Make wcrtomb() more readable by weeding out range errors up front,

doing ASCII handling once rather than twice, and using <= rather
than ((&~)==) obfuscation (which already caused a bug in the past).
No functional change.
Joint work with and OK stsp@ semarie@ bentley@

diff --git a/lib/libc/citrus/citrus_utf8.c b/lib/libc/citrus/citrus_utf8.c
index c80f886..42ee2a3 100644 (file)
--- a/lib/libc/citrus/citrus_utf8.c
+++ b/lib/libc/citrus/citrus_utf8.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: citrus_utf8.c,v 1.12 2015/10/10 13:54:22 schwarze Exp $ */
+/*     $OpenBSD: citrus_utf8.c,v 1.13 2015/10/12 17:50:51 schwarze Exp $ */
 
 /*-
  * Copyright (c) 2002-2004 Tim J. Robbins
@@ -292,10 +292,9 @@ _citrus_utf8_ctype_wcrtomb(char * __restrict s,
                return (1);
        }
 
-       if ((wc & ~0x7f) == 0) {
-               /* Fast path for plain ASCII characters. */
-               *s = (char)wc;
-               return (1);
+       if (wc < 0 || wc > 0x10ffff) {
+               errno = EILSEQ;
+               return ((size_t)-1);
        }
 
        /*
@@ -304,21 +303,19 @@ _citrus_utf8_ctype_wcrtomb(char * __restrict s,
         * first few bits of the first octet, which contains the information
         * about the sequence length.
         */
-       if ((wc & ~0x7f) == 0) {
-               lead = 0;
-               len = 1;
-       } else if ((wc & ~0x7ff) == 0) {
+       if (wc <= 0x7f) {
+               /* Fast path for plain ASCII characters. */
+               *s = (char)wc;
+               return (1);
+       } else if (wc <= 0x7ff) {
                lead = 0xc0;
                len = 2;
-       } else if ((wc & ~0xffff) == 0) {
+       } else if (wc <= 0xffff) {
                lead = 0xe0;
                len = 3;
-       } else if ((wc & ~0xfffff) == 0 || (wc & ~0x10ffff) == 0) {
+       } else {
                lead = 0xf0;
                len = 4;
-       } else {
-               errno = EILSEQ;
-               return ((size_t)-1);
        }
 
        /*