===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/less/line.c,v
retrieving revision 1.27
retrieving revision 1.28
diff -u -r1.27 -r1.28
--- src/usr.bin/less/line.c	2019/03/12 11:59:24	1.27
+++ src/usr.bin/less/line.c	2019/03/13 11:22:56	1.28
@@ -16,6 +16,7 @@
  */
 
 #include <wchar.h>
+#include <wctype.h>
 
 #include "charset.h"
 #include "less.h"
@@ -774,8 +775,8 @@
 static int
 do_append(LWCHAR ch, char *rep, off_t pos)
 {
+	wchar_t prev_ch;
 	int a;
-	LWCHAR prev_ch;
 
 	a = AT_NORMAL;
 
@@ -813,7 +814,10 @@
 		 */
 		overstrike = utf_mode ? -1 : 0;
 		/* To be correct, this must be a base character.  */
-		prev_ch = get_wchar(linebuf + curr);
+		if (mbtowc(&prev_ch, linebuf + curr, MB_CUR_MAX) == -1) {
+			(void)mbtowc(NULL, NULL, MB_CUR_MAX);
+			prev_ch = L'\0';
+		}
 		a = attr[curr];
 		if (ch == prev_ch) {
 			/*
@@ -835,7 +839,7 @@
 			} else {
 				a |= AT_BOLD;
 			}
-		} else if (ch == '_') {
+		} else if (ch == '_' && prev_ch != L'\0') {
 			a |= AT_UNDERLINE;
 			ch = prev_ch;
 			rep = linebuf + curr;
@@ -844,8 +848,7 @@
 		}
 		/* Else we replace prev_ch, but we keep its attributes.  */
 	} else if (overstrike < 0) {
-		if (is_composing_char(ch) ||
-		    is_combining_char(get_wchar(linebuf + curr), ch)) {
+		if (wcwidth(ch) == 0) {
 			/* Continuation of the same overstrike.  */
 			if (curr > 0)
 				a = attr[curr - 1] & (AT_UNDERLINE | AT_BOLD);
@@ -868,7 +871,8 @@
 				return (1);
 			break;
 		}
-	} else if ((!utf_mode || is_ascii_char(ch)) && control_char((char)ch)) {
+	} else if ((!utf_mode || is_ascii_char(ch)) &&
+	    !isprint((unsigned char)ch)) {
 do_control_char:
 		if (ctldisp == OPT_ON ||
 		    (ctldisp == OPT_ONPLUS && ch == ESC)) {
@@ -881,7 +885,7 @@
 			if (store_prchar(ch, pos))
 				return (1);
 		}
-	} else if (utf_mode && ctldisp != OPT_ON && is_ubin_char(ch)) {
+	} else if (utf_mode && ctldisp != OPT_ON && !iswprint(ch)) {
 		char *s;
 
 		s = prutfchar(ch);