From: Martin Willi <martin@revosec.ch>
Date: Thu, 19 Aug 2010 09:23:07 +0000 (+0200)
Subject: Added helper macros to define portable bitfields with gcc
X-Git-Tag: 4.5.0~450
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ba89ccd7f312a7ff51024e390f0e306e36fcf68;p=thirdparty%2Fstrongswan.git

Added helper macros to define portable bitfields with gcc
---

diff --git a/src/libstrongswan/utils.h b/src/libstrongswan/utils.h
index 04551835e8..35d3bebd15 100644
--- a/src/libstrongswan/utils.h
+++ b/src/libstrongswan/utils.h
@@ -137,6 +137,28 @@
 	static const typeof(name) *_##name = (const typeof(name)*)name; \
 	static ret name(this, ##__VA_ARGS__)
 
+/**
+ * Architecture independent bitfield definition helpers (at least with GCC).
+ *
+ * Defines a bitfield with a type t and a fixed size of bitfield members, e.g.:
+ * BITFIELD2(u_int8_t,
+ *     low: 4,
+ *     high: 4,
+ * ) flags;
+ * The member defined first placed at bit 0.
+ */
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define BITFIELD2(t, a, b,...)			struct { t a; t b; __VA_ARGS__}
+#define BITFIELD3(t, a, b, c,...)		struct { t a; t b; t c; __VA_ARGS__}
+#define BITFIELD4(t, a, b, c, d,...)	struct { t a; t b; t c; t d; __VA_ARGS__}
+#define BITFIELD5(t, a, b, c, d, e,...)	struct { t a; t b; t c; t d; t e; __VA_ARGS__}
+#elif BYTE_ORDER == BIG_ENDIAN
+#define BITFIELD2(t, a, b,...)			struct { t b; t a; __VA_ARGS__}
+#define BITFIELD3(t, a, b, c,...)		struct { t c; t b; t a; __VA_ARGS__}
+#define BITFIELD4(t, a, b, c, d,...)	struct { t d; t c; t b; t a; __VA_ARGS__}
+#define BITFIELD5(t, a, b, c, d, e,...)	struct { t e; t d; t c; t b; t a; __VA_ARGS__}
+#endif
+
 /**
  * Macro to allocate a sized type.
  */