[src/trunk]: src/lib/libcurses Use WCOL rather than wcwidth(3) as we should a...

[roy <roy%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/692b8946d44c
branches:  trunk
changeset: 997868:692b8946d44c
user:      roy <roy%NetBSD.org@localhost>
date:      Fri Mar 29 16:56:58 2019 +0000

description:
Use WCOL rather than wcwidth(3) as we should already know the width
during refresh.
Ensure the character width is not negative when advancing during refresh
(unlikely) and we actually have something to insert in the lower right
corner depending on terminal caps.

Fixes PR lib/54085

diffstat:

 lib/libcurses/refresh.c |  20 ++++++++++----------
 1 files changed, 10 insertions(+), 10 deletions(-)

diffs (51 lines):

diff -r c03899e635f6 -r 692b8946d44c lib/libcurses/refresh.c
--- a/lib/libcurses/refresh.c   Fri Mar 29 16:08:06 2019 +0000
+++ b/lib/libcurses/refresh.c   Fri Mar 29 16:56:58 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: refresh.c,v 1.105 2019/01/06 04:27:53 uwe Exp $        */
+/*     $NetBSD: refresh.c,v 1.106 2019/03/29 16:56:58 roy Exp $        */
 
 /*
  * Copyright (c) 1981, 1993, 1994
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)refresh.c  8.7 (Berkeley) 8/13/94";
 #else
-__RCSID("$NetBSD: refresh.c,v 1.105 2019/01/06 04:27:53 uwe Exp $");
+__RCSID("$NetBSD: refresh.c,v 1.106 2019/03/29 16:56:58 roy Exp $");
 #endif
 #endif                         /* not lint */
 
@@ -1042,16 +1042,14 @@
                return error;
        }
 
-       /* We need to insert characters.
-        * To do this, work out their widths.
-        * XXX This does not work when the bottom right corner is an ACS. */
+       /* We need to insert characters. */
 #ifdef HAVE_WCHAR
-       cw = wcwidth(nsp->ch);
-       pcw = psp == NULL ? 0 : wcwidth(psp->ch);
-       if (pcw < 1)
+       cw = WCOL(*nsp);
+       pcw = WCOL(*psp);
+       if (cw < 1 || pcw < 1)
                return ERR; /* Nothing to insert */
 
-       /* When wide characters we need something other than
+       /* When inserting a wide character, we need something other than
         * insert_character. */
        if (pcw > 1 &&
            !(parm_ich != NULL ||
@@ -1317,7 +1315,9 @@
                        }
 
 #ifdef HAVE_WCHAR
-                       chw = wcwidth(nsp->ch);
+                       chw = WCOL(*nsp);
+                       if (chw < 0)
+                               chw = 1;
 #else
                        chw = 1;
 #endif /* HAVE_WCHAR */