[OTS] TAG() macro for big endian

src/ots.cc

Index: src/ots.cc
===================================================================
--- src/ots.cc	(revision 86)
+++ src/ots.cc	(working copy)
@@ -82,8 +82,12 @@
 };
 
 // Use a macro instead of a function because gcc 4.4.3 creates static
-// initializers in that case. Note this macro assumes a little-endian system.
+// initializers in that case.
+#if defined(__BIG_ENDIAN__) || defined(_BIG_ENDIAN)

[jfkthame, 2012/04/28 09:10:46]

Unfortunately, this doesn't work as intended on some systems - in the Android
NDK, and (at least some) OpenBSD systems, <endian.h> defines the symbol
_BIG_ENDIAN (with various levels of underscore-decoration) not to mean "this
system is big-endian" but as a magic constant to compare with _BYTE_ORDER. As a
result, the big-endian option here is chosen even on little-endian
architectures.

(See mozilla issue https://bugzilla.mozilla.org/show_bug.cgi?id=747816#c10.)

+#define TAG(d, c, b, a) (a | (b << 8) | (c << 16) | (d << 24))
+#else
 #define TAG(a, b, c, d) (a | (b << 8) | (c << 16) | (d << 24))
+#endif
 
 const struct {
   uint32_t tag;