Filter directional markers that corrupt the screen. (closes #3854)

Thanks to Vincent Lefèvre for working on these utf-8 screen display issues.

1 files changed, 13 insertions, 6 deletions

diff --git a/mbyte.c b/mbyte.c
index d476a3a8..3df143f5 100644
--- a/mbyte.c
+++ b/mbyte.c
@@ -525,6 +525,18 @@ wchar_t replacement_char (void)
   return Charset_is_utf8 ? 0xfffd : '?';
 }
 
+int is_display_corrupting_utf8 (wchar_t wc)
+{
+  if (wc == (wchar_t)0x200f ||   /* bidi markers: #3827 */
+      wc == (wchar_t)0x200e ||
+      wc == (wchar_t)0x00ad ||   /* soft hyphen: #3848 */
+      (wc >= (wchar_t)0x202a &&  /* misc directional markers: #3854 */
+       wc <= (wchar_t)0x202e))
+    return 1;
+  else
+    return 0;
+}
+
 int mutt_filter_unprintable (char **s)
 {
   BUFFER *b = NULL;
@@ -548,13 +560,8 @@ int mutt_filter_unprintable (char **s)
     }
     if (!IsWPrint (wc))
       wc = '?';
-    /* Filter out the RIGHT-TO-LEFT and LEFT-TO-RIGHT bidi markers because
-     * they result in screen corruption.   See ticket #3827.
-     * Filter soft-hypen.  See ticket #3848.
-     */
     else if (Charset_is_utf8 &&
-             ((wc == (wchar_t)0x200f) || (wc == (wchar_t)0x200e) ||
-              (wc == (wchar_t)0x00ad)))
+             is_display_corrupting_utf8 (wc))
       continue;
     k2 = wcrtomb (scratch, wc, &mbstate2);
     scratch[k2] = '\0';