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379 lines
7.5 KiB
C++
379 lines
7.5 KiB
C++
//
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// AutoPtr.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/AutoPtr.h#1 $
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//
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// Library: Foundation
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// Package: Core
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// Module: AutoPtr
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//
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// Definition of the AutoPtr template class.
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//
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// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// Permission is hereby granted, free of charge, to any person or organization
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// obtaining a copy of the software and accompanying documentation covered by
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// this license (the "Software") to use, reproduce, display, distribute,
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// execute, and transmit the Software, and to prepare derivative works of the
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// Software, and to permit third-parties to whom the Software is furnished to
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// do so, all subject to the following:
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//
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// The copyright notices in the Software and this entire statement, including
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// the above license grant, this restriction and the following disclaimer,
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// must be included in all copies of the Software, in whole or in part, and
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// all derivative works of the Software, unless such copies or derivative
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// works are solely in the form of machine-executable object code generated by
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// a source language processor.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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//
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#ifndef Foundation_AutoPtr_INCLUDED
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#define Foundation_AutoPtr_INCLUDED
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#include "Poco/Foundation.h"
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#include "Poco/Exception.h"
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#include <algorithm>
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namespace Poco {
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template <class C>
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class AutoPtr
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/// AutoPtr is a "smart" pointer for classes implementing
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/// reference counting based garbage collection.
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/// To be usable with the AutoPtr template, a class must
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/// implement the following behaviour:
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/// A class must maintain a reference count.
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/// The constructors of the object initialize the reference
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/// count to one.
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/// The class must implement a public duplicate() method:
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/// void duplicate();
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/// that increments the reference count by one.
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/// The class must implement a public release() method:
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/// void release()
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/// that decrements the reference count by one, and,
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/// if the reference count reaches zero, deletes the
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/// object.
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///
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/// AutoPtr works in the following way:
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/// If an AutoPtr is assigned an ordinary pointer to
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/// an object (via the constructor or the assignment operator),
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/// it takes ownership of the object and the object's reference
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/// count remains unchanged.
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/// If the AutoPtr is assigned another AutoPtr, the
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/// object's reference count is incremented by one by
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/// calling duplicate() on its object.
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/// The destructor of AutoPtr calls release() on its
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/// object.
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/// AutoPtr supports dereferencing with both the ->
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/// and the * operator. An attempt to dereference a null
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/// AutoPtr results in a NullPointerException being thrown.
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/// AutoPtr also implements all relational operators.
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/// Note that AutoPtr allows casting of its encapsulated data types.
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{
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public:
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AutoPtr(): _ptr(0)
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{
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}
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AutoPtr(C* ptr): _ptr(ptr)
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{
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}
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AutoPtr(C* ptr, bool shared): _ptr(ptr)
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{
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if (shared && _ptr) _ptr->duplicate();
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}
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AutoPtr(const AutoPtr& ptr): _ptr(ptr._ptr)
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{
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if (_ptr) _ptr->duplicate();
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}
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template <class Other>
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AutoPtr(const AutoPtr<Other>& ptr): _ptr(const_cast<Other*>(ptr.get()))
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{
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if (_ptr) _ptr->duplicate();
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}
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~AutoPtr()
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{
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if (_ptr) _ptr->release();
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}
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AutoPtr& assign(C* ptr)
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{
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if (_ptr != ptr)
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{
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if (_ptr) _ptr->release();
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_ptr = ptr;
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}
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return *this;
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}
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AutoPtr& assign(C* ptr, bool shared)
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{
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if (_ptr != ptr)
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{
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if (_ptr) _ptr->release();
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_ptr = ptr;
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if (shared && _ptr) _ptr->duplicate();
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}
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return *this;
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}
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AutoPtr& assign(const AutoPtr& ptr)
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{
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if (&ptr != this)
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{
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if (_ptr) _ptr->release();
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_ptr = ptr._ptr;
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if (_ptr) _ptr->duplicate();
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}
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return *this;
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}
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template <class Other>
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AutoPtr& assign(const AutoPtr<Other>& ptr)
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{
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if (ptr.get() != _ptr)
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{
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if (_ptr) _ptr->release();
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_ptr = const_cast<Other*>(ptr.get());
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if (_ptr) _ptr->duplicate();
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}
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return *this;
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}
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AutoPtr& operator = (C* ptr)
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{
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return assign(ptr);
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}
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AutoPtr& operator = (const AutoPtr& ptr)
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{
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return assign(ptr);
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}
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template <class Other>
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AutoPtr& operator = (const AutoPtr<Other>& ptr)
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{
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return assign<Other>(ptr);
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}
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void swap(AutoPtr& ptr)
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{
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std::swap(_ptr, ptr._ptr);
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}
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template <class Other>
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AutoPtr<Other> cast() const
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/// Casts the AutoPtr via a dynamic cast to the given type.
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/// Returns an AutoPtr containing NULL if the cast fails.
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/// Example: (assume class Sub: public Super)
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/// AutoPtr<Super> super(new Sub());
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/// AutoPtr<Sub> sub = super.cast<Sub>();
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/// poco_assert (sub.get());
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{
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Other* pOther = dynamic_cast<Other*>(_ptr);
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return AutoPtr<Other>(pOther, true);
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}
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template <class Other>
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AutoPtr<Other> unsafeCast() const
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/// Casts the AutoPtr via a static cast to the given type.
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/// Example: (assume class Sub: public Super)
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/// AutoPtr<Super> super(new Sub());
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/// AutoPtr<Sub> sub = super.unsafeCast<Sub>();
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/// poco_assert (sub.get());
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{
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Other* pOther = static_cast<Other*>(_ptr);
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return AutoPtr<Other>(pOther, true);
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}
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C* operator -> ()
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{
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if (_ptr)
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return _ptr;
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else
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throw NullPointerException();
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}
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const C* operator -> () const
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{
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if (_ptr)
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return _ptr;
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else
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throw NullPointerException();
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}
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C& operator * ()
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{
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if (_ptr)
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return *_ptr;
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else
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throw NullPointerException();
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}
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const C& operator * () const
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{
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if (_ptr)
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return *_ptr;
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else
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throw NullPointerException();
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}
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C* get()
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{
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return _ptr;
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}
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const C* get() const
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{
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return _ptr;
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}
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operator C* ()
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{
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return _ptr;
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}
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operator const C* () const
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{
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return _ptr;
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}
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bool operator ! () const
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{
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return _ptr == 0;
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}
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bool isNull() const
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{
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return _ptr == 0;
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}
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C* duplicate()
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{
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if (_ptr) _ptr->duplicate();
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return _ptr;
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}
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bool operator == (const AutoPtr& ptr) const
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{
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return _ptr == ptr._ptr;
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}
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bool operator == (const C* ptr) const
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{
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return _ptr == ptr;
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}
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bool operator == (C* ptr) const
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{
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return _ptr == ptr;
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}
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bool operator != (const AutoPtr& ptr) const
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{
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return _ptr != ptr._ptr;
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}
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bool operator != (const C* ptr) const
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{
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return _ptr != ptr;
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}
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bool operator != (C* ptr) const
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{
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return _ptr != ptr;
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}
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bool operator < (const AutoPtr& ptr) const
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{
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return _ptr < ptr._ptr;
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}
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bool operator < (const C* ptr) const
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{
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return _ptr < ptr;
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}
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bool operator < (C* ptr) const
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{
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return _ptr < ptr;
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}
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bool operator <= (const AutoPtr& ptr) const
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{
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return _ptr <= ptr._ptr;
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}
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bool operator <= (const C* ptr) const
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{
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return _ptr <= ptr;
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}
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bool operator <= (C* ptr) const
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{
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return _ptr <= ptr;
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}
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bool operator > (const AutoPtr& ptr) const
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{
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return _ptr > ptr._ptr;
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}
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bool operator > (const C* ptr) const
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{
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return _ptr > ptr;
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}
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bool operator > (C* ptr) const
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{
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return _ptr > ptr;
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}
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bool operator >= (const AutoPtr& ptr) const
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{
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return _ptr >= ptr._ptr;
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}
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bool operator >= (const C* ptr) const
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{
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return _ptr >= ptr;
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}
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bool operator >= (C* ptr) const
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{
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return _ptr >= ptr;
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}
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private:
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C* _ptr;
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};
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template <class C>
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inline void swap(AutoPtr<C>& p1, AutoPtr<C>& p2)
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{
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p1.swap(p2);
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}
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} // namespace Poco
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#endif // Foundation_AutoPtr_INCLUDED
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