williamr@2: // See http://www.boost.org/libs/any for Documentation.
williamr@2: 
williamr@2: #ifndef BOOST_ANY_INCLUDED
williamr@2: #define BOOST_ANY_INCLUDED
williamr@2: 
williamr@2: // what:  variant type boost::any
williamr@2: // who:   contributed by Kevlin Henney,
williamr@2: //        with features contributed and bugs found by
williamr@2: //        Ed Brey, Mark Rodgers, Peter Dimov, and James Curran
williamr@2: // when:  July 2001
williamr@2: // where: tested with BCC 5.5, MSVC 6.0, and g++ 2.95
williamr@2: 
williamr@2: #include <algorithm>
williamr@2: #include <typeinfo>
williamr@2: 
williamr@2: #include "boost/config.hpp"
williamr@2: #include <boost/type_traits/remove_reference.hpp>
williamr@2: #include <boost/type_traits/is_reference.hpp>
williamr@2: #include <boost/throw_exception.hpp>
williamr@2: #include <boost/static_assert.hpp>
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2:     class any
williamr@2:     {
williamr@2:     public: // structors
williamr@2: 
williamr@2:         any()
williamr@2:           : content(0)
williamr@2:         {
williamr@2:         }
williamr@2: 
williamr@2:         template<typename ValueType>
williamr@2:         any(const ValueType & value)
williamr@2:           : content(new holder<ValueType>(value))
williamr@2:         {
williamr@2:         }
williamr@2: 
williamr@2:         any(const any & other)
williamr@2:           : content(other.content ? other.content->clone() : 0)
williamr@2:         {
williamr@2:         }
williamr@2: 
williamr@2:         ~any()
williamr@2:         {
williamr@2:             delete content;
williamr@2:         }
williamr@2: 
williamr@2:     public: // modifiers
williamr@2: 
williamr@2:         any & swap(any & rhs)
williamr@2:         {
williamr@2:             std::swap(content, rhs.content);
williamr@2:             return *this;
williamr@2:         }
williamr@2: 
williamr@2:         template<typename ValueType>
williamr@2:         any & operator=(const ValueType & rhs)
williamr@2:         {
williamr@2:             any(rhs).swap(*this);
williamr@2:             return *this;
williamr@2:         }
williamr@2: 
williamr@2:         any & operator=(const any & rhs)
williamr@2:         {
williamr@2:             any(rhs).swap(*this);
williamr@2:             return *this;
williamr@2:         }
williamr@2: 
williamr@2:     public: // queries
williamr@2: 
williamr@2:         bool empty() const
williamr@2:         {
williamr@2:             return !content;
williamr@2:         }
williamr@2: 
williamr@2:         const std::type_info & type() const
williamr@2:         {
williamr@2:             return content ? content->type() : typeid(void);
williamr@2:         }
williamr@2: 
williamr@2: #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
williamr@2:     private: // types
williamr@2: #else
williamr@2:     public: // types (public so any_cast can be non-friend)
williamr@2: #endif
williamr@2: 
williamr@2:         class placeholder
williamr@2:         {
williamr@2:         public: // structors
williamr@2: 
williamr@2:             virtual ~placeholder()
williamr@2:             {
williamr@2:             }
williamr@2: 
williamr@2:         public: // queries
williamr@2: 
williamr@2:             virtual const std::type_info & type() const = 0;
williamr@2: 
williamr@2:             virtual placeholder * clone() const = 0;
williamr@2: 
williamr@2:         };
williamr@2: 
williamr@2:         template<typename ValueType>
williamr@2:         class holder : public placeholder
williamr@2:         {
williamr@2:         public: // structors
williamr@2: 
williamr@2:             holder(const ValueType & value)
williamr@2:               : held(value)
williamr@2:             {
williamr@2:             }
williamr@2: 
williamr@2:         public: // queries
williamr@2: 
williamr@2:             virtual const std::type_info & type() const
williamr@2:             {
williamr@2:                 return typeid(ValueType);
williamr@2:             }
williamr@2: 
williamr@2:             virtual placeholder * clone() const
williamr@2:             {
williamr@2:                 return new holder(held);
williamr@2:             }
williamr@2: 
williamr@2:         public: // representation
williamr@2: 
williamr@2:             ValueType held;
williamr@2: 
williamr@2:         };
williamr@2: 
williamr@2: #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
williamr@2: 
williamr@2:     private: // representation
williamr@2: 
williamr@2:         template<typename ValueType>
williamr@2:         friend ValueType * any_cast(any *);
williamr@2: 
williamr@2:         template<typename ValueType>
williamr@2:         friend ValueType * unsafe_any_cast(any *);
williamr@2: 
williamr@2: #else
williamr@2: 
williamr@2:     public: // representation (public so any_cast can be non-friend)
williamr@2: 
williamr@2: #endif
williamr@2: 
williamr@2:         placeholder * content;
williamr@2: 
williamr@2:     };
williamr@2: 
williamr@2:     class bad_any_cast : public std::bad_cast
williamr@2:     {
williamr@2:     public:
williamr@2:         virtual const char * what() const throw()
williamr@2:         {
williamr@2:             return "boost::bad_any_cast: "
williamr@2:                    "failed conversion using boost::any_cast";
williamr@2:         }
williamr@2:     };
williamr@2: 
williamr@2:     template<typename ValueType>
williamr@2:     ValueType * any_cast(any * operand)
williamr@2:     {
williamr@2:         return operand && operand->type() == typeid(ValueType)
williamr@2:                     ? &static_cast<any::holder<ValueType> *>(operand->content)->held
williamr@2:                     : 0;
williamr@2:     }
williamr@2: 
williamr@2:     template<typename ValueType>
williamr@2:     const ValueType * any_cast(const any * operand)
williamr@2:     {
williamr@2:         return any_cast<ValueType>(const_cast<any *>(operand));
williamr@2:     }
williamr@2: 
williamr@2:     template<typename ValueType>
williamr@2:     ValueType any_cast(const any & operand)
williamr@2:     {
williamr@2:         typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
williamr@2: 
williamr@2: #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2:         // If 'nonref' is still reference type, it means the user has not
williamr@2:         // specialized 'remove_reference'.
williamr@2: 
williamr@2:         // Please use BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION macro
williamr@2:         // to generate specialization of remove_reference for your class
williamr@2:         // See type traits library documentation for details
williamr@2:         BOOST_STATIC_ASSERT(!is_reference<nonref>::value);
williamr@2: #endif
williamr@2: 
williamr@2:         const nonref * result = any_cast<nonref>(&operand);
williamr@2:         if(!result)
williamr@2:             boost::throw_exception(bad_any_cast());
williamr@2:         return *result;
williamr@2:     }
williamr@2: 
williamr@2:     template<typename ValueType>
williamr@2:     ValueType any_cast(any & operand)
williamr@2:     {
williamr@2:         typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
williamr@2: 
williamr@2: #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2:         // The comment in the above version of 'any_cast' explains when this
williamr@2:         // assert is fired and what to do.
williamr@2:         BOOST_STATIC_ASSERT(!is_reference<nonref>::value);
williamr@2: #endif
williamr@2: 
williamr@2:         nonref * result = any_cast<nonref>(&operand);
williamr@2:         if(!result)
williamr@2:             boost::throw_exception(bad_any_cast());
williamr@2:         return *result;
williamr@2:     }
williamr@2: 
williamr@2:     // Note: The "unsafe" versions of any_cast are not part of the
williamr@2:     // public interface and may be removed at any time. They are
williamr@2:     // required where we know what type is stored in the any and can't
williamr@2:     // use typeid() comparison, e.g., when our types may travel across
williamr@2:     // different shared libraries.
williamr@2:     template<typename ValueType>
williamr@2:     inline ValueType * unsafe_any_cast(any * operand)
williamr@2:     {
williamr@2:         return &static_cast<any::holder<ValueType> *>(operand->content)->held;
williamr@2:     }
williamr@2: 
williamr@2:     template<typename ValueType>
williamr@2:     inline const ValueType * unsafe_any_cast(const any * operand)
williamr@2:     {
williamr@2:         return unsafe_any_cast<ValueType>(const_cast<any *>(operand));
williamr@2:     }
williamr@2: }
williamr@2: 
williamr@2: // Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: #endif