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+/****************************************************************************
+**
+** Copyright (C) 2011 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; // ### Qt5: remove
+ 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
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