61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/* mpf_urandomb (rop, state, nbits) -- Generate a uniform pseudorandom
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real number between 0 (inclusive) and 1 (exclusive) of size NBITS,
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using STATE as the random state previously initialized by a call to
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gmp_randinit().
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Copyright 1999, 2000, 2001, 2002 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 "gmp.h"
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#include "gmp-impl.h"
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void
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mpf_urandomb (mpf_t rop, gmp_randstate_t rstate, unsigned long int nbits)
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{
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mp_ptr rp;
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mp_size_t nlimbs;
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mp_exp_t exp;
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mp_size_t prec;
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rp = PTR (rop);
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nlimbs = BITS_TO_LIMBS (nbits);
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prec = PREC (rop);
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if (nlimbs > prec + 1 || nlimbs == 0)
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{
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nlimbs = prec + 1;
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nbits = nlimbs * GMP_NUMB_BITS;
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}
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_gmp_rand (rp, rstate, nbits);
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/* If nbits isn't a multiple of GMP_NUMB_BITS, shift up. */
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if (nbits % GMP_NUMB_BITS != 0)
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mpn_lshift (rp, rp, nlimbs, GMP_NUMB_BITS - nbits % GMP_NUMB_BITS);
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exp = 0;
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while (nlimbs != 0 && rp[nlimbs - 1] == 0)
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{
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nlimbs--;
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exp--;
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}
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EXP (rop) = exp;
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SIZ (rop) = nlimbs;
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}
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