ksharedptr.h

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/* This file is part of the KDE libraries
   Copyright (c) 1999 Waldo Bastian <bastian@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   This library 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 KSharedPTR_H
#define KSharedPTR_H

class KShared {
public:
   KShared() : count(0) { }

   KShared( const KShared & ) : count(0) { }

   KShared &operator=(const KShared & ) { return *this; }

   void _KShared_ref() { count++; }

   void _KShared_unref() { if (!--count) delete this; }

   int _KShared_count() { return count; }

protected:
   virtual ~KShared() { }
   int count; // ### KDE 3.0: rename to something like _KShared_count
              // or make private
};

template< class T >
struct KSharedPtr
{
public:
  KSharedPtr()
    : ptr(0) { }
  KSharedPtr( T* t )
    : ptr(t) { if ( ptr ) ptr->_KShared_ref(); }
  KSharedPtr( const KSharedPtr& p )
    : ptr(p.ptr) { if ( ptr ) ptr->_KShared_ref(); }

  ~KSharedPtr() { if ( ptr ) ptr->_KShared_unref(); }

  KSharedPtr<T>& operator= ( const KSharedPtr<T>& p ) {
    if ( ptr == p.ptr ) return *this;
    if ( ptr ) ptr->_KShared_unref();
    ptr = p.ptr;
    if ( ptr ) ptr->_KShared_ref();
    return *this;
  }
  KSharedPtr<T>& operator= ( T* p ) {
    if ( ptr == p ) return *this;
    if ( ptr ) ptr->_KShared_unref();
    ptr = p;
    if ( ptr ) ptr->_KShared_ref();
    return *this;
  }
  bool operator== ( const KSharedPtr<T>& p ) const { return ( ptr == p.ptr ); }
  bool operator!= ( const KSharedPtr<T>& p ) const { return ( ptr != p.ptr ); }
  bool operator== ( const T* p ) const { return ( ptr == p ); }
  bool operator!= ( const T* p ) const { return ( ptr != p ); }
  bool operator!() const { return ( ptr == 0 ); }
  operator T*() const { return ptr; }

  T* data() { return ptr; }
  const T* data() const { return ptr; }

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

  int count() const { return ptr->_KShared_count(); } // for debugging purposes
private:
  T* ptr;
};

#endif

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