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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 <string.h>
#include <errno.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
#include "mpfr.h"
#include "mpfr-impl.h"
/* from mpf/set_str.c */
static int
digit_value_in_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;
}
int
mpfr_set_str (mpfr_ptr x, __gmp_const char *str, int base, mp_rnd_t rnd_mode)
{
mpz_t mantissa;
int negative, inex, value;
long k = 0;
unsigned char c;
long e;
mp_prec_t q;
mpfr_t y, z;
const char *str0 = str;
if (base < 2 || base > 36)
return -1;
/* be careful that 'nan' is a valid number in base >= 24,
since n=23, a=10, n=23 */
if (((base < 24) ? strncasecmp : strncmp) (str, "NaN", 3) == 0)
{
MPFR_SET_NAN(x);
/* MPFR_RET_NAN not used as the return value isn't a ternary value */
__gmpfr_flags |= MPFR_FLAGS_NAN;
return 3;
}
negative = *str == '-';
if (negative || *str == '+')
str++;
/* be careful that 'inf' is a valid number in base >= 24,
since i=18, n=23, f=15 */
if (((base < 24) ? strncasecmp : strncmp) (str, "Inf", 3) == 0)
{
MPFR_CLEAR_NAN(x);
MPFR_SET_INF(x);
if (negative)
MPFR_SET_NEG(x);
else
MPFR_SET_POS(x);
return 3 + (str - str0);
}
mpz_init (mantissa);
mpz_set_ui (mantissa, 0);
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,
(value = digit_value_in_base (c, base)) >= 0)
{
str++;
mpz_mul_ui (mantissa, mantissa, base);
mpz_add_ui (mantissa, mantissa, value);
}
/* 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 ((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 '@' */
#ifdef REQUIRE_END_OF_STRING
if (*endptr != '\0')
{
mpz_clear (mantissa);
return -1;
}
#endif
str = endptr;
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 /* no exponent */
{
#ifdef REQUIRE_END_OF_STRING
if (*str != '\0')
{
mpz_clear (mantissa);
return -1;
}
#endif
e = -k;
}
/* 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 str - str0;
}
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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