1/* mpfr_check -- Check if a floating-point number has not been corrupted.
2
3Copyright 2003, 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
25/*
26 * Check if x is a valid mpfr_t initializes by mpfr_init
27 * Returns 0 if isn't valid
28 */
29int
30mpfr_check (mpfr_srcptr x)
31{
32  mp_size_t s, i;
33  mp_limb_t tmp;
34  volatile mp_limb_t *xm;
35  int rw;
36
37  /* Check Sign */
38  if (MPFR_SIGN(x) != MPFR_SIGN_POS && MPFR_SIGN(x) != MPFR_SIGN_NEG)
39    return 0;
40  /* Check Precision */
41  if ( (MPFR_PREC(x) < MPFR_PREC_MIN) || (MPFR_PREC(x) > MPFR_PREC_MAX))
42    return 0;
43  /* Check Mantissa */
44  xm = MPFR_MANT(x);
45  if (!xm)
46    return 0;
47  /* Check size of mantissa */
48  s = MPFR_GET_ALLOC_SIZE(x);
49  if (s<=0 || s > MP_SIZE_T_MAX ||
50      MPFR_PREC(x) > ((mpfr_prec_t)s*GMP_NUMB_BITS))
51    return 0;
52  /* Acces all the mp_limb of the mantissa: may do a seg fault */
53  for(i = 0 ; i < s ; i++)
54    tmp = xm[i];
55  /* Check if it isn't singular*/
56  if (! MPFR_IS_SINGULAR (x))
57    {
58      /* Check first mp_limb of mantissa (Must start with a 1 bit) */
59      if ( ((xm[MPFR_LIMB_SIZE(x)-1])>>(GMP_NUMB_BITS-1)) == 0)
60        return 0;
61      /* Check last mp_limb of mantissa */
62      rw = (MPFR_PREC(x) % GMP_NUMB_BITS);
63      if (rw != 0)
64        {
65          tmp = MPFR_LIMB_MASK (GMP_NUMB_BITS - rw);
66          if ((xm[0] & tmp) != 0)
67            return 0;
68        }
69      /* Check exponent range */
70      if ((MPFR_EXP (x) < __gmpfr_emin) || (MPFR_EXP (x) > __gmpfr_emax))
71        return 0;
72    }
73  else
74    {
75      /* Singular value is zero, inf or nan */
76      MPFR_ASSERTD(MPFR_IS_ZERO(x) || MPFR_IS_NAN(x) || MPFR_IS_INF(x));
77    }
78  return 1;
79}
80
81