned long int m2exp; /* Modulus is 2 ^ m2exp. */
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const char *astr; /* Multiplier in string form. */
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unsigned long int c; /* Addend. */
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};
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static const struct __gmp_rand_lc_scheme_struct __gmp_rand_lc_scheme[] =
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{
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{32, "29CF535", 1},
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{33, "51F666D", 1},
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{34, "A3D73AD", 1},
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{35, "147E5B85", 1},
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{36, "28F725C5", 1},
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{37, "51EE3105", 1},
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{38, "A3DD5CDD", 1},
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{39, "147AF833D", 1},
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{40, "28F5DA175", 1},
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{56, "AA7D735234C0DD", 1},
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{64, "BAECD515DAF0B49D", 1},
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{100, "292787EBD3329AD7E7575E2FD", 1},
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{128, "48A74F367FA7B5C8ACBB36901308FA85", 1},
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{156, "78A7FDDDC43611B527C3F1D760F36E5D7FC7C45", 1},
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{196, "41BA2E104EE34C66B3520CE706A56498DE6D44721E5E24F5", 1},
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{200, "4E5A24C38B981EAFE84CD9D0BEC48E83911362C114F30072C5", 1},
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{256, "AF66BA932AAF58A071FD8F0742A99A0C76982D648509973DB802303128A14CB5", 1},
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{0, NULL, 0} /* End of array. */
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};
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int
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gmp_randinit_lc_2exp_size (gmp_randstate_t rstate, mp_bitcnt_t size)
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{
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const struct __gmp_rand_lc_scheme_struct *sp;
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mpz_t a;
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/* Pick a scheme. */
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for (sp = __gmp_rand_lc_scheme; sp->m2exp != 0; sp++)
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if (sp->m2exp / 2 >= size)
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goto found;
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return 0;
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found:
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/* Install scheme. */
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mpz_init_set_str (a, sp->astr, 16);
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gmp_randinit_lc_2exp (rstate, a, sp->c, sp->m2exp);
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mpz_clear (a);
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return 1;
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}
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