projects / lttng-ust.git / blame
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1 | #ifndef _UST_ALIGN_H |
| 2 | #define _UST_ALIGN_H | |
| 3 | ||
| 4 | /* | |
| 4318ae1b | 5 | * lttng/align.h |
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6 | * |
| 7 | * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 8 | * | |
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9 | * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED |
| 10 | * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. | |
| 11 | * | |
| 12 | * Permission is hereby granted to use or copy this program | |
| 13 | * for any purpose, provided the above notices are retained on all copies. | |
| 14 | * Permission to modify the code and to distribute modified code is granted, | |
| 15 | * provided the above notices are retained, and a notice that the code was | |
| 16 | * modified is included with the above copyright notice. | |
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17 | */ |
| 18 | ||
| 4318ae1b | 19 | #include <lttng/bug.h> |
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20 | |
| 21 | /* | |
| 22 | * Align pointer on natural object alignment. | |
| 23 | */ | |
| 24 | #define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj))) | |
| 25 | #define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj))) | |
| 26 | ||
| 27 | /** | |
| 28 | * offset_align - Calculate the offset needed to align an object on its natural | |
| 29 | * alignment towards higher addresses. | |
| 30 | * @align_drift: object offset from an "alignment"-aligned address. | |
| 31 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
| 32 | * | |
| 33 | * Returns the offset that must be added to align towards higher | |
| 34 | * addresses. | |
| 35 | */ | |
| 36 | #define offset_align(align_drift, alignment) \ | |
| 37 | ({ \ | |
| 38 | BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
| 39 | || ((alignment) & ((alignment) - 1))); \ | |
| 40 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ | |
| 41 | }) | |
| 42 | ||
| 43 | /** | |
| 44 | * offset_align_floor - Calculate the offset needed to align an object | |
| 45 | * on its natural alignment towards lower addresses. | |
| 46 | * @align_drift: object offset from an "alignment"-aligned address. | |
| 47 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
| 48 | * | |
| 49 | * Returns the offset that must be substracted to align towards lower addresses. | |
| 50 | */ | |
| 51 | #define offset_align_floor(align_drift, alignment) \ | |
| 52 | ({ \ | |
| 53 | BUILD_RUNTIME_BUG_ON((alignment) == 0 \ | |
| 54 | || ((alignment) & ((alignment) - 1))); \ | |
| 55 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
| 56 | }) | |
| 57 | ||
| 58 | #endif /* _UST_ALIGN_H */ |