spot  0.9.2
fixpool.hh
Go to the documentation of this file.
1 // Copyright (C) 2011 Laboratoire de Recherche et Developpement de
2 // l'Epita (LRDE)
3 //
4 // This file is part of Spot, a model checking library.
5 //
6 // Spot is free software; you can redistribute it and/or modify it
7 // under the terms of the GNU General Public License as published by
8 // the Free Software Foundation; either version 2 of the License, or
9 // (at your option) any later version.
10 //
11 // Spot is distributed in the hope that it will be useful, but WITHOUT
12 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 // License for more details.
15 //
16 // You should have received a copy of the GNU General Public License
17 // along with Spot; see the file COPYING. If not, write to the Free
18 // Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
19 // 02111-1307, USA.
20 
21 #ifndef SPOT_MISC_FIXPOOL_HH
22 # define SPOT_MISC_FIXPOOL_HH
23 
24 #include <new>
25 #include <cstddef>
26 #include <cstdlib>
27 #include <cassert>
28 
29 namespace spot
30 {
31 
34  {
35  public:
37  fixed_size_pool(size_t size)
38  : freelist_(0), free_start_(0), free_end_(0), chunklist_(0)
39  {
40  const size_t alignement = 2 * sizeof(size_t);
41  size_ = ((size >= sizeof(block_) ? size : sizeof(block_))
42  + alignement - 1) & ~(alignement - 1);
43  }
44 
47  {
48  while (chunklist_)
49  {
50  chunk_* prev = chunklist_->prev;
51  free(chunklist_);
52  chunklist_ = prev;
53  }
54  }
55 
57  void*
59  {
60  block_* f = freelist_;
61  // If we have free blocks available, return the first one.
62  if (f)
63  {
64  freelist_ = f->next;
65  return f;
66  }
67 
68  // Else, create a block out of the last chunk of allocated
69  // memory.
70 
71  // If all the last chunk has been used, allocate one more.
72  if (free_start_ + size_ > free_end_)
73  {
74  const size_t requested = (size_ > 128 ? size_ : 128) * 8192 - 64;
75  chunk_* c = reinterpret_cast<chunk_*>(malloc(requested));
76  if (!c)
77  throw std::bad_alloc();
78  c->prev = chunklist_;
79  chunklist_ = c;
80 
81  free_start_ = c->data_ + size_;
82  free_end_ = c->data_ + requested;
83  }
84 
85  void* res = free_start_;
86  free_start_ += size_;
87  return res;
88  }
89 
96  void
97  deallocate (const void* ptr)
98  {
99  assert(ptr);
100  block_* b = reinterpret_cast<block_*>(const_cast<void*>(ptr));
101  b->next = freelist_;
102  freelist_ = b;
103  }
104 
105  private:
106  size_t size_;
107  struct block_ { block_* next; }* freelist_;
108  char* free_start_;
109  char* free_end_;
110  // chunk = several agglomerated blocks
111  union chunk_ { chunk_* prev; char data_[1]; }* chunklist_;
112  };
113 
114 }
115 
116 #endif // SPOT_MISC_FIXPOOL_HH

Please comment this page and report errors about it on the RefDocComments page.
Generated on Mon Jul 2 2012 17:35:47 for spot by doxygen 1.8.1.1