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309 lines
7.3 KiB
C++
309 lines
7.3 KiB
C++
//
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// AutoPtr.h
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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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// SPDX-License-Identifier: BSL-1.0
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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 <algorithm>
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#include "Poco/Exception.h"
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#include "Poco/Foundation.h"
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namespace Poco
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{
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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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AutoPtr(C * ptr) : _ptr(ptr) { }
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AutoPtr(C * ptr, bool shared) : _ptr(ptr)
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{
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if (shared && _ptr)
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_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)
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_ptr->duplicate(); // NOLINT
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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)
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_ptr->duplicate();
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}
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~AutoPtr()
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{
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if (_ptr)
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_ptr->release(); // NOLINT
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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)
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_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)
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_ptr->release();
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_ptr = ptr;
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if (shared && _ptr)
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_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)
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_ptr->release();
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_ptr = ptr._ptr;
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if (_ptr)
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_ptr->duplicate(); // NOLINT
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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)
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_ptr->release();
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_ptr = const_cast<Other *>(ptr.get());
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if (_ptr)
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_ptr->duplicate();
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}
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return *this;
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}
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void reset()
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{
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if (_ptr)
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{
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_ptr->release();
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_ptr = 0;
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}
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}
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void reset(C * ptr) { assign(ptr); }
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void reset(C * ptr, bool shared) { assign(ptr, shared); }
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void reset(const AutoPtr & ptr) { assign(ptr); }
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template <class Other>
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void reset(const AutoPtr<Other> & ptr)
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{
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assign<Other>(ptr);
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}
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AutoPtr & operator=(C * ptr) { return assign(ptr); }
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AutoPtr & operator=(const AutoPtr & ptr) { return assign(ptr); }
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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) { std::swap(_ptr, ptr._ptr); }
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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; // NOLINT
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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; // NOLINT
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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() { return _ptr; }
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const C * get() const { return _ptr; }
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operator C *()
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{
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return _ptr; // NOLINT
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}
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operator const C *() const { return _ptr; }
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bool operator!() const { return _ptr == 0; }
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bool isNull() const { return _ptr == 0; }
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C * duplicate()
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{
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if (_ptr)
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_ptr->duplicate();
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return _ptr;
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}
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bool operator==(const AutoPtr & ptr) const { return _ptr == ptr._ptr; }
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bool operator==(const C * ptr) const { return _ptr == ptr; }
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bool operator==(C * ptr) const { return _ptr == ptr; }
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bool operator!=(const AutoPtr & ptr) const { return _ptr != ptr._ptr; }
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bool operator!=(const C * ptr) const { return _ptr != ptr; }
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bool operator!=(C * ptr) const { return _ptr != ptr; }
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bool operator<(const AutoPtr & ptr) const { return _ptr < ptr._ptr; }
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bool operator<(const C * ptr) const { return _ptr < ptr; }
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bool operator<(C * ptr) const { return _ptr < ptr; }
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bool operator<=(const AutoPtr & ptr) const { return _ptr <= ptr._ptr; }
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bool operator<=(const C * ptr) const { return _ptr <= ptr; }
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bool operator<=(C * ptr) const { return _ptr <= ptr; }
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bool operator>(const AutoPtr & ptr) const { return _ptr > ptr._ptr; }
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bool operator>(const C * ptr) const { return _ptr > ptr; }
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bool operator>(C * ptr) const { return _ptr > ptr; }
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bool operator>=(const AutoPtr & ptr) const { return _ptr >= ptr._ptr; }
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bool operator>=(const C * ptr) const { return _ptr >= ptr; }
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bool operator>=(C * ptr) const { return _ptr >= ptr; }
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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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