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 | * 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 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| 20 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| 21 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| 22 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| 23 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| 24 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| 25 | * SOFTWARE. | |
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26 | */ |
| 27 | ||
| 4318ae1b | 28 | #include <lttng/bug.h> |
| 993e8a49 | 29 | #include <unistd.h> |
| 8e3484cf | 30 | #include <limits.h> |
| 8c4127c5 | 31 | |
| 8e3484cf | 32 | #ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE */ |
| 993e8a49 | 33 | #define PAGE_SIZE sysconf(_SC_PAGE_SIZE) |
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34 | #endif |
| 35 | ||
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36 | #define PAGE_MASK (~(PAGE_SIZE - 1)) |
| 37 | #define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask)) | |
| 6423c313 | 38 | #define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1) |
| 993e8a49 | 39 | #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE) |
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40 | |
| 41 | /** | |
| 42 | * offset_align - Calculate the offset needed to align an object on its natural | |
| 43 | * alignment towards higher addresses. | |
| 44 | * @align_drift: object offset from an "alignment"-aligned address. | |
| 45 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
| 46 | * | |
| 47 | * Returns the offset that must be added to align towards higher | |
| 48 | * addresses. | |
| 49 | */ | |
| 50 | #define offset_align(align_drift, alignment) \ | |
| 51 | ({ \ | |
| 3f12fcef | 52 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ |
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53 | || ((alignment) & ((alignment) - 1))); \ |
| 54 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ | |
| 55 | }) | |
| 56 | ||
| 57 | /** | |
| 58 | * offset_align_floor - Calculate the offset needed to align an object | |
| 59 | * on its natural alignment towards lower addresses. | |
| 60 | * @align_drift: object offset from an "alignment"-aligned address. | |
| 61 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
| 62 | * | |
| 63 | * Returns the offset that must be substracted to align towards lower addresses. | |
| 64 | */ | |
| 65 | #define offset_align_floor(align_drift, alignment) \ | |
| 66 | ({ \ | |
| 3f12fcef | 67 | LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \ |
| 8c4127c5 | 68 | || ((alignment) & ((alignment) - 1))); \ |
| e7ec8848 | 69 | (((align_drift) - (alignment)) & ((alignment) - 1)); \ |
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70 | }) |
| 71 | ||
| 72 | #endif /* _UST_ALIGN_H */ |