Cleanup: namespace 'align' macros
[lttng-tools.git] / src / common / align.h
CommitLineData
953192ba 1/*
ab5be9fa 2 * Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
953192ba 3 *
ab5be9fa 4 * SPDX-License-Identifier: MIT
953192ba 5 *
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6 */
7
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8#ifndef _LTTNG_ALIGN_H
9#define _LTTNG_ALIGN_H
10
8564ccbd 11#include "bug.h"
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12#include <unistd.h>
13#include <limits.h>
14
d575a7f8 15#ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE. */
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16#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
17#endif
18
d575a7f8 19
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20/*
21 * Align value to the next multiple of align. Returns val if it already is a
22 * multiple of align. Align must be a power of two.
23 */
24#define __lttng_align_ceil_mask(v, mask) (((v) + (mask)) & ~(mask))
d575a7f8 25
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26#define lttng_align_ceil(v, align) \
27 __lttng_align_ceil_mask(v, (__typeof__(v)) (align) - 1)
d4ad24a3 28
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29/*
30 * Align value to the previous multiple of align. Returns val if it already is a
31 * multiple of align. Align must be a power of two.
32 */
33#define __lttng_align_floor_mask(v, mask) ((v) & ~(mask))
d4ad24a3 34
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35#define lttng_align_floor(v, align) \
36 __lttng_align_floor_mask(v, (__typeof__(v)) (align) - 1)
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37
38/**
1cbd136b 39 * lttng_offset_align - Calculate the offset needed to align an object on its natural
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40 * alignment towards higher addresses.
41 * @align_drift: object offset from an "alignment"-aligned address.
42 * @alignment: natural object alignment. Must be non-zero, power of 2.
43 *
44 * Returns the offset that must be added to align towards higher
45 * addresses.
46 */
1cbd136b 47#define lttng_offset_align(align_drift, alignment) \
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48 ({ \
49 LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
50 || ((alignment) & ((alignment) - 1))); \
51 (((alignment) - (align_drift)) & ((alignment) - 1)); \
52 })
53
54/**
1cbd136b 55 * lttng_offset_align_floor - Calculate the offset needed to align an object
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56 * on its natural alignment towards lower addresses.
57 * @align_drift: object offset from an "alignment"-aligned address.
58 * @alignment: natural object alignment. Must be non-zero, power of 2.
59 *
60 * Returns the offset that must be substracted to align towards lower addresses.
61 */
1cbd136b 62#define lttng_offset_align_floor(align_drift, alignment) \
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63 ({ \
64 LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
65 || ((alignment) & ((alignment) - 1))); \
d07ceecd 66 (((align_drift) - (alignment)) & ((alignment) - 1)); \
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67 })
68
69#endif /* _LTTNG_ALIGN_H */
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