nano

commit 10b99d8ac0f85e23c88ddb860bb5c76682178713
parent 0693d6974a86ce8b3eeb4d475bc7556de6a41a71
Author: Benno Schulenberg <bensberg@telfort.nl>
Date:   Wed,  6 Jan 2021 20:01:55 +0100

chars: short-circuit determining the width of characters under U+0300

The combining characters (that are zero-width) start at U+0300.
After that it's pretty much chaos, width-wise.

The mbwidth() function is not called for control characters (whose
representation takes up two columns), as they are handled separately.

The calls of mbwidth() that *can* happen with a control character as
argument are only to determine whether the character is zero-width,
and then it doesn't matter whether the exact width is 1 or 2.

Diffstat:
M
src/chars.c
 | 
4
++--

1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/chars.c b/src/chars.c
@@ -179,8 +179,8 @@ char control_mbrep(const char *c, bool isdata)
 /* Return the width in columns of the given (multibyte) character. */
 int mbwidth(const char *c)
 {
-	/* Ask for the width only when the character isn't plain ASCII. */
-	if ((unsigned char)*c > 0xC1) {
+	/* Only characters beyond U+02FF can be other than one column wide. */
+	if ((unsigned char)*c > 0xCB) {
 		wchar_t wc;
 		int width;