#define UTF8_IS_CONTINUED(c) (((U8)c) & 0x80)
#define UTF8_IS_DOWNGRADEABLE_START(c) (((U8)c & 0xfc) == 0xc0)
-#define UTF_START_MARK(len) ((len > 7) ? 0xFF : (0xFE << (7-len)))
-#define UTF_START_MASK(len) ((len >= 7) ? 0x00 : (0x1F >> (len-2)))
+#define UTF_START_MARK(len) (((len) > 7) ? 0xFF : (0xFE << (7-(len))))
+#define UTF_START_MASK(len) (((len) >= 7) ? 0x00 : (0x1F >> ((len)-2)))
#define UTF_CONTINUATION_MARK 0x80
#define UTF_ACCUMULATION_SHIFT 6