diff options
Diffstat (limited to 'lib/asio/associated_allocator.hpp')
-rw-r--r-- | lib/asio/associated_allocator.hpp | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/lib/asio/associated_allocator.hpp b/lib/asio/associated_allocator.hpp new file mode 100644 index 0000000..8b488bb --- /dev/null +++ b/lib/asio/associated_allocator.hpp @@ -0,0 +1,131 @@ +// +// associated_allocator.hpp +// ~~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// + +#ifndef ASIO_ASSOCIATED_ALLOCATOR_HPP +#define ASIO_ASSOCIATED_ALLOCATOR_HPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include "asio/detail/config.hpp" +#include <memory> +#include "asio/detail/type_traits.hpp" + +#include "asio/detail/push_options.hpp" + +namespace asio { +namespace detail { + +template <typename> +struct associated_allocator_check +{ + typedef void type; +}; + +template <typename T, typename E, typename = void> +struct associated_allocator_impl +{ + typedef E type; + + static type get(const T&, const E& e) ASIO_NOEXCEPT + { + return e; + } +}; + +template <typename T, typename E> +struct associated_allocator_impl<T, E, + typename associated_allocator_check<typename T::allocator_type>::type> +{ + typedef typename T::allocator_type type; + + static type get(const T& t, const E&) ASIO_NOEXCEPT + { + return t.get_allocator(); + } +}; + +} // namespace detail + +/// Traits type used to obtain the allocator associated with an object. +/** + * A program may specialise this traits type if the @c T template parameter in + * the specialisation is a user-defined type. The template parameter @c + * Allocator shall be a type meeting the Allocator requirements. + * + * Specialisations shall meet the following requirements, where @c t is a const + * reference to an object of type @c T, and @c a is an object of type @c + * Allocator. + * + * @li Provide a nested typedef @c type that identifies a type meeting the + * Allocator requirements. + * + * @li Provide a noexcept static member function named @c get, callable as @c + * get(t) and with return type @c type. + * + * @li Provide a noexcept static member function named @c get, callable as @c + * get(t,a) and with return type @c type. + */ +template <typename T, typename Allocator = std::allocator<void> > +struct associated_allocator +{ + /// If @c T has a nested type @c allocator_type, <tt>T::allocator_type</tt>. + /// Otherwise @c Allocator. +#if defined(GENERATING_DOCUMENTATION) + typedef see_below type; +#else // defined(GENERATING_DOCUMENTATION) + typedef typename detail::associated_allocator_impl<T, Allocator>::type type; +#endif // defined(GENERATING_DOCUMENTATION) + + /// If @c T has a nested type @c allocator_type, returns + /// <tt>t.get_allocator()</tt>. Otherwise returns @c a. + static type get(const T& t, + const Allocator& a = Allocator()) ASIO_NOEXCEPT + { + return detail::associated_allocator_impl<T, Allocator>::get(t, a); + } +}; + +/// Helper function to obtain an object's associated allocator. +/** + * @returns <tt>associated_allocator<T>::get(t)</tt> + */ +template <typename T> +inline typename associated_allocator<T>::type +get_associated_allocator(const T& t) ASIO_NOEXCEPT +{ + return associated_allocator<T>::get(t); +} + +/// Helper function to obtain an object's associated allocator. +/** + * @returns <tt>associated_allocator<T, Allocator>::get(t, a)</tt> + */ +template <typename T, typename Allocator> +inline typename associated_allocator<T, Allocator>::type +get_associated_allocator(const T& t, const Allocator& a) ASIO_NOEXCEPT +{ + return associated_allocator<T, Allocator>::get(t, a); +} + +#if defined(ASIO_HAS_ALIAS_TEMPLATES) + +template <typename T, typename Allocator = std::allocator<void> > +using associated_allocator_t + = typename associated_allocator<T, Allocator>::type; + +#endif // defined(ASIO_HAS_ALIAS_TEMPLATES) + +} // namespace asio + +#include "asio/detail/pop_options.hpp" + +#endif // ASIO_ASSOCIATED_ALLOCATOR_HPP |