openscad/src/cache.h

185 lines
5.0 KiB
C
Raw Permalink Normal View History

/****************************************************************************
**
** 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.
** $QT_END_LICENSE$
**
****************************************************************************/
#pragma once
#include <boost/unordered_map.hpp>
#include <boost/format.hpp>
#include "printutils.h"
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;
#ifdef DEBUG
2015-01-14 00:51:02 +03:00
PRINTB("Trimming cache: %1% (%2% bytes)", u->keyPtr->substr(0, 40) % u->c);
#endif
unlink(*u);
}
}