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/*
* Copyright (C) 2002,2003 Daniel Heck
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef ECL_CACHE_HH
#define ECL_CACHE_HH
/* -------------------- Cache -------------------- */
/*
A generic class for caching external data. Stored data is owned by
the cache and is automatically `release'd on destruction. Missing
values are automatically retrieved using the `acquire' method.
*/
#include "ecl_dict.hh"
namespace ecl
{
template <class T>
class DeleteDisposer {
public:
static void dispose (T p)
{ delete p; }
};
template <class T, class Disposer>
class Cache {
public:
Cache();
virtual ~Cache() {}
// ---------- Methods ----------
void clear();
T get (const std::string &key);
void remove (const std::string &key);
unsigned size() const;
bool has_key(const std::string &key) const;
protected:
T store (const std::string &key, T value);
private:
Cache (const Cache &other);
Cache &operator= (const Cache &other);
void release (T value) {
Disposer::dispose (value);
}
// ---------- Interface ----------
virtual T acquire (const std::string &name) = 0;
// ---------- Variables ----------
typedef ecl::Dict<T> Map;
typedef typename Map::iterator iterator;
Map cache;
};
template <class T, class D>
Cache<T,D>::Cache() : cache(1223) {
}
template <class T, class D>
void Cache<T, D>::clear() {
for (iterator i=cache.begin(); i!=cache.end(); ++i)
release(i->second);
cache.clear();
}
template <class T, class D>
void Cache<T, D>::remove (const std::string &key)
{
cache.remove (key);
}
template <class T, class D>
T Cache<T,D>::store (const std::string &key, T value) {
cache.insert(key, value);
return value;
}
template <class T, class D>
T Cache<T,D>::get(const std::string &key) {
iterator i=cache.find(key);
if (i!=cache.end())
return i->second;
else
return store (key, acquire(key));
}
template <class T, class D>
unsigned Cache<T,D>::size() const {
return cache.size();
}
template <class T, class D>
bool Cache<T, D>::has_key(const std::string &key) const {
return cache.has_key(key);
}
/* -------------------- PtrCache -------------------- */
template <class T>
class PtrCache : public Cache<T*, DeleteDisposer<T*> > {
public:
~PtrCache() { this->clear(); }
// void release (T *value) { delete value; }
};
}
#endif
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