projects / babeltrace.git / blame
| Commit | Line | Data |
|---|---|---|
| d79865b9 MD |
1 | #ifndef _BABELTRACE_ALIGN_H |
| 2 | #define _BABELTRACE_ALIGN_H | |
| 6dc2ca62 | 3 | |
| de0ba614 | 4 | /* |
| d79865b9 | 5 | * BabelTrace align.h - alignment header |
| de0ba614 MD |
6 | * |
| 7 | * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 8 | * | |
| 9 | * This library is free software; you can redistribute it and/or | |
| 10 | * modify it under the terms of the GNU Lesser General Public | |
| 11 | * License as published by the Free Software Foundation; either | |
| 12 | * version 2.1 of the License, or (at your option) any later version. | |
| 13 | * | |
| 14 | * This library is distributed in the hope that it will be useful, | |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 17 | * Lesser General Public License for more details. | |
| 18 | * | |
| 19 | * You should have received a copy of the GNU Lesser General Public | |
| 20 | * License along with this library; if not, write to the Free Software | |
| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| 22 | */ | |
| 23 | ||
| 6dc2ca62 MD |
24 | #include <ctf/compiler.h> |
| 25 | ||
| 26 | #define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a) - 1) | |
| 27 | #define __ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask)) | |
| 28 | #define PTR_ALIGN(p, a) ((typeof(p)) ALIGN((unsigned long) (p), a)) | |
| 29 | #define ALIGN_FLOOR(x, a) __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1) | |
| 30 | #define __ALIGN_FLOOR_MASK(x, mask) ((x) & ~(mask)) | |
| 31 | #define PTR_ALIGN_FLOOR(p, a) \ | |
| 32 | ((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a)) | |
| 33 | #define IS_ALIGNED(x, a) (((x) & ((typeof(x)) (a) - 1)) == 0) | |
| 34 | ||
| 35 | /* | |
| 36 | * Align pointer on natural object alignment. | |
| 37 | */ | |
| 38 | #define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj))) | |
| 39 | #define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj))) | |
| 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 | ({ \ | |
| 52 | MAYBE_BUILD_BUG_ON((alignment) == 0 \ | |
| 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 | ({ \ | |
| 67 | MAYBE_BUILD_BUG_ON((alignment) == 0 \ | |
| 68 | || ((alignment) & ((alignment) - 1))); \ | |
| 69 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
| 70 | }) | |
| 71 | ||
| d79865b9 | 72 | #endif /* _BABELTRACE_ALIGN_H */ |