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Teuchos_any.hpp
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00043 
00044 #ifndef TEUCHOS_ANY_HPP
00045 #define TEUCHOS_ANY_HPP
00046 
00051 #include "Teuchos_Assert.hpp"
00052 #include "Teuchos_TypeNameTraits.hpp"
00053 
00054 //
00055 // This file was taken from the boost library which contained the
00056 // following notice:
00057 //
00058 // *************************************************************
00059 //
00060 // what:  variant type boost::any
00061 // who:   contributed by Kevlin Henney,
00062 //        with features contributed and bugs found by
00063 //        Ed Brey, Mark Rodgers, Peter Dimov, and James Curran
00064 // when:  July 2001
00065 // where: tested with BCC 5.5, MSVC 6.0, and g++ 2.95
00066 //
00067 // Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
00068 //
00069 // Permission to use, copy, modify, and distribute this software for any
00070 // purpose is hereby granted without fee, provided that this copyright and
00071 // permissions notice appear in all copies and derivatives.
00072 //
00073 // This software is provided "as is" without express or implied warranty.
00074 //
00075 // *************************************************************
00076 //
00077 // RAB modified the file for use in Teuchos.  I changed the nature of
00078 // the any_cast<> to be easier to use.
00079 //
00080 
00081 namespace Teuchos {
00082 
00086 class TEUCHOSCORE_LIB_DLL_EXPORT any
00087 {
00088 public:
00090   any()
00091     : content(0)
00092     {}
00093 
00095   template<typename ValueType>
00096   explicit any(const ValueType & value)
00097     : content(new holder<ValueType>(value))
00098     {}
00099   
00101   any(const any & other)
00102     : content(other.content ? other.content->clone() : 0)
00103     {}
00104 
00106   ~any()
00107     {
00108       delete content;
00109     }
00110 
00112   any & swap(any & rhs)
00113     {
00114       std::swap(content, rhs.content);
00115       return *this;
00116     }
00117   
00119   template<typename ValueType>
00120   any & operator=(const ValueType & rhs)
00121     {
00122       any(rhs).swap(*this);
00123       return *this;
00124     }
00125   
00127   any & operator=(const any & rhs)
00128     {
00129       any(rhs).swap(*this);
00130       return *this;
00131     }
00132   
00134   bool empty() const
00135     {
00136       return !content;
00137     }
00138   
00140   const std::type_info & type() const
00141     {
00142       return content ? content->type() : typeid(void);
00143     }
00144   
00146   std::string typeName() const
00147     {
00148       return content ? content->typeName() : "NONE";
00149     }
00150   
00152   bool same( const any &other ) const
00153     {
00154       if( this->empty() && other.empty() )
00155         return true;
00156       else if( this->empty() && !other.empty() )
00157         return false;
00158       else if( !this->empty() && other.empty() )
00159         return false;
00160       // !this->empty() && !other.empty()
00161       return content->same(*other.content);
00162     }
00163 
00165   void print(std::ostream& os) const
00166     {
00167       if (content) content->print(os);
00168     }
00169 
00170 #ifndef DOXYGEN_SHOULD_SKIP_THIS
00171 
00173 
00175   class placeholder
00176   {
00177   public:
00179     virtual ~placeholder() {}
00181     virtual const std::type_info & type() const = 0;
00183     virtual std::string typeName() const = 0;
00185     virtual placeholder * clone() const = 0;
00187     virtual bool same( const placeholder &other ) const = 0;
00189     virtual void print(std::ostream & os) const = 0;
00190   };
00191   
00193   template<typename ValueType>
00194   class holder : public placeholder
00195   {
00196   public:
00198     holder(const ValueType & value)
00199       : held(value)
00200       {}
00202     const std::type_info & type() const
00203       { return typeid(ValueType); }
00205     std::string typeName() const
00206       { return TypeNameTraits<ValueType>::name(); }
00208     placeholder * clone() const
00209       { return new holder(held); }
00211     bool same( const placeholder &other ) const
00212       {
00213         if( type() != other.type() ) {
00214           return false;
00215         }
00216         // type() == other.type()
00217         const ValueType
00218           &other_held = dynamic_cast<const holder<ValueType>&>(other).held;
00219         return held == other_held;
00220       }
00222     void print(std::ostream & os) const
00223       { os << held; }
00225     ValueType held;
00226   };
00227 
00229 
00230 public:
00231   // Danger: This is made public to allow any_cast to be non-friend
00232   placeholder* access_content()
00233     { return content; }
00234   const placeholder* access_content() const
00235     { return content; }
00236 #endif
00237 
00238 private:
00239 
00240   // /////////////////////////
00241   // Private data members
00242   
00243   placeholder * content;
00244 
00245 };
00246 
00250 class bad_any_cast : public std::runtime_error
00251 {
00252 public:
00253   bad_any_cast( const std::string msg ) : std::runtime_error(msg) {}
00254 };
00255 
00264 template<typename ValueType>
00265 ValueType& any_cast(any &operand)
00266 {
00267   const std::string ValueTypeName = TypeNameTraits<ValueType>::name();
00268   TEUCHOS_TEST_FOR_EXCEPTION(
00269     operand.type() != typeid(ValueType), bad_any_cast,
00270     "any_cast<"<<ValueTypeName<<">(operand): Error, cast to type "
00271     << "any::holder<"<<ValueTypeName<<"> failed since the actual underlying type is \'"
00272     << typeName(*operand.access_content()) << "!"
00273     );
00274   TEUCHOS_TEST_FOR_EXCEPTION(
00275     !operand.access_content(), bad_any_cast
00276     ,"any_cast<"<<ValueTypeName<<">(operand): Error, cast to type "
00277     << "any::holder<"<<ValueTypeName<<"> failed because the content is NULL"
00278     );
00279   any::holder<ValueType>
00280     *dyn_cast_content = dynamic_cast<any::holder<ValueType>*>(operand.access_content());
00281   TEUCHOS_TEST_FOR_EXCEPTION(
00282     !dyn_cast_content, std::logic_error
00283     ,"any_cast<"<<ValueTypeName <<">(operand): Error, cast to type "
00284     << "any::holder<"<<ValueTypeName<<"> failed but should not have and the actual underlying type is \'"
00285     << typeName(*operand.access_content()) << "!"
00286     << "  The problem might be related to incompatible RTTI systems in static and shared libraries!"
00287     );
00288   return dyn_cast_content->held;
00289 }
00290 
00300 template<typename ValueType>
00301 const ValueType& any_cast(const any &operand)
00302 {
00303   return any_cast<ValueType>(const_cast<any&>(operand));
00304 }
00305 
00309 inline std::string toString(const any &rhs)
00310 {
00311   std::ostringstream oss;
00312   rhs.print(oss);
00313   return oss.str();
00314 }
00315 
00319 inline bool operator==( const any &a, const any &b )
00320 {
00321   return a.same(b);
00322 }
00323 
00327 inline bool operator!=( const any &a, const any &b )
00328 {
00329   return !a.same(b);
00330 }
00331 
00335 inline std::ostream & operator<<(std::ostream & os, const any &rhs)
00336 {
00337   rhs.print(os);
00338   return os;
00339 }
00340 
00341 } // namespace Teuchos
00342 
00343 #endif // TEUCHOS_ANY_HPP
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