Merge commit 'a39d4083cab589d7cd6a13e8a4b8db8875261d75'

[gnulib.git] / lib / strtod.c

diff --git a/lib/strtod.c b/lib/strtod.c
index 64b62ff..e554a84 100644 (file)
--- a/lib/strtod.c
+++ b/lib/strtod.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991-1992, 1997, 1999, 2003, 2006, 2008-2010 Free Software
+/* Copyright (C) 1991-1992, 1997, 1999, 2003, 2006, 2008-2014 Free Software
    Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
@@ -24,15 +24,13 @@
 #include <limits.h>
 #include <math.h>
 #include <stdbool.h>
+#include <string.h>
 
 #include "c-ctype.h"
 
 #ifndef HAVE_LDEXP_IN_LIBC
 #define HAVE_LDEXP_IN_LIBC 0
 #endif
-#ifndef HAVE_RAW_DECL_STRTOD
-#define HAVE_RAW_DECL_STRTOD 0
-#endif
 
 /* Return true if C is a space in the current locale, avoiding
    problems with signed char and isspace.  */
@@ -148,7 +146,7 @@ parse_number (const char *nptr,
       else
         {
           /* The value of the digit doesn't matter, since we have already
-             gotten as many digits as can be represented in a `double'.
+             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.
 
@@ -189,6 +187,21 @@ parse_number (const char *nptr,
 
 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
@@ -202,6 +215,7 @@ strtod (const char *nptr, char **endptr)
   const char *s = nptr;
   const char *end;
   char *endbuf;
+  int saved_errno;
 
   /* Eat whitespace.  */
   while (locale_isspace (*s))
@@ -212,6 +226,7 @@ strtod (const char *nptr, char **endptr)
   if (*s == '-' || *s == '+')
     ++s;
 
+  saved_errno = errno;
   num = underlying_strtod (s, &endbuf);
   end = endbuf;
 
@@ -239,6 +254,35 @@ strtod (const char *nptr, char **endptr)
                 end = p;
             }
         }
+      else
+        {
+          /* 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;
+            }
+        }
 
       s = end;
     }
@@ -256,6 +300,7 @@ strtod (const char *nptr, char **endptr)
           && c_tolower (s[4]) == 'y')
         s += 5;
       num = HUGE_VAL;
+      errno = saved_errno;
     }
   else if (c_tolower (*s) == 'n'
            && c_tolower (s[1]) == 'a'
@@ -278,6 +323,7 @@ strtod (const char *nptr, char **endptr)
          to interpreting n-char-sequence as a hexadecimal number.  */
       if (s != end)
         num = NAN;
+      errno = saved_errno;
     }
   else
     {
@@ -288,27 +334,18 @@ strtod (const char *nptr, char **endptr)
 
   if (endptr != NULL)
     *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;
 }
 
-/* The "underlying" strtod implementation.  This must be defined
+/* The underlying strtod implementation.  This must be defined
    after strtod because it #undefs strtod.  */
 static double
 underlying_strtod (const char *nptr, char **endptr)
 {
-  if (HAVE_RAW_DECL_STRTOD)
-    {
-      /* Prefer the native strtod if available.  Usually it should
-         work and it should give more-accurate results than our
-         approximation.  */
-      #undef strtod
-      return strtod (nptr, endptr);
-    }
-  else
-    {
-      /* Approximate strtod well enough for this module.  There's no
-         need to handle anything but finite unsigned decimal
-         numbers with nonnull ENDPTR.  */
-      return parse_number (nptr, 10, 10, 1, 'e', endptr);
-    }
+#undef strtod
+  return strtod (nptr, endptr);
 }