sl@0: // See http://www.boost.org/libs/any for Documentation.
sl@0: 
sl@0: #ifndef BOOST_ANY_INCLUDED
sl@0: #define BOOST_ANY_INCLUDED
sl@0: 
sl@0: // what:  variant type boost::any
sl@0: // who:   contributed by Kevlin Henney,
sl@0: //        with features contributed and bugs found by
sl@0: //        Ed Brey, Mark Rodgers, Peter Dimov, and James Curran
sl@0: // when:  July 2001
sl@0: // where: tested with BCC 5.5, MSVC 6.0, and g++ 2.95
sl@0: 
sl@0: #include <algorithm>
sl@0: #include <typeinfo>
sl@0: 
sl@0: #include "boost/config.hpp"
sl@0: #include <boost/type_traits/remove_reference.hpp>
sl@0: #include <boost/type_traits/is_reference.hpp>
sl@0: #include <boost/throw_exception.hpp>
sl@0: #include <boost/static_assert.hpp>
sl@0: 
sl@0: namespace boost
sl@0: {
sl@0:     class any
sl@0:     {
sl@0:     public: // structors
sl@0: 
sl@0:         any()
sl@0:           : content(0)
sl@0:         {
sl@0:         }
sl@0: 
sl@0:         template<typename ValueType>
sl@0:         any(const ValueType & value)
sl@0:           : content(new holder<ValueType>(value))
sl@0:         {
sl@0:         }
sl@0: 
sl@0:         any(const any & other)
sl@0:           : content(other.content ? other.content->clone() : 0)
sl@0:         {
sl@0:         }
sl@0: 
sl@0:         ~any()
sl@0:         {
sl@0:             delete content;
sl@0:         }
sl@0: 
sl@0:     public: // modifiers
sl@0: 
sl@0:         any & swap(any & rhs)
sl@0:         {
sl@0:             std::swap(content, rhs.content);
sl@0:             return *this;
sl@0:         }
sl@0: 
sl@0:         template<typename ValueType>
sl@0:         any & operator=(const ValueType & rhs)
sl@0:         {
sl@0:             any(rhs).swap(*this);
sl@0:             return *this;
sl@0:         }
sl@0: 
sl@0:         any & operator=(const any & rhs)
sl@0:         {
sl@0:             any(rhs).swap(*this);
sl@0:             return *this;
sl@0:         }
sl@0: 
sl@0:     public: // queries
sl@0: 
sl@0:         bool empty() const
sl@0:         {
sl@0:             return !content;
sl@0:         }
sl@0: 
sl@0:         const std::type_info & type() const
sl@0:         {
sl@0:             return content ? content->type() : typeid(void);
sl@0:         }
sl@0: 
sl@0: #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
sl@0:     private: // types
sl@0: #else
sl@0:     public: // types (public so any_cast can be non-friend)
sl@0: #endif
sl@0: 
sl@0:         class placeholder
sl@0:         {
sl@0:         public: // structors
sl@0: 
sl@0:             virtual ~placeholder()
sl@0:             {
sl@0:             }
sl@0: 
sl@0:         public: // queries
sl@0: 
sl@0:             virtual const std::type_info & type() const = 0;
sl@0: 
sl@0:             virtual placeholder * clone() const = 0;
sl@0: 
sl@0:         };
sl@0: 
sl@0:         template<typename ValueType>
sl@0:         class holder : public placeholder
sl@0:         {
sl@0:         public: // structors
sl@0: 
sl@0:             holder(const ValueType & value)
sl@0:               : held(value)
sl@0:             {
sl@0:             }
sl@0: 
sl@0:         public: // queries
sl@0: 
sl@0:             virtual const std::type_info & type() const
sl@0:             {
sl@0:                 return typeid(ValueType);
sl@0:             }
sl@0: 
sl@0:             virtual placeholder * clone() const
sl@0:             {
sl@0:                 return new holder(held);
sl@0:             }
sl@0: 
sl@0:         public: // representation
sl@0: 
sl@0:             ValueType held;
sl@0: 
sl@0:         };
sl@0: 
sl@0: #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
sl@0: 
sl@0:     private: // representation
sl@0: 
sl@0:         template<typename ValueType>
sl@0:         friend ValueType * any_cast(any *);
sl@0: 
sl@0:         template<typename ValueType>
sl@0:         friend ValueType * unsafe_any_cast(any *);
sl@0: 
sl@0: #else
sl@0: 
sl@0:     public: // representation (public so any_cast can be non-friend)
sl@0: 
sl@0: #endif
sl@0: 
sl@0:         placeholder * content;
sl@0: 
sl@0:     };
sl@0: 
sl@0:     class bad_any_cast : public std::bad_cast
sl@0:     {
sl@0:     public:
sl@0:         virtual const char * what() const throw()
sl@0:         {
sl@0:             return "boost::bad_any_cast: "
sl@0:                    "failed conversion using boost::any_cast";
sl@0:         }
sl@0:     };
sl@0: 
sl@0:     template<typename ValueType>
sl@0:     ValueType * any_cast(any * operand)
sl@0:     {
sl@0:         return operand && operand->type() == typeid(ValueType)
sl@0:                     ? &static_cast<any::holder<ValueType> *>(operand->content)->held
sl@0:                     : 0;
sl@0:     }
sl@0: 
sl@0:     template<typename ValueType>
sl@0:     const ValueType * any_cast(const any * operand)
sl@0:     {
sl@0:         return any_cast<ValueType>(const_cast<any *>(operand));
sl@0:     }
sl@0: 
sl@0:     template<typename ValueType>
sl@0:     ValueType any_cast(const any & operand)
sl@0:     {
sl@0:         typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
sl@0: 
sl@0: #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
sl@0:         // If 'nonref' is still reference type, it means the user has not
sl@0:         // specialized 'remove_reference'.
sl@0: 
sl@0:         // Please use BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION macro
sl@0:         // to generate specialization of remove_reference for your class
sl@0:         // See type traits library documentation for details
sl@0:         BOOST_STATIC_ASSERT(!is_reference<nonref>::value);
sl@0: #endif
sl@0: 
sl@0:         const nonref * result = any_cast<nonref>(&operand);
sl@0:         if(!result)
sl@0:             boost::throw_exception(bad_any_cast());
sl@0:         return *result;
sl@0:     }
sl@0: 
sl@0:     template<typename ValueType>
sl@0:     ValueType any_cast(any & operand)
sl@0:     {
sl@0:         typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
sl@0: 
sl@0: #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
sl@0:         // The comment in the above version of 'any_cast' explains when this
sl@0:         // assert is fired and what to do.
sl@0:         BOOST_STATIC_ASSERT(!is_reference<nonref>::value);
sl@0: #endif
sl@0: 
sl@0:         nonref * result = any_cast<nonref>(&operand);
sl@0:         if(!result)
sl@0:             boost::throw_exception(bad_any_cast());
sl@0:         return *result;
sl@0:     }
sl@0: 
sl@0:     // Note: The "unsafe" versions of any_cast are not part of the
sl@0:     // public interface and may be removed at any time. They are
sl@0:     // required where we know what type is stored in the any and can't
sl@0:     // use typeid() comparison, e.g., when our types may travel across
sl@0:     // different shared libraries.
sl@0:     template<typename ValueType>
sl@0:     inline ValueType * unsafe_any_cast(any * operand)
sl@0:     {
sl@0:         return &static_cast<any::holder<ValueType> *>(operand->content)->held;
sl@0:     }
sl@0: 
sl@0:     template<typename ValueType>
sl@0:     inline const ValueType * unsafe_any_cast(const any * operand)
sl@0:     {
sl@0:         return unsafe_any_cast<ValueType>(const_cast<any *>(operand));
sl@0:     }
sl@0: }
sl@0: 
sl@0: // Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
sl@0: //
sl@0: // Distributed under the Boost Software License, Version 1.0. (See
sl@0: // accompanying file LICENSE_1_0.txt or copy at
sl@0: // http://www.boost.org/LICENSE_1_0.txt)
sl@0: 
sl@0: #endif