[PATCH] strtod: fix replacement bug on AIX.

[Eric Blake]

* lib/strtod.c (strtod): Special case broken "0x" parse in
underlying strtod.
Reported by Rainer Tammer.

Signed-off-by: Eric Blake <address@hidden>
---

> test-strtod.c:389: assertion failed
> > 
> >   {
> >     const char input[] = "0x";
> >     char *ptr;
> >     double result;
> >     errno = 0;
> >     result = strtod (input, &ptr);
> >     ASSERT (result == 0.0);
> >     ASSERT (!signbit (result));
> > ->    ASSERT (ptr == input + 1);          /* glibc-2.3.6, MacOS X 10.3,
> > FreeBSD 6.2 */
> >     ASSERT (errno == 0);
> >   }

I'm guessing the bug is that your underlying strtod misparses "0x";
whereas glibc correctly consumes just the "0", not all platforms
do.  While I haven't tested this on a platform where it matters,
I think this will do the trick.

 ChangeLog    |    7 +++++++
 lib/strtod.c |   13 +++++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7f1c52e..11641cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2010-07-29  Eric Blake  <address@hidden>
+
+       strtod: fix replacement bug on AIX.
+       * lib/strtod.c (strtod): Special case broken "0x" parse in
+       underlying strtod.
+       Reported by Rainer Tammer.
+
 2010-02-17  Eric Blake  <address@hidden>

        manywarnings: add more warnings
diff --git a/lib/strtod.c b/lib/strtod.c
index 83b858a..7035adc 100644
--- a/lib/strtod.c
+++ b/lib/strtod.c
@@ -215,10 +215,15 @@ strtod (const char *nptr, char **endptr)

   if (c_isdigit (s[*s == '.']))
     {
-      /* If a hex float was converted incorrectly, do it ourselves.  */
-      if (*s == '0' && c_tolower (s[1]) == 'x' && end <= s + 2
-          && c_isxdigit (s[2 + (s[2] == '.')]))
-        num = parse_number (s + 2, 16, 2, 4, 'p', &end);
+      /* If a hex float was converted incorrectly, do it ourselves.
+         If the string was exactly "0x", consume just "0" ourselves.  */
+      if (*s == '0' && c_tolower (s[1]) == 'x' && end <= s + 2)
+        {
+          if (c_isxdigit (s[2 + (s[2] == '.')]))
+            num = parse_number (s + 2, 16, 2, 4, 'p', &end);
+          else if (!s[2])
+            end = s + 1;
+        }

       s = end;
     }
-- 
1.7.2