Common Trace Format 2 generation

[lttng-tools.git] / src / common / align.hpp

diff --git a/src/common/align.hpp b/src/common/align.hpp
new file mode 100644 (file)
index 0000000..c957824
--- /dev/null
+++ b/src/common/align.hpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+#ifndef _LTTNG_ALIGN_H
+#define _LTTNG_ALIGN_H
+
+#include "bug.hpp"
+
+/*
+ * Align value to the next multiple of align. Returns val if it already is a
+ * multiple of align. Align must be a power of two.
+ */
+#define __lttng_align_ceil_mask(v, mask)       (((v) + (mask)) & ~(mask))
+
+#define lttng_align_ceil(v, align) \
+       __lttng_align_ceil_mask(v, (__typeof__(v)) (align) - 1)
+
+/*
+ * Align value to the previous multiple of align. Returns val if it already is a
+ * multiple of align. Align must be a power of two.
+ */
+#define __lttng_align_floor_mask(v, mask)      ((v) & ~(mask))
+
+#define lttng_align_floor(v, align) \
+       __lttng_align_floor_mask(v, (__typeof__(v)) (align) - 1)
+
+/**
+ * lttng_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 lttng_offset_align(align_drift, alignment)                                    \
+       ({                                                                     \
+               LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0                    \
+                                  || ((alignment) & ((alignment) - 1)));      \
+               (((alignment) - (align_drift)) & ((alignment) - 1));           \
+       })
+
+/**
+ * lttng_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 lttng_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 */