glibc/stdlib/strtod_nan_main.c

64 lines
2.0 KiB
C

/* Convert string for NaN payload to corresponding NaN.
Copyright (C) 1997-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C 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 2.1 of the License, or (at your option) any later version.
The GNU C 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 C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <ieee754.h>
#include <locale.h>
#include <math.h>
#include <stdlib.h>
#include <wchar.h>
/* If STR starts with an optional n-char-sequence as defined by ISO C
(a sequence of ASCII letters, digits and underscores), followed by
ENDC, return a NaN whose payload is set based on STR. Otherwise,
return a default NAN. If ENDPTR is not NULL, set *ENDPTR to point
to the character after the initial n-char-sequence. */
internal_function
FLOAT
STRTOD_NAN (const STRING_TYPE *str, STRING_TYPE **endptr, STRING_TYPE endc)
{
const STRING_TYPE *cp = str;
while ((*cp >= L_('0') && *cp <= L_('9'))
|| (*cp >= L_('A') && *cp <= L_('Z'))
|| (*cp >= L_('a') && *cp <= L_('z'))
|| *cp == L_('_'))
++cp;
FLOAT retval = NAN;
if (*cp != endc)
goto out;
/* This is a system-dependent way to specify the bitmask used for
the NaN. We expect it to be a number which is put in the
mantissa of the number. */
STRING_TYPE *endp;
unsigned long long int mant;
mant = STRTOULL (str, &endp, 0);
if (endp == cp)
SET_MANTISSA (retval, mant);
out:
if (endptr != NULL)
*endptr = (STRING_TYPE *) cp;
return retval;
}
libc_hidden_def (STRTOD_NAN)