BlockAllocator.h

/*
 *  BlockAllocator class interface
 *
 *  This file is part of OTAWA
 *  Copyright (c) 2010, IRIT UPS.
 *
 *  OTAWA is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  OTAWA is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with OTAWA; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef ELM_ALLOC_BLOCKALLOCATOR_H_
#define ELM_ALLOC_BLOCKALLOCATOR_H_
 
#include <elm/alloc/StackAllocator.h>
#include <elm/compare.h>
 
namespace elm {
 
// RawBlockAllocator class
template <class T>
class BlockAllocator {
 
    typedef struct block_t {
        struct block_t *next;
    } block_t;
 
public:
    static const int default_block_per_chunk = 32;
 
    BlockAllocator(int block_per_chunk = default_block_per_chunk)
        : alloc(min(sizeof(T), sizeof(block_t)) * block_per_chunk), list(0) { }
 
    inline T *allocate() {
        if(list != nullptr) {
            block_t *res = list;
            list = list->next;
            return reinterpret_cast<T *>(res);
        }
        else
            return reinterpret_cast<T *>(alloc.allocate(sizeof(T)));
    }
 
    void free(T *p) {
        block_t *b = reinterpret_cast<block_t *>(p);
        b->next = list;
        list = b;
    }
 
private:
    StackAllocator alloc;
    block_t *list;
};
 
} // elm
 
#endif /* ELM_ALLOC_BLOCKALLOCATOR_H_ */