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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#ifndef INCLUDED_BINARYURP_SOURCE_CACHE_HXX
#define INCLUDED_BINARYURP_SOURCE_CACHE_HXX
#include "sal/config.h"
#include <cassert>
#include <cstddef>
#include <map>
#include "boost/noncopyable.hpp"
#include "sal/types.h"
namespace binaryurp {
namespace cache {
enum { size = 256, ignore = 0xFFFF };
}
template< typename T > class Cache: private boost::noncopyable {
public:
explicit Cache(std::size_t size):
size_(size), first_(map_.end()), last_(map_.end())
{
assert(size < cache::ignore);
}
sal_uInt16 add(T const & content, bool * found) {
assert(found != 0);
typename Map::iterator i(map_.find(content));
*found = i != map_.end();
if (i == map_.end()) {
typename Map::size_type n = map_.size();
if (n < size_) {
i =
(map_.insert(
typename Map::value_type(
content,
Entry(
static_cast< sal_uInt16 >(n), map_.end(),
first_)))).
first;
if (first_ == map_.end()) {
last_ = i;
} else {
first_->second.prev = i;
}
first_ = i;
} else if (last_ != map_.end()) {
i =
(map_.insert(
typename Map::value_type(
content,
Entry(last_->second.index, map_.end(), first_)))).
first;
first_->second.prev = i;
first_ = i;
typename Map::iterator j(last_);
last_ = last_->second.prev;
last_->second.next = map_.end();
map_.erase(j);
} else {
// Reached iff size_ == 0:
return cache::ignore;
}
} else if (i != first_) {
// Move to front (reached only if size_ > 1):
i->second.prev->second.next = i->second.next;
if (i->second.next == map_.end()) {
last_ = i->second.prev;
} else {
i->second.next->second.prev = i->second.prev;
}
i->second.prev = map_.end();
i->second.next = first_;
first_->second.prev = i;
first_ = i;
}
return i->second.index;
}
private:
struct Entry;
typedef std::map< T, Entry > Map;
struct Entry {
sal_uInt16 index;
typename Map::iterator prev;
typename Map::iterator next;
Entry(
sal_uInt16 theIndex, typename Map::iterator thePrev,
typename Map::iterator theNext):
index(theIndex), prev(thePrev), next(theNext) {}
};
std::size_t size_;
Map map_;
typename Map::iterator first_;
typename Map::iterator last_;
};
}
#endif
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