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/* mpfr_check -- Check if a floating-point number has not been corrupted.
Copyright 2003-2004, 2006-2020 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.
This file is part of the GNU MPFR Library.
The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The GNU MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#include "mpfr-impl.h"
/*
* Check if x is a valid mpfr_t initialized by mpfr_init
* Returns 0 if isn't valid
*
* Note: Due to the MPFR_GET_ALLOC_SIZE test, this function must not
* be called on statically allocated numbers (only used inside MPFR).
* Anyway, this test should not be useful on such numbers.
*/
int
mpfr_check (mpfr_srcptr x)
{
mp_size_t s, i;
mp_limb_t tmp;
volatile mp_limb_t *xm;
mpfr_prec_t prec;
int rw;
/* Check sign */
if (MPFR_SIGN(x) != MPFR_SIGN_POS &&
MPFR_SIGN(x) != MPFR_SIGN_NEG)
return 0;
/* Check precision */
prec = MPFR_PREC(x);
if (! MPFR_PREC_COND (prec))
return 0;
/* Check mantissa */
xm = MPFR_MANT(x);
if (xm == NULL)
return 0;
/* Check size of mantissa */
s = MPFR_GET_ALLOC_SIZE(x);
if (s <= 0 || s > MP_SIZE_T_MAX ||
prec > (mpfr_prec_t) s * GMP_NUMB_BITS)
return 0;
/* Access all the mp_limb of the mantissa: may do a seg fault */
for (i = 0 ; i < s ; i++)
tmp = xm[i];
/* Check singular numbers (do not use MPFR_IS_PURE_FP() in order to avoid
any assertion checking, as this function mpfr_check() does something
similar by returning a Boolean instead of doing an abort if the format
is incorrect). */
if (MPFR_IS_SINGULAR (x))
return MPFR_IS_ZERO(x) || MPFR_IS_NAN(x) || MPFR_IS_INF(x);
/* Check the most significant limb (its MSB must be 1) */
if (! MPFR_IS_NORMALIZED (x))
return 0;
/* Check the least significant limb (the trailing bits must be 0) */
rw = prec % GMP_NUMB_BITS;
if (rw != 0)
{
tmp = MPFR_LIMB_MASK (GMP_NUMB_BITS - rw);
if ((xm[0] & tmp) != 0)
return 0;
}
/* Check exponent range */
return MPFR_EXP_IN_RANGE (MPFR_EXP (x));
}
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