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/* mpfr_set_str -- set a floating-point number from a string
Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR 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 <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
#include "mpfr.h"
#include "mpfr-impl.h"
int
mpfr_set_str (mpfr_ptr x, __gmp_const char *str, int base, mp_rnd_t rnd_mode)
{
mpz_t mantissa;
int negative, inex;
long k = 0;
unsigned char c;
long e;
mp_prec_t q;
mpfr_t y, z;
if (base < 2 || base > 36)
return 1;
mpz_init(mantissa);
mpz_set_ui(mantissa, 0);
negative = *str == '-';
if (negative || *str == '+')
str++;
while (*str == '0')
str++; /* skip initial zeros */
/* allowed characters are '0' to '0'+base-1 if base <= 10,
and '0' to '9' plus 'a' to 'a'+base-11 if 10 < base <= 36 */
while (c = *str,
(isdigit(c) && c < '0' + base) ||
(islower(c) && c < 'a'-10 + base))
{
str++;
mpz_mul_ui(mantissa, mantissa, base);
mpz_add_ui(mantissa, mantissa, isdigit(c) ? c - '0' : c - ('a'-10));
}
/* k is the number of non-zero digits before the decimal point */
if (*str == '.')
{
str++;
while (c = *str,
(isdigit(c) && c < '0' + base) ||
(islower(c) && c < 'a'-10 + base))
{
if (k == LONG_MAX)
{
mpz_clear(mantissa);
return -1;
}
k++;
str++;
mpz_mul_ui(mantissa, mantissa, base);
mpz_add_ui(mantissa, mantissa, isdigit(c) ? c - '0' : c - ('a'-10));
}
}
if (*str == '\0') /* no exponent */
{
e = -k;
}
else if ((base <= 10 && (*str == 'e' || *str == 'E')) || *str == '@')
{
char *endptr;
if (*++str == '\0') /* exponent character but no exponent */
{
mpz_clear(mantissa);
return 1;
}
errno = 0;
e = strtol(str, &endptr, 10); /* signed exponent after 'e', 'E' or '@' */
if (*endptr != '\0')
{
mpz_clear(mantissa);
return 1;
}
if (errno)
{
mpz_clear(mantissa);
return -1;
}
if (e < 0 && (unsigned long) e - k < (unsigned long) LONG_MIN)
{
mpz_clear(mantissa);
return -1;
}
e -= k;
}
else /* unexpected character */
{
mpz_clear(mantissa);
return 1;
}
/* the number is mantissa*base^expn */
q = MPFR_PREC(x) & ~(mp_prec_t) (BITS_PER_MP_LIMB - 1);
mpfr_init(y);
mpfr_init(z);
do
{
q += BITS_PER_MP_LIMB;
mpfr_set_prec(y, q);
mpfr_set_z(y, mantissa, GMP_RNDN); /* error <= 1/2*ulp(y) */
mpfr_set_prec(z, q);
if (e > 0)
{
inex = mpfr_ui_pow_ui(z, base, e, GMP_RNDN);
mpfr_mul(y, y, z, GMP_RNDN);
}
else if (e < 0)
{
inex = mpfr_ui_pow_ui(z, base, -e, GMP_RNDN);
mpfr_div(y, y, z, GMP_RNDN);
}
else
inex = 1;
if (negative)
mpfr_neg(y, y, GMP_RNDN);
}
while (mpfr_can_round(y, q-inex, GMP_RNDN, rnd_mode, MPFR_PREC(x))==0
&& q<=2*MPFR_PREC(x));
mpfr_set(x, y, rnd_mode);
mpz_clear(mantissa);
mpfr_clear(y);
mpfr_clear(z);
return 0;
}
int
mpfr_init_set_str (mpfr_ptr x, char *str, int base, mp_rnd_t rnd_mode)
{
mpfr_init (x);
return mpfr_set_str (x, str, base, rnd_mode);
}
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