Fix wrap_rows at inner byte of multibyte sequence

Also fix UTF-8 inner byte bounds and make unittest for case this fixes.

1 files changed, 11 insertions, 3 deletions

diff --git a/src/util/string.h b/src/util/string.h
index 72d3c6075..b4ce5743d 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -33,7 +33,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define TOSTRING(x) STRINGIFY(x)
 
 // Checks whether a byte is an inner byte for an utf-8 multibyte sequence
-#define IS_UTF8_MULTB_INNER(x) (((unsigned char)x >= 0x80) && ((unsigned char)x <= 0xc0))
+#define IS_UTF8_MULTB_INNER(x) (((unsigned char)x >= 0x80) && ((unsigned char)x < 0xc0))
 
 typedef std::map<std::string, std::string> StringMap;
 
@@ -426,12 +426,20 @@ inline std::string wrap_rows(const std::string &from,
 {
 	std::string to;
 
+	bool need_to_wrap = false;
+
 	size_t character_idx = 0;
 	for (size_t i = 0; i < from.size(); i++) {
 		if (character_idx > 0 && character_idx % row_len == 0)
-			to += '\n';
-		if (!IS_UTF8_MULTB_INNER(from[i]))
+			need_to_wrap = true;
+		if (!IS_UTF8_MULTB_INNER(from[i])) {
+			// Wrap string if needed before next char started
+			if (need_to_wrap) {
+				to += '\n';
+				need_to_wrap = false;
+			}
 			character_idx++;
+		}
 		to += from[i];
 	}