Ported QCache and related code away from Qt

1 files changed, 183 insertions, 0 deletions

diff --git a/src/cache.h b/src/cache.h
new file mode 100644
index 0000000..284c6da
--- /dev/null
+++ b/src/cache.h
@@ -0,0 +1,183 @@
+/****************************************************************************
+**
+** OpenSCAD (www.openscad.org)
+** Copyright (C) 2009-2011 Clifford Wolf <clifford@clifford.at> and
+**                         Marius Kintel <marius@kintel.net>
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Commercial License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Nokia.
+**
+** 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.
+**
+** 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 have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef CACHE_H
+#define CACHE_H
+
+#include <boost/unordered_map.hpp>
+
+template <class Key, class T>
+class Cache
+{
+	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;
+	};
+	typedef typename boost::unordered_map<Key, Node> map_type;
+	typedef typename map_type::iterator iterator_type;
+	typedef typename map_type::value_type value_type;
+
+	boost::unordered_map<Key, Node> hash;
+	Node *f, *l;
+	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.erase(*n.keyPtr);
+		delete obj;
+	}
+	inline T *relink(const Key &key) {
+		iterator_type i = hash.find(key);
+		if (i == hash.end()) return 0;
+
+		Node &n = i->second;
+		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;
+	}
+
+public:
+	inline explicit Cache(int maxCost = 100)
+		: f(0), l(0), unused(0), mx(maxCost), total(0) { }
+	inline ~Cache() { clear(); }
+
+	inline int maxCost() const { return mx; }
+	void setMaxCost(int m) { mx = m; trim(mx); }
+	inline int totalCost() const { return total; }
+
+	inline int size() const { return hash.size(); }
+	inline bool empty() const { return hash.empty(); }
+
+	void clear() {
+		while (f) { delete f->t; f = f->n; }
+		hash.clear(); l = 0; total = 0;
+	}
+
+	bool insert(const Key &key, T *object, int cost = 1);
+	T *object(const Key &key) const { return const_cast<Cache<Key,T>*>(this)->relink(key); }
+	inline bool contains(const Key &key) const { return hash.find(key) != hash.end(); }
+	T *operator[](const Key &key) const { return object(key); }
+
+	bool remove(const Key &key);
+	T *take(const Key &key);
+
+private:
+	void trim(int m);
+};
+
+template <class Key, class T>
+inline bool Cache<Key,T>::remove(const Key &key)
+{
+	iterator_type i = hash.find(key);
+	if (i == hash.end()) {
+		return false;
+	} else {
+		unlink(i->second);
+		return true;
+	}
+}
+
+template <class Key, class T>
+inline T *Cache<Key,T>::take(const Key &key)
+{
+	iterator_type 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 Cache<Key,T>::insert(const Key &akey, T *aobject, int acost)
+{
+	remove(akey);
+	if (acost > mx) {
+		delete aobject;
+		return false;
+	}
+	trim(mx - acost);
+	Node node(aobject, acost);
+	hash[akey] = node;
+	iterator_type i = hash.find(akey);
+	total += acost;
+	Node *n = &i->second;
+	n->keyPtr = &i->first;
+	if (f) f->p = n;
+	n->n = f;
+	f = n;
+	if (!l) l = f;
+	return true;
+}
+
+template <class Key, class T>
+void Cache<Key,T>::trim(int m)
+{
+	Node *n = l;
+	while (n && total > m) {
+		Node *u = n;
+		n = n->p;
+		unlink(*u);
+	}
+}
+
+#endif
+