Imported from ../bash-2.02.tar.gz.

lib/sh/strtod.c

@@ -0,0 +1,197 @@
+/* Copyright (C) 1991, 1992 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 2, 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, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#ifndef HAVE_STRTOD
+
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
+
+#include <ctype.h>
+#include <math.h>
+
+#if HAVE_FLOAT_H
+# include <float.h>
+#else
+# define DBL_MAX 1.7976931348623159e+308
+# define DBL_MIN 2.2250738585072010e-308
+#endif
+
+#include <bashansi.h>
+
+#ifndef NULL
+#  define NULL 0
+#endif
+
+#ifndef HUGE_VAL
+#  define HUGE_VAL HUGE
+#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 (nptr, endptr)
+     const char *nptr;
+     char **endptr;
+{
+  register const char *s;
+  short sign;
+
+  /* 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;
+
+  /* Eat whitespace.  */
+  while (isspace (*s))
+    ++s;
+
+  /* Get the sign.  */
+  sign = *s == '-' ? -1 : 1;
+  if (*s == '-' || *s == '+')
+    ++s;
+
+  num = 0.0;
+  got_dot = 0;
+  got_digit = 0;
+  exponent = 0;
+  for (;; ++s)
+    {
+      if (isdigit (*s))
+	{
+	  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;
+      else
+	/* Any other character terminates the number.  */
+	break;
+    }
+
+  if (!got_digit)
+    goto noconv;
+
+  if (tolower (*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)
+    {
+      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);
+
+  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;
+
+noconv:
+  /* There was no number.  */
+  if (endptr != NULL)
+    *endptr = (char *) nptr;
+  return 0.0;
+}
+
+#endif /* !HAVE_STRTOD */