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block-allocator.icc

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00001 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
00002 /*
00003  *  Main authors:
00004  *     Christian Schulte <schulte@gecode.org>
00005  *
00006  *  Copyright:
00007  *     Christian Schulte, 2004
00008  *
00009  *  Last modified:
00010  *     $Date: 2007-09-11 14:20:32 +0200 (Tue, 11 Sep 2007) $ by $Author: schulte $
00011  *     $Revision: 4971 $
00012  *
00013  *  This file is part of Gecode, the generic constraint
00014  *  development environment:
00015  *     http://www.gecode.org
00016  *
00017  *  Permission is hereby granted, free of charge, to any person obtaining
00018  *  a copy of this software and associated documentation files (the
00019  *  "Software"), to deal in the Software without restriction, including
00020  *  without limitation the rights to use, copy, modify, merge, publish,
00021  *  distribute, sublicense, and/or sell copies of the Software, and to
00022  *  permit persons to whom the Software is furnished to do so, subject to
00023  *  the following conditions:
00024  *
00025  *  The above copyright notice and this permission notice shall be
00026  *  included in all copies or substantial portions of the Software.
00027  *
00028  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00029  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00030  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00031  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00032  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00033  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00034  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00035  *
00036  */
00037 
00038 namespace Gecode { namespace Support {
00039 
00048   template <class T>
00049   class BlockAllocator {
00050   private:
00052     class Block {
00053     public:
00054       static const int blocksize = 512;
00055       T      b[blocksize];
00056       Block* next;
00057     };
00059     Block* b;
00061     T*     n;
00063     size_t _size;
00065     void allocate(void);
00066   public:
00068     BlockAllocator(void);
00070     ~BlockAllocator(void);
00072     T* operator()(void);
00074     size_t size(void) const;
00075   };
00076 
00084   template <class T>
00085   class BlockClient {
00086   public:
00088     static void* operator new(size_t s, BlockAllocator<T>& ba);
00090     static void  operator delete(void*, BlockAllocator<T>& ba);
00092     static void  operator delete(void*);
00093   };
00094 
00095 
00096 
00097   template <class T>
00098   forceinline
00099   BlockAllocator<T>::BlockAllocator(void) {
00100     b = static_cast<Block*>(Memory::malloc(sizeof(Block)));
00101     b->next = NULL;
00102     n       = &b->b[Block::blocksize];
00103     _size = sizeof(Block);
00104   }
00105 
00106   template <class T>
00107   forceinline
00108   BlockAllocator<T>::~BlockAllocator(void) {
00109     while (b != NULL) {
00110       Block* f = b; b = b->next;
00111       Memory::free(f);
00112     }
00113   }
00114 
00115   template <class T>
00116   forceinline T*
00117   BlockAllocator<T>::operator()(void) {
00118     T* t = --n;
00119     if (t == &b->b[0])
00120       allocate();
00121     return t;
00122   }
00123 
00124   template <class T>
00125   void
00126   BlockAllocator<T>::allocate(void) {
00127     // Allocate another block
00128     Block* nb = static_cast<Block*>(Memory::malloc(sizeof(Block)));
00129     nb->next = b; b = nb;
00130     n = &nb->b[Block::blocksize];
00131     _size += sizeof(Block);
00132   }
00133 
00134   template <class T>
00135   forceinline size_t
00136   BlockAllocator<T>::size(void) const {
00137     return _size;
00138   }
00139 
00140 
00141 
00142   template <class T>
00143   forceinline void
00144   BlockClient<T>::operator delete(void*, BlockAllocator<T>&) {
00145   }
00146   template <class T>
00147   forceinline void
00148   BlockClient<T>::operator delete(void*) {
00149   }
00150   template <class T>
00151   forceinline void*
00152   BlockClient<T>::operator new(size_t, BlockAllocator<T>& ba) {
00153     return ba();
00154   }
00155 
00156 }}
00157 
00158 // STATISTICS: support-any