sfeed

commit c1b44cf790f8090ff25a2ff268c3f7a8d53e1bcf
parent 6403eadff853f470a859317f605dd306eb427bba
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Sat,  9 Jan 2021 16:05:27 +0100

printutf8pad: fix byte-seek issue with negative width codepoints in the range >= 127

For example: "\xef\xbf\xb7" (codepoint 0xfff7), returns wcwidth(wc) == -1.
The next byte was incorrected seeked, but the codepoint itself was valid
(mbtowc).

Diffstat:
M
util.c
 | 
7
+++----

1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/util.c b/util.c
@@ -241,19 +241,18 @@ printutf8pad(FILE *fp, const char *s, size_t len, int pad)
 
 	slen = strlen(s);
 	for (i = 0; i < slen; i += inc) {
-		inc = 1;
+		inc = 1; /* next byte */
 		if ((unsigned char)s[i] < 32) {
 			continue; /* skip control characters */
 		} else if ((unsigned char)s[i] >= 127) {
 			rl = mbtowc(&wc, s + i, slen - i < 4 ? slen - i : 4);
+			inc = rl;
 			if (rl < 0) {
 				mbtowc(NULL, NULL, 0); /* reset state */
-				inc = 1; /* next byte */
+				inc = 1; /* invalid, seek next byte */
 				w = 1; /* replacement char is one width */
 			} else if ((w = wcwidth(wc)) == -1) {
 				continue;
-			} else {
-				inc = rl;
 			}
 
 			if (col + w > len || (col + w == len && s[i + inc])) {