top: provide for zero length character in utf8 support

This commit is prompted by the preceding change to the
library's escape.c module which, in turn, was prompted
by that issue shown below (with thanks to Konstantin).

Reference(s):
https://gitlab.com/procps-ng/procps/-/issues/176

Signed-off-by: Jim Warner <james.warner@comcast.net>

diff --git a/top/top.c b/top/top.c
index fbb2f610df14fb1b42616af02602b34f7cd88d6f..626b5b80ceb0f46e147811c0de73d01ccddf8811 100644 (file)
--- a/top/top.c
+++ b/top/top.c
@@ -544,7 +544,8 @@ static inline int utf8_cols (const unsigned char *p, int n) {
 
    if (n > 1) {
       (void)mbtowc(&wc, (const char *)p, n);
-      if ((n = wcwidth(wc)) < 1) n = 1;
+      // allow a zero as valid, as with a 'combining acute accent'
+      if ((n = wcwidth(wc)) < 0) n = 1;
    }
    return n;
 #else