实现用类名来动态创建类

突发奇想写了这个非常简单，但是很有用的东西:
需要 boost 库支持

文件名：  Runtimeclass.hpp

#include <map>

#include <string>

#include <boost/function.hpp>

// Write by Jadedrip (Jadedrip@gmail.com)

#ifndef _TSTRDEFINED

    #define _TSTRDEFINED

    #ifdef _UNICODE

        #define tstring std::wstring

    #else

        #define tstring std::string

    #endif

#endif

class RuntimeClassFactory

{

private:

    typedef boost::function<void*()> RUNTIME_CREATE_REF;

protected:

    typedef std::map< tstring, RUNTIME_CREATE_REF > class_map;

    static class_map& cmap(){

        static class_map m_map;

        return m_map;

    }

public:

    static void register_class( tstring name, RUNTIME_CREATE_REF p ){

        (cmap())[name]=p;

    }

    static void* create( tstring name ){

        if( cmap().find( name )!=cmap().end() )

            return (cmap()[name])();

        else

            return NULL;

    }

};

template<typename T>

struct ClassObject

{

    ClassObject(const tstring class_name){ RuntimeClassFactory::register_class( class_name, &ClassObject<T>::create_object ); }

    static void* create_object(){ return new T; }

};

#define REGISTER_CLASS(X)      ClassObject<X> __class_help_##X(_T(#X));

#define REGISTER_CLASS_BY_NAME(X,CLASSNAME)        ClassObject<X> __class_help_##X(_T(CLASSNAME));

class A{

    ...

};

REGISTER_CLASS(A)

void main()

{

    tstring class_name=_T("A");

    A* a=(A*)RuntimeClassFactory::create(class_name);

}