projects / lttng-tools.git / blame
| Commit | Line | Data |
|---|---|---|
| 953192ba MD |
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))); \ | |
| 61 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
| 62 | }) | |
| 63 | ||
| 64 | #endif /* _LTTNG_ALIGN_H */ |