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
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
#ifndef AL_MALLOC_H
#define AL_MALLOC_H
#include <stddef.h>
#include <memory>
#include <limits>
#include <algorithm>
/* Minimum alignment required by posix_memalign. */
#define DEF_ALIGN sizeof(void*)
void *al_malloc(size_t alignment, size_t size);
void *al_calloc(size_t alignment, size_t size);
void al_free(void *ptr) noexcept;
size_t al_get_page_size(void) noexcept;
/**
* Returns non-0 if the allocation function has direct alignment handling.
* Otherwise, the standard malloc is used with an over-allocation and pointer
* offset strategy.
*/
int al_is_sane_alignment_allocator(void) noexcept;
#define DEF_NEWDEL(T) \
void *operator new(size_t size) \
{ \
void *ret = al_malloc(alignof(T), size); \
if(!ret) throw std::bad_alloc(); \
return ret; \
} \
void operator delete(void *block) noexcept { al_free(block); }
#define DEF_PLACE_NEWDEL() \
void *operator new(size_t /*size*/, void *ptr) noexcept { return ptr; } \
void operator delete(void *block) noexcept { al_free(block); } \
void operator delete(void* /*block*/, void* /*ptr*/) noexcept { }
namespace al {
template<typename T, size_t alignment=DEF_ALIGN>
struct allocator : public std::allocator<T> {
using size_type = size_t;
using pointer = T*;
using const_pointer = const T*;
template<typename U>
struct rebind {
using other = allocator<U, alignment>;
};
pointer allocate(size_type n, const void* = nullptr)
{
if(n > std::numeric_limits<size_t>::max() / sizeof(T))
throw std::bad_alloc();
void *ret{al_malloc(alignment, n*sizeof(T))};
if(!ret) throw std::bad_alloc();
return static_cast<pointer>(ret);
}
void deallocate(pointer p, size_type)
{ al_free(p); }
allocator() : std::allocator<T>() { }
allocator(const allocator &a) : std::allocator<T>(a) { }
template<class U>
allocator(const allocator<U,alignment> &a) : std::allocator<T>(a)
{ }
};
template<size_t alignment, typename T>
inline T* assume_aligned(T *ptr) noexcept
{
static_assert((alignment & (alignment-1)) == 0, "alignment must be a power of 2");
#ifdef __GNUC__
return static_cast<T*>(__builtin_assume_aligned(ptr, alignment));
#elif defined(_MSC_VER)
auto ptrval = reinterpret_cast<uintptr_t>(ptr);
if((ptrval&(alignment-1)) != 0) __assume(0);
return reinterpret_cast<T*>(ptrval);
#else
return ptr;
#endif
}
/* std::make_unique was added with C++14, so until we rely on that, make our
* own version.
*/
template<typename T, typename ...ArgsT>
std::unique_ptr<T> make_unique(ArgsT&&...args)
{ return std::unique_ptr<T>{new T{std::forward<ArgsT>(args)...}}; }
/* A flexible array type. Used either standalone or at the end of a parent
* struct, with placement new, to have a run-time-sized array that's embedded
* with its size.
*/
template<typename T,size_t alignment=DEF_ALIGN>
struct FlexArray {
const size_t mSize;
alignas(alignment) T mArray[];
static constexpr size_t Sizeof(size_t count, size_t base=0u) noexcept
{
return base +
std::max<size_t>(offsetof(FlexArray, mArray) + sizeof(T)*count, sizeof(FlexArray));
}
FlexArray(size_t size) : mSize{size}
{ new (mArray) T[mSize]; }
~FlexArray()
{
for(size_t i{0u};i < mSize;++i)
mArray[i].~T();
}
FlexArray(const FlexArray&) = delete;
FlexArray& operator=(const FlexArray&) = delete;
size_t size() const noexcept { return mSize; }
T *data() noexcept { return mArray; }
const T *data() const noexcept { return mArray; }
T& operator[](size_t i) noexcept { return mArray[i]; }
const T& operator[](size_t i) const noexcept { return mArray[i]; }
T& front() noexcept { return mArray[0]; }
const T& front() const noexcept { return mArray[0]; }
T& back() noexcept { return mArray[mSize-1]; }
const T& back() const noexcept { return mArray[mSize-1]; }
T *begin() noexcept { return mArray; }
const T *begin() const noexcept { return mArray; }
const T *cbegin() const noexcept { return mArray; }
T *end() noexcept { return mArray + mSize; }
const T *end() const noexcept { return mArray + mSize; }
const T *cend() const noexcept { return mArray + mSize; }
DEF_PLACE_NEWDEL()
};
} // namespace al
#endif /* AL_MALLOC_H */
|
