Include bind in ndnboost.
diff --git a/ndnboost/optional/optional.hpp b/ndnboost/optional/optional.hpp
new file mode 100644
index 0000000..19dc46b
--- /dev/null
+++ b/ndnboost/optional/optional.hpp
@@ -0,0 +1,991 @@
+// Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
+//
+// 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
+//
+#ifndef BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP
+#define BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP
+
+#include <new>
+#include <algorithm>
+
+#include <ndnboost/config.hpp>
+#include <ndnboost/assert.hpp>
+#include <ndnboost/type.hpp>
+#include <ndnboost/type_traits/alignment_of.hpp>
+#include <ndnboost/type_traits/has_nothrow_constructor.hpp>
+#include <ndnboost/type_traits/type_with_alignment.hpp>
+#include <ndnboost/type_traits/remove_reference.hpp>
+#include <ndnboost/type_traits/is_reference.hpp>
+#include <ndnboost/mpl/if.hpp>
+#include <ndnboost/mpl/bool.hpp>
+#include <ndnboost/mpl/not.hpp>
+#include <ndnboost/detail/reference_content.hpp>
+#include <ndnboost/none.hpp>
+#include <ndnboost/utility/swap.hpp>
+#include <ndnboost/utility/addressof.hpp>
+#include <ndnboost/utility/compare_pointees.hpp>
+#include <ndnboost/utility/in_place_factory.hpp>
+
+#include <ndnboost/optional/optional_fwd.hpp>
+
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1200)
+// VC6.0 has the following bug:
+// When a templated assignment operator exist, an implicit conversion
+// constructing an optional<T> is used when assigment of the form:
+// optional<T> opt ; opt = T(...);
+// is compiled.
+// However, optional's ctor is _explicit_ and the assignemt shouldn't compile.
+// Therefore, for VC6.0 templated assignment is disabled.
+//
+#define BOOST_OPTIONAL_NO_CONVERTING_ASSIGNMENT
+#endif
+
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
+// VC7.0 has the following bug:
+// When both a non-template and a template copy-ctor exist
+// and the templated version is made 'explicit', the explicit is also
+// given to the non-templated version, making the class non-implicitely-copyable.
+//
+#define BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR
+#endif
+
+#if BOOST_WORKAROUND(BOOST_MSVC, <= 1300) || BOOST_WORKAROUND(BOOST_INTEL_CXX_VERSION,<=700)
+// AFAICT only VC7.1 correctly resolves the overload set
+// that includes the in-place factory taking functions,
+// so for the other VC 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__) && (__GNUC__ * 100 + __GNUC_MINOR__) > 302 \
+ && !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 ndnboost.
+namespace ndnboost_optional_detail
+{
+ template <class T, class Factory>
+ inline void construct(Factory const& factory, void* address)
+ {
+ factory.BOOST_NESTED_TEMPLATE apply<T>(address);
+ }
+}
+
+
+namespace ndnboost {
+
+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<
+ ::ndnboost::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 ;
+ 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 ;
+ typedef raw_type* pointer_const_type ;
+ typedef raw_type* pointer_type ;
+ typedef raw_type& argument_type ;
+} ;
+
+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
+ ::ndnboost::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 bool (this_type::*unspecified_bool_type)() const;
+
+ typedef BOOST_DEDUCED_TYPENAME types::reference_type reference_type ;
+ typedef BOOST_DEDUCED_TYPENAME types::reference_const_type reference_const_type ;
+ 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);
+ }
+
+ // 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());
+ }
+
+
+ // 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);
+ }
+
+
+
+ // 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());
+ }
+ }
+
+ // 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() )
+ assign_value(static_cast<value_type>(rhs.get()), is_reference_predicate() );
+ else destroy();
+ }
+ else
+ {
+ if ( rhs.is_initialized() )
+ construct(static_cast<value_type>(rhs.get()));
+ }
+ }
+
+ // 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);
+ }
+
+ // Assigns from "none", destroying the current value, if any, leaving this UNINITIALIZED
+ // No-throw (assuming T::~T() doesn't)
+ void assign ( none_t ) { destroy(); }
+
+#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
+ 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
+
+ public :
+
+ // Destroys the current value, if any, leaving this UNINITIALIZED
+ // No-throw (assuming T::~T() doesn't)
+ void reset() { destroy(); }
+
+ // 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_NO_INPLACE_FACTORY_SUPPORT
+ // Constructs in-place using the given factory
+ template<class Expr>
+ void construct ( Expr const& factory, in_place_factory_base const* )
+ {
+ BOOST_STATIC_ASSERT ( ::ndnboost::mpl::not_<is_reference_predicate>::value ) ;
+ ndnboost_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 ( ::ndnboost::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
+
+ // Constructs using any expression implicitely 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 implicitely 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());
+ }
+
+#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
+ //
+ // 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
+
+ void assign_value ( argument_type val, is_not_reference_tag ) { get_impl() = val; }
+ void assign_value ( argument_type val, is_reference_tag ) { construct(val); }
+
+ void destroy()
+ {
+ if ( m_initialized )
+ destroy_impl(is_reference_predicate()) ;
+ }
+
+ unspecified_bool_type safe_bool() const { return m_initialized ? &this_type::is_initialized : 0 ; }
+
+ 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::~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 ;
+
+ typedef BOOST_DEDUCED_TYPENAME base::unspecified_bool_type unspecified_bool_type ;
+
+ 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 ;
+ 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() : base() {}
+
+ // Creates an optional<T> uninitialized.
+ // No-throw
+ optional( none_t none_ ) : base(none_) {}
+
+ // Creates an optional<T> initialized with 'val'.
+ // Can throw if T::T(T const&) does
+ optional ( argument_type val ) : base(val) {}
+
+ // 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) {}
+
+#ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR
+ // 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());
+ }
+#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 implicitely 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 is the resolved T ctor throws.
+ template<class Expr>
+ explicit optional ( Expr const& expr ) : base(expr,ndnboost::addressof(expr)) {}
+#endif
+
+ // 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) ) {}
+
+ // 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
+ template<class Expr>
+ optional& operator= ( Expr const& expr )
+ {
+ this->assign_expr(expr,ndnboost::addressof(expr));
+ return *this ;
+ }
+#endif
+
+
+#ifndef BOOST_OPTIONAL_NO_CONVERTING_ASSIGNMENT
+ // 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 ;
+ }
+#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 ;
+ }
+
+ // 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 ;
+ }
+
+ // 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_ )
+ {
+ this->assign( none_ ) ;
+ return *this ;
+ }
+
+ void swap( optional & arg )
+ {
+ // allow for Koenig lookup
+ using ndnboost::swap;
+ 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
+ reference_const_type operator *() const { return this->get() ; }
+ reference_type operator *() { return this->get() ; }
+
+ // implicit conversion to "bool"
+ // No-throw
+ operator unspecified_bool_type() const { return this->safe_bool() ; }
+
+ // This is provided for those compilers which don't like the conversion to bool
+ // on some contexts.
+ bool operator!() const { return !this->is_initialized() ; }
+} ;
+
+// 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() ;
+}
+
+// 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 )
+{ return equal_pointees(x, optional<T>() ); }
+
+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 y )
+{ return !( x == y ) ; }
+
+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 )
+{ return equal_pointees(optional<T>() ,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 x, optional<T> const& y )
+{ return !( x == 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 = ndnboost::in_place();
+ else if ( !hasY )
+ y = ndnboost::in_place();
+
+ // Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
+ ndnboost::swap(x.get(),y.get());
+
+ if( !hasX )
+ y = ndnboost::none ;
+ else if( !hasY )
+ x = ndnboost::none ;
+ }
+};
+
+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 = ndnboost::none ;
+ }
+ else if ( hasX && !hasY )
+ {
+ y = x.get();
+ x = ndnboost::none ;
+ }
+ else if ( hasX && hasY )
+ {
+ // Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
+ ndnboost::swap(x.get(),y.get());
+ }
+ }
+};
+
+} // namespace optional_detail
+
+template<class T>
+struct optional_swap_should_use_default_constructor : has_nothrow_default_constructor<T> {} ;
+
+template<class T> inline void swap ( optional<T>& x, optional<T>& y )
+{
+ optional_detail::swap_selector<optional_swap_should_use_default_constructor<T>::value>::optional_swap(x, y);
+}
+
+} // namespace ndnboost
+
+#endif