123 lines
3.4 KiB
C++
123 lines
3.4 KiB
C++
// SPDX-FileCopyrightText: 2014 Jannik Vogel <email@jannikvogel.de>
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// SPDX-License-Identifier: CC0-1.0
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#pragma once
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#include <bit>
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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_integral_v<T>
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[[nodiscard]] constexpr T AlignUp(T value_, size_t size) {
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using U = typename std::make_unsigned_t<T>;
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auto value{static_cast<U>(value_)};
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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_integral_v<T>
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[[nodiscard]] constexpr T AlignDown(T value_, size_t size) {
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using U = typename std::make_unsigned_t<T>;
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const auto value{static_cast<U>(value_)};
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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>
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requires std::is_integral_v<T>
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[[nodiscard]] constexpr T LeastSignificantOneBit(T x) {
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return x & ~(x - 1);
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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 T ResetLeastSignificantOneBit(T x) {
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return x & (x - 1);
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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 IsPowerOfTwo(T x) {
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return x > 0 && ResetLeastSignificantOneBit(x) == 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 T FloorPowerOfTwo(T x) {
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return T{1} << (sizeof(T) * 8 - std::countl_zero(x) - 1);
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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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