counted.h

00001 /*************************************************************************
00002  *              ESLA: Embeddable Scripting LAnguage
00003  *                  Copyright (C) 2003 Frantz Maerten
00004  *
00005  *   This  program  is  free  software;  you  can  redistribute it and/or
00006  *   modify  it  under  the  terms  of  the GNU General Public License as
00007  *   published  by  the Free Software Foundation; either version 2 of the
00008  *   License, or (at your option) any later version.
00009  *
00010  *   If  you modify this software, you should contact the author, include
00011  *   a  notice giving the name of the person performing the modification,
00012  *   the date of modification, and the reason for such modification.
00013  *
00014  *   Note   that   the   GNU  General  Public  License  does  not  permit
00015  *   incorporating the Software into proprietary programs.
00016  *
00017  *  Contact: Frantz Maerten
00018  *     frantz@pangea.stanford.edu
00019  *
00020  *     Dept. of Geological & Environmental Sciences
00021  *     Stanford University 
00022  *     Stanford, CA 94305-2115
00023  *     USA
00024  *
00025  * Adapted from Bruno Levy (levy@loria.fr)
00026  *************************************************************************/
00027 
00028 
00029 #ifndef COUNTED__
00030 #define COUNTED__
00031 
00032 #include "../esla_namespace.h"
00033 #include <iostream>
00034 #include <assert.h>
00035 
00036 BEGIN_LIB_NAMESPACE
00037 
00038 class Counted {
00039  public:
00040    Counted() ;
00041    virtual ~Counted() ;
00042    
00043    void inc_ref() const ;
00044    void dec_ref() const ;
00045    bool is_shared() const ;
00046    
00047    static void inc_ref(const Counted* counted) ;
00048    static void dec_ref(const Counted* counted) ;
00049 
00050    // For debug purpose only
00051    int nbr_ref() const ;
00052    
00053  private:
00054    int nb_refs_ ;
00055 } ;
00056 
00057 //------------------------------------------------------------------
00058 inline void Counted::inc_ref() const {
00059    Counted* non_const_this = (Counted *)this ;
00060    non_const_this-> nb_refs_++ ;
00061 }
00062 
00063 inline void Counted::dec_ref() const {
00064    Counted* non_const_this = (Counted *)this ;    
00065    non_const_this-> nb_refs_-- ;
00066    assert(nb_refs_ >= 0) ;
00067    
00068   if(nb_refs_ == 0) {
00069      delete this ;
00070   }
00071 }
00072 
00073 inline bool Counted::is_shared() const {
00074    return (nb_refs_ > 1) ;
00075 }
00076 
00077 inline int Counted::nbr_ref() const {
00078    return nb_refs_ ;
00079 }
00080 
00081 
00082 END_LIB_NAMESPACE
00083 
00084 //------------------------------------------------------------------
00085 
00086 #endif
00087