memstore.h

/*
    IL : Intlog Language
    Object Oriented Prolog Project
    Copyright (C) 1992-2021 - Ing. Capelli Carlo

    This program 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.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
*/


#ifndef MEMSTORE_H_
#define MEMSTORE_H_

#include "vectb.h"
#include "iafx.h"

typedef unsigned    MemStoreRef;
#define MSR_NULL    MemStoreRef(-1)

////////////////////////////////////////////////////////////
// allocation schema for frequently allocated items
//  dimensions must be power of 2, for fast address compute
//
//  now simplified to vector...
//
template <typename T>
class MemStorage : vect<T> {
public:

    // insert consecutive uninitialized
    MemStoreRef Reserve(unsigned n = 1) {
        MemStoreRef p = this->dim();
        this->grow(n);
        return p;
    }

    // release used cell
    void Delete(MemStoreRef) {
    }

    // release all memory
    void FreeMem() {
        this->resize(0);
    }

    MemStoreRef Store(const T& v) {
        MemStoreRef r = Reserve();
        *cell(r) = v;
        return r;
    }

    T* operator[](MemStoreRef c) const {
        return cell(c);
    }

protected:

    // get pointer to cell as index
    T* cell(MemStoreRef p) const {
        return this->getptr(p);
    }

    // true if cell is used
    int used(MemStoreRef r) const {
        return r >= 0 && r < this->dim();
    }
};

#endif