128 lines
3.9 KiB
C++
128 lines
3.9 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 "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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explicit Cache(std::size_t size):
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size_(size), first_(map_.end()), last_(map_.end())
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{
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assert(size < cache::ignore);
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}
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sal_uInt16 add(T const & content, bool * found) {
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assert(found != 0);
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typename Map::iterator i(map_.find(content));
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*found = i != map_.end();
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if (i == map_.end()) {
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typename Map::size_type n = map_.size();
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if (n < size_) {
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i =
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(map_.insert(
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typename Map::value_type(
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content,
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Entry(
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static_cast< sal_uInt16 >(n), map_.end(),
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first_)))).
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first;
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if (first_ == map_.end()) {
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last_ = i;
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} else {
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first_->second.prev = i;
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}
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first_ = i;
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} else if (last_ != map_.end()) {
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i =
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(map_.insert(
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typename Map::value_type(
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content,
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Entry(last_->second.index, map_.end(), first_)))).
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first;
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first_->second.prev = i;
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first_ = i;
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typename Map::iterator j(last_);
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last_ = last_->second.prev;
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last_->second.next = map_.end();
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map_.erase(j);
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} else {
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// Reached iff size_ == 0:
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return cache::ignore;
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}
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} else if (i != first_) {
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// Move to front (reached only if size_ > 1):
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i->second.prev->second.next = i->second.next;
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if (i->second.next == map_.end()) {
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last_ = i->second.prev;
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} else {
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i->second.next->second.prev = i->second.prev;
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}
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i->second.prev = map_.end();
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i->second.next = first_;
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first_->second.prev = i;
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first_ = i;
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}
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return i->second.index;
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}
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private:
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struct Entry;
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typedef std::map< T, Entry > Map;
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struct Entry {
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sal_uInt16 index;
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typename Map::iterator prev;
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typename Map::iterator next;
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Entry(
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sal_uInt16 theIndex, typename Map::iterator thePrev,
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typename Map::iterator theNext):
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index(theIndex), prev(thePrev), next(theNext) {}
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};
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std::size_t size_;
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Map map_;
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typename Map::iterator first_;
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typename Map::iterator last_;
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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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