1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
// This file is under the public domain.
#pragma once
#include <cstddef>
#include <new>
#include <type_traits>
namespace Common {
template <typename T>
constexpr T AlignUp(T value, std::size_t size) {
static_assert(std::is_unsigned_v<T>, "T must be an unsigned value.");
auto mod{static_cast<T>(value % size)};
value -= mod;
return static_cast<T>(mod == T{0} ? value : value + size);
}
template <typename T>
constexpr T AlignDown(T value, std::size_t size) {
static_assert(std::is_unsigned_v<T>, "T must be an unsigned value.");
return static_cast<T>(value - value % size);
}
template <typename T>
constexpr T AlignBits(T value, std::size_t align) {
static_assert(std::is_unsigned_v<T>, "T must be an unsigned value.");
return static_cast<T>((value + ((1ULL << align) - 1)) >> align << align);
}
template <typename T>
constexpr bool Is4KBAligned(T value) {
static_assert(std::is_unsigned_v<T>, "T must be an unsigned value.");
return (value & 0xFFF) == 0;
}
template <typename T>
constexpr bool IsWordAligned(T value) {
static_assert(std::is_unsigned_v<T>, "T must be an unsigned value.");
return (value & 0b11) == 0;
}
template <typename T>
constexpr bool IsAligned(T value, std::size_t alignment) {
using U = typename std::make_unsigned<T>::type;
const U mask = static_cast<U>(alignment - 1);
return (value & mask) == 0;
}
template <typename T, std::size_t Align = 16>
class AlignmentAllocator {
public:
using value_type = T;
using size_type = std::size_t;
using difference_type = std::ptrdiff_t;
using propagate_on_container_copy_assignment = std::true_type;
using propagate_on_container_move_assignment = std::true_type;
using propagate_on_container_swap = std::true_type;
using is_always_equal = std::true_type;
constexpr AlignmentAllocator() noexcept = default;
template <typename T2>
constexpr AlignmentAllocator(const AlignmentAllocator<T2, Align>&) noexcept {}
T* allocate(size_type n) {
return static_cast<T*>(::operator new (n * sizeof(T), std::align_val_t{Align}));
}
void deallocate(T* p, size_type n) {
::operator delete (p, n * sizeof(T), std::align_val_t{Align});
}
template <typename T2>
struct rebind {
using other = AlignmentAllocator<T2, Align>;
};
};
} // namespace Common
|
