Relicense BabelTrace library to MIT (BSD-style)
[babeltrace.git] / include / babeltrace / align.h
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1#ifndef _BABELTRACE_ALIGN_H
2#define _BABELTRACE_ALIGN_H
6dc2ca62 3
de0ba614 4/*
d79865b9 5 * BabelTrace align.h - alignment header
de0ba614 6 *
ccd7e1c8 7 * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
de0ba614 8 *
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9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
de0ba614 15 *
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16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
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18 */
19
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20#include <ctf/compiler.h>
21
22#define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a) - 1)
23#define __ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
24#define PTR_ALIGN(p, a) ((typeof(p)) ALIGN((unsigned long) (p), a))
25#define ALIGN_FLOOR(x, a) __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1)
26#define __ALIGN_FLOOR_MASK(x, mask) ((x) & ~(mask))
27#define PTR_ALIGN_FLOOR(p, a) \
28 ((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a))
29#define IS_ALIGNED(x, a) (((x) & ((typeof(x)) (a) - 1)) == 0)
30
31/*
32 * Align pointer on natural object alignment.
33 */
34#define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj)))
35#define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj)))
36
37/**
38 * offset_align - Calculate the offset needed to align an object on its natural
39 * alignment towards higher addresses.
40 * @align_drift: object offset from an "alignment"-aligned address.
41 * @alignment: natural object alignment. Must be non-zero, power of 2.
42 *
43 * Returns the offset that must be added to align towards higher
44 * addresses.
45 */
46#define offset_align(align_drift, alignment) \
47 ({ \
48 MAYBE_BUILD_BUG_ON((alignment) == 0 \
49 || ((alignment) & ((alignment) - 1))); \
50 (((alignment) - (align_drift)) & ((alignment) - 1)); \
51 })
52
53/**
54 * offset_align_floor - Calculate the offset needed to align an object
55 * on its natural alignment towards lower addresses.
56 * @align_drift: object offset from an "alignment"-aligned address.
57 * @alignment: natural object alignment. Must be non-zero, power of 2.
58 *
59 * Returns the offset that must be substracted to align towards lower addresses.
60 */
61#define offset_align_floor(align_drift, alignment) \
62 ({ \
63 MAYBE_BUILD_BUG_ON((alignment) == 0 \
64 || ((alignment) & ((alignment) - 1))); \
65 (((align_drift) - (alignment)) & ((alignment) - 1); \
66 })
67
d79865b9 68#endif /* _BABELTRACE_ALIGN_H */
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