EST_Contents.h

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/*************************************************************************/
/*                    Author :  Alan W Black                             */
/*                    Date   :  May 1996                                 */
/*-----------------------------------------------------------------------*/
/*            A class for representing ints floats and strings           */
/*                                                                       */
/*=======================================================================*/
#ifndef __EST_CONTENTS_H__
#define __EST_CONTENTS_H__

/** \class EST_Content_Data
    \brief A class for containing some other (arbitrary) class.
Not general enough to call itself a run-time type system  
Is designed to solve the problem of holding user          
specified information.
Keeps reference count to know when to delete contents     
                                                           
 This is done on two levels EST_Contents and Contents_Data 
*/
class EST_Content_Data{
  private:
    int refs;
    void *data;
    void (*free_func)(void *data);
  public:
    EST_Content_Data(void *d,void (*f)(void *d)) {free_func=f; data=d; refs=1;}
    ~EST_Content_Data() { free_func(data); }
    ///
    int unref() { return --refs; }
    ///
    int ref() { return ++refs; }
    ///
    int the_refs() { return refs; }
    void *contents() { return data; }
    EST_Content_Data &operator=(const EST_Content_Data &c)
    {refs = c.refs; data = c.data; free_func = c.free_func; return *this;}
};

/** More contents */

class EST_Contents{
private:
    EST_Content_Data *content_data;
    void unref_contents(void)
       { if ((content_data != 0) &&
         (content_data->unref() == 0))
         delete content_data;}
public:
    EST_Contents() { content_data = 0; }
    EST_Contents(void *p,void (*free_func)(void *p))
         { content_data = new EST_Content_Data(p,free_func); }
    ~EST_Contents() { unref_contents(); }
    void set_contents(void *p,void (*free_func)(void *p))
         { unref_contents(); content_data = new EST_Content_Data(p,free_func);}
    void *get_contents() const 
         {return (content_data ? content_data->contents() : 0);}
    ///
    int refs() const { return ((content_data == 0) ? 0 :
             content_data->the_refs());}
    EST_Contents &operator=(const EST_Contents &c)
         { unref_contents();
       content_data = c.content_data; 
       if (content_data != 0) content_data->ref();
           return *this; }
};

#endif