utf8.h: Use common macro to avoid repeating

This refactors two macros that have mostly the same guts to have a third
macro to define the common guts.

It also changes to use UV_IS_QUAD instead of a home-grown #define that a
future commit will remove.

diff --git a/utf8.h b/utf8.h
index 18e5a5e..4a964c4 100644 (file)
--- a/utf8.h
+++ b/utf8.h
@@ -243,25 +243,29 @@ Perl's extended UTF-8 means we can have start bytes up to FF.
 
 #if UVSIZE >= 8
 #  define UTF8_QUAD_MAX UINT64_C(0x1000000000)
+#endif
 
 /* Input is a true Unicode (not-native) code point */
-#define OFFUNISKIP(uv) ( (uv) < 0x80        ? 1 : \
+#define __COMMON_UNI_SKIP(uv)                                               \
                      (uv) < 0x800          ? 2 : \
                      (uv) < 0x10000        ? 3 : \
                      (uv) < 0x200000       ? 4 : \
                      (uv) < 0x4000000      ? 5 : \
-                     (uv) < 0x80000000     ? 6 : \
-                      (uv) < UTF8_QUAD_MAX ? 7 : UTF8_MAXBYTES )
+                     (uv) < 0x80000000     ? 6 :
+
+/* Internal macro to be used only in this file.
+ * This adds to __COMMON_UNI_SKIP the details at this platform's upper range.
+ * For 64-bit ASCII platforms, we need one more test
+ * to see if just 7 bytes is needed, or if the maximum is needed.  For 32-bit
+ * ASCII platforms, everything is representable by 7 bytes */
+#ifdef UV_IS_QUAD
+#   define __BASE_UNI_SKIP(uv) (__COMMON_UNI_SKIP(uv)                       \
+     (uv) < UTF8_QUAD_MAX ? 7 : UTF8_MAXBYTES )
 #else
-/* No, I'm not even going to *TRY* putting #ifdef inside a #define */
-#define OFFUNISKIP(uv) ( (uv) < 0x80        ? 1 : \
-                     (uv) < 0x800          ? 2 : \
-                     (uv) < 0x10000        ? 3 : \
-                     (uv) < 0x200000       ? 4 : \
-                     (uv) < 0x4000000      ? 5 : \
-                     (uv) < 0x80000000     ? 6 : 7 )
+#   define __BASE_UNI_SKIP(uv) (__COMMON_UNI_SKIP(uv) 7)
 #endif
 
+#define OFFUNISKIP(uv) ( OFFUNI_IS_INVARIANT(uv) ? 1 : __BASE_UNI_SKIP(uv))
 /*
 
 =for apidoc Am|STRLEN|UVCHR_SKIP|UV cp