Refactor WORD-like macros into types.h.

1 files changed, 55 insertions, 0 deletions

diff --git a/types.h b/types.h
index 1359c45..86e2a9a 100644
--- a/types.h
+++ b/types.h
@@ -1,7 +1,62 @@
 #ifndef TYPES_H
 #define TYPES_H
+
 typedef unsigned char u8;
 typedef unsigned short u16;
 typedef signed short i16;
 typedef unsigned int u32;
+
+/*
+ * These macros help us solve problems on systems that don't support
+ * non-aligned memory access. This isn't a big issue IMHO, since the tools
+ * in this package are intended mainly for Intel and compatible systems,
+ * which are little-endian and support non-aligned memory access. Anyway,
+ * you may use the following defines to control the way it works:
+ * - Define BIGENDIAN on big-endian systems.
+ * - Define ALIGNMENT_WORKAROUND if your system doesn't support
+ *   non-aligned memory access. In this case, we use a slower, but safer,
+ *   memory access method.
+ * You most probably will have to define none or the two of them.
+ */
+
+#ifdef BIGENDIAN
+typedef struct {
+	u32 h;
+	u32 l;
+} u64;
+#else
+typedef struct {
+	u32 l;
+	u32 h;
+} u64;
+#endif
+
+#ifdef ALIGNMENT_WORKAROUND
+static u64 U64(u32 low, u32 high)
+{
+	u64 self;
+	
+	self.l=low;
+	self.h=high;
+	
+	return self;
+}
+#endif
+
+#ifdef ALIGNMENT_WORKAROUND
+#	ifdef BIGENDIAN
+#	define WORD(x) (u16)((x)[1]+((x)[0]<<8))
+#	define DWORD(x) (u32)((x)[3]+((x)[2]<<8)+((x)[1]<<16)+((x)[0]<<24))
+#	define QWORD(x) (U64(DWORD(x+4), DWORD(x)))
+#	else /* BIGENDIAN */
+#	define WORD(x) (u16)((x)[0]+((x)[1]<<8))
+#	define DWORD(x) (u32)((x)[0]+((x)[1]<<8)+((x)[2]<<16)+((x)[3]<<24))
+#	define QWORD(x) (U64(DWORD(x), DWORD(x+4)))
+#	endif /* BIGENDIAN */
+#else /* ALIGNMENT_WORKAROUND */
+#define WORD(x) (u16)(*(const u16 *)(x))
+#define DWORD(x) (u32)(*(const u32 *)(x))
+#define QWORD(x) (*(const u64 *)(x))
+#endif /* ALIGNMENT_WORKAROUND */
+
 #endif