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 9ac3a454ead5482a0272011cb93e67b428e3035d..cc6f4f0c618f54c0804ceb29a2d33e2a6504c5d7 100644 (file)
--- a/top/top.c
+++ b/top/top.c
@@ -710,7 +710,8 @@ 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