alignment: Simplify AlignmentAllocator implementation

With C++20, much of the allocator interface has been simplified, so we
can make the same adjustments.
This commit is contained in:
Lioncash 2020-07-17 07:26:59 -04:00
parent 47956a3bbc
commit 723edb4c06

View File

@ -3,7 +3,6 @@
#pragma once #pragma once
#include <cstddef> #include <cstddef>
#include <memory>
#include <type_traits> #include <type_traits>
namespace Common { namespace Common {
@ -54,66 +53,28 @@ public:
using size_type = std::size_t; using size_type = std::size_t;
using difference_type = std::ptrdiff_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_copy_assignment = std::true_type;
using propagate_on_container_move_assignment = std::true_type; using propagate_on_container_move_assignment = std::true_type;
using propagate_on_container_swap = std::true_type; using propagate_on_container_swap = std::true_type;
using is_always_equal = std::true_type; using is_always_equal = std::true_type;
public:
constexpr AlignmentAllocator() noexcept = default; constexpr AlignmentAllocator() noexcept = default;
template <typename T2> template <typename T2>
constexpr AlignmentAllocator(const AlignmentAllocator<T2, Align>&) noexcept {} constexpr AlignmentAllocator(const AlignmentAllocator<T2, Align>&) noexcept {}
pointer address(reference r) noexcept { T* allocate(size_type n) {
return std::addressof(r); return static_cast<T*>(::operator new (n * sizeof(T), std::align_val_t{Align}));
} }
const_pointer address(const_reference r) const noexcept { void deallocate(T* p, size_type n) {
return std::addressof(r); ::operator delete (p, n * sizeof(T), std::align_val_t{Align});
}
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> template <typename T2>
struct rebind { struct rebind {
using other = AlignmentAllocator<T2, Align>; 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 } // namespace Common