osmartpointer.h

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// -*- Mode: C++; -*-
/*
                            This file is part of the Opie Project
                            Copyright (C) 2004 Rajko Albrecht <alwin@handhelds.org>
                            Copyright (C) The Opie Team <opie-devel@handhelds.org>
             =.
           .=l.
          .>+-=
_;:,     .>    :=|.         This program is free software; you can
.> <`_,   >  .   <=         redistribute it and/or  modify it under
:`=1 )Y*s>-.--   :          the terms of the GNU Library General Public
.="- .-=="i,     .._        License as published by the Free Software
- .   .-<_>     .<>         Foundation; either version 2 of the License,
    ._= =}       :          or (at your option) any later version.
   .%`+i>       _;_.
   .i_,=:_.      -<s.       This program is distributed in the hope that
    +  .  -:.       =       it will be useful,  but WITHOUT ANY WARRANTY;
   : ..    .:,     . . .    without even the implied warranty of
   =_        +     =;=|`    MERCHANTABILITY or FITNESS FOR A
 _.=:.       :    :=>`:     PARTICULAR PURPOSE. See the GNU
..}^=.=       =       ;     Library General Public License for more
++=   -.     .`     .:      details.
:     =  ...= . :.=-
-.   .:....=;==+<;          You should have received a copy of the GNU
 -_. . .   )=.  =           Library General Public License along with
   --        :-=`           this library; see the file COPYING.LIB.
                            If not, write to the Free Software Foundation,
                            Inc., 59 Temple Place - Suite 330,
                            Boston, MA 02111-1307, USA.
*/

#ifndef _OSmartPointer_h
#define _OSmartPointer_h

#include <stddef.h>

namespace Opie {
namespace Core {

class ORefCount {
protected:
    unsigned long m_RefCount;
public:
    ORefCount();
    virtual ~ORefCount();
    void Incr();
    void Decr();
    bool Shared();
};

template<class T> class OSmartPointer {

    T *ptr;
public:
    OSmartPointer() { ptr = NULL; }

    ~OSmartPointer()
    {
        if (ptr){
            ptr->Decr();
            if (!ptr->Shared())
                delete ptr;
        }
    }
    OSmartPointer(T* t) { if (ptr = t) ptr->Incr(); }
    OSmartPointer(const OSmartPointer<T>& p)
    { if (ptr = p.ptr) ptr->Incr(); }
    OSmartPointer<T>& operator= (const OSmartPointer<T>& p)
    {
        // already same: nothing to do
        if (ptr == p.ptr) return *this;
        // decouple reference
        if (ptr) { ptr->Decr(); if (!ptr->Shared()) delete ptr; }
        // establish new reference
        if (ptr = p.ptr) ptr->Incr();
        return *this;
    }
    OSmartPointer<T>& operator= (T*p)
    {
        if (ptr==p)return *this;
        if (ptr) {
            ptr->Decr();
            if (!ptr->Shared()) delete ptr;
        }
        if (ptr=p) ptr->Incr();
        return *this;
    }

    operator T* () const { return ptr; }

    T& operator* () {return *ptr; }
    const T& operator* ()const {return *ptr; }

    T* operator-> () {return ptr; }
    const T* operator-> ()const {return ptr; }

    operator bool () const { return (ptr != NULL); }
    operator bool () { return ptr != NULL;}

    bool operator! () const { return (ptr == NULL); }
    bool operator! () { return (ptr == NULL); }
};

}
}

#endif

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