qgcache.h

/****************************************************************************
** $Id: //depot/qt/main/src/tools/qgcache.h#28 $
**
** Definition of QGCache and QGCacheIterator classes
**
** Created : 950208
**
** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of the tools module of the Qt GUI Toolkit.
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** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
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** licenses may use this file in accordance with the Qt Commercial License
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**********************************************************************/

#ifndef QGCACHE_H
#define QGCACHE_H

#ifndef QT_H
#include "qcollection.h"
#include "qglist.h"
#include "qgdict.h"
#endif // QT_H


class QCList;                                   // internal classes
class QCListIt;
class QCDict;


class Q_EXPORT QGCache : public QCollection     // generic LRU cache
{
friend class QGCacheIterator;
protected:
    enum KeyType { StringKey, AsciiKey, IntKey, PtrKey };
      // identical to QGDict's, but PtrKey is not used at the moment

    QGCache( int maxCost, uint size, KeyType kt, bool caseSensitive,
             bool copyKeys );
    QGCache( const QGCache & );                 // not allowed, calls fatal()
   ~QGCache();
    QGCache &operator=( const QGCache & );      // not allowed, calls fatal()

    uint    count()     const   { return ((QGDict*)dict)->count(); }
    uint    size()      const   { return ((QGDict*)dict)->size(); }
    int     maxCost()   const   { return mCost; }
    int     totalCost() const   { return tCost; }
    void    setMaxCost( int maxCost );
    void    clear();

    bool    insert_string( const QString &key, QCollection::Item,
                           int cost, int priority );
    bool    insert_other( const char *key, QCollection::Item,
                          int cost, int priority );
    bool    remove_string( const QString &key );
    bool    remove_other( const char *key );
    QCollection::Item take_string( const QString &key );
    QCollection::Item take_other( const char *key );

    QCollection::Item find_string( const QString &key, bool ref=TRUE ) const;
    QCollection::Item find_other( const char *key, bool ref=TRUE ) const;

    void    statistics() const;

private:
    bool    makeRoomFor( int cost, int priority = -1 );
    KeyType keytype;
    QCList *lruList;
    QCDict *dict;
    int     mCost;
    int     tCost;
    bool    copyk;
};


class Q_EXPORT QGCacheIterator                  // generic cache iterator
{
protected:
    QGCacheIterator( const QGCache & );
    QGCacheIterator( const QGCacheIterator & );
   ~QGCacheIterator();
    QGCacheIterator &operator=( const QGCacheIterator & );

    uint              count()   const;
    bool              atFirst() const;
    bool              atLast()  const;
    QCollection::Item toFirst();
    QCollection::Item toLast();

    QCollection::Item get() const;
    QString           getKeyString() const;
    const char       *getKeyAscii()  const;
    long              getKeyInt()    const;

    QCollection::Item operator()();
    QCollection::Item operator++();
    QCollection::Item operator+=( uint );
    QCollection::Item operator--();
    QCollection::Item operator-=( uint );

protected:
    QCListIt *it;                               // iterator on cache list
};


#endif // QGCACHE_H