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