1  /* mpfr_set_prec -- reset the precision of a floating-point number
       2  
       3  Copyright 1999, 2001-2002, 2004, 2006-2023 Free Software Foundation, Inc.
       4  Contributed by the AriC and Caramba projects, INRIA.
       5  
       6  This file is part of the GNU MPFR Library.
       7  
       8  The GNU MPFR Library is free software; you can redistribute it and/or modify
       9  it under the terms of the GNU Lesser General Public License as published by
      10  the Free Software Foundation; either version 3 of the License, or (at your
      11  option) any later version.
      12  
      13  The GNU MPFR Library is distributed in the hope that it will be useful, but
      14  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      15  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
      16  License for more details.
      17  
      18  You should have received a copy of the GNU Lesser General Public License
      19  along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
      20  https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
      21  51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
      22  
      23  #include "mpfr-impl.h"
      24  
      25  MPFR_HOT_FUNCTION_ATTR void
      26  mpfr_set_prec (mpfr_ptr x, mpfr_prec_t p)
      27  {
      28    mp_size_t xsize, xoldsize;
      29  
      30    MPFR_LOG_MSG (("prec=%Pd\n", p));
      31  
      32    /* first, check if p is correct */
      33    MPFR_ASSERTN (MPFR_PREC_COND (p));
      34  
      35    /* Calculate the new number of limbs */
      36    xsize = MPFR_PREC2LIMBS (p);
      37  
      38    /* Realloc only if the new size is greater than the old */
      39    xoldsize = MPFR_GET_ALLOC_SIZE (x);
      40    if (xsize > xoldsize)
      41      {
      42        mpfr_size_limb_t *tmp;
      43  
      44        tmp = (mpfr_size_limb_t *) mpfr_reallocate_func
      45          (MPFR_GET_REAL_PTR(x),
      46           MPFR_MALLOC_SIZE(xoldsize),
      47           MPFR_MALLOC_SIZE(xsize));
      48        MPFR_SET_MANT_PTR(x, tmp);
      49        MPFR_SET_ALLOC_SIZE(x, xsize);
      50      }
      51    MPFR_PREC (x) = p;
      52    MPFR_SET_NAN (x); /* initializes to NaN */
      53  }
      54  
      55  #undef mpfr_get_prec
      56  mpfr_prec_t
      57  mpfr_get_prec (mpfr_srcptr x)
      58  {
      59    return MPFR_PREC(x);
      60  }