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Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12

1 files changed, 217 insertions, 0 deletions

diff --git a/src/corelib/tools/qcache.h b/src/corelib/tools/qcache.h
new file mode 100644
index 0000000000..7f6b86919f
--- /dev/null
+++ b/src/corelib/tools/qcache.h
@@ -0,0 +1,217 @@
+/****************************************************************************
+**
+** 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