1/* mpfr_set_prec -- reset the precision of a floating-point number
2
3Copyright 1999, 2001, 2002, 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
4Contributed by the AriC and Caramel projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7
8The GNU MPFR Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MPFR Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2151 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23#include "mpfr-impl.h"
24
25void
26mpfr_set_prec (mpfr_ptr x, mpfr_prec_t p)
27{
28  mp_size_t xsize, xoldsize;
29  mpfr_limb_ptr tmp;
30
31  /* first, check if p is correct */
32  MPFR_ASSERTN (p >= MPFR_PREC_MIN && p <= MPFR_PREC_MAX);
33
34  /* Calculate the new number of limbs */
35  xsize = MPFR_PREC2LIMBS (p);
36
37  /* Realloc only if the new size is greater than the old */
38  xoldsize = MPFR_GET_ALLOC_SIZE (x);
39  if (xsize > xoldsize)
40    {
41      tmp = (mpfr_limb_ptr) (*__gmp_reallocate_func)
42        (MPFR_GET_REAL_PTR(x), MPFR_MALLOC_SIZE(xoldsize), MPFR_MALLOC_SIZE(xsize));
43      MPFR_SET_MANT_PTR(x, tmp);
44      MPFR_SET_ALLOC_SIZE(x, xsize);
45    }
46  MPFR_PREC (x) = p;
47  MPFR_SET_NAN (x); /* initializes to NaN */
48}
49
50#undef mpfr_get_prec
51mpfr_prec_t
52mpfr_get_prec (mpfr_srcptr x)
53{
54  return MPFR_PREC(x);
55}
56