120 lines
3.3 KiB
C++
120 lines
3.3 KiB
C++
// This file is under the public domain.
|
|
|
|
#pragma once
|
|
|
|
#include <cstddef>
|
|
#include <memory>
|
|
#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 pointer = T*;
|
|
using const_pointer = const T*;
|
|
|
|
using reference = T&;
|
|
using const_reference = const 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;
|
|
|
|
public:
|
|
constexpr AlignmentAllocator() noexcept = default;
|
|
|
|
template <typename T2>
|
|
constexpr AlignmentAllocator(const AlignmentAllocator<T2, Align>&) noexcept {}
|
|
|
|
pointer address(reference r) noexcept {
|
|
return std::addressof(r);
|
|
}
|
|
|
|
const_pointer address(const_reference r) const noexcept {
|
|
return std::addressof(r);
|
|
}
|
|
|
|
pointer allocate(size_type n) {
|
|
return static_cast<pointer>(::operator new (n, std::align_val_t{Align}));
|
|
}
|
|
|
|
void deallocate(pointer p, size_type) {
|
|
::operator delete (p, std::align_val_t{Align});
|
|
}
|
|
|
|
void construct(pointer p, const value_type& wert) {
|
|
new (p) value_type(wert);
|
|
}
|
|
|
|
void destroy(pointer p) {
|
|
p->~value_type();
|
|
}
|
|
|
|
size_type max_size() const noexcept {
|
|
return size_type(-1) / sizeof(value_type);
|
|
}
|
|
|
|
template <typename T2>
|
|
struct rebind {
|
|
using other = AlignmentAllocator<T2, Align>;
|
|
};
|
|
|
|
bool operator!=(const AlignmentAllocator<T, Align>& other) const noexcept {
|
|
return !(*this == other);
|
|
}
|
|
|
|
// Returns true if and only if storage allocated from *this
|
|
// can be deallocated from other, and vice versa.
|
|
// Always returns true for stateless allocators.
|
|
bool operator==(const AlignmentAllocator<T, Align>& other) const noexcept {
|
|
return true;
|
|
}
|
|
};
|
|
|
|
} // namespace Common
|