yuzu/ext-boost
1
0
Fork 0
mirror of https://github.com/yuzu-emu/ext-boost.git synced 2024-12-23 14:15:27 +00:00
Code Issues Packages Projects Releases Wiki Activity
ext-boost/boost/optional/optional.hpp

1568 lines
48 KiB
C++
Raw Normal View History

Add boost::optional
2016-01-25 23:31:44 +00:00
// Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
// Copyright (C) 2014, 2015 Andrzej Krzemienski.
//
// Use, modification, and distribution is subject to 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)
//
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// fernando_cacciola@hotmail.com
//
// Revisions:
// 27 Apr 2008 (improved swap) Fernando Cacciola, Niels Dekker, Thorsten Ottosen
// 05 May 2014 (Added move semantics) Andrzej Krzemienski
//
#ifndef BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP
#define BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP
#include <new>
#include <iosfwd>
#include <boost/config.hpp>
#include <boost/assert.hpp>
#include <boost/core/addressof.hpp>
#include <boost/core/enable_if.hpp>
#include <boost/core/explicit_operator_bool.hpp>
#include <boost/core/swap.hpp>
#include <boost/optional/bad_optional_access.hpp>
#include <boost/static_assert.hpp>
#include <boost/throw_exception.hpp>
#include <boost/type.hpp>
#include <boost/type_traits/alignment_of.hpp>
#include <boost/type_traits/has_nothrow_constructor.hpp>
#include <boost/type_traits/type_with_alignment.hpp>
#include <boost/type_traits/remove_const.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/decay.hpp>
#include <boost/type_traits/is_base_of.hpp>
#include <boost/type_traits/is_lvalue_reference.hpp>
#include <boost/type_traits/is_nothrow_move_assignable.hpp>
#include <boost/type_traits/is_nothrow_move_constructible.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/is_rvalue_reference.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/not.hpp>
#include <boost/detail/reference_content.hpp>
#include <boost/move/utility.hpp>
#include <boost/none.hpp>
#include <boost/utility/compare_pointees.hpp>
#include <boost/optional/optional_fwd.hpp>
#if (defined BOOST_NO_CXX11_RVALUE_REFERENCES) || (defined BOOST_OPTIONAL_CONFIG_NO_RVALUE_REFERENCES)
#define BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
#endif
#if BOOST_WORKAROUND(BOOST_INTEL_CXX_VERSION,<=700)
// AFAICT only Intel 7 correctly resolves the overload set
// that includes the in-place factory taking functions,
// so for the other icc versions, in-place factory support
// is disabled
#define BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
#endif
#if BOOST_WORKAROUND(__BORLANDC__, <= 0x551)
// BCB (5.5.1) cannot parse the nested template struct in an inplace factory.
#define BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
#endif
#if !defined(BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT) \
&& BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581) )
// BCB (up to 5.64) has the following bug:
// If there is a member function/operator template of the form
// template<class Expr> mfunc( Expr expr ) ;
// some calls are resolved to this even if there are other better matches.
// The effect of this bug is that calls to converting ctors and assignments
// are incrorrectly sink to this general catch-all member function template as shown above.
#define BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
#endif
#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
// GCC since 3.3 has may_alias attribute that helps to alleviate optimizer issues with
// regard to violation of the strict aliasing rules. The optional< T > storage type is marked
// with this attribute in order to let the compiler know that it will alias objects of type T
// and silence compilation warnings.
#define BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS
#endif
// Daniel Wallin discovered that bind/apply.hpp badly interacts with the apply<>
// member template of a factory as used in the optional<> implementation.
// He proposed this simple fix which is to move the call to apply<> outside
// namespace boost.
namespace boost_optional_detail
{
template <class T, class Factory>
inline void construct(Factory const& factory, void* address)
{
factory.BOOST_NESTED_TEMPLATE apply<T>(address);
}
}
namespace boost {
class in_place_factory_base ;
class typed_in_place_factory_base ;
// This forward is needed to refer to namespace scope swap from the member swap
template<class T> void swap ( optional<T>& x, optional<T>& y );
namespace optional_detail {
// This local class is used instead of that in "aligned_storage.hpp"
// because I've found the 'official' class to ICE BCB5.5
// when some types are used with optional<>
// (due to sizeof() passed down as a non-type template parameter)
template <class T>
class aligned_storage
{
// Borland ICEs if unnamed unions are used for this!
union
// This works around GCC warnings about breaking strict aliasing rules when casting storage address to T*
#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
__attribute__((__may_alias__))
#endif
dummy_u
{
char data[ sizeof(T) ];
BOOST_DEDUCED_TYPENAME type_with_alignment<
::boost::alignment_of<T>::value >::type aligner_;
} dummy_ ;
public:
#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
void const* address() const { return &dummy_; }
void * address() { return &dummy_; }
#else
void const* address() const { return dummy_.data; }
void * address() { return dummy_.data; }
#endif
} ;
template<class T>
struct types_when_isnt_ref
{
typedef T const& reference_const_type ;
typedef T & reference_type ;
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
typedef T && rval_reference_type ;
typedef T && reference_type_of_temporary_wrapper;
#ifdef BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES
// GCC 4.4 has support for an early draft of rvalue references. The conforming version below
// causes warnings about returning references to a temporary.
static T&& move(T&& r) { return r; }
#else
static rval_reference_type move(reference_type r) { return boost::move(r); }
#endif
#endif
typedef T const* pointer_const_type ;
typedef T * pointer_type ;
typedef T const& argument_type ;
} ;
template<class T>
struct types_when_is_ref
{
typedef BOOST_DEDUCED_TYPENAME remove_reference<T>::type raw_type ;
typedef raw_type& reference_const_type ;
typedef raw_type& reference_type ;
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
typedef BOOST_DEDUCED_TYPENAME remove_const<raw_type>::type&& rval_reference_type ;
typedef raw_type& reference_type_of_temporary_wrapper;
static reference_type move(reference_type r) { return r; }
#endif
typedef raw_type* pointer_const_type ;
typedef raw_type* pointer_type ;
typedef raw_type& argument_type ;
} ;
template <class To, class From>
void prevent_binding_rvalue_ref_to_optional_lvalue_ref()
{
#ifndef BOOST_OPTIONAL_CONFIG_ALLOW_BINDING_TO_RVALUES
BOOST_STATIC_ASSERT_MSG(
!boost::is_lvalue_reference<To>::value || !boost::is_rvalue_reference<From>::value,
"binding rvalue references to optional lvalue references is disallowed");
#endif
}
struct optional_tag {} ;
template<class T>
class optional_base : public optional_tag
{
private :
typedef
#if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
BOOST_DEDUCED_TYPENAME
#endif
::boost::detail::make_reference_content<T>::type internal_type ;
typedef aligned_storage<internal_type> storage_type ;
typedef types_when_isnt_ref<T> types_when_not_ref ;
typedef types_when_is_ref<T> types_when_ref ;
typedef optional_base<T> this_type ;
protected :
typedef T value_type ;
typedef mpl::true_ is_reference_tag ;
typedef mpl::false_ is_not_reference_tag ;
typedef BOOST_DEDUCED_TYPENAME is_reference<T>::type is_reference_predicate ;
public:
typedef BOOST_DEDUCED_TYPENAME mpl::if_<is_reference_predicate,types_when_ref,types_when_not_ref>::type types ;
protected:
typedef BOOST_DEDUCED_TYPENAME types::reference_type reference_type ;
typedef BOOST_DEDUCED_TYPENAME types::reference_const_type reference_const_type ;
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
typedef BOOST_DEDUCED_TYPENAME types::rval_reference_type rval_reference_type ;
typedef BOOST_DEDUCED_TYPENAME types::reference_type_of_temporary_wrapper reference_type_of_temporary_wrapper ;
#endif
typedef BOOST_DEDUCED_TYPENAME types::pointer_type pointer_type ;
typedef BOOST_DEDUCED_TYPENAME types::pointer_const_type pointer_const_type ;
typedef BOOST_DEDUCED_TYPENAME types::argument_type argument_type ;
// Creates an optional<T> uninitialized.
// No-throw
optional_base()
:
m_initialized(false) {}
// Creates an optional<T> uninitialized.
// No-throw
optional_base ( none_t )
:
m_initialized(false) {}
// Creates an optional<T> initialized with 'val'.
// Can throw if T::T(T const&) does
optional_base ( argument_type val )
:
m_initialized(false)
{
construct(val);
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// move-construct an optional<T> initialized from an rvalue-ref to 'val'.
// Can throw if T::T(T&&) does
optional_base ( rval_reference_type val )
:
m_initialized(false)
{
construct( boost::move(val) );
}
#endif
// Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialzed optional<T>.
// Can throw if T::T(T const&) does
optional_base ( bool cond, argument_type val )
:
m_initialized(false)
{
if ( cond )
construct(val);
}
// Creates a deep copy of another optional<T>
// Can throw if T::T(T const&) does
optional_base ( optional_base const& rhs )
:
m_initialized(false)
{
if ( rhs.is_initialized() )
construct(rhs.get_impl());
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Creates a deep move of another optional<T>
// Can throw if T::T(T&&) does
optional_base ( optional_base&& rhs )
:
m_initialized(false)
{
if ( rhs.is_initialized() )
construct( boost::move(rhs.get_impl()) );
}
#endif
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
template<class Expr, class PtrExpr>
explicit 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 optional_base ( Expr const& expr, Expr const* tag )
:
m_initialized(false)
{
construct(expr,tag);
}
#endif
// No-throw (assuming T::~T() doesn't)
~optional_base() { destroy() ; }
// Assigns from another optional<T> (deep-copies the rhs value)
void assign ( optional_base const& rhs )
{
if (is_initialized())
{
if ( rhs.is_initialized() )
assign_value(rhs.get_impl(), is_reference_predicate() );
else destroy();
}
else
{
if ( rhs.is_initialized() )
construct(rhs.get_impl());
}
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Assigns from another optional<T> (deep-moves the rhs value)
void assign ( optional_base&& rhs )
{
if (is_initialized())
{
if ( rhs.is_initialized() )
assign_value(boost::move(rhs.get_impl()), is_reference_predicate() );
else destroy();
}
else
{
if ( rhs.is_initialized() )
construct(boost::move(rhs.get_impl()));
}
}
#endif
// Assigns from another _convertible_ optional<U> (deep-copies the rhs value)
template<class U>
void assign ( optional<U> const& rhs )
{
if (is_initialized())
{
if ( rhs.is_initialized() )
#ifndef BOOST_OPTIONAL_CONFIG_RESTORE_ASSIGNMENT_OF_NONCONVERTIBLE_TYPES
assign_value(rhs.get(), is_reference_predicate() );
#else
assign_value(static_cast<value_type>(rhs.get()), is_reference_predicate() );
#endif
else destroy();
}
else
{
if ( rhs.is_initialized() )
#ifndef BOOST_OPTIONAL_CONFIG_RESTORE_ASSIGNMENT_OF_NONCONVERTIBLE_TYPES
construct(rhs.get());
#else
construct(static_cast<value_type>(rhs.get()));
#endif
}
}
#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 (is_initialized())
{
if ( rhs.is_initialized() )
assign_value(static_cast<ref_type>(rhs.get()), is_reference_predicate() );
else destroy();
}
else
{
if ( rhs.is_initialized() )
construct(static_cast<ref_type>(rhs.get()));
}
}
#endif
// Assigns from a T (deep-copies the rhs value)
void assign ( argument_type val )
{
if (is_initialized())
assign_value(val, is_reference_predicate() );
else construct(val);
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Assigns from a T (deep-moves the rhs value)
void assign ( rval_reference_type val )
{
if (is_initialized())
assign_value( boost::move(val), is_reference_predicate() );
else construct( boost::move(val) );
}
#endif
// Assigns from "none", destroying the current value, if any, leaving this UNINITIALIZED
// No-throw (assuming T::~T() doesn't)
void assign ( none_t ) BOOST_NOEXCEPT { 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 )
{
if (is_initialized())
assign_expr_to_initialized(boost::forward<Expr>(expr),tag);
else construct(boost::forward<Expr>(expr),tag);
}
#else
template<class Expr>
void assign_expr ( Expr const& expr, Expr const* tag )
{
if (is_initialized())
assign_expr_to_initialized(expr,tag);
else construct(expr,tag);
}
#endif
#endif
public :
// **DEPPRECATED** 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 ) { 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 )
{
::new (m_storage.address()) internal_type(val) ;
m_initialized = true ;
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
void construct ( rval_reference_type val )
{
::new (m_storage.address()) internal_type( types::move(val) ) ;
m_initialized = true ;
}
#endif
#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 emplace_assign ( Args&&... args )
{
destroy();
::new (m_storage.address()) internal_type( boost::forward<Args>(args)... );
m_initialized = true ;
}
#elif (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
template<class Arg>
void emplace_assign ( Arg&& arg )
{
destroy();
::new (m_storage.address()) internal_type( boost::forward<Arg>(arg) );
m_initialized = true ;
}
void emplace_assign ()
{
destroy();
::new (m_storage.address()) internal_type();
m_initialized = true ;
}
#else
template<class Arg>
void emplace_assign ( const Arg& arg )
{
destroy();
::new (m_storage.address()) internal_type( arg );
m_initialized = true ;
}
template<class Arg>
void emplace_assign ( Arg& arg )
{
destroy();
::new (m_storage.address()) internal_type( arg );
m_initialized = true ;
}
void emplace_assign ()
{
destroy();
::new (m_storage.address()) internal_type();
m_initialized = true ;
}
#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_STATIC_ASSERT ( ::boost::mpl::not_<is_reference_predicate>::value ) ;
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&& factory, typed_in_place_factory_base const* )
{
BOOST_STATIC_ASSERT ( ::boost::mpl::not_<is_reference_predicate>::value ) ;
factory.apply(m_storage.address()) ;
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_STATIC_ASSERT ( ::boost::mpl::not_<is_reference_predicate>::value ) ;
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* )
{
BOOST_STATIC_ASSERT ( ::boost::mpl::not_<is_reference_predicate>::value ) ;
factory.apply(m_storage.address()) ;
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* )
{
new (m_storage.address()) internal_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), is_reference_predicate());
}
#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* )
{
new (m_storage.address()) internal_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, is_reference_predicate());
}
#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 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.
new (m_storage.address()) internal_type(types::move(expr.get())) ;
m_initialized = true ;
}
}
#else
// Notice that 'Expr' will be optional<T> or optional<U> (but not 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.
new (m_storage.address()) internal_type(expr.get()) ;
m_initialized = true ;
}
}
#endif
#endif // defined BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
void assign_value ( argument_type val, is_not_reference_tag ) { get_impl() = val; }
void assign_value ( argument_type val, is_reference_tag ) { construct(val); }
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
void assign_value ( rval_reference_type val, is_not_reference_tag ) { get_impl() = static_cast<rval_reference_type>(val); }
void assign_value ( rval_reference_type val, is_reference_tag ) { construct( static_cast<rval_reference_type>(val) ); }
#endif
void destroy()
{
if ( m_initialized )
destroy_impl(is_reference_predicate()) ;
}
reference_const_type get_impl() const { return dereference(get_object(), is_reference_predicate() ) ; }
reference_type get_impl() { return dereference(get_object(), is_reference_predicate() ) ; }
pointer_const_type get_ptr_impl() const { return cast_ptr(get_object(), is_reference_predicate() ) ; }
pointer_type get_ptr_impl() { return cast_ptr(get_object(), is_reference_predicate() ) ; }
private :
// internal_type can be either T or reference_content<T>
#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
// This workaround is supposed to silence GCC warnings about broken strict aliasing rules
internal_type const* get_object() const
{
union { void const* ap_pvoid; internal_type const* as_ptype; } caster = { m_storage.address() };
return caster.as_ptype;
}
internal_type * get_object()
{
union { void* ap_pvoid; internal_type* as_ptype; } caster = { m_storage.address() };
return caster.as_ptype;
}
#else
internal_type const* get_object() const { return static_cast<internal_type const*>(m_storage.address()); }
internal_type * get_object() { return static_cast<internal_type *> (m_storage.address()); }
#endif
// reference_content<T> lacks an implicit conversion to T&, so the following is needed to obtain a proper reference.
reference_const_type dereference( internal_type const* p, is_not_reference_tag ) const { return *p ; }
reference_type dereference( internal_type* p, is_not_reference_tag ) { return *p ; }
reference_const_type dereference( internal_type const* p, is_reference_tag ) const { return p->get() ; }
reference_type dereference( internal_type* p, is_reference_tag ) { return p->get() ; }
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581))
void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->internal_type::~internal_type() ; m_initialized = false ; }
#else
void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->~T() ; m_initialized = false ; }
#endif
void destroy_impl ( is_reference_tag ) { m_initialized = false ; }
// If T is of reference type, trying to get a pointer to the held value must result in a compile-time error.
// Decent compilers should disallow conversions from reference_content<T>* to T*, but just in case,
// the following olverloads are used to filter out the case and guarantee an error in case of T being a reference.
pointer_const_type cast_ptr( internal_type const* p, is_not_reference_tag ) const { return p ; }
pointer_type cast_ptr( internal_type * p, is_not_reference_tag ) { return p ; }
pointer_const_type cast_ptr( internal_type const* p, is_reference_tag ) const { return &p->get() ; }
pointer_type cast_ptr( internal_type * p, is_reference_tag ) { return &p->get() ; }
bool m_initialized ;
storage_type m_storage ;
} ;
} // namespace optional_detail
template<class T>
class optional : public optional_detail::optional_base<T>
{
typedef optional_detail::optional_base<T> base ;
public :
typedef optional<T> this_type ;
typedef BOOST_DEDUCED_TYPENAME base::value_type value_type ;
typedef BOOST_DEDUCED_TYPENAME base::reference_type reference_type ;
typedef BOOST_DEDUCED_TYPENAME base::reference_const_type reference_const_type ;
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
typedef BOOST_DEDUCED_TYPENAME base::rval_reference_type rval_reference_type ;
typedef BOOST_DEDUCED_TYPENAME base::reference_type_of_temporary_wrapper reference_type_of_temporary_wrapper ;
#endif
typedef BOOST_DEDUCED_TYPENAME base::pointer_type pointer_type ;
typedef BOOST_DEDUCED_TYPENAME base::pointer_const_type pointer_const_type ;
typedef BOOST_DEDUCED_TYPENAME base::argument_type argument_type ;
// Creates an optional<T> uninitialized.
// No-throw
optional() BOOST_NOEXCEPT : base() {}
// Creates an optional<T> uninitialized.
// No-throw
optional( none_t none_ ) BOOST_NOEXCEPT : base(none_) {}
// Creates an optional<T> initialized with 'val'.
// Can throw if T::T(T const&) does
optional ( argument_type val ) : base(val) {}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Creates an optional<T> initialized with 'move(val)'.
// Can throw if T::T(T &&) does
optional ( rval_reference_type val ) : base( boost::forward<T>(val) )
{optional_detail::prevent_binding_rvalue_ref_to_optional_lvalue_ref<T, rval_reference_type>();}
#endif
// Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialized optional.
// Can throw if T::T(T const&) does
optional ( bool cond, argument_type val ) : base(cond,val) {}
// NOTE: MSVC needs templated versions first
// Creates a deep copy of another convertible optional<U>
// Requires a valid conversion from U to T.
// Can throw if T::T(U const&) does
template<class U>
explicit optional ( optional<U> const& rhs )
:
base()
{
if ( rhs.is_initialized() )
this->construct(rhs.get());
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Creates a deep move of another convertible optional<U>
// Requires a valid conversion from U to T.
// Can throw if T::T(U&&) does
template<class U>
explicit optional ( optional<U> && rhs )
:
base()
{
if ( rhs.is_initialized() )
this->construct( boost::move(rhs.get()) );
}
#endif
#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
// Creates an optional<T> with an expression which can be either
// (a) An instance of InPlaceFactory (i.e. in_place(a,b,...,n);
// (b) An instance of TypedInPlaceFactory ( i.e. in_place<T>(a,b,...,n);
// (c) Any expression implicitly convertible to the single type
// of a one-argument T's constructor.
// (d*) Weak compilers (BCB) might also resolved Expr as optional<T> and optional<U>
// even though explicit overloads are present for these.
// Depending on the above some T ctor is called.
// Can throw if the resolved T ctor throws.
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
template<class Expr>
explicit optional ( Expr&& expr,
BOOST_DEDUCED_TYPENAME boost::disable_if_c<
(boost::is_base_of<optional_detail::optional_tag, BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type>::value) ||
boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type, none_t>::value >::type* = 0
)
: base(boost::forward<Expr>(expr),boost::addressof(expr))
{optional_detail::prevent_binding_rvalue_ref_to_optional_lvalue_ref<T, Expr&&>();}
#else
template<class Expr>
explicit optional ( Expr const& expr ) : base(expr,boost::addressof(expr)) {}
#endif // !defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
#endif // !defined BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
// Creates a deep copy of another optional<T>
// Can throw if T::T(T const&) does
optional ( optional const& rhs ) : base( static_cast<base const&>(rhs) ) {}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Creates a deep move of another optional<T>
// Can throw if T::T(T&&) does
optional ( optional && rhs )
BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value)
: base( boost::move(rhs) )
{}
#endif
// No-throw (assuming T::~T() doesn't)
~optional() {}
#if !defined(BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT) && !defined(BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION)
// Assigns from an expression. See corresponding constructor.
// Basic Guarantee: If the resolved T ctor throws, this is left UNINITIALIZED
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
template<class Expr>
BOOST_DEDUCED_TYPENAME boost::disable_if_c<
boost::is_base_of<optional_detail::optional_tag, BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type>::value ||
boost::is_same<BOOST_DEDUCED_TYPENAME boost::decay<Expr>::type, none_t>::value,
optional&
>::type
operator= ( Expr&& expr )
{
optional_detail::prevent_binding_rvalue_ref_to_optional_lvalue_ref<T, Expr&&>();
this->assign_expr(boost::forward<Expr>(expr),boost::addressof(expr));
return *this ;
}
#else
template<class Expr>
optional& operator= ( Expr const& expr )
{
this->assign_expr(expr,boost::addressof(expr));
return *this ;
}
#endif // !defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
#endif // !defined(BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT) && !defined(BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION)
// Copy-assigns from another convertible optional<U> (converts && deep-copies the rhs value)
// Requires a valid conversion from U to T.
// Basic Guarantee: If T::T( U const& ) throws, this is left UNINITIALIZED
template<class U>
optional& operator= ( optional<U> const& rhs )
{
this->assign(rhs);
return *this ;
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Move-assigns from another convertible optional<U> (converts && deep-moves the rhs value)
// Requires a valid conversion from U to T.
// Basic Guarantee: If T::T( U && ) throws, this is left UNINITIALIZED
template<class U>
optional& operator= ( optional<U> && rhs )
{
this->assign(boost::move(rhs));
return *this ;
}
#endif
// Assigns from another optional<T> (deep-copies the rhs value)
// Basic Guarantee: If T::T( T const& ) throws, this is left UNINITIALIZED
// (NOTE: On BCB, this operator is not actually called and left is left UNMODIFIED in case of a throw)
optional& operator= ( optional const& rhs )
{
this->assign( static_cast<base const&>(rhs) ) ;
return *this ;
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Assigns from another optional<T> (deep-moves the rhs value)
optional& operator= ( optional && rhs )
BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
{
this->assign( static_cast<base &&>(rhs) ) ;
return *this ;
}
#endif
// Assigns from a T (deep-copies the rhs value)
// Basic Guarantee: If T::( T const& ) throws, this is left UNINITIALIZED
optional& operator= ( argument_type val )
{
this->assign( val ) ;
return *this ;
}
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
// Assigns from a T (deep-moves the rhs value)
optional& operator= ( rval_reference_type val )
{
optional_detail::prevent_binding_rvalue_ref_to_optional_lvalue_ref<T, rval_reference_type>();
this->assign( boost::move(val) ) ;
return *this ;
}
#endif
// Assigns from a "none"
// Which destroys the current value, if any, leaving this UNINITIALIZED
// No-throw (assuming T::~T() doesn't)
optional& operator= ( none_t none_ ) BOOST_NOEXCEPT
{
this->assign( none_ ) ;
return *this ;
}
#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 emplace ( Args&&... args )
{
this->emplace_assign( boost::forward<Args>(args)... );
}
#elif (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
template<class Arg>
void emplace ( Arg&& arg )
{
this->emplace_assign( boost::forward<Arg>(arg) );
}
void emplace ()
{
this->emplace_assign();
}
#else
template<class Arg>
void emplace ( const Arg& arg )
{
this->emplace_assign( arg );
}
template<class Arg>
void emplace ( Arg& arg )
{
this->emplace_assign( arg );
}
void emplace ()
{
this->emplace_assign();
}
#endif
void swap( optional & arg )
BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && ::boost::is_nothrow_move_assignable<T>::value)
{
// allow for Koenig lookup
boost::swap(*this, arg);
}
// Returns a reference to the value if this is initialized, otherwise,
// the behaviour is UNDEFINED
// No-throw
reference_const_type get() const { BOOST_ASSERT(this->is_initialized()) ; return this->get_impl(); }
reference_type get() { BOOST_ASSERT(this->is_initialized()) ; return this->get_impl(); }
// Returns a copy of the value if this is initialized, 'v' otherwise
reference_const_type get_value_or ( reference_const_type v ) const { return this->is_initialized() ? get() : v ; }
reference_type get_value_or ( reference_type v ) { return this->is_initialized() ? get() : v ; }
// Returns a pointer to the value if this is initialized, otherwise,
// the behaviour is UNDEFINED
// No-throw
pointer_const_type operator->() const { BOOST_ASSERT(this->is_initialized()) ; return this->get_ptr_impl() ; }
pointer_type operator->() { BOOST_ASSERT(this->is_initialized()) ; return this->get_ptr_impl() ; }
// Returns a reference to the value if this is initialized, otherwise,
// the behaviour is UNDEFINED
// No-throw
#if (!defined BOOST_NO_CXX11_REF_QUALIFIERS) && (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
reference_const_type operator *() const& { return this->get() ; }
reference_type operator *() & { return this->get() ; }
reference_type_of_temporary_wrapper operator *() && { return base::types::move(this->get()) ; }
#else
reference_const_type operator *() const { return this->get() ; }
reference_type operator *() { return this->get() ; }
#endif // !defined BOOST_NO_CXX11_REF_QUALIFIERS
#if (!defined BOOST_NO_CXX11_REF_QUALIFIERS) && (!defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES)
reference_const_type value() const&
{
if (this->is_initialized())
return this->get() ;
else
throw_exception(bad_optional_access());
}
reference_type value() &
{
if (this->is_initialized())
return this->get() ;
else
throw_exception(bad_optional_access());
}
reference_type_of_temporary_wrapper value() &&
{
if (this->is_initialized())
return base::types::move(this->get()) ;
else
throw_exception(bad_optional_access());
}
#else
reference_const_type value() const
{
if (this->is_initialized())
return this->get() ;
else
throw_exception(bad_optional_access());
}
reference_type value()
{
if (this->is_initialized())
return this->get() ;
else
throw_exception(bad_optional_access());
}
#endif
#ifndef BOOST_NO_CXX11_REF_QUALIFIERS
template <class U>
value_type value_or ( U&& v ) const&
{
if (this->is_initialized())
return get();
else
return boost::forward<U>(v);
}
template <class U>
value_type value_or ( U&& v ) &&
{
if (this->is_initialized())
return base::types::move(get());
else
return boost::forward<U>(v);
}
#elif !defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
template <class U>
value_type value_or ( U&& v ) const
{
if (this->is_initialized())
return get();
else
return boost::forward<U>(v);
}
#else
template <class U>
value_type value_or ( U const& v ) const
{
if (this->is_initialized())
return get();
else
return v;
}
template <class U>
value_type value_or ( U& v ) const
{
if (this->is_initialized())
return get();
else
return v;
}
#endif
#ifndef BOOST_NO_CXX11_REF_QUALIFIERS
template <typename F>
value_type value_or_eval ( F f ) const&
{
if (this->is_initialized())
return get();
else
return f();
}
template <typename F>
value_type value_or_eval ( F f ) &&
{
if (this->is_initialized())
return base::types::move(get());
else
return f();
}
#else
template <typename F>
value_type value_or_eval ( F f ) const
{
if (this->is_initialized())
return get();
else
return f();
}
#endif
bool operator!() const BOOST_NOEXCEPT { return !this->is_initialized() ; }
BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()
} ;
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
template<class T>
class optional<T&&>
{
BOOST_STATIC_ASSERT_MSG(sizeof(T) == 0, "Optional rvalue references are illegal.");
} ;
#endif
// Returns optional<T>(v)
template<class T>
inline
optional<T> make_optional ( T const& v )
{
return optional<T>(v);
}
// Returns optional<T>(cond,v)
template<class T>
inline
optional<T> make_optional ( bool cond, T const& v )
{
return optional<T>(cond,v);
}
// Returns a reference to the value if this is initialized, otherwise, the behaviour is UNDEFINED.
// No-throw
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::reference_const_type
get ( optional<T> const& opt )
{
return opt.get() ;
}
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::reference_type
get ( optional<T>& opt )
{
return opt.get() ;
}
// Returns a pointer to the value if this is initialized, otherwise, returns NULL.
// No-throw
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::pointer_const_type
get ( optional<T> const* opt )
{
return opt->get_ptr() ;
}
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::pointer_type
get ( optional<T>* opt )
{
return opt->get_ptr() ;
}
// Returns a reference to the value if this is initialized, otherwise, the behaviour is UNDEFINED.
// No-throw
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::reference_const_type
get_optional_value_or ( optional<T> const& opt, BOOST_DEDUCED_TYPENAME optional<T>::reference_const_type v )
{
return opt.get_value_or(v) ;
}
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::reference_type
get_optional_value_or ( optional<T>& opt, BOOST_DEDUCED_TYPENAME optional<T>::reference_type v )
{
return opt.get_value_or(v) ;
}
// Returns a pointer to the value if this is initialized, otherwise, returns NULL.
// No-throw
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::pointer_const_type
get_pointer ( optional<T> const& opt )
{
return opt.get_ptr() ;
}
template<class T>
inline
BOOST_DEDUCED_TYPENAME optional<T>::pointer_type
get_pointer ( optional<T>& opt )
{
return opt.get_ptr() ;
}
// The following declaration prevents a bug where operator safe-bool is used upon streaming optional object if you forget the IO header.
template<class CharType, class CharTrait>
std::basic_ostream<CharType, CharTrait>&
operator<<(std::basic_ostream<CharType, CharTrait>& os, optional_detail::optional_tag const&)
{
BOOST_STATIC_ASSERT_MSG(sizeof(CharType) == 0, "If you want to output boost::optional, include header <boost/optional/optional_io.hpp>");
return os;
}
// optional's relational operators ( ==, !=, <, >, <=, >= ) have deep-semantics (compare values).
// WARNING: This is UNLIKE pointers. Use equal_pointees()/less_pointess() in generic code instead.
//
// optional<T> vs optional<T> cases
//
template<class T>
inline
bool operator == ( optional<T> const& x, optional<T> const& y )
{ return equal_pointees(x,y); }
template<class T>
inline
bool operator < ( optional<T> const& x, optional<T> const& y )
{ return less_pointees(x,y); }
template<class T>
inline
bool operator != ( optional<T> const& x, optional<T> const& y )
{ return !( x == y ) ; }
template<class T>
inline
bool operator > ( optional<T> const& x, optional<T> const& y )
{ return y < x ; }
template<class T>
inline
bool operator <= ( optional<T> const& x, optional<T> const& y )
{ return !( y < x ) ; }
template<class T>
inline
bool operator >= ( optional<T> const& x, optional<T> const& y )
{ return !( x < y ) ; }
//
// optional<T> vs T cases
//
template<class T>
inline
bool operator == ( optional<T> const& x, T const& y )
{ return equal_pointees(x, optional<T>(y)); }
template<class T>
inline
bool operator < ( optional<T> const& x, T const& y )
{ return less_pointees(x, optional<T>(y)); }
template<class T>
inline
bool operator != ( optional<T> const& x, T const& y )
{ return !( x == y ) ; }
template<class T>
inline
bool operator > ( optional<T> const& x, T const& y )
{ return y < x ; }
template<class T>
inline
bool operator <= ( optional<T> const& x, T const& y )
{ return !( y < x ) ; }
template<class T>
inline
bool operator >= ( optional<T> const& x, T const& y )
{ return !( x < y ) ; }
//
// T vs optional<T> cases
//
template<class T>
inline
bool operator == ( T const& x, optional<T> const& y )
{ return equal_pointees( optional<T>(x), y ); }
template<class T>
inline
bool operator < ( T const& x, optional<T> const& y )
{ return less_pointees( optional<T>(x), y ); }
template<class T>
inline
bool operator != ( T const& x, optional<T> const& y )
{ return !( x == y ) ; }
template<class T>
inline
bool operator > ( T const& x, optional<T> const& y )
{ return y < x ; }
template<class T>
inline
bool operator <= ( T const& x, optional<T> const& y )
{ return !( y < x ) ; }
template<class T>
inline
bool operator >= ( T const& x, optional<T> const& y )
{ return !( x < y ) ; }
//
// optional<T> vs none cases
//
template<class T>
inline
bool operator == ( optional<T> const& x, none_t ) BOOST_NOEXCEPT
{ return !x; }
template<class T>
inline
bool operator < ( optional<T> const& x, none_t )
{ return less_pointees(x,optional<T>() ); }
template<class T>
inline
bool operator != ( optional<T> const& x, none_t ) BOOST_NOEXCEPT
{ return bool(x); }
template<class T>
inline
bool operator > ( optional<T> const& x, none_t y )
{ return y < x ; }
template<class T>
inline
bool operator <= ( optional<T> const& x, none_t y )
{ return !( y < x ) ; }
template<class T>
inline
bool operator >= ( optional<T> const& x, none_t y )
{ return !( x < y ) ; }
//
// none vs optional<T> cases
//
template<class T>
inline
bool operator == ( none_t , optional<T> const& y ) BOOST_NOEXCEPT
{ return !y; }
template<class T>
inline
bool operator < ( none_t , optional<T> const& y )
{ return less_pointees(optional<T>() ,y); }
template<class T>
inline
bool operator != ( none_t, optional<T> const& y ) BOOST_NOEXCEPT
{ return bool(y); }
template<class T>
inline
bool operator > ( none_t x, optional<T> const& y )
{ return y < x ; }
template<class T>
inline
bool operator <= ( none_t x, optional<T> const& y )
{ return !( y < x ) ; }
template<class T>
inline
bool operator >= ( none_t x, optional<T> const& y )
{ return !( x < y ) ; }
namespace optional_detail {
template<bool use_default_constructor> struct swap_selector;
template<>
struct swap_selector<true>
{
template<class T>
static void optional_swap ( optional<T>& x, optional<T>& y )
{
const bool hasX = !!x;
const bool hasY = !!y;
if ( !hasX && !hasY )
return;
if( !hasX )
x.emplace();
else if ( !hasY )
y.emplace();
// Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
boost::swap(x.get(),y.get());
if( !hasX )
y = boost::none ;
else if( !hasY )
x = boost::none ;
}
};
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
template<>
struct swap_selector<false>
{
template<class T>
static void optional_swap ( optional<T>& x, optional<T>& y )
//BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && BOOST_NOEXCEPT_EXPR(boost::swap(*x, *y)))
{
if(x)
{
if (y)
{
boost::swap(*x, *y);
}
else
{
y = boost::move(*x);
x = boost::none;
}
}
else
{
if (y)
{
x = boost::move(*y);
y = boost::none;
}
}
}
};
#else
template<>
struct swap_selector<false>
{
template<class T>
static void optional_swap ( optional<T>& x, optional<T>& y )
{
const bool hasX = !!x;
const bool hasY = !!y;
if ( !hasX && hasY )
{
x = y.get();
y = boost::none ;
}
else if ( hasX && !hasY )
{
y = x.get();
x = boost::none ;
}
else if ( hasX && hasY )
{
// Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
boost::swap(x.get(),y.get());
}
}
};
#endif // !defined BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
} // namespace optional_detail
#if (!defined BOOST_NO_CXX11_RVALUE_REFERENCES) && (!defined BOOST_CONFIG_RESTORE_OBSOLETE_SWAP_IMPLEMENTATION)
template<class T>
struct optional_swap_should_use_default_constructor : boost::false_type {} ;
#else
template<class T>
struct optional_swap_should_use_default_constructor : has_nothrow_default_constructor<T> {} ;
#endif //BOOST_NO_CXX11_RVALUE_REFERENCES
template<class T> inline void swap ( optional<T>& x, optional<T>& y )
//BOOST_NOEXCEPT_IF(::boost::is_nothrow_move_constructible<T>::value && BOOST_NOEXCEPT_EXPR(boost::swap(*x, *y)))
{
optional_detail::swap_selector<optional_swap_should_use_default_constructor<T>::value>::optional_swap(x, y);
}
} // namespace boost
#endif
Reference in a new issue Copy permalink