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Diffstat (limited to 'src/corelib/tools/qcache.h')
| -rw-r--r-- | src/corelib/tools/qcache.h | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/corelib/tools/qcache.h b/src/corelib/tools/qcache.h new file mode 100644 index 0000000..38adac6 --- /dev/null +++ b/src/corelib/tools/qcache.h @@ -0,0 +1,216 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@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; + delete n.t; + hash.remove(*n.keyPtr); + } + 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), 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 |