mbrtoc32: Use the system's mbrtoc32 if it exists and basically works.

* m4/mbrtoc32.m4 (gl_MBRTOC32_SANITYCHECK): New macro.
(gl_FUNC_MBRTOC32): Require it. Set REPLACE_MBRTOC32 if mbrtoc32 exists
but is not working.
* lib/mbrtoc32.c: Include hard-locale.h, <locale.h>.
(mbrtoc32): If the char32_t encoding and the wchar_t encoding may
differ, use the system's mbrtoc32, adding workarounds.
* modules/mbrtoc32 (Depends-on): Add hard-locale.
* doc/posix-functions/mbrtoc32.texi: Mention the Solaris and native
Windows problem.
* lib/btoc32.c: Include <stdio.h>, <string.h>.
(btoc32): If the char32_t encoding and the wchar_t encoding may differ,
use mbrtoc32, not btowc.
* modules/btoc32 (Depends-on): Add mbrtoc32.
* lib/mbsrtoc32s.c (mbsrtoc32s): If the char32_t encoding and the
wchar_t encoding may differ, use mbrtoc32, not mbsrtowcs.
* modules/mbsrtoc32s (Depends-on): Update conditions.
(configure.ac): Compile mbsrtoc32s-state.c unconditionally.
* lib/mbsnrtoc32s.c (mbsnrtoc32s): If the char32_t encoding and the
wchar_t encoding may differ, use mbrtoc32, not mbsnrtowcs.
* modules/mbsnrtoc32s (Depends-on): Update conditions.
(configure.ac): Compile mbsrtoc32s-state.c unconditionally.

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/btoc32.c b/lib/btoc32.c
index 8b27875813..d8ce087ec6 100644
--- a/lib/btoc32.c
+++ b/lib/btoc32.c
@@ -21,10 +21,30 @@
 /* Specification.  */
 #include <uchar.h>
 
+#include <stdio.h>
+#include <string.h>
+
 wint_t
 btoc32 (int c)
 {
+#if HAVE_WORKING_MBRTOC32 && !defined __GLIBC__
+  /* The char32_t encoding of a multibyte character may be different than its
+     wchar_t encoding.  */
+  if (c != EOF)
+    {
+      mbstate_t state;
+      char s[1];
+      char32_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      s[0] = (unsigned char) c;
+      if (mbrtoc32 (&wc, s, 1, &state) <= 1)
+        return wc;
+    }
+  return WEOF;
+#else
   /* In all known locale encodings, unibyte characters correspond only to
      characters in the BMP.  */
   return btowc (c);
+#endif
 }