ef1d096ddc
- replaced osl_trace with sal_info - added new log areas to log-area.dox Change-Id: Ib47c4b4c9604bca1f8a635dd01bb89702b47b591 Reviewed-on: https://gerrit.libreoffice.org/2010 Reviewed-by: Thorsten Behrens <tbehrens@suse.com> Tested-by: Thorsten Behrens <tbehrens@suse.com>
239 lines
8.2 KiB
C++
239 lines
8.2 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 _LRU_CACHE_HXX_
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#define _LRU_CACHE_HXX_
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// __CACHE_DIAGNOSE forces cache size to 4 and works only for OUString keys
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// #define __CACHE_DIAGNOSE 1
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#include <osl/mutex.hxx>
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#include "rtl/ustring.hxx"
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#include "sal/log.hxx"
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#include <boost/unordered_map.hpp>
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/** Implementation of a least recently used (lru) cache.
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<br>
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@author Daniel Boelzle
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*/
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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class LRU_Cache
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{
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struct CacheEntry
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{
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t_Key aKey;
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t_Val aVal;
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CacheEntry * pPred;
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CacheEntry * pSucc;
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};
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typedef ::boost::unordered_map< t_Key, CacheEntry *, t_KeyHash, t_KeyEqual > t_Key2Element;
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mutable ::osl::Mutex _aCacheMutex;
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sal_Int32 _nCachedElements;
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t_Key2Element _aKey2Element;
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CacheEntry * _pBlock;
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mutable CacheEntry * _pHead;
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mutable CacheEntry * _pTail;
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inline void toFront( CacheEntry * pEntry ) const;
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public:
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/** Constructor:
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<br>
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@param nCachedElements number of elements to be cached; default param set to 128
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*/
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inline LRU_Cache( sal_Int32 nCachedElements = 128 );
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/** Destructor: releases all cached elements and keys.
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<br>
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*/
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inline ~LRU_Cache();
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/** Retrieves a value from the cache. Returns default constructed value,
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if none was found.
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<br>
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@param rKey a key
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@return value
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*/
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inline t_Val getValue( const t_Key & rKey ) const;
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/** Sets a value to be cached for given key.
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<br>
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@param rKey a key
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@param rValue a value
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*/
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inline void setValue( const t_Key & rKey, const t_Val & rValue );
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/** Tests whether a value is cached for given key.
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<br>
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@param rKey a key
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@return true, if value is cached
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*/
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inline sal_Bool hasValue( const t_Key & rKey ) const;
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/** Clears the cache, thus releasing all cached elements and keys.
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<br>
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*/
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inline void clear();
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};
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::LRU_Cache( sal_Int32 nCachedElements )
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#ifdef __CACHE_DIAGNOSE
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: _nCachedElements( 4 )
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#else
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: _nCachedElements( nCachedElements )
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#endif
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, _pBlock( 0 )
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{
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if (_nCachedElements > 0)
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{
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_pBlock = new CacheEntry[_nCachedElements];
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_pHead = _pBlock;
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_pTail = _pBlock + _nCachedElements -1;
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for ( sal_Int32 nPos = _nCachedElements; nPos--; )
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{
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_pBlock[nPos].pPred = _pBlock + nPos -1;
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_pBlock[nPos].pSucc = _pBlock + nPos +1;
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}
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}
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}
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::~LRU_Cache()
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{
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delete [] _pBlock;
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}
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline void LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::toFront( CacheEntry * pEntry ) const
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{
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if (pEntry != _pHead)
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{
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// cut out element
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if (pEntry == _pTail)
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{
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_pTail = pEntry->pPred;
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}
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else
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{
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pEntry->pSucc->pPred = pEntry->pPred;
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pEntry->pPred->pSucc = pEntry->pSucc;
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}
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// push to front
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_pHead->pPred = pEntry;
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pEntry->pSucc = _pHead;
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_pHead = pEntry;
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}
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}
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline sal_Bool LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::hasValue( const t_Key & rKey ) const
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{
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::osl::MutexGuard aGuard( _aCacheMutex );
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const typename t_Key2Element::const_iterator iFind( _aKey2Element.find( rKey ) );
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return (iFind != _aKey2Element.end());
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}
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline t_Val LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::getValue( const t_Key & rKey ) const
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{
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::osl::MutexGuard aGuard( _aCacheMutex );
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const typename t_Key2Element::const_iterator iFind( _aKey2Element.find( rKey ) );
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if (iFind != _aKey2Element.end())
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{
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CacheEntry * pEntry = (*iFind).second;
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toFront( pEntry );
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#ifdef __CACHE_DIAGNOSE
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SAL_INFO("stoc.corerefl", "> retrieved element \"" );
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SAL_INFO("stoc.corerefl", "" << pEntry->aKey);
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SAL_INFO("stoc.corerefl", "\" from cache <" );
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#endif
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return pEntry->aVal;
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}
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return t_Val();
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}
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline void LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::setValue(
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const t_Key & rKey, const t_Val & rValue )
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{
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::osl::MutexGuard aGuard( _aCacheMutex );
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if (_nCachedElements > 0)
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{
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const typename t_Key2Element::const_iterator iFind( _aKey2Element.find( rKey ) );
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CacheEntry * pEntry;
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if (iFind == _aKey2Element.end())
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{
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pEntry = _pTail; // erase last element
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#ifdef __CACHE_DIAGNOSE
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if (pEntry->aKey.getLength())
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{
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SAL_INFO("stoc.corerefl", "> kicking element \"" );
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SAL_INFO("stoc.corerefl", "" << pEntry->aKey);
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SAL_INFO("stoc.corerefl", "\" from cache <" );
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}
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#endif
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_aKey2Element.erase( pEntry->aKey );
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_aKey2Element[ pEntry->aKey = rKey ] = pEntry;
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}
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else
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{
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pEntry = (*iFind).second;
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#ifdef __CACHE_DIAGNOSE
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SAL_INFO("stoc.corerefl", "> replacing element \"" );
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SAL_INFO("stoc.corerefl", "" << pEntry->aKey);
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SAL_INFO("stoc.corerefl", "\" in cache <" );
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#endif
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}
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pEntry->aVal = rValue;
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toFront( pEntry );
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}
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}
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//__________________________________________________________________________________________________
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template< class t_Key, class t_Val, class t_KeyHash, class t_KeyEqual >
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inline void LRU_Cache< t_Key, t_Val, t_KeyHash, t_KeyEqual >::clear()
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{
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::osl::MutexGuard aGuard( _aCacheMutex );
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_aKey2Element.clear();
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for ( sal_Int32 nPos = _nCachedElements; nPos--; )
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{
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_pBlock[nPos].aKey = t_Key();
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_pBlock[nPos].aVal = t_Val();
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}
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_nCachedElements = 0;
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#ifdef __CACHE_DIAGNOSE
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SAL_INFO("stoc.corerefl", "> cleared cache <" );
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#endif
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}
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//==================================================================================================
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struct FctHashOUString : public ::std::unary_function< const ::rtl::OUString &, size_t >
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{
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size_t operator()( const ::rtl::OUString & rKey ) const
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{ return rKey.hashCode(); }
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};
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/** Template instance for OUString keys, Any values.<br>
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*/
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typedef LRU_Cache< ::rtl::OUString, ::com::sun::star::uno::Any,
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FctHashOUString, ::std::equal_to< ::rtl::OUString > >
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LRU_CacheAnyByOUString;
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#endif
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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