/*

* Copyright (c) 2005,2006 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Optimizer module for CXnDomStringPool.

*

*/

#ifndef XN_DOM_STRING_POOL_OPTIMIZER_H

#define XN_DOM_STRING_POOL_OPTIMIZER_H

//  INCLUDES

#include <e32base.h>

// CLASS DECLARATION

/**

*  @ingroup group_domdocument

*  Optimizer module entry for CXnDomStringPool.

*

*  @lib xndomdocument.lib

*  @since Series 60 5.2

*/

class TXnDomStringPoolOptimizerEntry

    {

    public: // Construction.

        /**

         * Constructor.

         * 

         * @param aIndex    Index.

         * @param aString   String.

         */

        TXnDomStringPoolOptimizerEntry( TInt aIndex, const TDesC8& aString ); 

    public: // Data.

        /**

         * Index of string in actual string pool.

         */

        TInt iIndex;

        /**

         * Reference to string in string pool.

         */

        const TDesC8& iString;                    

    };        

/**

*  @ingroup group_domdocument

*  Optimizer module for CXnDomStringPool.

*

*  @lib xndomdocument.lib

*  @since Series 60 5.2

*/

class TXnDomStringPoolOptimizer

    {

    public:

        /**

         * Add entry to optimizer list.

         * 

         * @param aEntry    Entry to be added.

         */

        void AddEntryL( TXnDomStringPoolOptimizerEntry& aEntry );

        /**

         * Get index for string.

         * 

         * @param   aString     Reference to given string.

         * @return  TInt        Index to actual string pool for string if found.

         *                      If string is not found will return KErrNotFound. 

         */

        TInt GetIndex( const TDesC8& aString );

        /**

         * Reset.

         */

        void Reset();        

        /**

         * Close allocated resources.

         */

        void Close();

        /**

         * Get item count.

         */

        TInt Count();        

        /**

         * Get entry.

         * 

         * @param aIndex    Index to Entry.

         */

        TXnDomStringPoolOptimizerEntry& Entry( const TInt aIndex );        

    private:

        /**

         * Find entry from alphabetic list.

         * Uses binary search.

         * 

         * @param       aString Reference to string to be searched for.

         * @param       aLeft   Left limit for binary search

         * @param       aRight  Right limit for binary search.

         * 

         * @return      Index to OPTIMIZER ARRAY. KErrNotFound if

         *              given string is not found.

         */

        TInt FindEntry( const TDesC8& aString,

                        const TInt aLeft,

                        const TInt aRight );

        /**

         * Find a position clue for given string.

         * 

         * Will return index that can be used to initiate linear

         * search. Uses binary search to limit required comparisons

         * when string pools starts to fill.

         * 

         * Note: Returned index is not absolute! it must be

         * only used as a start index for linear searching.

         * 

         * Returned index will be quite close to actual insertion position.

         * it will be 0 - 2 steps backward from actual position.

         * 

         * @param       aString Reference to string.

         * @param       aLeft   Left limit for binary search

         * @param       aRight  Right limit for binary search.

         * 

         * @return      Index to start searching for position

         *              for given string.

         */

        TInt FindInsertionIndexEstimate( const TDesC8& aString,

                                         const TInt aLeft,

                                         const TInt aRight );

    private: // Data.

        /**

         * Array of optimizer entries.

         */

        RArray<TXnDomStringPoolOptimizerEntry> iEntries;

    }; 

#endif      // XN_DOM_STRING_POOL_OPTIMIZER_H  

// End of File