286 lines
5.9 KiB
C++
286 lines
5.9 KiB
C++
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/*
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Copyright 2017-2021 Glen Joseph Fernandes
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(glenjofe@gmail.com)
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Distributed under the Boost Software License, Version 1.0.
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(http://www.boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_CORE_POINTER_TRAITS_HPP
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#define BOOST_CORE_POINTER_TRAITS_HPP
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#include <boost/config.hpp>
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#include <boost/core/addressof.hpp>
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#include <cstddef>
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namespace boost {
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namespace detail {
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struct ptr_none { };
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template<class>
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struct ptr_valid {
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typedef void type;
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};
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template<class>
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struct ptr_first {
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typedef ptr_none type;
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};
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#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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template<template<class, class...> class T, class U, class... Args>
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struct ptr_first<T<U, Args...> > {
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typedef U type;
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};
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#else
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template<template<class> class T, class U>
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struct ptr_first<T<U> > {
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typedef U type;
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};
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template<template<class, class> class T, class U1, class U2>
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struct ptr_first<T<U1, U2> > {
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typedef U1 type;
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};
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template<template<class, class, class> class T, class U1, class U2, class U3>
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struct ptr_first<T<U1, U2, U3> > {
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typedef U1 type;
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};
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#endif
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template<class T, class = void>
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struct ptr_element {
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typedef typename ptr_first<T>::type type;
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};
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template<class T>
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struct ptr_element<T, typename ptr_valid<typename T::element_type>::type> {
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typedef typename T::element_type type;
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};
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template<class, class = void>
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struct ptr_difference {
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typedef std::ptrdiff_t type;
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};
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template<class T>
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struct ptr_difference<T,
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typename ptr_valid<typename T::difference_type>::type> {
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typedef typename T::difference_type type;
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};
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template<class, class>
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struct ptr_transform { };
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#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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template<template<class, class...> class T, class U, class... Args, class V>
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struct ptr_transform<T<U, Args...>, V> {
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typedef T<V, Args...> type;
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};
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#else
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template<template<class> class T, class U, class V>
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struct ptr_transform<T<U>, V> {
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typedef T<V> type;
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};
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template<template<class, class> class T, class U1, class U2, class V>
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struct ptr_transform<T<U1, U2>, V> {
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typedef T<V, U2> type;
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};
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template<template<class, class, class> class T,
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class U1, class U2, class U3, class V>
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struct ptr_transform<T<U1, U2, U3>, V> {
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typedef T<V, U2, U3> type;
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};
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#endif
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template<class T, class U, class = void>
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struct ptr_rebind
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: ptr_transform<T, U> { };
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#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
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template<class T, class U>
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struct ptr_rebind<T, U,
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typename ptr_valid<typename T::template rebind<U> >::type> {
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typedef typename T::template rebind<U> type;
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};
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#else
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template<class T, class U>
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struct ptr_rebind<T, U,
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typename ptr_valid<typename T::template rebind<U>::other>::type> {
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typedef typename T::template rebind<U>::other type;
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};
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#endif
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#if !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
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template<class T, class E>
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class ptr_to_expr {
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template<class>
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struct result {
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char x, y;
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};
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static E& source();
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template<class O>
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static auto check(int) -> result<decltype(O::pointer_to(source()))>;
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template<class>
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static char check(long);
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public:
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BOOST_STATIC_CONSTEXPR bool value = sizeof(check<T>(0)) > 1;
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};
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template<class T, class E>
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struct ptr_to_expr<T*, E> {
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BOOST_STATIC_CONSTEXPR bool value = true;
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};
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template<class T, class E>
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struct ptr_has_to {
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BOOST_STATIC_CONSTEXPR bool value = ptr_to_expr<T, E>::value;
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};
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#else
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template<class, class>
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struct ptr_has_to {
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BOOST_STATIC_CONSTEXPR bool value = true;
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};
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#endif
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template<class T>
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struct ptr_has_to<T, void> {
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BOOST_STATIC_CONSTEXPR bool value = false;
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};
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template<class T>
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struct ptr_has_to<T, const void> {
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BOOST_STATIC_CONSTEXPR bool value = false;
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};
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template<class T>
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struct ptr_has_to<T, volatile void> {
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BOOST_STATIC_CONSTEXPR bool value = false;
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};
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template<class T>
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struct ptr_has_to<T, const volatile void> {
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BOOST_STATIC_CONSTEXPR bool value = false;
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};
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template<class T, class E, bool = ptr_has_to<T, E>::value>
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struct ptr_to { };
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template<class T, class E>
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struct ptr_to<T, E, true> {
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static T pointer_to(E& v) {
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return T::pointer_to(v);
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}
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};
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template<class T>
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struct ptr_to<T*, T, true> {
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static T* pointer_to(T& v) BOOST_NOEXCEPT {
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return boost::addressof(v);
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}
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};
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template<class T, class E>
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struct ptr_traits
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: ptr_to<T, E> {
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typedef T pointer;
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typedef E element_type;
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typedef typename ptr_difference<T>::type difference_type;
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template<class U>
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struct rebind_to
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: ptr_rebind<T, U> { };
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#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
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template<class U>
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using rebind = typename rebind_to<U>::type;
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#endif
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};
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template<class T>
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struct ptr_traits<T, ptr_none> { };
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} /* detail */
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template<class T>
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struct pointer_traits
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: detail::ptr_traits<T, typename detail::ptr_element<T>::type> { };
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template<class T>
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struct pointer_traits<T*>
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: detail::ptr_to<T*, T> {
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typedef T* pointer;
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typedef T element_type;
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typedef std::ptrdiff_t difference_type;
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template<class U>
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struct rebind_to {
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typedef U* type;
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};
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#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
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template<class U>
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using rebind = typename rebind_to<U>::type;
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#endif
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};
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template<class T>
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BOOST_CONSTEXPR inline T*
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to_address(T* v) BOOST_NOEXCEPT
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{
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return v;
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}
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#if !defined(BOOST_NO_CXX14_RETURN_TYPE_DEDUCTION)
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namespace detail {
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template<class T>
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inline T*
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ptr_address(T* v, int) BOOST_NOEXCEPT
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{
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return v;
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}
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template<class T>
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inline auto
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ptr_address(const T& v, int) BOOST_NOEXCEPT
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-> decltype(boost::pointer_traits<T>::to_address(v))
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{
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return boost::pointer_traits<T>::to_address(v);
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}
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template<class T>
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inline auto
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ptr_address(const T& v, long) BOOST_NOEXCEPT
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{
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return boost::detail::ptr_address(v.operator->(), 0);
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}
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} /* detail */
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template<class T>
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inline auto
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to_address(const T& v) BOOST_NOEXCEPT
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{
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return boost::detail::ptr_address(v, 0);
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}
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#else
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template<class T>
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inline typename pointer_traits<T>::element_type*
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to_address(const T& v) BOOST_NOEXCEPT
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{
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return boost::to_address(v.operator->());
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}
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#endif
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} /* boost */
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#endif
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