Dune Core Modules (2.4.1)

alignment.hh
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1// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2// vi: set et ts=4 sw=2 sts=2:
3#ifndef DUNE_ALIGNMENT_HH
4#define DUNE_ALIGNMENT_HH
5
6#include <cstddef>
7#include <type_traits>
8
9namespace Dune
10{
11
23 namespace
24 {
25
30 template<class T>
31 struct AlignmentStruct
32 {
33 char c;
34 T t;
35 void hack();
36 };
37
42 template<class T, std::size_t N>
43 struct AlignmentHelper
44 {
45 enum { N2 = sizeof(AlignmentStruct<T>) - sizeof(T) - N };
46 char padding1[N];
47 T t;
48 char padding2[N2];
49 };
50
51#define ALIGNMENT_MODULO(a, b) (a % b == 0 ? \
52 static_cast<std::size_t>(b) : \
53 static_cast<std::size_t>(a % b))
54#define ALIGNMENT_MIN(a, b) (static_cast<std::size_t>(a) < \
55 static_cast<std::size_t>(b) ? \
56 static_cast<std::size_t>(a) : \
57 static_cast<std::size_t>(b))
59 template <class T, std::size_t N>
60 struct AlignmentTester
61 {
62 typedef AlignmentStruct<T> s;
63 typedef AlignmentHelper<T, N> h;
64 typedef AlignmentTester<T, N - 1> next;
65 enum
66 {
67 a1 = ALIGNMENT_MODULO(N , sizeof(T)),
68 a2 = ALIGNMENT_MODULO(h::N2 , sizeof(T)),
69 a3 = ALIGNMENT_MODULO(sizeof(h), sizeof(T)),
70 a = sizeof(h) == sizeof(s) ? ALIGNMENT_MIN(a1, a2) : a3,
71 result = ALIGNMENT_MIN(a, next::result)
72 };
73 };
74
76 template <class T>
77 struct AlignmentTester<T, 0>
78 {
79 enum
80 {
81 result = ALIGNMENT_MODULO(sizeof(AlignmentStruct<T>), sizeof(T))
82 };
83 };
84 } //end anonymous namespace
85
94 template <class T>
96 {
97
98 enum
99 {
101 value = std::alignment_of<T>::value
102 };
103 };
104
106}
107#endif
Dune namespace.
Definition: alignment.hh:10
Calculates the alignment requirement of a type.
Definition: alignment.hh:96
@ value
The alignment requirement.
Definition: alignment.hh:101
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