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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_STORE_SOURCE_STORCACH_HXX
#define INCLUDED_STORE_SOURCE_STORCACH_HXX
#include <sal/config.h>
#include <memory>
#include "sal/types.h"
#include "rtl/ref.hxx"
#include "store/types.h"
#include "storbase.hxx"
#include "object.hxx"
namespace store
{
struct Entry;
/*========================================================================
*
* PageCache interface.
*
*======================================================================*/
class PageCache :
public store::OStoreObject
{
// Representation
static size_t const theTableSize = 32;
static_assert((theTableSize & (theTableSize-1)) == 0, "table size should be a power of 2");
Entry ** m_hash_table;
Entry * m_hash_table_0[theTableSize];
size_t m_hash_size;
size_t m_hash_shift;
size_t const m_page_shift;
size_t m_hash_entries; // total number of entries in table.
size_t m_nHit;
size_t m_nMissed;
static int hash_Impl(sal_uInt32 a, size_t s, size_t q, size_t m)
{
return static_cast<int>((((a) + ((a) >> (s)) + ((a) >> ((s) << 1))) >> (q)) & (m));
}
int hash_index_Impl (sal_uInt32 nOffset)
{
return hash_Impl(nOffset, m_hash_shift, m_page_shift, m_hash_size - 1);
}
Entry * lookup_Impl (Entry * entry, sal_uInt32 nOffset);
void rescale_Impl (std::size_t new_size);
public:
// Construction
explicit PageCache (sal_uInt16 nPageSize);
PageCache(const PageCache&) = delete;
PageCache& operator=(const PageCache&) = delete;
/** load.
*/
storeError lookupPageAt (
std::shared_ptr<PageData> & rxPage,
sal_uInt32 nOffset);
/** insert.
*/
storeError insertPageAt (
std::shared_ptr<PageData> const & rxPage,
sal_uInt32 nOffset);
/** update, or insert.
*/
storeError updatePageAt (
std::shared_ptr<PageData> const & rxPage,
sal_uInt32 nOffset);
/** remove (invalidate).
*/
storeError removePageAt (
sal_uInt32 nOffset);
protected:
// Destruction
virtual ~PageCache() override;
};
/*========================================================================
*
* PageCache factory.
*
*======================================================================*/
storeError
PageCache_createInstance (
rtl::Reference< store::PageCache > & rxCache,
sal_uInt16 nPageSize
);
/*========================================================================
*
* The End.
*
*======================================================================*/
} // namespace store
#endif // INCLUDED_STORE_SOURCE_STORCACH_HXX
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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