598243b2d8
Change-Id: I863499cccfe586b570d0021e143718bd3e4e1181 Reviewed-on: https://gerrit.libreoffice.org/8236 Reviewed-by: Caolán McNamara <caolanm@redhat.com> Tested-by: Caolán McNamara <caolanm@redhat.com>
98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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#ifndef INCLUDED_BINARYURP_SOURCE_CACHE_HXX
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#define INCLUDED_BINARYURP_SOURCE_CACHE_HXX
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#include "sal/config.h"
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#include <cassert>
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#include <cstddef>
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#include <map>
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#include <list>
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#include "boost/noncopyable.hpp"
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#include "sal/types.h"
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namespace binaryurp {
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namespace cache {
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enum { size = 256, ignore = 0xFFFF };
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}
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template< typename T > class Cache : private boost::noncopyable {
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public:
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typedef sal_uInt16 IdxType;
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explicit Cache(std::size_t size):
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size_(size)
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{
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assert(size < cache::ignore);
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}
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IdxType add( const T& rContent, bool* pbFound) {
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assert( pbFound != NULL);
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if( !size_) {
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*pbFound = false;
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return cache::ignore;
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}
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// try to insert into the map
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list_.push_front( rContent); // create a temp entry
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typedef std::pair<typename LruList::iterator, IdxType> MappedType;
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typedef std::pair<typename LruItMap::iterator,bool> MapPair;
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MapPair aMP = map_.insert( MappedType( list_.begin(), 0));
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*pbFound = !aMP.second;
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if( !aMP.second) { // insertion not needed => found the entry
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list_.pop_front(); // remove the temp entry
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list_.splice( list_.begin(), list_, aMP.first->first); // the found entry is moved to front
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return aMP.first->second;
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}
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// test insertion successful => it was new so we keep it
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IdxType n = static_cast<IdxType>( map_.size() - 1);
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if( n >= size_) { // cache full => replace the LRU entry
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// find the least recently used element in the map
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typename LruItMap::iterator it = map_.find( --list_.end());
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n = it->second;
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map_.erase( it); // remove it from the map
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list_.pop_back(); // remove from the list
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}
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aMP.first->second = n;
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return n;
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}
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private:
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typedef std::list<T> LruList; // last recently used list
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typedef typename LruList::iterator LruListIt;
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struct CmpT{ bool operator()( const LruListIt& rA, const LruListIt& rB) const { return (*rA<*rB);}};
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typedef ::std::map< LruListIt, IdxType, CmpT > LruItMap; // a map into a LruList
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std::size_t size_;
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LruItMap map_;
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LruList list_;
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};
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}
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#endif
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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