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1 | #ifndef _LTTNG_ALIGN_H |
2 | #define _LTTNG_ALIGN_H | |
3 | ||
4 | /* | |
5 | * align.h | |
6 | * | |
7 | * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
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: | |
15 | * | |
16 | * The above copyright notice and this permission notice shall be included in | |
17 | * all copies or substantial portions of the Software. | |
18 | */ | |
19 | ||
8564ccbd | 20 | #include "bug.h" |
953192ba MD |
21 | #include <unistd.h> |
22 | #include <limits.h> | |
23 | ||
d575a7f8 | 24 | #ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE. */ |
953192ba MD |
25 | #define PAGE_SIZE sysconf(_SC_PAGE_SIZE) |
26 | #endif | |
27 | ||
d575a7f8 | 28 | #ifndef PAGE_MASK /* macOS defines its own PAGE_MASK. */ |
953192ba | 29 | #define PAGE_MASK (~(PAGE_SIZE - 1)) |
d575a7f8 FD |
30 | #endif |
31 | ||
953192ba | 32 | #define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask)) |
d575a7f8 FD |
33 | |
34 | #ifndef ALIGN /* macOS defines its own ALIGN. */ | |
953192ba | 35 | #define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1) |
d575a7f8 FD |
36 | #endif |
37 | ||
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38 | #define __ALIGN_FLOOR_MASK(v, mask) ((v) & ~(mask)) |
39 | ||
40 | #ifndef ALIGN_FLOOR | |
41 | #define ALIGN_FLOOR(v, align) __ALIGN_FLOOR_MASK(v, (__typeof__(v)) (align) - 1) | |
42 | #endif | |
43 | ||
953192ba MD |
44 | #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE) |
45 | ||
46 | /** | |
47 | * offset_align - Calculate the offset needed to align an object on its natural | |
48 | * alignment towards higher addresses. | |
49 | * @align_drift: object offset from an "alignment"-aligned address. | |
50 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
51 | * | |
52 | * Returns the offset that must be added to align towards higher | |
53 | * addresses. | |
54 | */ | |
55 | #define offset_align(align_drift, alignment) \ | |
56 | ({ \ | |
57 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
58 | || ((alignment) & ((alignment) - 1))); \ | |
59 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ | |
60 | }) | |
61 | ||
62 | /** | |
63 | * offset_align_floor - Calculate the offset needed to align an object | |
64 | * on its natural alignment towards lower addresses. | |
65 | * @align_drift: object offset from an "alignment"-aligned address. | |
66 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
67 | * | |
68 | * Returns the offset that must be substracted to align towards lower addresses. | |
69 | */ | |
70 | #define offset_align_floor(align_drift, alignment) \ | |
71 | ({ \ | |
72 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
73 | || ((alignment) & ((alignment) - 1))); \ | |
d07ceecd | 74 | (((align_drift) - (alignment)) & ((alignment) - 1)); \ |
953192ba MD |
75 | }) |
76 | ||
77 | #endif /* _LTTNG_ALIGN_H */ |