source: XMLIO_V2/external/src/POCO/Foundation.save/Poco/AutoPtr.h @ 80

//
// AutoPtr.h
//
// $Id: //poco/1.3/Foundation/include/Poco/AutoPtr.h#2 $
//
// Library: Foundation
// Package: Core
// Module:  AutoPtr
//
// Definition of the AutoPtr template class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_AutoPtr_INCLUDED
#define Foundation_AutoPtr_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/Exception.h"
#include <algorithm>


namespace Poco {


template <class C>
class AutoPtr
        /// AutoPtr is a "smart" pointer for classes implementing
        /// reference counting based garbage collection.
        /// To be usable with the AutoPtr template, a class must
        /// implement the following behaviour:
        /// A class must maintain a reference count.
        /// The constructors of the object initialize the reference
        /// count to one.
        /// The class must implement a public duplicate() method:
        ///     void duplicate();
        /// that increments the reference count by one.
        /// The class must implement a public release() method:
        ///     void release()
        /// that decrements the reference count by one, and,
        /// if the reference count reaches zero, deletes the
        /// object.
        ///
        /// AutoPtr works in the following way:
        /// If an AutoPtr is assigned an ordinary pointer to
        /// an object (via the constructor or the assignment operator),
        /// it takes ownership of the object and the object's reference 
        /// count remains unchanged.
        /// If the AutoPtr is assigned another AutoPtr, the
        /// object's reference count is incremented by one by
        /// calling duplicate() on its object.
        /// The destructor of AutoPtr calls release() on its
        /// object.
        /// AutoPtr supports dereferencing with both the ->
        /// and the * operator. An attempt to dereference a null
        /// AutoPtr results in a NullPointerException being thrown.
        /// AutoPtr also implements all relational operators.
        /// Note that AutoPtr allows casting of its encapsulated data types.
{
public:
        AutoPtr(): _ptr(0)
        {
        }

        AutoPtr(C* ptr): _ptr(ptr)
        {
        }

        AutoPtr(C* ptr, bool shared): _ptr(ptr)
        {
                if (shared && _ptr) _ptr->duplicate();
        }

        AutoPtr(const AutoPtr& ptr): _ptr(ptr._ptr)
        {
                if (_ptr) _ptr->duplicate();
        }

        template <class Other> 
        AutoPtr(const AutoPtr<Other>& ptr): _ptr(const_cast<Other*>(ptr.get()))
        {
                if (_ptr) _ptr->duplicate();
        }

        ~AutoPtr()
        {
                if (_ptr) _ptr->release();
        }
        
        AutoPtr& assign(C* ptr)
        {
                if (_ptr != ptr)
                {
                        if (_ptr) _ptr->release();
                        _ptr = ptr;
                }
                return *this;
        }

        AutoPtr& assign(C* ptr, bool shared)
        {
                if (_ptr != ptr)
                {
                        if (_ptr) _ptr->release();
                        _ptr = ptr;
                        if (shared && _ptr) _ptr->duplicate();
                }
                return *this;
        }
        
        AutoPtr& assign(const AutoPtr& ptr)
        {
                if (&ptr != this)
                {
                        if (_ptr) _ptr->release();
                        _ptr = ptr._ptr;
                        if (_ptr) _ptr->duplicate();
                }
                return *this;
        }
        
        template <class Other> 
        AutoPtr& assign(const AutoPtr<Other>& ptr)
        {
                if (ptr.get() != _ptr)
                {
                        if (_ptr) _ptr->release();
                        _ptr = const_cast<Other*>(ptr.get());
                        if (_ptr) _ptr->duplicate();
                }
                return *this;
        }

        AutoPtr& operator = (C* ptr)
        {
                return assign(ptr);
        }

        AutoPtr& operator = (const AutoPtr& ptr)
        {
                return assign(ptr);
        }
        
        template <class Other> 
        AutoPtr& operator = (const AutoPtr<Other>& ptr)
        {
                return assign<Other>(ptr);
        }

        void swap(AutoPtr& ptr)
        {
                std::swap(_ptr, ptr._ptr);
        }
        
        template <class Other> 
        AutoPtr<Other> cast() const
                /// Casts the AutoPtr via a dynamic cast to the given type.
                /// Returns an AutoPtr containing NULL if the cast fails.
                /// Example: (assume class Sub: public Super)
                ///    AutoPtr<Super> super(new Sub());
                ///    AutoPtr<Sub> sub = super.cast<Sub>();
                ///    poco_assert (sub.get());
        {
                Other* pOther = dynamic_cast<Other*>(_ptr);
                return AutoPtr<Other>(pOther, true);
        }

        template <class Other> 
        AutoPtr<Other> unsafeCast() const
                /// Casts the AutoPtr via a static cast to the given type.
                /// Example: (assume class Sub: public Super)
                ///    AutoPtr<Super> super(new Sub());
                ///    AutoPtr<Sub> sub = super.unsafeCast<Sub>();
                ///    poco_assert (sub.get());
        {
                Other* pOther = static_cast<Other*>(_ptr);
                return AutoPtr<Other>(pOther, true);
        }

        C* operator -> ()
        {
                if (_ptr)
                        return _ptr;
                else
                        throw NullPointerException();
        }

        const C* operator -> () const
        {
                if (_ptr)
                        return _ptr;
                else
                        throw NullPointerException();
        }

        C& operator * ()
        {
                if (_ptr)
                        return *_ptr;
                else
                        throw NullPointerException();
        }

        const C& operator * () const
        {
                if (_ptr)
                        return *_ptr;
                else
                        throw NullPointerException();
        }

        C* get()
        {
                return _ptr;
        }

        const C* get() const
        {
                return _ptr;
        }

        operator C* ()
        {
                return _ptr;
        }
        
        operator const C* () const
        {
                return _ptr;
        }
        
        bool operator ! () const
        {
                return _ptr == 0;
        }

        bool isNull() const
        {
                return _ptr == 0;
        }
        
        C* duplicate()
        {
                if (_ptr) _ptr->duplicate();
                return _ptr;
        }

        bool operator == (const AutoPtr& ptr) const
        {
                return _ptr == ptr._ptr;
        }

        bool operator == (const C* ptr) const
        {
                return _ptr == ptr;
        }

        bool operator == (C* ptr) const
        {
                return _ptr == ptr;
        }

        bool operator != (const AutoPtr& ptr) const
        {
                return _ptr != ptr._ptr;
        }

        bool operator != (const C* ptr) const
        {
                return _ptr != ptr;
        }

        bool operator != (C* ptr) const
        {
                return _ptr != ptr;
        }

        bool operator < (const AutoPtr& ptr) const
        {
                return _ptr < ptr._ptr;
        }

        bool operator < (const C* ptr) const
        {
                return _ptr < ptr;
        }

        bool operator < (C* ptr) const
        {
                return _ptr < ptr;
        }

        bool operator <= (const AutoPtr& ptr) const
        {
                return _ptr <= ptr._ptr;
        }

        bool operator <= (const C* ptr) const
        {
                return _ptr <= ptr;
        }

        bool operator <= (C* ptr) const
        {
                return _ptr <= ptr;
        }

        bool operator > (const AutoPtr& ptr) const
        {
                return _ptr > ptr._ptr;
        }

        bool operator > (const C* ptr) const
        {
                return _ptr > ptr;
        }

        bool operator > (C* ptr) const
        {
                return _ptr > ptr;
        }

        bool operator >= (const AutoPtr& ptr) const
        {
                return _ptr >= ptr._ptr;
        }

        bool operator >= (const C* ptr) const
        {
                return _ptr >= ptr;
        }

        bool operator >= (C* ptr) const
        {
                return _ptr >= ptr;
        }

private:
        C* _ptr;
};


template <class C>
inline void swap(AutoPtr<C>& p1, AutoPtr<C>& p2)
{
        p1.swap(p2);
}


} // namespace Poco


#endif // Foundation_AutoPtr_INCLUDED