Re: [ECOS] wcstombs

[Jonathan Larmour <jifl at eCosCentric dot com>]

Klaas Gadeyne wrote:
> On Wed, 9 Aug 2006, Jonathan Larmour wrote:
> > Klaas Gadeyne wrote:
> > > So the next question: Is there reason why the implementation is not
> > > conform the Single unix spec?
> >
> > The short answer: eCos is not UNIX.
> >
> > The longer answer: eCos does try to comply with C90 and C99 (although 
> > it doesn't by a long way with the latter), and selected parts of 
> > POSIX. UNIX compatibility is a "would be nice" thing, but not if it 
> > means adding bells and whistles that just bloat code until eCos slowly 
> > grows to be the size of UNIX. Therefore bells and whistles that only 
> > exist in the SUS are unlikely to be implemented.
>
> Then, only for those who are interested:  The following patch works fine
> for me (without too much code bloat I hope :-), but please check...

It isn't right as it disregards n. I've checked in the attached patch. 
Update your CVS and check it's ok.

Jifl

Index: ChangeLog
===================================================================
RCS file: /cvs/ecos/ecos/packages/language/c/libc/i18n/current/ChangeLog,v
retrieving revision 1.8
diff -u -5 -p -r1.8 ChangeLog
--- ChangeLog   3 Aug 2005 20:53:09 -0000       1.8
+++ ChangeLog   10 Aug 2006 13:18:49 -0000
@@ -1,5 +1,11 @@
+2006-08-10  Jonathan Larmour  <jifl@eCosCentric.com>
+
+       * src/wcstombs.cxx (wcstombs): Follow Single Unix Spec
+       and if string is NULL, return chars that would have been
+       returned.
+
 2005-07-30  Andrew Lunn  <andrew.lunn@ascom.ch>

        * tests/i18nmb.c (main): Really silence the warnings.

 2004-02-17  Jonathan Larmour  <jifl@eCosCentric.com>
Index: src/wcstombs.cxx
===================================================================
RCS file: 
/cvs/ecos/ecos/packages/language/c/libc/i18n/current/src/wcstombs.cxx,v
retrieving revision 1.3
diff -u -5 -p -r1.3 wcstombs.cxx
--- src/wcstombs.cxx    23 May 2002 23:07:07 -0000      1.3
+++ src/wcstombs.cxx    10 Aug 2006 13:18:49 -0000
@@ -83,16 +83,17 @@ repeatedly to perform the conversion, pa
 decoding.  The result is based on the locale setting which may
 be restricted to a defined set of locales.

 RETURNS
 This implementation of <<wcstombs>> returns <<0>> if
-<[s]> is <<NULL>> or is the empty string;
+<[s]> is the empty string;
 it returns <<-1>> if CYGINT_LIBC_I18N_MB_REQUIRED and one of the
 wide-char characters does not represent a valid multi-byte character;
 otherwise it returns the minimum of: <<n>> or the
 number of bytes that are transferred to <<s>>, not including the
-nul terminator.
+nul terminator. If <[s]> is <<NULL>> it returns the number of
+bytes that would have been transferred.

 If the return value is -1, the state of the <<pwc>> string is
 indeterminate.  If the input has a length of 0, the output
 string will be modified to contain a wchar_t nul terminator if
 <<n>> > 0.
@@ -191,15 +192,19 @@ wcstombs ( char *s, const wchar_t *pwcs,
       return retval;
     }
 #endif /* CYGINT_LIBC_I18N_MB_REQUIRED */

   int count = 0;
+  char c;

   if (n != 0) {
     do {
-      if ((*s++ = (char) *pwcs++) == 0)
-       break;
+      c = (char) *pwcs++;
+      if (s)
+        *s++ = c;
+      if (0 == c)
+        break;
       count++;
     } while (--n != 0);
   }

   retval = count;

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