X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fstrtod.c;h=76e37d6920976a0852bd8b7d382f849212d5beeb;hb=8041b27617211a5762e58670b0acf474ffcfa610;hp=fdfc09f1bc0ca61909db5116774e57d134d5b896;hpb=0632e115747ff96e93330c88f536d7354a7ce507;p=gnulib.git
diff --git a/lib/strtod.c b/lib/strtod.c
index fdfc09f1b..76e37d692 100644
--- a/lib/strtod.c
+++ b/lib/strtod.c
@@ -1,9 +1,10 @@
-/* Copyright (C) 1991, 1992, 1997, 1999, 2003, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 1991-1992, 1997, 1999, 2003, 2006, 2008-2013 Free Software
+ Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -11,164 +12,340 @@
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see . */
#include
-#include
+#include
#include
-
-#include
-
+#include
#include
-#include
+#include
+#include
+#include
#include
+#include "c-ctype.h"
+
+#ifndef HAVE_LDEXP_IN_LIBC
+#define HAVE_LDEXP_IN_LIBC 0
+#endif
+
+/* Return true if C is a space in the current locale, avoiding
+ problems with signed char and isspace. */
+static bool
+locale_isspace (char c)
+{
+ unsigned char uc = c;
+ return isspace (uc) != 0;
+}
+
+#if !HAVE_LDEXP_IN_LIBC
+ #define ldexp dummy_ldexp
+ /* A dummy definition that will never be invoked. */
+ static double ldexp (double x _GL_UNUSED, int exponent _GL_UNUSED)
+ {
+ abort ();
+ return 0.0;
+ }
+#endif
+
+/* Return X * BASE**EXPONENT. Return an extreme value and set errno
+ to ERANGE if underflow or overflow occurs. */
+static double
+scale_radix_exp (double x, int radix, long int exponent)
+{
+ /* If RADIX == 10, this code is neither precise nor fast; it is
+ merely a straightforward and relatively portable approximation.
+ If N == 2, this code is precise on a radix-2 implementation,
+ albeit perhaps not fast if ldexp is not in libc. */
+
+ long int e = exponent;
+
+ if (HAVE_LDEXP_IN_LIBC && radix == 2)
+ return ldexp (x, e < INT_MIN ? INT_MIN : INT_MAX < e ? INT_MAX : e);
+ else
+ {
+ double r = x;
+
+ if (r != 0)
+ {
+ if (e < 0)
+ {
+ while (e++ != 0)
+ {
+ r /= radix;
+ if (r == 0 && x != 0)
+ {
+ errno = ERANGE;
+ break;
+ }
+ }
+ }
+ else
+ {
+ while (e-- != 0)
+ {
+ if (r < -DBL_MAX / radix)
+ {
+ errno = ERANGE;
+ return -HUGE_VAL;
+ }
+ else if (DBL_MAX / radix < r)
+ {
+ errno = ERANGE;
+ return HUGE_VAL;
+ }
+ else
+ r *= radix;
+ }
+ }
+ }
+
+ return r;
+ }
+}
+
+/* Parse a number at NPTR; this is a bit like strtol (NPTR, ENDPTR)
+ except there are no leading spaces or signs or "0x", and ENDPTR is
+ nonnull. The number uses a base BASE (either 10 or 16) fraction, a
+ radix RADIX (either 10 or 2) exponent, and exponent character
+ EXPCHAR. To convert from a number of digits to a radix exponent,
+ multiply by RADIX_MULTIPLIER (either 1 or 4). */
+static double
+parse_number (const char *nptr,
+ int base, int radix, int radix_multiplier, char expchar,
+ char **endptr)
+{
+ const char *s = nptr;
+ bool got_dot = false;
+ long int exponent = 0;
+ double num = 0;
+
+ for (;; ++s)
+ {
+ int digit;
+ if (c_isdigit (*s))
+ digit = *s - '0';
+ else if (base == 16 && c_isxdigit (*s))
+ digit = c_tolower (*s) - ('a' - 10);
+ else if (! got_dot && *s == '.')
+ {
+ /* Record that we have found the decimal point. */
+ got_dot = true;
+ continue;
+ }
+ else
+ /* Any other character terminates the number. */
+ break;
+
+ /* Make sure that multiplication by base will not overflow. */
+ if (num <= DBL_MAX / base)
+ num = num * base + digit;
+ else
+ {
+ /* The value of the digit doesn't matter, since we have already
+ gotten as many digits as can be represented in a 'double'.
+ This doesn't necessarily mean the result will overflow.
+ The exponent may reduce it to within range.
+
+ We just need to record that there was another
+ digit so that we can multiply by 10 later. */
+ exponent += radix_multiplier;
+ }
+
+ /* Keep track of the number of digits after the decimal point.
+ If we just divided by base here, we might lose precision. */
+ if (got_dot)
+ exponent -= radix_multiplier;
+ }
+
+ if (c_tolower (*s) == expchar && ! locale_isspace (s[1]))
+ {
+ /* Add any given exponent to the implicit one. */
+ int save = errno;
+ char *end;
+ long int value = strtol (s + 1, &end, 10);
+ errno = save;
+
+ if (s + 1 != end)
+ {
+ /* Skip past the exponent, and add in the implicit exponent,
+ resulting in an extreme value on overflow. */
+ s = end;
+ exponent =
+ (exponent < 0
+ ? (value < LONG_MIN - exponent ? LONG_MIN : exponent + value)
+ : (LONG_MAX - exponent < value ? LONG_MAX : exponent + value));
+ }
+ }
+
+ *endptr = (char *) s;
+ return scale_radix_exp (num, radix, exponent);
+}
+
+static double underlying_strtod (const char *, char **);
+
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
+ ICC 10.0 has a bug when optimizing the expression -zero.
+ The expression -DBL_MIN * DBL_MIN does not work when cross-compiling
+ to PowerPC on Mac OS X 10.5. */
+#if defined __hpux || defined __sgi || defined __ICC
+static double
+compute_minus_zero (void)
+{
+ return -DBL_MIN * DBL_MIN;
+}
+# define minus_zero compute_minus_zero ()
+#else
+double minus_zero = -0.0;
+#endif
+
/* Convert NPTR to a double. If ENDPTR is not NULL, a pointer to the
character after the last one used in the number is put in *ENDPTR. */
double
strtod (const char *nptr, char **endptr)
{
- register const char *s;
- short int sign;
+ bool negative = false;
/* The number so far. */
double num;
- int got_dot; /* Found a decimal point. */
- int got_digit; /* Seen any digits. */
-
- /* The exponent of the number. */
- long int exponent;
-
- if (nptr == NULL)
- {
- errno = EINVAL;
- goto noconv;
- }
-
- s = nptr;
+ const char *s = nptr;
+ const char *end;
+ char *endbuf;
+ int saved_errno;
/* Eat whitespace. */
- while (isspace ((unsigned char) *s))
+ while (locale_isspace (*s))
++s;
/* Get the sign. */
- sign = *s == '-' ? -1 : 1;
+ negative = *s == '-';
if (*s == '-' || *s == '+')
++s;
- num = 0.0;
- got_dot = 0;
- got_digit = 0;
- exponent = 0;
- for (;; ++s)
+ saved_errno = errno;
+ num = underlying_strtod (s, &endbuf);
+ end = endbuf;
+
+ if (c_isdigit (s[*s == '.']))
{
- if ('0' <= *s && *s <= '9')
- {
- got_digit = 1;
-
- /* Make sure that multiplication by 10 will not overflow. */
- if (num > DBL_MAX * 0.1)
- /* The value of the digit doesn't matter, since we have already
- gotten as many digits as can be represented in a `double'.
- This doesn't necessarily mean the result will overflow.
- The exponent may reduce it to within range.
-
- We just need to record that there was another
- digit so that we can multiply by 10 later. */
- ++exponent;
- else
- num = (num * 10.0) + (*s - '0');
-
- /* Keep track of the number of digits after the decimal point.
- If we just divided by 10 here, we would lose precision. */
- if (got_dot)
- --exponent;
- }
- else if (!got_dot && *s == '.')
- /* Record that we have found the decimal point. */
- got_dot = 1;
+ /* If a hex float was converted incorrectly, do it ourselves.
+ If the string starts with "0x" but does not contain digits,
+ consume the "0" ourselves. If a hex float is followed by a
+ 'p' but no exponent, then adjust the end pointer. */
+ if (*s == '0' && c_tolower (s[1]) == 'x')
+ {
+ if (! c_isxdigit (s[2 + (s[2] == '.')]))
+ end = s + 1;
+ else if (end <= s + 2)
+ {
+ num = parse_number (s + 2, 16, 2, 4, 'p', &endbuf);
+ end = endbuf;
+ }
+ else
+ {
+ const char *p = s + 2;
+ while (p < end && c_tolower (*p) != 'p')
+ p++;
+ if (p < end && ! c_isdigit (p[1 + (p[1] == '-' || p[1] == '+')]))
+ end = p;
+ }
+ }
else
- /* Any other character terminates the number. */
- break;
- }
-
- if (!got_digit)
- goto noconv;
+ {
+ /* If "1e 1" was misparsed as 10.0 instead of 1.0, re-do the
+ underlying strtod on a copy of the original string
+ truncated to avoid the bug. */
+ const char *e = s + 1;
+ while (e < end && c_tolower (*e) != 'e')
+ e++;
+ if (e < end && ! c_isdigit (e[1 + (e[1] == '-' || e[1] == '+')]))
+ {
+ char *dup = strdup (s);
+ errno = saved_errno;
+ if (!dup)
+ {
+ /* Not really our day, is it. Rounding errors are
+ better than outright failure. */
+ num = parse_number (s, 10, 10, 1, 'e', &endbuf);
+ }
+ else
+ {
+ dup[e - s] = '\0';
+ num = underlying_strtod (dup, &endbuf);
+ saved_errno = errno;
+ free (dup);
+ errno = saved_errno;
+ }
+ end = e;
+ }
+ }
- if (tolower ((unsigned char) *s) == 'e')
- {
- /* Get the exponent specified after the `e' or `E'. */
- int save = errno;
- char *end;
- long int exp;
-
- errno = 0;
- ++s;
- exp = strtol (s, &end, 10);
- if (errno == ERANGE)
- {
- /* The exponent overflowed a `long int'. It is probably a safe
- assumption that an exponent that cannot be represented by
- a `long int' exceeds the limits of a `double'. */
- if (endptr != NULL)
- *endptr = end;
- if (exp < 0)
- goto underflow;
- else
- goto overflow;
- }
- else if (end == s)
- /* There was no exponent. Reset END to point to
- the 'e' or 'E', so *ENDPTR will be set there. */
- end = (char *) s - 1;
- errno = save;
s = end;
- exponent += exp;
}
- if (endptr != NULL)
- *endptr = (char *) s;
-
- if (num == 0.0)
- return 0.0;
-
- /* Multiply NUM by 10 to the EXPONENT power,
- checking for overflow and underflow. */
-
- if (exponent < 0)
+ /* Check for infinities and NaNs. */
+ else if (c_tolower (*s) == 'i'
+ && c_tolower (s[1]) == 'n'
+ && c_tolower (s[2]) == 'f')
{
- if (num < DBL_MIN * pow (10.0, (double) -exponent))
- goto underflow;
+ s += 3;
+ if (c_tolower (*s) == 'i'
+ && c_tolower (s[1]) == 'n'
+ && c_tolower (s[2]) == 'i'
+ && c_tolower (s[3]) == 't'
+ && c_tolower (s[4]) == 'y')
+ s += 5;
+ num = HUGE_VAL;
+ errno = saved_errno;
}
- else if (exponent > 0)
+ else if (c_tolower (*s) == 'n'
+ && c_tolower (s[1]) == 'a'
+ && c_tolower (s[2]) == 'n')
{
- if (num > DBL_MAX * pow (10.0, (double) -exponent))
- goto overflow;
+ s += 3;
+ if (*s == '(')
+ {
+ const char *p = s + 1;
+ while (c_isalnum (*p))
+ p++;
+ if (*p == ')')
+ s = p + 1;
+ }
+
+ /* If the underlying implementation misparsed the NaN, assume
+ its result is incorrect, and return a NaN. Normally it's
+ better to use the underlying implementation's result, since a
+ nice implementation populates the bits of the NaN according
+ to interpreting n-char-sequence as a hexadecimal number. */
+ if (s != end)
+ num = NAN;
+ errno = saved_errno;
+ }
+ else
+ {
+ /* No conversion could be performed. */
+ errno = EINVAL;
+ s = nptr;
}
- num *= pow (10.0, (double) exponent);
-
- return num * sign;
-
-overflow:
- /* Return an overflow error. */
- errno = ERANGE;
- return HUGE_VAL * sign;
-
-underflow:
- /* Return an underflow error. */
if (endptr != NULL)
- *endptr = (char *) nptr;
- errno = ERANGE;
- return 0.0;
+ *endptr = (char *) s;
+ /* Special case -0.0, since at least ICC miscompiles negation. We
+ can't use copysign(), as that drags in -lm on some platforms. */
+ if (!num && negative)
+ return minus_zero;
+ return negative ? -num : num;
+}
-noconv:
- /* There was no number. */
- if (endptr != NULL)
- *endptr = (char *) nptr;
- return 0.0;
+/* The underlying strtod implementation. This must be defined
+ after strtod because it #undefs strtod. */
+static double
+underlying_strtod (const char *nptr, char **endptr)
+{
+#undef strtod
+ return strtod (nptr, endptr);
}