/* -*- 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 .

 */

#pragma once

#include <assert.h>

#include "swdllapi.h"

#include <array>

#include <memory>

struct BlockInfo;

class BigPtrArray;

class BigPtrEntry

{

    friend class BigPtrArray;

    BlockInfo*  m_pBlock;

    sal_uInt16  m_nOffset;

public:

    BigPtrEntry() : m_pBlock(nullptr), m_nOffset(0) {}

    BigPtrEntry(BigPtrEntry const &) = default;

    virtual ~BigPtrEntry() = default;

    BigPtrEntry & operator =(BigPtrEntry const &) = default;

    inline sal_Int32 GetPos() const;

    inline BigPtrArray& GetArray() const;

    bool IsDisconnected() const { return m_pBlock == nullptr; }

};

// 1000 entries per Block = a bit less than 4K

#define MAXENTRY 1000

// number of entries that may remain free during compression

// this value is for the worst case; because we defined MAXBLOCK with ca 25%

// overhead, 80% = 800 entries are enough

// if complete compression is desired, 100 has to be specified

#define COMPRESSLVL 80

struct BlockInfo final

{

    BigPtrArray* pBigArr;              ///< in this array the block is located

    sal_Int32    nStart, nEnd;         ///< start- and end index

    sal_uInt16   nElem;                ///< number of elements

    std::array<BigPtrEntry*, MAXENTRY>

                 mvData;               ///< data block

};

class BigPtrArray

{

protected:

    std::unique_ptr<BlockInfo*[]>

                    m_ppInf;              ///< block info

    sal_Int32       m_nSize;              ///< number of elements

    sal_uInt16      m_nMaxBlock;          ///< current max. number of blocks

    sal_uInt16      m_nBlock;             ///< number of blocks

    mutable

        sal_uInt16  m_nCur;               ///< last used block

    sal_uInt16  Index2Block( sal_Int32 ) const; ///< block search

    BlockInfo*  InsBlock( sal_uInt16 );         ///< insert block

    void        BlockDel( sal_uInt16 );         ///< some blocks were deleted

    void        UpdIndex( sal_uInt16 );         ///< recalculate indices

    void        ImplRemove( sal_Int32 pos, sal_Int32 n, bool bClearElement );

    void        ImplReplace( sal_Int32 idx, BigPtrEntry* pElem, bool bClearElement );

    // fill all blocks

    sal_uInt16 Compress();

public:

    BigPtrArray();

    ~BigPtrArray();

    sal_Int32 Count() const { return m_nSize; }

    void Insert( BigPtrEntry* p, sal_Int32 pos );

    void Remove( sal_Int32 pos, sal_Int32 n = 1 );

    void Move( sal_Int32 from, sal_Int32 to );

    void Replace( sal_Int32 pos, BigPtrEntry* p);

    /** Speed up the complicated removal logic in SwNodes::RemoveNode.

        Returns the entry before pNotTheOne.

    */

    BigPtrEntry* ReplaceTheOneAfter( BigPtrEntry* pNotTheOne, BigPtrEntry* pNewEntry);

    SW_DLLPUBLIC BigPtrEntry* operator[]( sal_Int32 ) const;

};

inline sal_Int32 BigPtrEntry::GetPos() const

{

    assert(this == m_pBlock->mvData[ m_nOffset ]); // element not in the block

    return m_pBlock->nStart + m_nOffset;

}

inline BigPtrArray& BigPtrEntry::GetArray() const

{

    return *m_pBlock->pBigArr;

}

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