139 lines
3.4 KiB
C++
139 lines
3.4 KiB
C++
//
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// recycling_allocator.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_RECYCLING_ALLOCATOR_HPP
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#define ASIO_RECYCLING_ALLOCATOR_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include "asio/detail/recycling_allocator.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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/// An allocator that caches memory blocks in thread-local storage for reuse.
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/**
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* The @recycling_allocator uses a simple strategy where a limited number of
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* small memory blocks are cached in thread-local storage, if the current
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* thread is running an @c io_context or is part of a @c thread_pool.
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*/
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template <typename T>
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class recycling_allocator
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{
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public:
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/// The type of object allocated by the recycling allocator.
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typedef T value_type;
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/// Rebind the allocator to another value_type.
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template <typename U>
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struct rebind
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{
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/// The rebound @c allocator type.
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typedef recycling_allocator<U> other;
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};
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/// Default constructor.
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ASIO_CONSTEXPR recycling_allocator() ASIO_NOEXCEPT
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{
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}
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/// Converting constructor.
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template <typename U>
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ASIO_CONSTEXPR recycling_allocator(
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const recycling_allocator<U>&) ASIO_NOEXCEPT
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{
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}
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/// Equality operator. Always returns true.
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ASIO_CONSTEXPR bool operator==(
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const recycling_allocator&) const ASIO_NOEXCEPT
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{
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return true;
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}
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/// Inequality operator. Always returns false.
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ASIO_CONSTEXPR bool operator!=(
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const recycling_allocator&) const ASIO_NOEXCEPT
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{
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return false;
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}
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/// Allocate memory for the specified number of values.
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T* allocate(std::size_t n)
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{
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return detail::recycling_allocator<T>().allocate(n);
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}
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/// Deallocate memory for the specified number of values.
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void deallocate(T* p, std::size_t n)
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{
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detail::recycling_allocator<T>().deallocate(p, n);
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}
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};
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/// A proto-allocator that caches memory blocks in thread-local storage for
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/// reuse.
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/**
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* The @recycling_allocator uses a simple strategy where a limited number of
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* small memory blocks are cached in thread-local storage, if the current
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* thread is running an @c io_context or is part of a @c thread_pool.
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*/
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template <>
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class recycling_allocator<void>
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{
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public:
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/// No values are allocated by a proto-allocator.
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typedef void value_type;
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/// Rebind the allocator to another value_type.
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template <typename U>
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struct rebind
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{
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/// The rebound @c allocator type.
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typedef recycling_allocator<U> other;
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};
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/// Default constructor.
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ASIO_CONSTEXPR recycling_allocator() ASIO_NOEXCEPT
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{
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}
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/// Converting constructor.
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template <typename U>
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ASIO_CONSTEXPR recycling_allocator(
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const recycling_allocator<U>&) ASIO_NOEXCEPT
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{
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}
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/// Equality operator. Always returns true.
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ASIO_CONSTEXPR bool operator==(
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const recycling_allocator&) const ASIO_NOEXCEPT
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{
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return true;
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}
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/// Inequality operator. Always returns false.
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ASIO_CONSTEXPR bool operator!=(
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const recycling_allocator&) const ASIO_NOEXCEPT
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{
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return false;
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}
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};
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#endif // ASIO_RECYCLING_ALLOCATOR_HPP
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