Return to urandomb.c CVS log

Up to [local] / OpenXM_contrib / gmp / mpf

Annotation of OpenXM_contrib/gmp/mpf/urandomb.c, Revision 1.1.1.2

1.1       maekawa     1: /* mpf_urandomb (rop, state, nbits) -- Generate a uniform pseudorandom
                      2:    real number between 0 (inclusive) and 1 (exclusive) of size NBITS,
                      3:    using STATE as the random state previously initialized by a call to
                      4:    gmp_randinit().
                      5:
1.1.1.2 ! ohara       6: Copyright 1999, 2000, 2001, 2002  Free Software Foundation, Inc.
1.1       maekawa     7:
                      8: This file is part of the GNU MP Library.
                      9:
                     10: The GNU MP Library is free software; you can redistribute it and/or modify
                     11: it under the terms of the GNU Lesser General Public License as published by
                     12: the Free Software Foundation; either version 2.1 of the License, or (at your
                     13: option) any later version.
                     14:
                     15: The GNU MP Library is distributed in the hope that it will be useful, but
                     16: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     17: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
                     18: License for more details.
                     19:
                     20: You should have received a copy of the GNU Lesser General Public License
                     21: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     22: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     23: MA 02111-1307, USA. */
                     24:
                     25: #include "gmp.h"
                     26: #include "gmp-impl.h"
                     27:
                     28: void
                     29: mpf_urandomb (mpf_t rop, gmp_randstate_t rstate, unsigned long int nbits)
                     30: {
                     31:   mp_ptr rp;
                     32:   mp_size_t nlimbs;
                     33:   mp_exp_t exp;
                     34:
1.1.1.2 ! ohara      35:   nbits = MIN (nbits, __GMPF_PREC_TO_BITS (rop->_mp_prec));
        !            36:
1.1       maekawa    37:   rp = PTR (rop);
1.1.1.2 ! ohara      38:   nlimbs = (nbits + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS;
1.1       maekawa    39:
                     40:   _gmp_rand (rp, rstate, nbits);
                     41:
1.1.1.2 ! ohara      42:   /* If nbits isn't a multiple of GMP_NUMB_BITS, shift up.  */
1.1       maekawa    43:   if (nlimbs != 0)
                     44:     {
1.1.1.2 ! ohara      45:       if (nbits % GMP_NUMB_BITS != 0)
        !            46:        mpn_lshift (rp, rp, nlimbs, GMP_NUMB_BITS - nbits % GMP_NUMB_BITS);
1.1       maekawa    47:     }
                     48:
                     49:   exp = 0;
                     50:   while (nlimbs != 0 && rp[nlimbs - 1] == 0)
                     51:     {
                     52:       nlimbs--;
                     53:       exp--;
                     54:     }
                     55:   EXP (rop) = exp;
                     56:   SIZ (rop) = nlimbs;
                     57: }