memorymanager.h

template<class T> class MemoryManager {
    struct MemoryPool {
        T * _pool;
        vector<unsigned long> _freeList;

    };
public:
    MemoryManager(unsigned long initSize=10000) : size(initSize){
        createNewPool();
    }

    ~MemoryManager() {
        for(int i = 0; i < _pools.size(); ++i) {
            delete [] _pools[i]._pool;
        }
    }

    T* allocate() {
        if ( _pools[current]._freeList.size() == 0) {
            int i=0;
            // try to find a pool that has space
            for( ; i < _pools.size(); ++i) {
                if( _pools[i]._freeList.size() > 0) {
                    current = i;
                    break;
                }
            }
            if ( i == _pools.size()) // no pools to be found
                createNewPool();
        }
        unsigned long index = _pools[current]._freeList.back();
        _pools[current]._freeList.pop_back();
        return &_pools[current]._pool[index];           
    }

    // frees the index of the used pointer,
    void deallocate(T* object) {
        unsigned long ptr = (unsigned long)object;      
        for(int i=0 ; i < _pools.size(); ++i) {
            unsigned long begin = (unsigned long)_pools[i]._pool;
            unsigned long end = begin + sizeof(T)*size;
            if ( ptr >= begin && ptr <= end) {
                unsigned long index = (end - ptr) / sizeof(T);
                current = i;
                if ( index > 0){
                    _pools[current]._freeList.push_back(size - index);
                    break;
                }
            }
        }
    }

private:
    void createNewPool() {
        list<unsigned long> newList;
        MemoryPool p;
        p._pool = new T[size];
        _pools.push_back(p);
        current = _pools.size() - 1;
        _pools[current]._freeList.resize(size);
        for(unsigned long index = 0; index< size; ++index)
            _pools[current]._freeList[index] = index;
        


    }
    vector<MemoryPool> _pools;
    int current;
    unsigned long size;

};