freebsd-dev/contrib/libgmp/mpbsd/xtom.c

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/* xtom -- convert a hexadecimal string to a MINT, and return a pointer to
the MINT.
Copyright (C) 1991, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
The GNU MP 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "mp.h"
#include "gmp.h"
#include "gmp-impl.h"
static int
digit_value_in_base (c, base)
int c;
int base;
{
int digit;
if (isdigit (c))
digit = c - '0';
else if (islower (c))
digit = c - 'a' + 10;
else if (isupper (c))
digit = c - 'A' + 10;
else
return -1;
if (digit < base)
return digit;
return -1;
}
MINT *
#if __STDC__
xtom (const char *str)
#else
xtom (str)
const char *str;
#endif
{
size_t str_size;
char *s, *begs;
size_t i;
mp_size_t xsize;
int c;
int negative;
MINT *x = (MINT *) (*_mp_allocate_func) (sizeof (MINT));
TMP_DECL (marker);
/* Skip whitespace. */
do
c = *str++;
while (isspace (c));
negative = 0;
if (c == '-')
{
negative = 1;
c = *str++;
}
if (digit_value_in_base (c, 16) < 0)
return 0; /* error if no digits */
TMP_MARK (marker);
str_size = strlen (str - 1);
s = begs = (char *) TMP_ALLOC (str_size + 1);
for (i = 0; i < str_size; i++)
{
if (!isspace (c))
{
int dig = digit_value_in_base (c, 16);
if (dig < 0)
{
TMP_FREE (marker);
return 0;
}
*s++ = dig;
}
c = *str++;
}
str_size = s - begs;
xsize = str_size / __mp_bases[16].chars_per_limb + 1;
x->_mp_alloc = xsize;
x->_mp_d = (mp_ptr) (*_mp_allocate_func) (xsize * BYTES_PER_MP_LIMB);
xsize = mpn_set_str (x->_mp_d, (unsigned char *) begs, str_size, 16);
x->_mp_size = negative ? -xsize : xsize;
TMP_FREE (marker);
return x;
}