mirror of https://github.com/macssh/macssh.git
75 lines
2.0 KiB
C
Executable File
75 lines
2.0 KiB
C
Executable File
/* mpfr_random -- generate a random floating-point number
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Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
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This file is part of the MPFR Library.
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The MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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The MPFR 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 Library General Public
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License for more details.
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You should have received a copy of the GNU Library General Public License
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along with the MPFR Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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#include <stdio.h>
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#include "gmp.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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#include "mpfr.h"
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/* Computes a random mpfr in [0, 1[ with precision PREC */
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extern long random _PROTO((void));
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extern int srandom _PROTO((unsigned int));
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/* extracted from GNU mpf */
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#if defined (__hpux) || defined (__alpha)
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/* HPUX lacks random(). DEC OSF/1 1.2 random() returns a double. */
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#define random mrand48
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#define srandom srand48
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#endif
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void
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#if __STDC__
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mpfr_random(mpfr_ptr x)
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#else
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mpfr_random(x)
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mpfr_ptr x;
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#endif
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{
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mp_limb_t *xp; unsigned long xn, i, cnt, prec=PREC(x);
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xp = MANT(x);
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xn = (prec-1)/BITS_PER_MP_LIMB + 1;
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for (i = 0; i < xn; i++)
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{
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/* random() c/sh/ould be replaced by a homemade random number generator.
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Indeed, if on Linux random is a good RNG, this is definitely not
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the case in most Un*xes. */
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xp[i] = random();
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}
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count_leading_zeros(cnt, xp[xn - 1]);
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if (cnt) mpn_lshift(xp, xp, xn, cnt);
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EXP(x) = -cnt;
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cnt = xn*BITS_PER_MP_LIMB - prec;
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/* cnt is the number of non significant bits in the low limb */
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xp[0] &= ~((((mp_limb_t)1)<<cnt) - 1);
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}
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void
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mpfr_srandom(unsigned long seed)
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{
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srandom(seed);
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}
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