From d9028b23944172cea94e70d5cf3d089e537716a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sun, 31 May 2020 12:41:35 +0200
Subject: [PATCH] vt: utf8: use mbtowc() instead of mbrtowc()

This is slightly faster, since we don't need to initialize an
mbstate_t struct (using mbrtowc() with a NULL-pointer for 'ps' also
works).

Also, avoid a branch by setting wc=0 and then ignoring the
result/error code from mbtowc().
---
 vt.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/vt.c b/vt.c
index 6472d173..0db90069 100644
--- a/vt.c
+++ b/vt.c
@@ -512,14 +512,8 @@ action_utf8_entry(struct terminal *term, uint8_t c)
 static void
 action_utf8_print(struct terminal *term, uint8_t c)
 {
-    /* Convert to wchar */
-    mbstate_t ps = {};
-    wchar_t wc;
-    size_t count = mbrtowc(
-        &wc, (const char *)term->vt.utf8.data, term->vt.utf8.idx, &ps);
-
-    if ((ssize_t)count < 0)
-        wc = 0;
+    wchar_t wc = 0;
+    mbtowc(&wc, (const char *)term->vt.utf8.data, term->vt.utf8.idx);
 
     int width = wcwidth(wc);