1 /******************************************************************************
2  * Project:  libspatialindex - A C++ library for spatial indexing
3  * Author:   Marios Hadjieleftheriou, mhadji@gmail.com
4  ******************************************************************************
5  * Copyright (c) 2004, Marios Hadjieleftheriou
6  *
7  * All rights reserved.
8  *
9  * Permission is hereby granted, free of charge, to any person obtaining a
10  * copy of this software and associated documentation files (the "Software"),
11  * to deal in the Software without restriction, including without limitation
12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13  * and/or sell copies of the Software, and to permit persons to whom the
14  * Software is furnished to do so, subject to the following conditions:
15  *
16  * The above copyright notice and this permission notice shall be included
17  * in all copies or substantial portions of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25  * DEALINGS IN THE SOFTWARE.
26 ******************************************************************************/
27 
28 #pragma once
29 
30 #include "PointerPool.h"
31 
32 namespace Tools
33 {
34 	template <class X> class PointerPool;
35 
36 	template <class X> class PoolPointer
37 	{
38 	public:
m_pointer(p)39 		explicit PoolPointer(X* p = 0) : m_pointer(p), m_pPool(0) { m_prev = m_next = this; }
PoolPointer(X * p,PointerPool<X> * pPool)40 		explicit PoolPointer(X* p, PointerPool<X>* pPool) throw() : m_pointer(p), m_pPool(pPool) { m_prev = m_next = this; }
~PoolPointer()41 		~PoolPointer() { release(); }
throw()42 		PoolPointer(const PoolPointer& p) throw() { acquire(p); }
43 		PoolPointer& operator=(const PoolPointer& p)
44 		{
45 			if (this != &p)
46 			{
47 				release();
48 				acquire(p);
49 			}
50 			return *this;
51 		}
52 
throw()53 		X& operator*() const throw() { return *m_pointer; }
54 		X* operator->() const throw() { return m_pointer; }
get()55 		X* get() const throw() { return m_pointer; }
unique()56 		bool unique() const throw() { return m_prev ? m_prev == this : true; }
relinquish()57 		void relinquish() throw()
58 		{
59 			m_pPool = 0;
60 			m_pointer = 0;
61 			release();
62 		}
63 
64 	private:
65 		X* m_pointer;
66 		mutable const PoolPointer* m_prev;
67 		mutable const PoolPointer* m_next;
68 		PointerPool<X>* m_pPool;
69 
acquire(const PoolPointer & p)70 		void acquire(const PoolPointer& p) throw()
71 		{
72 			m_pPool = p.m_pPool;
73 			m_pointer = p.m_pointer;
74 			m_next = p.m_next;
75 			m_next->m_prev = this;
76 			m_prev = &p;
77 			#ifndef mutable
78 			p.m_next = this;
79 			#else
80 			(const_cast<linked_ptr<X>*>(&p))->m_next = this;
81 			#endif
82 		}
83 
release()84 		void release()
85 		{
86 			if (unique())
87 			{
88 				if (m_pPool != 0) m_pPool->release(m_pointer);
89 				else delete m_pointer;
90 			}
91 			else
92 			{
93 				m_prev->m_next = m_next;
94 				m_next->m_prev = m_prev;
95 				m_prev = m_next = 0;
96 			}
97 			m_pointer = 0;
98 			m_pPool = 0;
99 		}
100 	};
101 }
102 
103