strtold: New module.

* lib/stdlib.in.h (strtold): New declaration.
* lib/strtold.c: New file.
* lib/strtod.c: Consider USE_LONG_DOUBLE.
(STRTOD, LDEXP, HAVE_UNDERLYING_STRTOD, DOUBLE, MIN, MAX, L_,
USE_LDEXP): New macros.
(LDEXP, scale_radix_exp, parse_number, STRTOD): Adapt for
USE_LONG_DOUBLE.
(underlying_strtod): Remove function. Replace with some macros.
Re-add the code for a missing underlying function that was removed on
2013-02-19.
* m4/strtold.m4: New file.
* m4/stdlib_h.m4 (gl_STDLIB_H): Test whether strtold is declared.
(gl_STDLIB_H_DEFAULTS): Initialize GNULIB_STRTOLD, HAVE_STRTOLD,
REPLACE_STRTOLD.
* modules/stdlib (Makefile.am): Substitute GNULIB_STRTOLD, HAVE_STRTOLD,
REPLACE_STRTOLD.
* modules/strtold: New file.
* doc/posix-functions/strtold.texi: Document the new module.

1 files changed, 73 insertions, 40 deletions

diff --git a/lib/strtod.c b/lib/strtod.c
index 9a28f4bc54..1d1ba2797b 100644
--- a/lib/strtod.c
+++ b/lib/strtod.c
@@ -14,8 +14,11 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
-#include <config.h>
+#if ! defined USE_LONG_DOUBLE
+# include <config.h>
+#endif
 
+/* Specification.  */
 #include <stdlib.h>
 
 #include <ctype.h>
@@ -28,8 +31,36 @@
 
 #include "c-ctype.h"
 
-#ifndef HAVE_LDEXP_IN_LIBC
-#define HAVE_LDEXP_IN_LIBC 0
+#undef MIN
+#undef MAX
+#ifdef USE_LONG_DOUBLE
+# define STRTOD strtold
+# define LDEXP ldexpl
+# if defined __hpux && defined __hppa
+   /* We cannot call strtold on HP-UX/hppa, because its return type is a struct,
+      not a 'long double'.  */
+#  define HAVE_UNDERLYING_STRTOD 0
+# else
+#  define HAVE_UNDERLYING_STRTOD HAVE_STRTOLD
+# endif
+# define DOUBLE long double
+# define MIN LDBL_MIN
+# define MAX LDBL_MAX
+# define L_(literal) literal##L
+#else
+# define STRTOD strtod
+# define LDEXP ldexp
+# define HAVE_UNDERLYING_STRTOD 1
+# define DOUBLE double
+# define MIN DBL_MIN
+# define MAX DBL_MAX
+# define L_(literal) literal
+#endif
+
+#if (defined USE_LONG_DOUBLE ? HAVE_LDEXPM_IN_LIBC : HAVE_LDEXP_IN_LIBC)
+# define USE_LDEXP 1
+#else
+# define USE_LDEXP 0
 #endif
 
 /* Return true if C is a space in the current locale, avoiding
@@ -41,20 +72,21 @@ locale_isspace (char c)
   return isspace (uc) != 0;
 }
 
-#if !HAVE_LDEXP_IN_LIBC
- #define ldexp dummy_ldexp
+#if !USE_LDEXP
+ #undef LDEXP
+ #define LDEXP dummy_ldexp
  /* A dummy definition that will never be invoked.  */
- static double ldexp (double x _GL_UNUSED, int exponent _GL_UNUSED)
+ static DOUBLE LDEXP (DOUBLE x _GL_UNUSED, int exponent _GL_UNUSED)
  {
    abort ();
-   return 0.0;
+   return L_(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)
+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.
@@ -63,11 +95,11 @@ scale_radix_exp (double x, int radix, long int exponent)
 
   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);
+  if (USE_LDEXP && radix == 2)
+    return LDEXP (x, e < INT_MIN ? INT_MIN : INT_MAX < e ? INT_MAX : e);
   else
     {
-      double r = x;
+      DOUBLE r = x;
 
       if (r != 0)
         {
@@ -87,12 +119,12 @@ scale_radix_exp (double x, int radix, long int exponent)
             {
               while (e-- != 0)
                 {
-                  if (r < -DBL_MAX / radix)
+                  if (r < -MAX / radix)
                     {
                       errno = ERANGE;
                       return -HUGE_VAL;
                     }
-                  else if (DBL_MAX / radix < r)
+                  else if (MAX / radix < r)
                     {
                       errno = ERANGE;
                       return HUGE_VAL;
@@ -113,7 +145,7 @@ scale_radix_exp (double x, int radix, long int exponent)
    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
+static DOUBLE
 parse_number (const char *nptr,
               int base, int radix, int radix_multiplier, char expchar,
               char **endptr)
@@ -121,7 +153,7 @@ parse_number (const char *nptr,
   const char *s = nptr;
   bool got_dot = false;
   long int exponent = 0;
-  double num = 0;
+  DOUBLE num = 0;
 
   for (;; ++s)
     {
@@ -141,12 +173,12 @@ parse_number (const char *nptr,
         break;
 
       /* Make sure that multiplication by base will not overflow.  */
-      if (num <= DBL_MAX / base)
+      if (num <= 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'.
+             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.
 
@@ -185,32 +217,42 @@ parse_number (const char *nptr,
   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
+   The expression -MIN * MIN does not work when cross-compiling
    to PowerPC on Mac OS X 10.5.  */
 #if defined __hpux || defined __sgi || defined __ICC
-static double
+static DOUBLE
 compute_minus_zero (void)
 {
-  return -DBL_MIN * DBL_MIN;
+  return -MIN * MIN;
 }
 # define minus_zero compute_minus_zero ()
 #else
-double minus_zero = -0.0;
+DOUBLE minus_zero = -0.0;
 #endif
 
-/* Convert NPTR to a double.  If ENDPTR is not NULL, a pointer to the
+/* 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)
+DOUBLE
+STRTOD (const char *nptr, char **endptr)
+#if HAVE_UNDERLYING_STRTOD
+# ifdef USE_LONG_DOUBLE
+#  undef strtold
+# else
+#  undef strtod
+# endif
+#else
+# undef STRTOD
+# define STRTOD(NPTR,ENDPTR) parse_number (NPTR, 10, 10, 1, 'e', ENDPTR)
+#endif
+/* From here on, STRTOD refers to the underlying implementation.  It needs
+   to handle only finite unsigned decimal numbers with non-null ENDPTR.  */
 {
   bool negative = false;
 
   /* The number so far.  */
-  double num;
+  DOUBLE num;
 
   const char *s = nptr;
   const char *end;
@@ -226,7 +268,7 @@ strtod (const char *nptr, char **endptr)
   if (*s == '-' || *s == '+')
     ++s;
 
-  num = underlying_strtod (s, &endbuf);
+  num = STRTOD (s, &endbuf);
   end = endbuf;
 
   if (c_isdigit (s[*s == '.']))
@@ -261,7 +303,7 @@ strtod (const char *nptr, char **endptr)
       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
+             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')
@@ -279,7 +321,7 @@ strtod (const char *nptr, char **endptr)
               else
                 {
                   dup[e - s] = '\0';
-                  num = underlying_strtod (dup, &endbuf);
+                  num = STRTOD (dup, &endbuf);
                   saved_errno = errno;
                   free (dup);
                   errno = saved_errno;
@@ -344,12 +386,3 @@ strtod (const char *nptr, char **endptr)
     return minus_zero;
   return negative ? -num : num;
 }
-
-/* 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);
-}