+/* Consider all legal codepoints as printable except for:
+ * - C0 and C1 control characters
+ * - U+2028 and U+2029 (line/para break)
+ * - U+FFF9 through U+FFFB (interlinear annotation controls)
+ * The following code is optimized heavily to make hot paths for the
+ * expected printable characters. */
+