1/* mpfr_get_uj -- convert a MPFR number to a huge machine unsigned integer
2
3Copyright 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#ifdef HAVE_CONFIG_H
24# include "config.h"       /* for a build within gmp */
25#endif
26
27#include "mpfr-intmax.h"
28#include "mpfr-impl.h"
29
30#ifdef _MPFR_H_HAVE_INTMAX_T
31
32uintmax_t
33mpfr_get_uj (mpfr_srcptr f, mpfr_rnd_t rnd)
34{
35  uintmax_t r;
36  mpfr_prec_t prec;
37  mpfr_t x;
38
39  if (MPFR_UNLIKELY (!mpfr_fits_uintmax_p (f, rnd)))
40    {
41      MPFR_SET_ERANGE ();
42      return MPFR_IS_NAN (f) || MPFR_IS_NEG (f) ?
43        (uintmax_t) 0 : MPFR_UINTMAX_MAX;
44    }
45
46  if (MPFR_IS_ZERO (f))
47    return (uintmax_t) 0;
48
49  /* determine the precision of uintmax_t */
50  for (r = MPFR_UINTMAX_MAX, prec = 0; r != 0; r /= 2, prec++)
51    { }
52
53  /* Now, r = 0. */
54
55  mpfr_init2 (x, prec);
56  mpfr_rint (x, f, rnd);
57  MPFR_ASSERTN (MPFR_IS_FP (x));
58
59  if (MPFR_NOTZERO (x))
60    {
61      mp_limb_t *xp;
62      int sh, n;  /* An int should be sufficient in this context. */
63
64      MPFR_ASSERTN (MPFR_IS_POS (x));
65      xp = MPFR_MANT (x);
66      sh = MPFR_GET_EXP (x);
67      MPFR_ASSERTN ((mpfr_prec_t) sh <= prec);
68      for (n = MPFR_LIMB_SIZE(x) - 1; n >= 0; n--)
69        {
70          sh -= GMP_NUMB_BITS;
71          r += (sh >= 0
72                ? (uintmax_t) xp[n] << sh
73                : (uintmax_t) xp[n] >> (- sh));
74        }
75    }
76
77  mpfr_clear (x);
78
79  return r;
80}
81
82#endif
83