optimize iswprint

src/ctype/iswprint.c

@@ -1,10 +1,19 @@
 #include <wctype.h>
 
+/* 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. */
+
 int iswprint(wint_t wc)
 {
-	unsigned c = wc;
-	/* assume any non-control, non-illegal codepoint is printable */
-	if (c>0x10ffff || c-0xd800<0x800 || (c&0xfffe)==0xfffe || iswcntrl(c))
+	if (wc < 0xffU)
+		return (wc+1 & 0x7f) >= 0x21;
+	if (wc < 0x2028U || wc-0x202aU < 0xd800-0x202a || wc-0xe000U < 0xfff9-0xe000)
+		return 1;
+	if (wc-0xfffcU > 0x10ffff-0xfffc || (wc&0xfffe)==0xfffe)
 		return 0;
 	return 1;
 }