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-rwxr-xr-xgnu/strtod.c276
1 files changed, 276 insertions, 0 deletions
diff --git a/gnu/strtod.c b/gnu/strtod.c
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--- /dev/null
+++ b/gnu/strtod.c
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+/* Copyright (C) 1991-1992, 1997, 1999, 2003, 2006, 2008-2010 Free Software
+ Foundation, Inc.
+
+ 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 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
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ 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, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
+ optimizes away the nptr == NULL test below. */
+#define _GL_ARG_NONNULL(params)
+
+#include <stdlib.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <float.h>
+#include <math.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "c-ctype.h"
+
+/* 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)
+{
+ const unsigned char *s;
+ bool negative = false;
+
+ /* The number so far. */
+ double num;
+
+ bool got_dot; /* Found a decimal point. */
+ bool got_digit; /* Seen any digits. */
+ bool hex = false; /* Look for hex float exponent. */
+
+ /* The exponent of the number. */
+ long int exponent;
+
+ if (nptr == NULL)
+ {
+ errno = EINVAL;
+ goto noconv;
+ }
+
+ /* Use unsigned char for the ctype routines. */
+ s = (unsigned char *) nptr;
+
+ /* Eat whitespace. */
+ while (isspace (*s))
+ ++s;
+
+ /* Get the sign. */
+ negative = *s == '-';
+ if (*s == '-' || *s == '+')
+ ++s;
+
+ num = 0.0;
+ got_dot = false;
+ got_digit = false;
+ exponent = 0;
+
+ /* Check for hex float. */
+ if (*s == '0' && c_tolower (s[1]) == 'x'
+ && (c_isxdigit (s[2]) || ('.' == s[2] && c_isxdigit (s[3]))))
+ {
+ hex = true;
+ s += 2;
+ for (;; ++s)
+ {
+ if (c_isxdigit (*s))
+ {
+ got_digit = true;
+
+ /* Make sure that multiplication by 16 will not overflow. */
+ if (num > DBL_MAX / 16)
+ /* 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 16 later. */
+ ++exponent;
+ else
+ num = ((num * 16.0)
+ + (c_tolower (*s) - (c_isdigit (*s) ? '0' : 'a' - 10)));
+
+ /* Keep track of the number of digits after the decimal point.
+ If we just divided by 16 here, we would lose precision. */
+ if (got_dot)
+ --exponent;
+ }
+ else if (!got_dot && *s == '.')
+ /* Record that we have found the decimal point. */
+ got_dot = true;
+ else
+ /* Any other character terminates the number. */
+ break;
+ }
+ }
+
+ /* Not a hex float. */
+ else
+ {
+ for (;; ++s)
+ {
+ if (c_isdigit (*s))
+ {
+ got_digit = true;
+
+ /* 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 = true;
+ else
+ /* Any other character terminates the number. */
+ break;
+ }
+ }
+
+ if (!got_digit)
+ {
+ /* Check for infinities and NaNs. */
+ if (c_tolower (*s) == 'i'
+ && c_tolower (s[1]) == 'n'
+ && c_tolower (s[2]) == 'f')
+ {
+ s += 3;
+ num = HUGE_VAL;
+ 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;
+ goto valid;
+ }
+#ifdef NAN
+ else if (c_tolower (*s) == 'n'
+ && c_tolower (s[1]) == 'a'
+ && c_tolower (s[2]) == 'n')
+ {
+ s += 3;
+ num = NAN;
+ /* Since nan(<n-char-sequence>) is implementation-defined,
+ we define it by ignoring <n-char-sequence>. A nicer
+ implementation would populate the bits of the NaN
+ according to interpreting n-char-sequence as a
+ hexadecimal number, but the result is still a NaN. */
+ if (*s == '(')
+ {
+ const unsigned char *p = s + 1;
+ while (c_isalnum (*p))
+ p++;
+ if (*p == ')')
+ s = p + 1;
+ }
+ goto valid;
+ }
+#endif
+ goto noconv;
+ }
+
+ if (c_tolower (*s) == (hex ? 'p' : 'e') && !isspace (s[1]))
+ {
+ /* Get the exponent specified after the `e' or `E'. */
+ int save = errno;
+ char *end;
+ long int value;
+
+ errno = 0;
+ ++s;
+ value = strtol ((char *) s, &end, 10);
+ if (errno == ERANGE && num)
+ {
+ /* 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 (value < 0)
+ goto underflow;
+ else
+ goto overflow;
+ }
+ else if (end == (char *) 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 = (unsigned char *) end;
+ exponent += value;
+ }
+
+ if (num == 0.0)
+ goto valid;
+
+ if (hex)
+ {
+ /* ldexp takes care of range errors. */
+ num = ldexp (num, exponent);
+ goto valid;
+ }
+
+ /* Multiply NUM by 10 to the EXPONENT power,
+ checking for overflow and underflow. */
+
+ if (exponent < 0)
+ {
+ if (num < DBL_MIN * pow (10.0, (double) -exponent))
+ goto underflow;
+ }
+ else if (exponent > 0)
+ {
+ if (num > DBL_MAX * pow (10.0, (double) -exponent))
+ goto overflow;
+ }
+
+ num *= pow (10.0, (double) exponent);
+
+ valid:
+ if (endptr != NULL)
+ *endptr = (char *) s;
+ return negative ? -num : num;
+
+ overflow:
+ /* Return an overflow error. */
+ if (endptr != NULL)
+ *endptr = (char *) s;
+ errno = ERANGE;
+ return negative ? -HUGE_VAL : HUGE_VAL;
+
+ underflow:
+ /* Return an underflow error. */
+ if (endptr != NULL)
+ *endptr = (char *) s;
+ errno = ERANGE;
+ return negative ? -0.0 : 0.0;
+
+ noconv:
+ /* There was no number. */
+ if (endptr != NULL)
+ *endptr = (char *) nptr;
+ errno = EINVAL;
+ return 0.0;
+}
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