diff --git a/include/boost/optional/optional.hpp b/include/boost/optional/optional.hpp index 5ae52f0..99f3af0 100644 --- a/include/boost/optional/optional.hpp +++ b/include/boost/optional/optional.hpp @@ -1,1498 +1,749 @@ // Copyright (C) 2003, 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/lib/optional for documentation. - // - // You are welcome to contact the author at: - // fernando_cacciola@hotmail.com - // - #ifndef BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP - #define BOOST_OPTIONAL_OPTIONAL_FLC_19NOV2002_HPP - - #include - #include - - #include "boost/config.hpp" - #include "boost/assert.hpp" - #include "boost/type.hpp" - #include "boost/type_traits/alignment_of.hpp" - #include "boost/type_traits/type_with_alignment.hpp" - #include "boost/type_traits/remove_reference.hpp" - #include "boost/type_traits/is_reference.hpp" - #include "boost/mpl/if.hpp" - #include "boost/mpl/bool.hpp" - #include "boost/mpl/not.hpp" - #include "boost/detail/reference_content.hpp" - #include "boost/none_t.hpp" - #include "boost/utility/compare_pointees.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 is used when assigment of the form: - // optional 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__, <= 0x564) - // BCB (up to 5.64) has the following bug: - // If there is a member function/operator template of the form - // template 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 - - - namespace boost { - - class in_place_factory_base ; - class typed_in_place_factory_base ; - - 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 aligned_storage - { - // Borland ICEs if unnamed unions are used for this! - union dummy_u - { - char data[ sizeof(T) ]; - BOOST_DEDUCED_TYPENAME type_with_alignment< - ::boost::alignment_of::value >::type aligner_; - } dummy_ ; - - public: - - void const* address() const { return &dummy_.data[0]; } - void * address() { return &dummy_.data[0]; } - } ; - - template - 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 - struct types_when_is_ref - { - typedef BOOST_DEDUCED_TYPENAME remove_reference::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 optional_base : public optional_tag - { - private : - - typedef BOOST_DEDUCED_TYPENAME detail::make_reference_content::type internal_type ; - - typedef aligned_storage storage_type ; - - typedef types_when_isnt_ref types_when_not_ref ; - typedef types_when_is_ref types_when_ref ; - - typedef optional_base 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::type is_reference_predicate ; - - typedef BOOST_DEDUCED_TYPENAME mpl::if_::type types ; - - 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 uninitialized. - // No-throw - optional_base() - : - m_initialized(false) {} - - // Creates an optional uninitialized. - // No-throw - optional_base ( none_t const& ) - : - m_initialized(false) {} - - // Creates an optional initialized with 'val'. - // Can throw if T::T(T const&) does - optional_base ( argument_type val ) - : - m_initialized(false) - { - construct(val); - } - - // Creates a deep copy of another optional - // 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 - 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 (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 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 const& ) { destroy(); } - - #ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT - template - 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 - void construct ( Expr const& factory, in_place_factory_base const* ) - { - BOOST_STATIC_ASSERT ( ::boost::mpl::not_::value ) ; - factory.BOOST_NESTED_TEMPLATE apply(m_storage.address()) ; - m_initialized = true ; - } - - // Constructs in-place using the given typed factory - template - void construct ( Expr const& factory, typed_in_place_factory_base const* ) - { - BOOST_STATIC_ASSERT ( ::boost::mpl::not_::value ) ; - factory.apply(m_storage.address()) ; - m_initialized = true ; - } - - template - 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 - 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 from optional uses this function with - // 'Expr' being of type 'U' and relying on a converting constructor of T from U. - template - 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 from optional uses this function with - // 'Expr' being of type 'U' and relying on a converting assignment of T from U. - template - 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 and optional - // 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 or optional (but not optional_base<..>) - template - 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 - internal_type const* get_object() const { return static_cast(m_storage.address()); } - internal_type * get_object() { return static_cast (m_storage.address()); } - - // reference_content 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__, <= 0x564) - 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* 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 ; } - - bool m_initialized ; - storage_type m_storage ; - } ; - - } // namespace optional_detail - - template - class optional : public optional_detail::optional_base - { - typedef optional_detail::optional_base base ; - - typedef BOOST_DEDUCED_TYPENAME base::unspecified_bool_type unspecified_bool_type ; - - public : - - typedef optional 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 uninitialized. - // No-throw - optional() : base() {} - - // Creates an optional uninitialized. - // No-throw - optional( none_t const& none_ ) : base(none_) {} - - // Creates an optional initialized with 'val'. - // Can throw if T::T(T const&) does - optional ( argument_type val ) : base(val) {} - - - #ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR - // NOTE: MSVC needs templated versions first - - // Creates a deep copy of another convertible optional - // Requires a valid conversion from U to T. - // Can throw if T::T(U const&) does - template - explicit optional ( optional const& rhs ) - : - base() - { - if ( rhs.is_initialized() ) - this->construct(rhs.get()); - } - #endif - - #ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT - // Creates an optional 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(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 and optional - // 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 - explicit optional ( Expr const& expr ) : base(expr,&expr) {} - #endif - - // Creates a deep copy of another optional - // Can throw if T::T(T const&) does - optional ( optional const& rhs ) : base(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 - optional& operator= ( Expr expr ) - { - this->assign_expr(expr,&expr); - return *this ; - } - #endif - - #ifndef BOOST_OPTIONAL_NO_CONVERTING_ASSIGNMENT - // Assigns from another convertible optional (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 - optional& operator= ( optional const& rhs ) - { - this->assign(rhs.get()); - return *this ; - } - #endif - - // Assigns from another optional (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( 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 const& none_ ) - { - this->assign( none_ ) ; - return *this ; - } - - // 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 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 a reference to the value if this is initialized, otherwise, the behaviour is UNDEFINED. - // No-throw - template - inline - BOOST_DEDUCED_TYPENAME optional::reference_const_type - get ( optional const& opt ) - { - return opt.get() ; - } - - template - inline - BOOST_DEDUCED_TYPENAME optional::reference_type - get ( optional& opt ) - { - return opt.get() ; - } - - // Returns a pointer to the value if this is initialized, otherwise, returns NULL. - // No-throw - template - inline - BOOST_DEDUCED_TYPENAME optional::pointer_const_type - get ( optional const* opt ) - { - return opt->get_ptr() ; - } - - template - inline - BOOST_DEDUCED_TYPENAME optional::pointer_type - get ( optional* opt ) - { - return opt->get_ptr() ; - } - - // Returns a pointer to the value if this is initialized, otherwise, returns NULL. - // No-throw - template - inline - BOOST_DEDUCED_TYPENAME optional::pointer_const_type - get_pointer ( optional const& opt ) - { - return opt.get_ptr() ; - } - - template - inline - BOOST_DEDUCED_TYPENAME optional::pointer_type - get_pointer ( optional& 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. - - template - inline - bool operator == ( optional const& x, optional const& y ) - { return equal_pointees(x,y); } - - template - inline - bool operator < ( optional const& x, optional const& y ) - { return less_pointees(x,y); } - - template - inline - bool operator != ( optional const& x, optional const& y ) - { return !( x == y ) ; } - - template - inline - bool operator > ( optional const& x, optional const& y ) - { return y < x ; } - - template - inline - bool operator <= ( optional const& x, optional const& y ) - { return !( y < x ) ; } - - template - inline - bool operator >= ( optional const& x, optional const& y ) - { return !( x < y ) ; } - - template - inline - bool operator == ( optional const& x, none_t const& ) - { return equal_pointees(x, optional() ); } - - template - inline - bool operator < ( optional const& x, none_t const& ) - { return less_pointees(x,optional() ); } - - template - inline - bool operator != ( optional const& x, none_t const& y ) - { return !( x == y ) ; } - - template - inline - bool operator > ( optional const& x, none_t const& y ) - { return y < x ; } - - template - inline - bool operator <= ( optional const& x, none_t const& y ) - { return !( y < x ) ; } - - template - inline - bool operator >= ( optional const& x, none_t const& y ) - { return !( x < y ) ; } - - template - inline - bool operator == ( none_t const& x, optional const& y ) - { return equal_pointees(optional() ,y); } - - template - inline - bool operator < ( none_t const& x, optional const& y ) - { return less_pointees(optional() ,y); } - - template - inline - bool operator != ( none_t const& x, optional const& y ) - { return !( x == y ) ; } - - template - inline - bool operator > ( none_t const& x, optional const& y ) - { return y < x ; } - - template - inline - bool operator <= ( none_t const& x, optional const& y ) - { return !( y < x ) ; } - - template - inline - bool operator >= ( none_t const& x, optional const& y ) - { return !( x < y ) ; } - - // - // The following swap implementation follows the GCC workaround as found in - // "boost/detail/compressed_pair.hpp" - // - namespace optional_detail { - - // GCC < 3.2 gets the using declaration at namespace scope (FLC, DWA) - #if BOOST_WORKAROUND(__GNUC__, < 3) \ - || BOOST_WORKAROUND(__GNUC__, == 3) && __GNUC_MINOR__ <= 2 - using std::swap; - #define BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE - #endif - - // optional's swap: - // If both are initialized, calls swap(T&, T&). If this swap throws, both will remain initialized but their values are now unspecified. - // If only one is initialized, calls U.reset(*I), THEN I.reset(). - // If U.reset(*I) throws, both are left UNCHANGED (U is kept uinitialized and I is never reset) - // If both are uninitialized, do nothing (no-throw) - template - inline - void optional_swap ( optional& x, optional& y ) - { - if ( !x && !!y ) - { - x.reset(*y); - y.reset(); - } - else if ( !!x && !y ) - { - y.reset(*x); - x.reset(); - } - else if ( !!x && !!y ) - { - // GCC > 3.2 and all other compilers have the using declaration at function scope (FLC) - #ifndef BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE - // allow for Koenig lookup - using std::swap ; - #endif - swap(*x,*y); - } - } - - } // namespace optional_detail - - template inline void swap ( optional& x, optional& y ) - { - optional_detail::optional_swap(x,y); - } - - } // namespace boost - - #endif - -