Bruno Haible wrote:
You can assume that mbrtowc returns 0 if and only if the multibyte sequence is a NUL byte - but you had chosen srcend in such a way that this would not happen in the loop.
Thanks for the correction. I mistakenly thought that C allows multibyte encodings in which a null wide character's multibyte representation contains an all-bits-zero byte. I installed the attached to omit the unnecessary test.
From 34e261fa2768533f34cf35158489ea6a22115c17 Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Fri, 27 Jul 2018 12:00:02 -0700 Subject: [PATCH] df: omit redundant comparison Trivial inefficiency reported by Bruno Haible in: http://lists.gnu.org/r/bug-gnulib/2018-07/msg00109.html * src/df.c (hide_problematic_chars): Omit redundant test. --- src/df.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/df.c b/src/df.c index 9b65872..5553221 100644 --- a/src/df.c +++ b/src/df.c @@ -288,7 +288,7 @@ hide_problematic_chars (char *cell) wchar_t wc; size_t srcbytes = srcend - src; n = mbrtowc (&wc, src, srcbytes, &mbstate); - bool ok = 0 < n && n <= srcbytes; + bool ok = n <= srcbytes; if (ok) ok = !iswcntrl (wc); -- 2.7.4
