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