bfstd: Check that wcwidth() is positive

wcwidth() returns -1 for non-printable characters, but terminals
typically don't print anything for them, so treat them as 0.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/bfstd.c b/src/bfstd.c
index c6c2e7f..5b64452 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -695,8 +695,12 @@ size_t xstrwidth(const char *str) {
 		if (wc == WEOF) {
 			// Assume a single-width '?'
 			++ret;
-		} else {
-			ret += xwcwidth(wc);
+			continue;
+		}
+
+		int width = xwcwidth(wc);
+		if (width > 0) {
+			ret += width;
 		}
 	}