/****************************************************************************+
−
**+
−
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).+
−
** All rights reserved.+
−
** Contact: Nokia Corporation (qt-info@nokia.com)+
−
**+
−
** This file is part of the QtCore module of the Qt Toolkit.+
−
**+
−
** $QT_BEGIN_LICENSE:LGPL$+
−
** No Commercial Usage+
−
** This file contains pre-release code and may not be distributed.+
−
** You may use this file in accordance with the terms and conditions+
−
** contained in the Technology Preview License Agreement accompanying+
−
** this package.+
−
**+
−
** GNU Lesser General Public License Usage+
−
** Alternatively, this file may be used under the terms of the GNU Lesser+
−
** General Public License version 2.1 as published by the Free Software+
−
** Foundation and appearing in the file LICENSE.LGPL included in the+
−
** packaging of this file.  Please review the following information to+
−
** ensure the GNU Lesser General Public License version 2.1 requirements+
−
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.+
−
**+
−
** In addition, as a special exception, Nokia gives you certain additional+
−
** rights.  These rights are described in the Nokia Qt LGPL Exception+
−
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.+
−
**+
−
** If you have questions regarding the use of this file, please contact+
−
** Nokia at qt-info@nokia.com.+
−
**+
−
**+
−
**+
−
**+
−
**+
−
**+
−
**+
−
**+
−
** $QT_END_LICENSE$+
−
**+
−
****************************************************************************/+
−
+
−
#ifndef QCACHE_H+
−
#define QCACHE_H+
−
+
−
#include <QtCore/qhash.h>+
−
+
−
QT_BEGIN_HEADER+
−
+
−
QT_BEGIN_NAMESPACE+
−
+
−
QT_MODULE(Core)+
−
+
−
template <class Key, class T>+
−
class QCache+
−
{+
−
    struct Node {+
−
        inline Node() : keyPtr(0) {}+
−
        inline Node(T *data, int cost)+
−
            : keyPtr(0), t(data), c(cost), p(0), n(0) {}+
−
        const Key *keyPtr; T *t; int c; Node *p,*n;+
−
    };+
−
    Node *f, *l;+
−
    QHash<Key, Node> hash;+
−
    void *unused;+
−
    int mx, total;+
−
+
−
    inline void unlink(Node &n) {+
−
        if (n.p) n.p->n = n.n;+
−
        if (n.n) n.n->p = n.p;+
−
        if (l == &n) l = n.p;+
−
        if (f == &n) f = n.n;+
−
        total -= n.c;+
−
        T *obj = n.t;+
−
        hash.remove(*n.keyPtr);+
−
        delete obj;+
−
    }+
−
    inline T *relink(const Key &key) {+
−
        typename QHash<Key, Node>::iterator i = hash.find(key);+
−
        if (typename QHash<Key, Node>::const_iterator(i) == hash.constEnd())+
−
            return 0;+
−
+
−
        Node &n = *i;+
−
        if (f != &n) {+
−
            if (n.p) n.p->n = n.n;+
−
            if (n.n) n.n->p = n.p;+
−
            if (l == &n) l = n.p;+
−
            n.p = 0;+
−
            n.n = f;+
−
            f->p = &n;+
−
            f = &n;+
−
        }+
−
        return n.t;+
−
    }+
−
+
−
    Q_DISABLE_COPY(QCache)+
−
+
−
public:+
−
    inline explicit QCache(int maxCost = 100);+
−
#ifdef QT3_SUPPORT+
−
    inline QT3_SUPPORT_CONSTRUCTOR QCache(int maxCost, int /* dummy */)+
−
        : f(0), l(0), mx(maxCost), total(0) {}+
−
#endif+
−
    inline ~QCache() { clear(); }+
−
+
−
    inline int maxCost() const { return mx; }+
−
    void setMaxCost(int m);+
−
    inline int totalCost() const { return total; }+
−
+
−
    inline int size() const { return hash.size(); }+
−
    inline int count() const { return hash.size(); }+
−
    inline bool isEmpty() const { return hash.isEmpty(); }+
−
    inline QList<Key> keys() const { return hash.keys(); }+
−
+
−
    void clear();+
−
+
−
    bool insert(const Key &key, T *object, int cost = 1);+
−
    T *object(const Key &key) const;+
−
    inline bool contains(const Key &key) const { return hash.contains(key); }+
−
    T *operator[](const Key &key) const;+
−
+
−
    bool remove(const Key &key);+
−
    T *take(const Key &key);+
−
+
−
private:+
−
    void trim(int m);+
−
+
−
#ifdef QT3_SUPPORT+
−
    inline QT3_SUPPORT T *find(const Key &key) const { return object(key); }+
−
#endif+
−
+
−
};+
−
+
−
template <class Key, class T>+
−
inline QCache<Key, T>::QCache(int amaxCost)+
−
    : f(0), l(0), unused(0), mx(amaxCost), total(0) {}+
−
+
−
template <class Key, class T>+
−
inline void QCache<Key,T>::clear()+
−
{ while (f) { delete f->t; f = f->n; }+
−
 hash.clear(); l = 0; total = 0; }+
−
+
−
template <class Key, class T>+
−
inline void QCache<Key,T>::setMaxCost(int m)+
−
{ mx = m; trim(mx); }+
−
+
−
template <class Key, class T>+
−
inline T *QCache<Key,T>::object(const Key &key) const+
−
{ return const_cast<QCache<Key,T>*>(this)->relink(key); }+
−
+
−
template <class Key, class T>+
−
inline T *QCache<Key,T>::operator[](const Key &key) const+
−
{ return object(key); }+
−
+
−
template <class Key, class T>+
−
inline bool QCache<Key,T>::remove(const Key &key)+
−
{+
−
    typename QHash<Key, Node>::iterator i = hash.find(key);+
−
    if (typename QHash<Key, Node>::const_iterator(i) == hash.constEnd()) {+
−
        return false;+
−
    } else {+
−
        unlink(*i);+
−
        return true;+
−
    }+
−
}+
−
+
−
template <class Key, class T>+
−
inline T *QCache<Key,T>::take(const Key &key)+
−
{+
−
    typename QHash<Key, Node>::iterator i = hash.find(key);+
−
    if (i == hash.end())+
−
        return 0;+
−
+
−
    Node &n = *i;+
−
    T *t = n.t;+
−
    n.t = 0;+
−
    unlink(n);+
−
    return t;+
−
}+
−
+
−
template <class Key, class T>+
−
bool QCache<Key,T>::insert(const Key &akey, T *aobject, int acost)+
−
{+
−
    remove(akey);+
−
    if (acost > mx) {+
−
        delete aobject;+
−
        return false;+
−
    }+
−
    trim(mx - acost);+
−
    Node sn(aobject, acost);+
−
    typename QHash<Key, Node>::iterator i = hash.insert(akey, sn);+
−
    total += acost;+
−
    Node *n = &i.value();+
−
    n->keyPtr = &i.key();+
−
    if (f) f->p = n;+
−
    n->n = f;+
−
    f = n;+
−
    if (!l) l = f;+
−
    return true;+
−
}+
−
+
−
template <class Key, class T>+
−
void QCache<Key,T>::trim(int m)+
−
{+
−
    Node *n = l;+
−
    while (n && total > m) {+
−
        Node *u = n;+
−
        n = n->p;+
−
        if (qIsDetached(*u->t))+
−
            unlink(*u);+
−
    }+
−
}+
−
+
−
QT_END_NAMESPACE+
−
+
−
QT_END_HEADER+
−
+
−
#endif // QCACHE_H+
−