utf8: fix returning negative string width
The `utf8_strnwidth()` function calls `utf8_width()` in a loop and adds
its returned width to the end result. `utf8_width()` can return `-1`
though in case it reads a control character, which means that the
computed string width is going to be wrong. In the worst case where
there are more control characters than non-control characters, we may
even return a negative string width.
Fix this bug by treating control characters as having zero width.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/utf8.c b/utf8.c
index 504e517..6a21fd6 100644
--- a/utf8.c
+++ b/utf8.c
@@ -212,11 +212,15 @@ int utf8_strnwidth(const char *string, size_t len, int skip_ansi)
const char *orig = string;
while (string && string < orig + len) {
- int skip;
+ int glyph_width, skip;
+
while (skip_ansi &&
(skip = display_mode_esc_sequence_len(string)) != 0)
string += skip;
- width += utf8_width(&string, NULL);
+
+ glyph_width = utf8_width(&string, NULL);
+ if (glyph_width > 0)
+ width += glyph_width;
}
return string ? width : len;
}
