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1 | #ifndef _UST_ALIGN_H |
2 | #define _UST_ALIGN_H | |
3 | ||
4 | /* | |
4318ae1b | 5 | * lttng/align.h |
8c4127c5 MD |
6 | * |
7 | * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
e92f3e28 MD |
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: | |
a60d70e6 | 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 | ||
4318ae1b | 20 | #include <lttng/bug.h> |
993e8a49 | 21 | #include <unistd.h> |
8e3484cf | 22 | #include <limits.h> |
8c4127c5 | 23 | |
8e3484cf | 24 | #ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE */ |
993e8a49 | 25 | #define PAGE_SIZE sysconf(_SC_PAGE_SIZE) |
8e3484cf MD |
26 | #endif |
27 | ||
993e8a49 MD |
28 | #define PAGE_MASK (~(PAGE_SIZE - 1)) |
29 | #define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask)) | |
6423c313 | 30 | #define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1) |
993e8a49 | 31 | #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE) |
8c4127c5 MD |
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 | ({ \ | |
3f12fcef | 44 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ |
8c4127c5 MD |
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 | ({ \ | |
3f12fcef | 59 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ |
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60 | || ((alignment) & ((alignment) - 1))); \ |
61 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
62 | }) | |
63 | ||
64 | #endif /* _UST_ALIGN_H */ |