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1 | #ifndef _BABELTRACE_ALIGN_H |
2 | #define _BABELTRACE_ALIGN_H | |
3 | ||
4 | /* | |
5 | * BabelTrace align.h - alignment header | |
6 | * | |
7 | * Copyright 2010 - 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 | * 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. | |
26 | */ | |
27 | ||
28 | #include <babeltrace/compiler.h> | |
29 | #include <unistd.h> | |
30 | #include <limits.h> | |
31 | ||
32 | #ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE */ | |
33 | #define PAGE_SIZE sysconf(_SC_PAGE_SIZE) | |
34 | #endif | |
35 | ||
36 | #define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a) - 1) | |
37 | #define __ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask)) | |
38 | #define PTR_ALIGN(p, a) ((typeof(p)) ALIGN((unsigned long) (p), a)) | |
39 | #define ALIGN_FLOOR(x, a) __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1) | |
40 | #define __ALIGN_FLOOR_MASK(x, mask) ((x) & ~(mask)) | |
41 | #define PTR_ALIGN_FLOOR(p, a) \ | |
42 | ((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a)) | |
43 | #define IS_ALIGNED(x, a) (((x) & ((typeof(x)) (a) - 1)) == 0) | |
44 | ||
45 | /* | |
46 | * Align pointer on natural object alignment. | |
47 | */ | |
48 | #define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj))) | |
49 | #define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj))) | |
50 | ||
51 | /** | |
52 | * offset_align - Calculate the offset needed to align an object on its natural | |
53 | * alignment towards higher addresses. | |
54 | * @align_drift: object offset from an "alignment"-aligned address. | |
55 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
56 | * | |
57 | * Returns the offset that must be added to align towards higher | |
58 | * addresses. | |
59 | */ | |
60 | #define offset_align(align_drift, alignment) \ | |
61 | ({ \ | |
62 | MAYBE_BUILD_BUG_ON((alignment) == 0 \ | |
63 | || ((alignment) & ((alignment) - 1))); \ | |
64 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ | |
65 | }) | |
66 | ||
67 | /** | |
68 | * offset_align_floor - Calculate the offset needed to align an object | |
69 | * on its natural alignment towards lower addresses. | |
70 | * @align_drift: object offset from an "alignment"-aligned address. | |
71 | * @alignment: natural object alignment. Must be non-zero, power of 2. | |
72 | * | |
73 | * Returns the offset that must be substracted to align towards lower addresses. | |
74 | */ | |
75 | #define offset_align_floor(align_drift, alignment) \ | |
76 | ({ \ | |
77 | MAYBE_BUILD_BUG_ON((alignment) == 0 \ | |
78 | || ((alignment) & ((alignment) - 1))); \ | |
79 | (((align_drift) - (alignment)) & ((alignment) - 1); \ | |
80 | }) | |
81 | ||
82 | #endif /* _BABELTRACE_ALIGN_H */ |