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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 | ||
24 | #ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE */ | |
25 | #define PAGE_SIZE sysconf(_SC_PAGE_SIZE) | |
26 | #endif | |
27 | ||
28 | #define PAGE_MASK (~(PAGE_SIZE - 1)) | |
29 | #define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask)) | |
30 | #define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1) | |
31 | #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE) | |
32 | ||
33 | /** | |
34 | * offset_align - Calculate the offset needed to align an object on its natural | |
35 | * alignment towards higher addresses. | |
36 | * @align_drift: object offset from an "alignment"-aligned address. | |
37 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
38 | * | |
39 | * Returns the offset that must be added to align towards higher | |
40 | * addresses. | |
41 | */ | |
42 | #define offset_align(align_drift, alignment) \ | |
43 | ({ \ | |
44 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
45 | || ((alignment) & ((alignment) - 1))); \ | |
46 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ | |
47 | }) | |
48 | ||
49 | /** | |
50 | * offset_align_floor - Calculate the offset needed to align an object | |
51 | * on its natural alignment towards lower addresses. | |
52 | * @align_drift: object offset from an "alignment"-aligned address. | |
53 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
54 | * | |
55 | * Returns the offset that must be substracted to align towards lower addresses. | |
56 | */ | |
57 | #define offset_align_floor(align_drift, alignment) \ | |
58 | ({ \ | |
59 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
60 | || ((alignment) & ((alignment) - 1))); \ | |
d07ceecd | 61 | (((align_drift) - (alignment)) & ((alignment) - 1)); \ |
953192ba MD |
62 | }) |
63 | ||
64 | #endif /* _LTTNG_ALIGN_H */ |