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// Copyright (C) 2015-2025 Jonathan Müller and foonathan/memory contributors
// SPDX-License-Identifier: Zlib
#ifndef FOONATHAN_MEMORY_DETAIL_ALIGN_HPP_INCLUDED
#define FOONATHAN_MEMORY_DETAIL_ALIGN_HPP_INCLUDED
#include <cstdint>
#include "../config.hpp"
#include "assert.hpp"
namespace foonathan
{
namespace memory
{
namespace detail
{
// whether or not an alignment is valid, i.e. a power of two not zero
constexpr bool is_valid_alignment(std::size_t alignment) noexcept
{
return alignment && (alignment & (alignment - 1)) == 0u;
}
constexpr std::size_t round_up_to_multiple_of_alignment(std::size_t size,
std::size_t alignment) noexcept
{
FOONATHAN_MEMORY_ASSERT(is_valid_alignment(alignment));
return (size + alignment - 1) & ~(alignment - 1);
}
// returns the offset needed to align ptr for given alignment
// alignment must be valid
inline std::size_t align_offset(std::uintptr_t address, std::size_t alignment) noexcept
{
FOONATHAN_MEMORY_ASSERT(is_valid_alignment(alignment));
auto misaligned = address & (alignment - 1);
return misaligned != 0 ? (alignment - misaligned) : 0;
}
inline std::size_t align_offset(void* ptr, std::size_t alignment) noexcept
{
return align_offset(reinterpret_cast<std::uintptr_t>(ptr), alignment);
}
// whether or not the pointer is aligned for given alignment
// alignment must be valid
bool is_aligned(void* ptr, std::size_t alignment) noexcept;
// maximum alignment value
constexpr std::size_t max_alignment = alignof(std::max_align_t);
static_assert(is_valid_alignment(max_alignment), "ehm..?");
// returns the minimum alignment required for a node of given size
std::size_t alignment_for(std::size_t size) noexcept;
} // namespace detail
} // namespace memory
} // namespace foonathan
#endif // FOONATHAN_MEMORY_DETAIL_ALIGN_HPP_INCLUDED
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