326 lines
9.0 KiB
Plaintext
326 lines
9.0 KiB
Plaintext
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// See http://www.boost.org/libs/any for Documentation.
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#ifndef BOOST_ANY_INCLUDED
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#define BOOST_ANY_INCLUDED
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#if defined(_MSC_VER)
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# pragma once
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#endif
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// what: variant type boost::any
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// who: contributed by Kevlin Henney,
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// with features contributed and bugs found by
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// Antony Polukhin, Ed Brey, Mark Rodgers,
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// Peter Dimov, and James Curran
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// when: July 2001, April 2013 - May 2013
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#include <algorithm>
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#include "boost/config.hpp"
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#include <boost/type_index.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/type_traits/decay.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_traits/add_reference.hpp>
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#include <boost/type_traits/is_reference.hpp>
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#include <boost/type_traits/is_const.hpp>
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#include <boost/throw_exception.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/type_traits/is_const.hpp>
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#include <boost/mpl/if.hpp>
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namespace boost
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{
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class any
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{
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public: // structors
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any() BOOST_NOEXCEPT
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: content(0)
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{
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}
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template<typename ValueType>
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any(const ValueType & value)
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: content(new holder<
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BOOST_DEDUCED_TYPENAME remove_cv<BOOST_DEDUCED_TYPENAME decay<const ValueType>::type>::type
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>(value))
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{
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}
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any(const any & other)
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: content(other.content ? other.content->clone() : 0)
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{
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}
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
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// Move constructor
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any(any&& other) BOOST_NOEXCEPT
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: content(other.content)
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{
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other.content = 0;
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}
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// Perfect forwarding of ValueType
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template<typename ValueType>
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any(ValueType&& value
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, typename boost::disable_if<boost::is_same<any&, ValueType> >::type* = 0 // disable if value has type `any&`
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, typename boost::disable_if<boost::is_const<ValueType> >::type* = 0) // disable if value has type `const ValueType&&`
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: content(new holder< typename decay<ValueType>::type >(static_cast<ValueType&&>(value)))
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{
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}
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#endif
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~any() BOOST_NOEXCEPT
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{
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delete content;
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}
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public: // modifiers
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any & swap(any & rhs) BOOST_NOEXCEPT
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{
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std::swap(content, rhs.content);
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return *this;
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}
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#ifdef BOOST_NO_CXX11_RVALUE_REFERENCES
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template<typename ValueType>
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any & operator=(const ValueType & rhs)
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{
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any(rhs).swap(*this);
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return *this;
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}
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any & operator=(any rhs)
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{
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any(rhs).swap(*this);
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return *this;
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}
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#else
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any & operator=(const any& rhs)
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{
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any(rhs).swap(*this);
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return *this;
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}
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// move assignement
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any & operator=(any&& rhs) BOOST_NOEXCEPT
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{
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rhs.swap(*this);
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any().swap(rhs);
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return *this;
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}
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// Perfect forwarding of ValueType
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template <class ValueType>
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any & operator=(ValueType&& rhs)
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{
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any(static_cast<ValueType&&>(rhs)).swap(*this);
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return *this;
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}
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#endif
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public: // queries
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bool empty() const BOOST_NOEXCEPT
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{
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return !content;
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}
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void clear() BOOST_NOEXCEPT
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{
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any().swap(*this);
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}
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const boost::typeindex::type_info& type() const BOOST_NOEXCEPT
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{
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return content ? content->type() : boost::typeindex::type_id<void>().type_info();
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}
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#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
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private: // types
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#else
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public: // types (public so any_cast can be non-friend)
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#endif
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class placeholder
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{
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public: // structors
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virtual ~placeholder()
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{
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}
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public: // queries
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virtual const boost::typeindex::type_info& type() const BOOST_NOEXCEPT = 0;
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virtual placeholder * clone() const = 0;
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};
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template<typename ValueType>
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class holder : public placeholder
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{
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public: // structors
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holder(const ValueType & value)
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: held(value)
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{
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}
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
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holder(ValueType&& value)
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: held(static_cast< ValueType&& >(value))
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{
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}
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#endif
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public: // queries
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virtual const boost::typeindex::type_info& type() const BOOST_NOEXCEPT
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{
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return boost::typeindex::type_id<ValueType>().type_info();
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}
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virtual placeholder * clone() const
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{
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return new holder(held);
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}
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public: // representation
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ValueType held;
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private: // intentionally left unimplemented
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holder & operator=(const holder &);
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};
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#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
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private: // representation
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template<typename ValueType>
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friend ValueType * any_cast(any *) BOOST_NOEXCEPT;
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template<typename ValueType>
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friend ValueType * unsafe_any_cast(any *) BOOST_NOEXCEPT;
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#else
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public: // representation (public so any_cast can be non-friend)
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#endif
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placeholder * content;
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};
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inline void swap(any & lhs, any & rhs) BOOST_NOEXCEPT
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{
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lhs.swap(rhs);
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}
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class BOOST_SYMBOL_VISIBLE bad_any_cast :
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#ifndef BOOST_NO_RTTI
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public std::bad_cast
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#else
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public std::exception
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#endif
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{
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public:
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virtual const char * what() const BOOST_NOEXCEPT_OR_NOTHROW
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{
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return "boost::bad_any_cast: "
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"failed conversion using boost::any_cast";
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}
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};
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template<typename ValueType>
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ValueType * any_cast(any * operand) BOOST_NOEXCEPT
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{
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return operand && operand->type() == boost::typeindex::type_id<ValueType>()
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? &static_cast<any::holder<BOOST_DEDUCED_TYPENAME remove_cv<ValueType>::type> *>(operand->content)->held
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: 0;
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}
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template<typename ValueType>
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inline const ValueType * any_cast(const any * operand) BOOST_NOEXCEPT
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{
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return any_cast<ValueType>(const_cast<any *>(operand));
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}
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template<typename ValueType>
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ValueType any_cast(any & operand)
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{
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typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
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nonref * result = any_cast<nonref>(&operand);
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if(!result)
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boost::throw_exception(bad_any_cast());
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// Attempt to avoid construction of a temporary object in cases when
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// `ValueType` is not a reference. Example:
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// `static_cast<std::string>(*result);`
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// which is equal to `std::string(*result);`
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typedef BOOST_DEDUCED_TYPENAME boost::mpl::if_<
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boost::is_reference<ValueType>,
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ValueType,
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BOOST_DEDUCED_TYPENAME boost::add_reference<ValueType>::type
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>::type ref_type;
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return static_cast<ref_type>(*result);
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}
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template<typename ValueType>
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inline ValueType any_cast(const any & operand)
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{
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typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
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return any_cast<const nonref &>(const_cast<any &>(operand));
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}
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
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template<typename ValueType>
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inline ValueType any_cast(any&& operand)
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{
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BOOST_STATIC_ASSERT_MSG(
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boost::is_rvalue_reference<ValueType&&>::value /*true if ValueType is rvalue or just a value*/
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|| boost::is_const< typename boost::remove_reference<ValueType>::type >::value,
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"boost::any_cast shall not be used for getting nonconst references to temporary objects"
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);
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return any_cast<ValueType>(operand);
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}
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#endif
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// Note: The "unsafe" versions of any_cast are not part of the
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// public interface and may be removed at any time. They are
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// required where we know what type is stored in the any and can't
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// use typeid() comparison, e.g., when our types may travel across
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// different shared libraries.
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template<typename ValueType>
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inline ValueType * unsafe_any_cast(any * operand) BOOST_NOEXCEPT
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{
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return &static_cast<any::holder<ValueType> *>(operand->content)->held;
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}
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template<typename ValueType>
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inline const ValueType * unsafe_any_cast(const any * operand) BOOST_NOEXCEPT
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{
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return unsafe_any_cast<ValueType>(const_cast<any *>(operand));
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}
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}
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// Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#endif
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