locked_memory_allocator.hpp

// Copyright Take Vos 2021.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include <type_traits>
#include <cstddef>
 
namespace tt {
 
[[nodiscard]] std::byte *locked_memory_allocator_allocate(size_t n) noexcept;
 
void locked_memory_allocator_deallocate(std::byte *p, size_t n) noexcept;
 
template<typename T>
class locked_memory_allocator {
public:
    using value_type = T;
    using size_type = size_t;
    using difference_type = ptrdiff_t;
 
    template<typename U>
    struct rebind {
        using other = locked_memory_allocator<U>;
    };
 
    constexpr locked_memory_allocator() noexcept {};
 
    constexpr locked_memory_allocator(locked_memory_allocator const &other) noexcept {}
 
    template<typename U>
    constexpr locked_memory_allocator(locked_memory_allocator<U> const &other) noexcept {}
 
    [[nodiscard]] value_type *allocate(size_type n) const noexcept
    {
        auto *p = locked_memory_allocator_allocate(n * sizeof(value_type));
        return reinterpret_cast<value_type *>(p);
    }
 
    void deallocate(value_type *p, size_type n) const noexcept
    {
        locked_memory_allocator_deallocate(reinterpret_cast<std::byte *>(p), n * sizeof(value_type));
    }
};
 
}