X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Falign.h;fp=src%2Fcommon%2Falign.h;h=928c5b6c131ec36061662f7624fd74a000a87224;hb=c1b2f2e24cda9b60bce9380a3967b9207293a32d;hp=0000000000000000000000000000000000000000;hpb=008b967517e476b78600006565a7a1276d4023d6;p=lttng-tools.git

diff --git a/src/common/align.h b/src/common/align.h
new file mode 100644
index 000000000..928c5b6c1
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+++ b/src/common/align.h
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+#ifndef _LTTNG_ALIGN_H
+#define _LTTNG_ALIGN_H
+
+/*
+ * align.h
+ *
+ * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ */
+
+#include "bug.h"
+#include <unistd.h>
+#include <limits.h>
+
+#ifndef PAGE_SIZE	/* Cygwin limits.h defines its own PAGE_SIZE */
+#define PAGE_SIZE		sysconf(_SC_PAGE_SIZE)
+#endif
+
+#define PAGE_MASK		(~(PAGE_SIZE - 1))
+#define __ALIGN_MASK(v, mask)	(((v) + (mask)) & ~(mask))
+#define ALIGN(v, align)		__ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
+#define PAGE_ALIGN(addr)	ALIGN(addr, PAGE_SIZE)
+
+/**
+ * offset_align - Calculate the offset needed to align an object on its natural
+ *                alignment towards higher addresses.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @alignment:    natural object alignment. Must be non-zero, power of 2.
+ *
+ * Returns the offset that must be added to align towards higher
+ * addresses.
+ */
+#define offset_align(align_drift, alignment)				       \
+	({								       \
+		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
+				   || ((alignment) & ((alignment) - 1)));      \
+		(((alignment) - (align_drift)) & ((alignment) - 1));	       \
+	})
+
+/**
+ * offset_align_floor - Calculate the offset needed to align an object
+ *                      on its natural alignment towards lower addresses.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @alignment:    natural object alignment. Must be non-zero, power of 2.
+ *
+ * Returns the offset that must be substracted to align towards lower addresses.
+ */
+#define offset_align_floor(align_drift, alignment)			       \
+	({								       \
+		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
+				   || ((alignment) & ((alignment) - 1)));      \
+		(((align_drift) - (alignment)) & ((alignment) - 1));	       \
+	})
+
+#endif /* _LTTNG_ALIGN_H */