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dekker.one
1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Christian Schulte <schulte@gecode.org>
5 *
6 * Copyright:
7 * Christian Schulte, 2004
8 *
9 * This file is part of Gecode, the generic constraint
10 * development environment:
11 * http://www.gecode.org
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining
14 * a copy of this software and associated documentation files (the
15 * "Software"), to deal in the Software without restriction, including
16 * without limitation the rights to use, copy, modify, merge, publish,
17 * distribute, sublicense, and/or sell copies of the Software, and to
18 * permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be
22 * included in all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
28 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
29 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
30 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31 *
32 */
33
34namespace Gecode { namespace Support {
35
36 /**
37 * \brief Manage memory organized into block lists (allocator)
38 *
39 * The allocation policy is to free all memory allocated when
40 * the block allocator is deleted.
41 *
42 * \ingroup FuncSupport
43 */
44 template<class T, class A, int blocksize = 512>
45 class BlockAllocator {
46 private:
47 /// Memory allocator
48 A& a;
49 /// One block of memory
50 class Block {
51 public:
52 T b[blocksize];
53 Block* next;
54 };
55 /// Pointer to current block
56 Block* b;
57 /// Pointer to next part of block (decreasing)
58 T* n;
59 /// Size of allocated blocks
60 size_t _size;
61 /// Allocate additional block
62 void allocate(void);
63 public:
64 /// Initialize
65 BlockAllocator(A& a);
66 /// Free all allocated blocks
67 ~BlockAllocator(void);
68 /// Return allocator used
69 A& allocator(void);
70 /// Return memory of size required by \a T
71 T* operator ()(void);
72 /// Return size of memory required by allocator
73 size_t size(void) const;
74 };
75
76 /**
77 * \brief Client for block allocator of type \a T
78 *
79 * Provides memory management for objects of type \a T.
80 *
81 * \ingroup FuncSupport
82 */
83 template<class T, class A, int blocksize = 512>
84 class BlockClient {
85 public:
86 /// Allocate memory from block allocator \a ba
87 static void* operator new(size_t s, BlockAllocator<T,A,blocksize>& ba);
88 /// Noop (memory freed only when block allocator deleted)
89 static void operator delete(void*, BlockAllocator<T,A,blocksize>& ba);
90 /// Noop (memory freed only when block allocator deleted)
91 static void operator delete(void*);
92 };
93
94
95
96 template<class T, class A, int blocksize>
97 forceinline
98 BlockAllocator<T,A,blocksize>::BlockAllocator(A& a0) : a(a0) {
99 b = static_cast<Block*>(a.ralloc(sizeof(Block)));
100 b->next = nullptr;
101 n = &b->b[blocksize];
102 _size = sizeof(Block);
103 }
104
105 template<class T, class A, int blocksize>
106 forceinline
107 BlockAllocator<T,A,blocksize>::~BlockAllocator(void) {
108 while (b != nullptr) {
109 Block* f = b; b = b->next;
110 a.rfree(f,sizeof(Block));
111 }
112 }
113
114 template<class T, class A, int blocksize>
115 forceinline A&
116 BlockAllocator<T,A,blocksize>::allocator(void) {
117 return a;
118 }
119
120 template<class T, class A, int blocksize>
121 forceinline T*
122 BlockAllocator<T,A,blocksize>::operator ()(void) {
123 T* t = --n;
124 if (t == &b->b[0])
125 allocate();
126 return t;
127 }
128
129 template<class T, class A, int blocksize>
130 void
131 BlockAllocator<T,A,blocksize>::allocate(void) {
132 // Allocate another block
133 Block* nb = static_cast<Block*>(a.ralloc(sizeof(Block)));
134 nb->next = b; b = nb;
135 n = &nb->b[blocksize];
136 _size += sizeof(Block);
137 }
138
139 template<class T, class A, int blocksize>
140 forceinline size_t
141 BlockAllocator<T,A,blocksize>::size(void) const {
142 return _size;
143 }
144
145
146
147 template<class T, class A, int blocksize>
148 forceinline void
149 BlockClient<T,A,blocksize>::operator
150 delete(void*,BlockAllocator<T,A,blocksize>&) {
151 }
152 template<class T, class A, int blocksize>
153 forceinline void
154 BlockClient<T,A,blocksize>::operator delete(void*) {
155 }
156 template<class T, class A, int blocksize>
157 forceinline void*
158 BlockClient<T,A,blocksize>::operator new(size_t,
159 BlockAllocator<T,A,blocksize>& ba) {
160 return ba();
161 }
162
163}}
164
165// STATISTICS: support-any