[80] | 1 | // |
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| 2 | // AutoPtr.h |
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| 3 | // |
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| 4 | // $Id: //poco/1.3/Foundation/include/Poco/AutoPtr.h#2 $ |
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| 5 | // |
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| 6 | // Library: Foundation |
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| 7 | // Package: Core |
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| 8 | // Module: AutoPtr |
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| 9 | // |
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| 10 | // Definition of the AutoPtr template class. |
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| 11 | // |
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| 12 | // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. |
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| 13 | // and Contributors. |
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| 14 | // |
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| 15 | // Permission is hereby granted, free of charge, to any person or organization |
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| 16 | // obtaining a copy of the software and accompanying documentation covered by |
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| 17 | // this license (the "Software") to use, reproduce, display, distribute, |
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| 18 | // execute, and transmit the Software, and to prepare derivative works of the |
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| 19 | // Software, and to permit third-parties to whom the Software is furnished to |
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| 20 | // do so, all subject to the following: |
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| 21 | // |
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| 22 | // The copyright notices in the Software and this entire statement, including |
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| 23 | // the above license grant, this restriction and the following disclaimer, |
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| 24 | // must be included in all copies of the Software, in whole or in part, and |
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| 25 | // all derivative works of the Software, unless such copies or derivative |
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| 26 | // works are solely in the form of machine-executable object code generated by |
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| 27 | // a source language processor. |
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| 28 | // |
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| 29 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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| 30 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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| 31 | // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT |
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| 32 | // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE |
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| 33 | // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, |
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| 34 | // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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| 35 | // DEALINGS IN THE SOFTWARE. |
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| 36 | // |
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| 37 | |
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| 38 | |
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| 39 | #ifndef Foundation_AutoPtr_INCLUDED |
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| 40 | #define Foundation_AutoPtr_INCLUDED |
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| 41 | |
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| 42 | |
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| 43 | #include "Poco/Foundation.h" |
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| 44 | #include "Poco/Exception.h" |
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| 45 | #include <algorithm> |
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| 46 | |
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| 47 | |
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| 48 | namespace Poco { |
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| 49 | |
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| 50 | |
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| 51 | template <class C> |
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| 52 | class AutoPtr |
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| 53 | /// AutoPtr is a "smart" pointer for classes implementing |
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| 54 | /// reference counting based garbage collection. |
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| 55 | /// To be usable with the AutoPtr template, a class must |
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| 56 | /// implement the following behaviour: |
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| 57 | /// A class must maintain a reference count. |
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| 58 | /// The constructors of the object initialize the reference |
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| 59 | /// count to one. |
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| 60 | /// The class must implement a public duplicate() method: |
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| 61 | /// void duplicate(); |
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| 62 | /// that increments the reference count by one. |
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| 63 | /// The class must implement a public release() method: |
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| 64 | /// void release() |
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| 65 | /// that decrements the reference count by one, and, |
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| 66 | /// if the reference count reaches zero, deletes the |
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| 67 | /// object. |
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| 68 | /// |
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| 69 | /// AutoPtr works in the following way: |
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| 70 | /// If an AutoPtr is assigned an ordinary pointer to |
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| 71 | /// an object (via the constructor or the assignment operator), |
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| 72 | /// it takes ownership of the object and the object's reference |
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| 73 | /// count remains unchanged. |
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| 74 | /// If the AutoPtr is assigned another AutoPtr, the |
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| 75 | /// object's reference count is incremented by one by |
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| 76 | /// calling duplicate() on its object. |
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| 77 | /// The destructor of AutoPtr calls release() on its |
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| 78 | /// object. |
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| 79 | /// AutoPtr supports dereferencing with both the -> |
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| 80 | /// and the * operator. An attempt to dereference a null |
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| 81 | /// AutoPtr results in a NullPointerException being thrown. |
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| 82 | /// AutoPtr also implements all relational operators. |
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| 83 | /// Note that AutoPtr allows casting of its encapsulated data types. |
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| 84 | { |
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| 85 | public: |
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| 86 | AutoPtr(): _ptr(0) |
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| 87 | { |
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| 88 | } |
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| 89 | |
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| 90 | AutoPtr(C* ptr): _ptr(ptr) |
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| 91 | { |
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| 92 | } |
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| 93 | |
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| 94 | AutoPtr(C* ptr, bool shared): _ptr(ptr) |
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| 95 | { |
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| 96 | if (shared && _ptr) _ptr->duplicate(); |
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| 97 | } |
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| 98 | |
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| 99 | AutoPtr(const AutoPtr& ptr): _ptr(ptr._ptr) |
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| 100 | { |
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| 101 | if (_ptr) _ptr->duplicate(); |
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| 102 | } |
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| 103 | |
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| 104 | template <class Other> |
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| 105 | AutoPtr(const AutoPtr<Other>& ptr): _ptr(const_cast<Other*>(ptr.get())) |
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| 106 | { |
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| 107 | if (_ptr) _ptr->duplicate(); |
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| 108 | } |
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| 109 | |
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| 110 | ~AutoPtr() |
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| 111 | { |
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| 112 | if (_ptr) _ptr->release(); |
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| 113 | } |
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| 114 | |
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| 115 | AutoPtr& assign(C* ptr) |
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| 116 | { |
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| 117 | if (_ptr != ptr) |
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| 118 | { |
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| 119 | if (_ptr) _ptr->release(); |
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| 120 | _ptr = ptr; |
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| 121 | } |
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| 122 | return *this; |
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| 123 | } |
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| 124 | |
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| 125 | AutoPtr& assign(C* ptr, bool shared) |
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| 126 | { |
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| 127 | if (_ptr != ptr) |
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| 128 | { |
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| 129 | if (_ptr) _ptr->release(); |
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| 130 | _ptr = ptr; |
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| 131 | if (shared && _ptr) _ptr->duplicate(); |
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| 132 | } |
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| 133 | return *this; |
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| 134 | } |
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| 135 | |
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| 136 | AutoPtr& assign(const AutoPtr& ptr) |
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| 137 | { |
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| 138 | if (&ptr != this) |
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| 139 | { |
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| 140 | if (_ptr) _ptr->release(); |
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| 141 | _ptr = ptr._ptr; |
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| 142 | if (_ptr) _ptr->duplicate(); |
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| 143 | } |
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| 144 | return *this; |
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| 145 | } |
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| 146 | |
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| 147 | template <class Other> |
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| 148 | AutoPtr& assign(const AutoPtr<Other>& ptr) |
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| 149 | { |
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| 150 | if (ptr.get() != _ptr) |
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| 151 | { |
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| 152 | if (_ptr) _ptr->release(); |
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| 153 | _ptr = const_cast<Other*>(ptr.get()); |
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| 154 | if (_ptr) _ptr->duplicate(); |
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| 155 | } |
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| 156 | return *this; |
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| 157 | } |
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| 158 | |
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| 159 | AutoPtr& operator = (C* ptr) |
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| 160 | { |
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| 161 | return assign(ptr); |
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| 162 | } |
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| 163 | |
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| 164 | AutoPtr& operator = (const AutoPtr& ptr) |
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| 165 | { |
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| 166 | return assign(ptr); |
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| 167 | } |
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| 168 | |
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| 169 | template <class Other> |
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| 170 | AutoPtr& operator = (const AutoPtr<Other>& ptr) |
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| 171 | { |
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| 172 | return assign<Other>(ptr); |
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| 173 | } |
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| 174 | |
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| 175 | void swap(AutoPtr& ptr) |
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| 176 | { |
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| 177 | std::swap(_ptr, ptr._ptr); |
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| 178 | } |
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| 179 | |
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| 180 | template <class Other> |
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| 181 | AutoPtr<Other> cast() const |
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| 182 | /// Casts the AutoPtr via a dynamic cast to the given type. |
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| 183 | /// Returns an AutoPtr containing NULL if the cast fails. |
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| 184 | /// Example: (assume class Sub: public Super) |
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| 185 | /// AutoPtr<Super> super(new Sub()); |
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| 186 | /// AutoPtr<Sub> sub = super.cast<Sub>(); |
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| 187 | /// poco_assert (sub.get()); |
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| 188 | { |
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| 189 | Other* pOther = dynamic_cast<Other*>(_ptr); |
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| 190 | return AutoPtr<Other>(pOther, true); |
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| 191 | } |
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| 192 | |
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| 193 | template <class Other> |
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| 194 | AutoPtr<Other> unsafeCast() const |
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| 195 | /// Casts the AutoPtr via a static cast to the given type. |
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| 196 | /// Example: (assume class Sub: public Super) |
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| 197 | /// AutoPtr<Super> super(new Sub()); |
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| 198 | /// AutoPtr<Sub> sub = super.unsafeCast<Sub>(); |
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| 199 | /// poco_assert (sub.get()); |
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| 200 | { |
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| 201 | Other* pOther = static_cast<Other*>(_ptr); |
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| 202 | return AutoPtr<Other>(pOther, true); |
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| 203 | } |
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| 204 | |
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| 205 | C* operator -> () |
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| 206 | { |
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| 207 | if (_ptr) |
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| 208 | return _ptr; |
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| 209 | else |
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| 210 | throw NullPointerException(); |
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| 211 | } |
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| 212 | |
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| 213 | const C* operator -> () const |
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| 214 | { |
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| 215 | if (_ptr) |
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| 216 | return _ptr; |
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| 217 | else |
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| 218 | throw NullPointerException(); |
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| 219 | } |
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| 220 | |
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| 221 | C& operator * () |
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| 222 | { |
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| 223 | if (_ptr) |
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| 224 | return *_ptr; |
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| 225 | else |
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| 226 | throw NullPointerException(); |
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| 227 | } |
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| 228 | |
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| 229 | const C& operator * () const |
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| 230 | { |
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| 231 | if (_ptr) |
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| 232 | return *_ptr; |
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| 233 | else |
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| 234 | throw NullPointerException(); |
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| 235 | } |
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| 236 | |
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| 237 | C* get() |
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| 238 | { |
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| 239 | return _ptr; |
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| 240 | } |
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| 241 | |
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| 242 | const C* get() const |
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| 243 | { |
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| 244 | return _ptr; |
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| 245 | } |
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| 246 | |
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| 247 | operator C* () |
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| 248 | { |
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| 249 | return _ptr; |
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| 250 | } |
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| 251 | |
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| 252 | operator const C* () const |
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| 253 | { |
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| 254 | return _ptr; |
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| 255 | } |
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| 256 | |
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| 257 | bool operator ! () const |
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| 258 | { |
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| 259 | return _ptr == 0; |
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| 260 | } |
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| 261 | |
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| 262 | bool isNull() const |
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| 263 | { |
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| 264 | return _ptr == 0; |
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| 265 | } |
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| 266 | |
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| 267 | C* duplicate() |
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| 268 | { |
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| 269 | if (_ptr) _ptr->duplicate(); |
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| 270 | return _ptr; |
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| 271 | } |
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| 272 | |
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| 273 | bool operator == (const AutoPtr& ptr) const |
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| 274 | { |
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| 275 | return _ptr == ptr._ptr; |
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| 276 | } |
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| 277 | |
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| 278 | bool operator == (const C* ptr) const |
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| 279 | { |
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| 280 | return _ptr == ptr; |
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| 281 | } |
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| 282 | |
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| 283 | bool operator == (C* ptr) const |
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| 284 | { |
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| 285 | return _ptr == ptr; |
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| 286 | } |
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| 287 | |
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| 288 | bool operator != (const AutoPtr& ptr) const |
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| 289 | { |
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| 290 | return _ptr != ptr._ptr; |
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| 291 | } |
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| 292 | |
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| 293 | bool operator != (const C* ptr) const |
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| 294 | { |
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| 295 | return _ptr != ptr; |
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| 296 | } |
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| 297 | |
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| 298 | bool operator != (C* ptr) const |
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| 299 | { |
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| 300 | return _ptr != ptr; |
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| 301 | } |
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| 302 | |
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| 303 | bool operator < (const AutoPtr& ptr) const |
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| 304 | { |
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| 305 | return _ptr < ptr._ptr; |
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| 306 | } |
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| 307 | |
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| 308 | bool operator < (const C* ptr) const |
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| 309 | { |
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| 310 | return _ptr < ptr; |
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| 311 | } |
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| 312 | |
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| 313 | bool operator < (C* ptr) const |
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| 314 | { |
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| 315 | return _ptr < ptr; |
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| 316 | } |
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| 317 | |
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| 318 | bool operator <= (const AutoPtr& ptr) const |
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| 319 | { |
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| 320 | return _ptr <= ptr._ptr; |
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| 321 | } |
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| 322 | |
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| 323 | bool operator <= (const C* ptr) const |
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| 324 | { |
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| 325 | return _ptr <= ptr; |
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| 326 | } |
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| 327 | |
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| 328 | bool operator <= (C* ptr) const |
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| 329 | { |
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| 330 | return _ptr <= ptr; |
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| 331 | } |
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| 332 | |
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| 333 | bool operator > (const AutoPtr& ptr) const |
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| 334 | { |
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| 335 | return _ptr > ptr._ptr; |
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| 336 | } |
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| 337 | |
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| 338 | bool operator > (const C* ptr) const |
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| 339 | { |
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| 340 | return _ptr > ptr; |
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| 341 | } |
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| 342 | |
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| 343 | bool operator > (C* ptr) const |
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| 344 | { |
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| 345 | return _ptr > ptr; |
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| 346 | } |
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| 347 | |
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| 348 | bool operator >= (const AutoPtr& ptr) const |
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| 349 | { |
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| 350 | return _ptr >= ptr._ptr; |
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| 351 | } |
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| 352 | |
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| 353 | bool operator >= (const C* ptr) const |
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| 354 | { |
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| 355 | return _ptr >= ptr; |
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| 356 | } |
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| 357 | |
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| 358 | bool operator >= (C* ptr) const |
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| 359 | { |
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| 360 | return _ptr >= ptr; |
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| 361 | } |
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| 362 | |
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| 363 | private: |
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| 364 | C* _ptr; |
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| 365 | }; |
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| 366 | |
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| 367 | |
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| 368 | template <class C> |
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| 369 | inline void swap(AutoPtr<C>& p1, AutoPtr<C>& p2) |
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| 370 | { |
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| 371 | p1.swap(p2); |
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| 372 | } |
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| 373 | |
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| 374 | |
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| 375 | } // namespace Poco |
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| 376 | |
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| 377 | |
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| 378 | #endif // Foundation_AutoPtr_INCLUDED |
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