/*
 * autocreate_ptr - create-on-access auto-deleting pointer
 *
 * Useful for implementing the Singleton pattern.
 * Note: The instance never gets deleted. This is fine if the
 * destructor only frees memory, but may be problematic if it needs to
 * free other resources.
 */

#ifndef AUTO_CREATE_PTR_H
#define AUTO_CREATE_PTR_H


template <class X> class autocreate_ptr
{
public:
    typedef X element_type;

    autocreate_ptr() throw()    : itsPtr(0) {}
    ~autocreate_ptr()           {delete itsPtr;}
    X& operator*()              {create(); return *itsPtr;}
    X* operator->()             {create(); return itsPtr;}
    X* get()                    {create(); return itsPtr;}
private:
    X* itsPtr;
    void create()               {if (!itsPtr) itsPtr = new X;}
    autocreate_ptr(const autocreate_ptr&) {}
    autocreate_ptr& operator=(const autocreate_ptr&) {}
};

#endif //AUTO_CREATE_PTR_H