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500 lines
14 KiB
500 lines
14 KiB
// trivilally-copyable version of the storage
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template<class T>
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class tc_optional_base : public optional_tag
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{
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private :
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typedef tc_optional_base<T> this_type ;
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protected :
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typedef T value_type ;
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protected:
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typedef T & reference_type ;
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typedef T const& reference_const_type ;
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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typedef T && rval_reference_type ;
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typedef T && reference_type_of_temporary_wrapper ;
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#endif
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typedef T * pointer_type ;
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typedef T const* pointer_const_type ;
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typedef T const& argument_type ;
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tc_optional_base()
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:
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m_initialized(false) {}
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tc_optional_base ( none_t )
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:
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m_initialized(false) {}
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tc_optional_base ( init_value_tag, argument_type val )
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:
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m_initialized(true), m_storage(val) {}
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tc_optional_base ( bool cond, argument_type val )
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:
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m_initialized(cond), m_storage(val) {}
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// tc_optional_base ( tc_optional_base const& ) = default;
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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template<class Expr, class PtrExpr>
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explicit tc_optional_base ( Expr&& expr, PtrExpr const* tag )
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:
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m_initialized(false)
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{
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construct(boost::forward<Expr>(expr),tag);
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}
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#else
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// This is used for both converting and in-place constructions.
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// Derived classes use the 'tag' to select the appropriate
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// implementation (the correct 'construct()' overload)
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template<class Expr>
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explicit tc_optional_base ( Expr const& expr, Expr const* tag )
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:
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m_initialized(false)
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{
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construct(expr,tag);
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}
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#endif
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// tc_optional_base& operator= ( tc_optional_base const& ) = default;
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// ~tc_optional_base() = default;
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// Assigns from another optional<T> (deep-copies the rhs value)
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void assign ( tc_optional_base const& rhs )
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{
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*this = rhs;
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}
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// Assigns from another _convertible_ optional<U> (deep-copies the rhs value)
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template<class U>
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void assign ( optional<U> const& rhs )
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{
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if ( rhs.is_initialized() )
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#ifndef BOOST_OPTIONAL_CONFIG_RESTORE_ASSIGNMENT_OF_NONCONVERTIBLE_TYPES
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m_storage = rhs.get();
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#else
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m_storage = static_cast<value_type>(rhs.get());
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#endif
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m_initialized = rhs.is_initialized();
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}
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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// move-assigns from another _convertible_ optional<U> (deep-moves from the rhs value)
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template<class U>
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void assign ( optional<U>&& rhs )
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{
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typedef BOOST_DEDUCED_TYPENAME optional<U>::rval_reference_type ref_type;
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if ( rhs.is_initialized() )
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m_storage = static_cast<ref_type>(rhs.get());
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m_initialized = rhs.is_initialized();
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}
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#endif
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void assign ( argument_type val )
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{
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construct(val);
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}
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void assign ( none_t ) { destroy(); }
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#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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template<class Expr, class ExprPtr>
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void assign_expr ( Expr&& expr, ExprPtr const* tag )
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{
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construct(boost::forward<Expr>(expr),tag);
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}
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#else
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template<class Expr>
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void assign_expr ( Expr const& expr, Expr const* tag )
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{
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construct(expr,tag);
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}
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#endif
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#endif
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public :
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// Destroys the current value, if any, leaving this UNINITIALIZED
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// No-throw (assuming T::~T() doesn't)
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void reset() BOOST_NOEXCEPT { destroy(); }
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// **DEPPRECATED** Replaces the current value -if any- with 'val'
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void reset ( argument_type val ) BOOST_NOEXCEPT { assign(val); }
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// Returns a pointer to the value if this is initialized, otherwise,
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// returns NULL.
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// No-throw
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pointer_const_type get_ptr() const { return m_initialized ? get_ptr_impl() : 0 ; }
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pointer_type get_ptr() { return m_initialized ? get_ptr_impl() : 0 ; }
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bool is_initialized() const { return m_initialized ; }
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protected :
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void construct ( argument_type val )
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{
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m_storage = val ;
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m_initialized = true ;
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}
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#if (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES) && (!defined BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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// Constructs in-place
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// upon exception *this is always uninitialized
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template<class... Args>
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void construct ( in_place_init_t, Args&&... args )
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{
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m_storage = value_type( boost::forward<Args>(args)... ) ;
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m_initialized = true ;
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}
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template<class... Args>
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void emplace_assign ( Args&&... args )
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{
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construct(in_place_init, boost::forward<Args>(args)...);
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}
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template<class... Args>
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explicit tc_optional_base ( in_place_init_t, Args&&... args )
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:
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m_initialized(false)
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{
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construct(in_place_init, boost::forward<Args>(args)...);
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}
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template<class... Args>
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explicit tc_optional_base ( in_place_init_if_t, bool cond, Args&&... args )
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:
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m_initialized(false)
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{
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if ( cond )
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construct(in_place_init, boost::forward<Args>(args)...);
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}
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#elif (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
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template<class Arg>
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void construct ( in_place_init_t, Arg&& arg )
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{
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m_storage = value_type( boost::forward<Arg>(arg) );
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m_initialized = true ;
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}
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void construct ( in_place_init_t )
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{
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m_storage = value_type();
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m_initialized = true ;
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}
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template<class Arg>
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void emplace_assign ( Arg&& arg )
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{
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construct(in_place_init, boost::forward<Arg>(arg)) ;
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}
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void emplace_assign ()
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{
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construct(in_place_init) ;
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}
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template<class Arg>
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explicit tc_optional_base ( in_place_init_t, Arg&& arg )
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:
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m_initialized(false)
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{
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construct(in_place_init, boost::forward<Arg>(arg));
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}
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explicit tc_optional_base ( in_place_init_t )
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:
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m_initialized(false), m_storage() {}
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template<class Arg>
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explicit tc_optional_base ( in_place_init_if_t, bool cond, Arg&& arg )
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:
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m_initialized(false)
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{
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if ( cond )
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construct(in_place_init, boost::forward<Arg>(arg));
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}
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explicit tc_optional_base ( in_place_init_if_t, bool cond )
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:
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m_initialized(false)
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{
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if ( cond )
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construct(in_place_init);
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}
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#else
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template<class Arg>
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void construct ( in_place_init_t, const Arg& arg )
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{
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m_storage = value_type( arg );
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m_initialized = true ;
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}
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template<class Arg>
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void construct ( in_place_init_t, Arg& arg )
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{
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m_storage = value_type( arg );
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m_initialized = true ;
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}
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void construct ( in_place_init_t )
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{
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m_storage = value_type();
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m_initialized = true ;
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}
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template<class Arg>
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void emplace_assign ( const Arg& arg )
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{
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construct(in_place_init, arg);
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}
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template<class Arg>
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void emplace_assign ( Arg& arg )
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{
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construct(in_place_init, arg);
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}
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void emplace_assign ()
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{
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construct(in_place_init);
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}
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template<class Arg>
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explicit tc_optional_base ( in_place_init_t, const Arg& arg )
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: m_initialized(false)
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{
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construct(in_place_init, arg);
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}
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template<class Arg>
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explicit tc_optional_base ( in_place_init_t, Arg& arg )
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: m_initialized(false)
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{
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construct(in_place_init, arg);
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}
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explicit tc_optional_base ( in_place_init_t )
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: m_initialized(false)
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{
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construct(in_place_init);
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}
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template<class Arg>
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explicit tc_optional_base ( in_place_init_if_t, bool cond, const Arg& arg )
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: m_initialized(false)
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{
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if ( cond )
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construct(in_place_init, arg);
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}
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template<class Arg>
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explicit tc_optional_base ( in_place_init_if_t, bool cond, Arg& arg )
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: m_initialized(false)
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{
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if ( cond )
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construct(in_place_init, arg);
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}
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explicit tc_optional_base ( in_place_init_if_t, bool cond )
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: m_initialized(false)
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{
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if ( cond )
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construct(in_place_init);
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}
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#endif
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#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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// Constructs in-place using the given factory
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template<class Expr>
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void construct ( Expr&& factory, in_place_factory_base const* )
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{
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boost_optional_detail::construct<value_type>(factory, boost::addressof(m_storage));
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m_initialized = true ;
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}
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// Constructs in-place using the given typed factory
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template<class Expr>
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void construct ( Expr&& factory, typed_in_place_factory_base const* )
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{
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factory.apply(boost::addressof(m_storage)) ;
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m_initialized = true ;
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}
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template<class Expr>
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void assign_expr_to_initialized ( Expr&& factory, in_place_factory_base const* tag )
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{
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destroy();
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construct(factory,tag);
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}
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// Constructs in-place using the given typed factory
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template<class Expr>
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void assign_expr_to_initialized ( Expr&& factory, typed_in_place_factory_base const* tag )
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{
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destroy();
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construct(factory,tag);
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}
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#else
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// Constructs in-place using the given factory
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template<class Expr>
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void construct ( Expr const& factory, in_place_factory_base const* )
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{
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boost_optional_detail::construct<value_type>(factory, boost::addressof(m_storage));
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m_initialized = true ;
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}
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// Constructs in-place using the given typed factory
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template<class Expr>
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void construct ( Expr const& factory, typed_in_place_factory_base const* )
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{
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factory.apply(boost::addressof(m_storage)) ;
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m_initialized = true ;
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}
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template<class Expr>
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void assign_expr_to_initialized ( Expr const& factory, in_place_factory_base const* tag )
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{
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destroy();
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construct(factory,tag);
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}
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// Constructs in-place using the given typed factory
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template<class Expr>
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void assign_expr_to_initialized ( Expr const& factory, typed_in_place_factory_base const* tag )
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{
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destroy();
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construct(factory,tag);
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}
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#endif
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#endif
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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// Constructs using any expression implicitly convertible to the single argument
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// of a one-argument T constructor.
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// Converting constructions of optional<T> from optional<U> uses this function with
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// 'Expr' being of type 'U' and relying on a converting constructor of T from U.
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template<class Expr>
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void construct ( Expr&& expr, void const* )
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{
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m_storage = value_type(boost::forward<Expr>(expr)) ;
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m_initialized = true ;
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}
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// Assigns using a form any expression implicitly convertible to the single argument
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// of a T's assignment operator.
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// Converting assignments of optional<T> from optional<U> uses this function with
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// 'Expr' being of type 'U' and relying on a converting assignment of T from U.
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template<class Expr>
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void assign_expr_to_initialized ( Expr&& expr, void const* )
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{
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assign_value( boost::forward<Expr>(expr) );
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}
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#else
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// Constructs using any expression implicitly convertible to the single argument
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// of a one-argument T constructor.
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// Converting constructions of optional<T> from optional<U> uses this function with
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// 'Expr' being of type 'U' and relying on a converting constructor of T from U.
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template<class Expr>
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void construct ( Expr const& expr, void const* )
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{
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m_storage = value_type(expr) ;
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m_initialized = true ;
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}
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// Assigns using a form any expression implicitly convertible to the single argument
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// of a T's assignment operator.
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// Converting assignments of optional<T> from optional<U> uses this function with
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// 'Expr' being of type 'U' and relying on a converting assignment of T from U.
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template<class Expr>
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void assign_expr_to_initialized ( Expr const& expr, void const* )
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{
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assign_value(expr);
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}
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#endif
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#ifdef BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
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// BCB5.64 (and probably lower versions) workaround.
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// The in-place factories are supported by means of catch-all constructors
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// and assignment operators (the functions are parameterized in terms of
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// an arbitrary 'Expr' type)
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// This compiler incorrectly resolves the overload set and sinks optional<T> and optional<U>
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// to the 'Expr'-taking functions even though explicit overloads are present for them.
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// Thus, the following overload is needed to properly handle the case when the 'lhs'
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// is another optional.
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//
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// For VC<=70 compilers this workaround dosen't work becasue the comnpiler issues and error
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// instead of choosing the wrong overload
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//
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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// Notice that 'Expr' will be optional<T> or optional<U> (but not tc_optional_base<..>)
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template<class Expr>
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void construct ( Expr&& expr, optional_tag const* )
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{
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if ( expr.is_initialized() )
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{
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// An exception can be thrown here.
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// It it happens, THIS will be left uninitialized.
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m_storage = value_type(boost::move(expr.get())) ;
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m_initialized = true ;
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}
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}
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#else
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// Notice that 'Expr' will be optional<T> or optional<U> (but not tc_optional_base<..>)
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template<class Expr>
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void construct ( Expr const& expr, optional_tag const* )
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{
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if ( expr.is_initialized() )
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{
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// An exception can be thrown here.
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// It it happens, THIS will be left uninitialized.
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m_storage = value_type(expr.get()) ;
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m_initialized = true ;
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}
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}
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#endif
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#endif // defined BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
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void assign_value ( argument_type val ) { m_storage = val; }
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#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
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void assign_value ( rval_reference_type val ) { m_storage = static_cast<rval_reference_type>(val); }
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#endif
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void destroy()
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{
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m_initialized = false;
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}
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reference_const_type get_impl() const { return m_storage ; }
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reference_type get_impl() { return m_storage ; }
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pointer_const_type get_ptr_impl() const { return boost::addressof(m_storage); }
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pointer_type get_ptr_impl() { return boost::addressof(m_storage); }
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private :
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bool m_initialized ;
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T m_storage ;
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} ;
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