make is_valid_unicode() catch more invalid Unicode

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@3003 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

@@ -134,10 +134,10 @@ CVS code -
 	  get_key_buffer(), check_statusblank(), nanogetstr(),
 	  titlebar(), statusbar(), bottombars(), edit_refresh(),
 	  do_yesno(), and do_help(). (DLR)
-	- Treat the Unicode characters D800-DFFF and FFFE-FFFF as
-	  invalid, since the C library's multibyte functions don't seem
-	  to.  New function is_valid_unicode(); changes to mbrep() and
-	  make_mbchar(). (DLR)
+	- Treat the Unicode characters D800-DFFF, FDD0-FDEF, and
+	  xxFFFE-xxFFFF,  as invalid, since the C library's multibyte
+	  functions don't seem to.  New function is_valid_unicode();
+	  changes to mbrep() and make_mbchar(). (DLR)
 	- Store Unicode values in longs instead of ints, and cover the
 	  entire range of Unicode.  Changes to make_mbchar(),
 	  is_valid_unicode(), parse_kbinput(), get_unicode_kbinput(),

src/chars.c

@@ -884,12 +884,12 @@ bool has_blank_mbchars(const char *s)
 #endif /* !DISABLE_JUSTIFY */
 
 #ifdef ENABLE_UTF8
-/* Return TRUE if wc is valid Unicode (i.e, it's not negative or in the
- * ranges D800-DFFF or FFFE-FFFF), and FALSE otherwise. */
+/* Return TRUE if wc is valid Unicode, and FALSE otherwise. */
 bool is_valid_unicode(wchar_t wc)
 {
-    return (0 <= wc && (wc <= 0xD7FF || 0xE000 <= wc) && (wc <=
-	0xFFFD || 0x10000 <= wc));
+    return ((0 <= wc && wc <= 0x10FFFF) && (wc <= 0xD7FF || 0xE000 <=
+	wc) && (wc <= 0xFDCF || 0xFDF0 <= wc) && ((wc & 0xFFFF) <=
+	0xFFFD));
 }
 #endif