cache.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef BAGEL_BOFLIB_CACHE_H
#define BAGEL_BOFLIB_CACHE_H

#include "bagel/boflib/llist.h"
#include "bagel/boflib/stdinc.h"

namespace Bagel {

class CCache : private CLList {
private:
    virtual bool alloc() = 0;       // These pure-virtuals MUST be defined
    virtual void free() = 0;        // in the derived class.

    static CCache *_pCacheList;    // Linked cache list
    static uint32 _lOldest;        // Current oldest object in cache
    static uint32 _lYoungest;      // Current youngest object in cache
    static uint16 _nEntries;       // Number of CCache Objects

    uint32 _lAge;      // Age of this object
    int _nLockCount;   // # of locks held on this object
    bool _bCached;     // true if object is in the cache

    bool _bValid;      // true if this object is valid

public:
    CCache();

    virtual ~CCache();

    void load();

    bool release();

    void lock() {
        _nLockCount++;
        load();
    }
    void unlock() {
        _nLockCount--;
    }
    bool isLocked() {
        return (_nLockCount > 0);
    }

    static void initialize();

    static bool flush();

    static bool optimize(uint32 lRequestedFreeSpace);
};

} // namespace Bagel

#endif