1841f63a40
VS2022 seems to introduce an optimization when moving vectors to check for equality of the element values. AlignmentAllocator needed to overload the equality operator to fix compilation of its usage in vector moving.
93 lines
2.5 KiB
C++
93 lines
2.5 KiB
C++
// This file is under the public domain.
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#pragma once
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#include <cstddef>
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#include <new>
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#include <type_traits>
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namespace Common {
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template <typename T>
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requires std::is_unsigned_v<T>
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[[nodiscard]] constexpr T AlignUp(T value, size_t size) {
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auto mod{static_cast<T>(value % size)};
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value -= mod;
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return static_cast<T>(mod == T{0} ? value : value + size);
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}
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template <typename T>
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requires std::is_unsigned_v<T>
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[[nodiscard]] constexpr T AlignUpLog2(T value, size_t align_log2) {
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return static_cast<T>((value + ((1ULL << align_log2) - 1)) >> align_log2 << align_log2);
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}
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template <typename T>
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requires std::is_unsigned_v<T>
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[[nodiscard]] constexpr T AlignDown(T value, size_t size) {
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return static_cast<T>(value - value % size);
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}
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template <typename T>
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requires std::is_unsigned_v<T>
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[[nodiscard]] constexpr bool Is4KBAligned(T value) {
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return (value & 0xFFF) == 0;
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}
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template <typename T>
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requires std::is_unsigned_v<T>
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[[nodiscard]] constexpr bool IsWordAligned(T value) {
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return (value & 0b11) == 0;
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}
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template <typename T>
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requires std::is_integral_v<T>
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[[nodiscard]] constexpr bool IsAligned(T value, size_t alignment) {
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using U = typename std::make_unsigned_t<T>;
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const U mask = static_cast<U>(alignment - 1);
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return (value & mask) == 0;
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}
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template <typename T, typename U>
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requires std::is_integral_v<T>
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[[nodiscard]] constexpr T DivideUp(T x, U y) {
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return (x + (y - 1)) / y;
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}
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template <typename T, size_t Align = 16>
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class AlignmentAllocator {
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public:
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using value_type = T;
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using size_type = size_t;
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using difference_type = ptrdiff_t;
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using propagate_on_container_copy_assignment = std::true_type;
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using propagate_on_container_move_assignment = std::true_type;
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using propagate_on_container_swap = std::true_type;
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using is_always_equal = std::false_type;
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constexpr AlignmentAllocator() noexcept = default;
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template <typename T2>
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constexpr AlignmentAllocator(const AlignmentAllocator<T2, Align>&) noexcept {}
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[[nodiscard]] T* allocate(size_type n) {
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return static_cast<T*>(::operator new (n * sizeof(T), std::align_val_t{Align}));
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}
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void deallocate(T* p, size_type n) {
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::operator delete (p, n * sizeof(T), std::align_val_t{Align});
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}
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template <typename T2>
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struct rebind {
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using other = AlignmentAllocator<T2, Align>;
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};
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template <typename T2, size_t Align2>
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constexpr bool operator==(const AlignmentAllocator<T2, Align2>&) const noexcept {
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return std::is_same_v<T, T2> && Align == Align2;
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}
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};
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} // namespace Common
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