diff options
Diffstat (limited to 'src/common/alignment.h')
-rw-r--r-- | src/common/alignment.h | 69 |
1 files changed, 20 insertions, 49 deletions
diff --git a/src/common/alignment.h b/src/common/alignment.h index cdd4833f81..5040043de9 100644 --- a/src/common/alignment.h +++ b/src/common/alignment.h @@ -3,41 +3,50 @@ #pragma once #include <cstddef> -#include <memory> +#include <new> #include <type_traits> namespace Common { template <typename T> -constexpr T AlignUp(T value, std::size_t size) { +[[nodiscard]] constexpr T AlignUp(T value, std::size_t size) { static_assert(std::is_unsigned_v<T>, "T must be an unsigned value."); - return static_cast<T>(value + (size - value % size) % size); + 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) { +[[nodiscard]] 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) { +[[nodiscard]] 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) { +[[nodiscard]] 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) { +[[nodiscard]] 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> +[[nodiscard]] 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: @@ -45,66 +54,28 @@ public: 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})); + [[nodiscard]] T* allocate(size_type n) { + return static_cast<T*>(::operator new (n * sizeof(T), 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); + void deallocate(T* p, size_type n) { + ::operator delete (p, n * sizeof(T), std::align_val_t{Align}); } 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 |