// Copyright (c) 2000-2009 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:

// Attribute Look-Up-Table

// The Attribute Lookup Table maintains a global set of unique IDs to be defined for document

// node attributes and language tags. It does this by generating a unique ID for any descriptor

// passed to it. This descriptor is in fact a pointer to a copy of the string. Once a string

// has been seen once, any further references to it will map back to the same ID (pointer)

// value.

// 

//

// system includes

// -

#include <e32base.h>

#include <e32test.h>

// our include

//

#include <attrlut.h>

// Hash table size

//

#define KHashModulo 32

//==============================================================

// CAttributeLookupTableNode

//==============================================================

// Internal node class

//

//##ModelId=3B666737014E

class CAttributeLookupTableNode : public CBase

{

public:

	//##ModelId=3B6667370176

	CAttributeLookupTableNode() : CBase()

		{

		//iDes = 0;

		}

	//##ModelId=3B666737016C

	~CAttributeLookupTableNode()

		{

		delete iDes;

		}

	//##ModelId=3B6667370165

	HBufC* iDes;

};

//==============================================================

// CAttributeLookupTable

//==============================================================

CAttributeLookupTable::CAttributeLookupTable() : CBase()

	{

	}

/** Destructor.

*/

EXPORT_C CAttributeLookupTable::~CAttributeLookupTable()

	{

	Reset();

	delete iList;

	}

void CAttributeLookupTable::ConstructL()

	{

	iList = new (ELeave) CArrayPtrFlat<CArrayPtrSeg<CAttributeLookupTableNode> >( KHashModulo );

	iList->ResizeL( KHashModulo );

	for ( TInt i = 0; i < KHashModulo; i++ )

		{

		(*iList)[i] = NULL;

		}

	}

/** Allocates and constructs a new attribute lookup table.

@return New attribute lookup table

*/

EXPORT_C CAttributeLookupTable* CAttributeLookupTable::NewL()

	{

	CAttributeLookupTable* iLUT = new (ELeave) CAttributeLookupTable();

	CleanupStack::PushL( iLUT );

	iLUT->ConstructL();

	CleanupStack::Pop();

	return iLUT;

	}

// Lookup with allocating

//

/** Gets a unique ID for a specified descriptor.

If this is the first time the descriptor has been used, a new ID will be allocated.

@return ID

@param aAttributeName Descriptor to get ID for

*/

EXPORT_C const HBufC* CAttributeLookupTable::Des2IDL( const TDesC& aAttributeName )

	{

	// lookup the attribute

	CAttributeLookupTableNode* node = FindDes( aAttributeName );

	if ( node )

		return node->iDes;

	// create a new node at the end of the appropriate array

	CAttributeLookupTableNode* newnode = new (ELeave) CAttributeLookupTableNode();

	CleanupStack::PushL( newnode );

	newnode->iDes = aAttributeName.AllocL();

	TInt hash = Hash( aAttributeName );

	CArrayPtrSeg<CAttributeLookupTableNode>* list = iList->At( hash );

	if ( !list )

		list = iList->At( hash ) = new (ELeave) CArrayPtrSeg<CAttributeLookupTableNode>( 2 );

	list->AppendL(newnode);

	CleanupStack::Pop(); // newnode

	return newnode->iDes;

	}

// Lookup without allocating

//

/** Tests if an ID has been allocated for a specified descriptor.

@return ID, or NULL if none has been allocated

@param aKey Descriptor to test

*/

EXPORT_C const HBufC* CAttributeLookupTable::KeyExists( const TDesC& aKey )

	{

	CAttributeLookupTableNode* node = FindDes( aKey );

	if ( node )

		return node->iDes;

	return NULL; // 0 is an invalid ID

	}

// Find the given descriptor in the hash table

//

CAttributeLookupTableNode* CAttributeLookupTable::FindDes( const TDesC& aAttributeName )

	{

	CArrayPtrSeg<CAttributeLookupTableNode>* list = iList->At( Hash( aAttributeName ) );

	if ( list )

		{

		TInt length=aAttributeName.Length();

		TInt count = list->Count();

		for ( TInt i = 0; i < count; i++ )

			{

			CAttributeLookupTableNode* node = list->At(i);

			if ( node->iDes->Length()==length && node->iDes->Compare( aAttributeName ) == 0 ) // ** CASE SENSITIVE **

				return node;

			}

		}

	return NULL;

	}

// Generate a hash value

//

TUint CAttributeLookupTable::Hash( const TDesC& aDes )

	{

	// *** CASE SENSITIVE **

	TInt len=aDes.Length();

	TUint hash = 0;

	const TText* ptr=aDes.Ptr();

	for ( TInt i = 0; i < len; i++ )

		hash = 131*hash + *ptr++;

	return hash % KHashModulo;

	}

// Empty the table

//

/** Clears all allocated IDs.

*/

EXPORT_C void CAttributeLookupTable::Reset()

	{

	if ( iList )

		{

		for ( TInt i = 0; i < iList->Count(); i++ )

			{

			CArrayPtrSeg<CAttributeLookupTableNode>* list = iList->At( i );

			if ( list )

				{

				list->ResetAndDestroy();

				delete list;

				iList->At( i ) = 0;

				}

			}

		}

	}

// Debug hook

//

#if defined (_DEBUG)

EXPORT_C void CAttributeLookupTable::Debug(TDebugSelectorType aSelector, TAny* aParam1, TAny* /*aParam2*/)

	{

	switch(aSelector)

		{

		case EPrint:

			{

			RTest* console = REINTERPRET_CAST(RTest*,aParam1);

			for ( TInt i = 0; i < iList->Count(); i++ )

				{

				if ( i == 0 || (i%15) == 0 )

					console->Printf( _L("\n%d: "), i );

				TInt count = 0;

				CArrayPtrSeg<CAttributeLookupTableNode>* list = iList->At(i);

				if ( list )

					count = list->Count();

				console->Printf( _L("%d\t"), count );

				}

			console->Printf( _L("\n") );

			break;

			}

		default:

			break;

		}	

	}

#else

EXPORT_C void CAttributeLookupTable::Debug(TDebugSelectorType /*aSelector*/, TAny* /*aParam1*/, TAny* /*aParam2*/)

	{

	}

#endif