// Copyright (c) 2003-2009 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:

// CSMILDTD.cpp

// @file

// This file contains the definition of the SMILDTD class

// which describes the SMIL DTD and is responsible for validation

// of SMIL documents

// 

//

#include "smildtd.h"

#include "SmilData.h"

#include <stringpool.h>

#include "smilelements.h"

#include "smilattributes.h"

#include "smilgenericelements.h"

#include <gmxmlconstants.h>

//

// Global functions					//

//

EXPORT_C CSMILDtd* CSMILDtd::NewL()

//

// Two phase static factory function constructor

// @return Created CSMILDtd

// @leave can Leave due to OOM

//

	{

	CSMILDtd* self = NewLC();

	CleanupStack::Pop();

	return self;

	}

EXPORT_C CSMILDtd* CSMILDtd::NewLC()

//

// Two phase static factory function constructor

// @return Created CSMILDtd

// @leave can Leave due to OOM

//

	{

	CSMILDtd* self = new (ELeave) CSMILDtd();

	CleanupStack::PushL(self);

	self->ConstructL();

	return self;

	}

void CSMILDtd::ConstructL()

//

// Second stage constructor

// @leave can Leave due to OOM

//

	{

	// nothing to do

	}

CSMILDtd::CSMILDtd()

	{

	}

EXPORT_C CSMILDtd::~CSMILDtd()

	{

	}

TBool CSMILDtd::IsValidElementL(const TDesC& aElement) const

	{

//

// Checks to see if the element name passed in has been specified in the string table

// @param aElementName the element name to be checked

// @return ETrue if defined in the string table else EFalse

// @leave Leave due to OOM

//

	// Use the string table SMILElements to validate the element name

	TBool validElement = EFalse;

	RStringPool pool;

	CleanupClosePushL(pool);

	pool.OpenL(SMILElements::Table);

	int numTableEntries = SMILElements::Table.iCount;

	if(numTableEntries != 0)

		{

	    // Using a binary search since the table is always sorted alphabetically by element.

		// Set us search indices to outer bounds of array

		TInt left = 0;

		TInt right = numTableEntries - 1;

		TInt compareResult = 0;

		TInt pos;

		while (right >= left)

			{

			pos = (left + right) / 2;

			RStringF tableEntry = pool.StringF(pos, SMILElements::Table);

			HBufC* buf = HBufC::NewLC(tableEntry.DesC().Length());

			buf->Des().Copy(tableEntry.DesC());

			TLex string(*buf);

			TPtrC token = string.NextToken();

			compareResult = aElement.Compare(token);

			if(compareResult == 0)

				validElement = ETrue;

			CleanupStack::PopAndDestroy(buf);

			if(compareResult == 0)

				break;

			else if (compareResult > 0)

				left = pos + 1;

			else

				right = pos - 1;

  			}

		}

	CleanupStack::PopAndDestroy();  // close pool

	return validElement;

	}

TInt CSMILDtd::IsValidAttributeForElementL(const TDesC& aElement, const TDesC& aAttribute, const TDesC& aAttributeValue) const

	{

//

// Checks that both the Attribute Name & Attribute Value are valid using string tables stored in the document

// @param aAttributeName - name of attribute to be checked

// @param aAttributeValue - value of attribute to be checked

// @return KErrNone if attribute & value are valid, otherwise KErrXMLBadAttributeName or KErrXMLBadAttributeValue

// @leave Leave due to OOM

//

	// To reduce the size of the element/attribute/value generic element names are used

	// So for example 'img' and 'video' are both represented by the genericelement 'media'

	// A table exists (SMILGenericElements) detailing these relationships

	// So first we see if there is a generic element name for this element

	// If not then genericElementName will just be the element name passed in

	HBufC* genericElementName = NULL;

	RStringPool pool;

	CleanupClosePushL(pool);

	pool.OpenL(SMILGenericElements::Table);

	TInt numTableEntries = SMILGenericElements::Table.iCount;

	if(numTableEntries != 0)

		{

		// Using a binary search since the table is always sorted alphabetically by element.

		// Set us search indices to outer bounds of array

		TInt left = 0;

		TInt right = numTableEntries - 1;

		TInt pos;

		while (right >= left)

			{

			pos = (left + right) / 2;

			RStringF elementAndGeneric = pool.StringF(pos, SMILGenericElements::Table);

			HBufC* buf = HBufC::NewLC(elementAndGeneric.DesC().Length());

			buf->Des().Copy(elementAndGeneric.DesC());

			TLex string(*buf);

			TPtrC token = string.NextToken();

			TInt compare = aElement.Compare(token);

			if(compare == 0)

				{

				// We've got a match so use the generic name

				// This isn't pushed on the CleanupStack here as we need to be able to pop

				// buf and pool whilst genericElementName is still in scope.  It will be

				// pushed once these aren't necessary.  Because of this THERE MUST BE

				// NOTHING THAT LEAVES UNTIL genericElementName IS PUT ONTO THE CLEANUPSTACK

				genericElementName =(string.NextToken()).AllocL();

				}

			CleanupStack::PopAndDestroy(buf); //buf

			if(compare == 0)

				break;

			else if (compare > 0)

				left = pos + 1;

			else

				right = pos - 1;

			}

		}

	CleanupStack::PopAndDestroy();	// Close pool

	if(genericElementName != NULL)

		{

		CleanupStack::PushL(genericElementName);

		}

	else 

		{

		// We didn't find a generic name so use the element name passed in

		genericElementName = HBufC::NewLC(aElement.Length());

		genericElementName->Des().Copy(aElement);

		}

	// Using the generic element name test to see if we have a valid attribute and value

	// assume the attribute name is invalid

	TInt error = KErrXMLBadAttributeName;

	// retrieve the attributeValue string table

	// this is of the form elementName attributeName attribValue1 attribValue2 ...

	CleanupClosePushL(pool);

	pool.OpenL(SMILAttributes::Table);

	numTableEntries = SMILAttributes::Table.iCount;

	if(numTableEntries != 0)

		{

	    // Using a binary search since the table is always sorted alphabetically by element+attribute.

		// Set us search indices to outer bounds of array

		TInt left = 0;

		TInt right = numTableEntries - 1;

		TInt compareResult = 0;

		TInt pos;

		while (right >= left)

			{

			pos = (left + right) / 2;

			RStringF tableEntry = pool.StringF(pos, SMILAttributes::Table);

			HBufC* buf = HBufC::NewLC(tableEntry.DesC().Length());

			buf->Des().Copy(tableEntry.DesC());

			TLex string(*buf);

			// Get the element name from the string table (the first token)

			TPtrC token = string.NextToken();

			// Is this the element name we are interested in

			compareResult = genericElementName->Compare(token);

			if(compareResult == 0)

				{

				// we're looking at an entry in the string table for this element

				// so test to see if it's the correct attribute too.

				token.Set(string.NextToken());

				compareResult =  aAttribute.Compare(token);

				if(compareResult == 0)

					{

					// we've got the correct entry in the table (both element & attribute match)

					// so now assume the error is an incorrect attribute value

					error = KErrXMLBadAttributeValue;

					// get hold of the first valid attribure value

					token.Set(string.NextToken());

					// if we don't have a list of attribute values then we can assume whatever we've got is valid

					// so set the error to KErrNone

					if (token.Length() == 0)

						error = KErrNone;

					else

						{

						// Cycle through all listed attribute values to see if we have a valid one

						while (token.Length() != 0)

							{

							if (aAttributeValue.Compare(token) == 0)

								{

								// value of attribute is valid

								error = KErrNone;

								break;

								}

							else

								token.Set(string.NextToken());

							}

						}

					}

				}

			CleanupStack::PopAndDestroy(buf);	// buf

			if (compareResult == 0)         // Matching item found

				break;

			else if (compareResult > 0)

				left = pos + 1;

			else

				right = pos - 1;

  			}

		}

	CleanupStack::PopAndDestroy(2);  // pool, genericElementName

	return error;

	}

TBool CSMILDtd::AreValidChildElementsL(const TDesC& aParentElement, const CDesCArray& aChildElements) const

// Function to determine whether the parent/child relationship is valid in DTD

// @return ETrue if parent/child relationship is valid

// @param aParentElement the name of the parent element to be tested

// @param aChildElements an array of child element name to be tested

// @leave leave due to OOM

//

	{

	TBool retVal = EFalse;

	if(aParentElement == KSMILDTDElta)

		{

		retVal = CheckValidChildren(SMILDTDAChildStates,KSMILDTDAChildStateTranCount, aChildElements);

		}

	else if( aParentElement == KSMILDTDEltDoc)

		{

		retVal = ETrue;

		}

	else if(aParentElement == KSMILDTDEltanimation || aParentElement == KSMILDTDEltaudio || aParentElement == KSMILDTDEltimg || aParentElement == KSMILDTDEltref

		    || aParentElement == KSMILDTDElttext || aParentElement == KSMILDTDElttextstream || aParentElement == KSMILDTDEltvideo)

		{

		retVal = CheckValidChildren(SMILDTDMediaChildStates, KSMILDTDMediaChildStateTranCount, aChildElements);

		}

	else if(aParentElement == KSMILDTDEltbody)

		{

		retVal = CheckValidChildren(SMILDTDBodyChildStates, KSMILDTDBodyChildStateTranCount, aChildElements);

		}

	else if(aParentElement == KSMILDTDElthead)

		{

		retVal = CheckValidChildren(SMILDTDHeadChildStates, KSMILDTDHeadChildStateTranCount, aChildElements);

		}

	else if(aParentElement == KSMILDTDEltlayout)

		{

		retVal = CheckValidChildren(SMILDTDLayoutChildStates, KSMILDTDLayoutChildStateTranCount, aChildElements);

		}

	else if(aParentElement == KSMILDTDEltpar || aParentElement == KSMILDTDEltseq)

		{

		retVal = CheckValidChildren(SMILDTDTimingChildStates, KSMILDTDTimingChildStateTranCount, aChildElements);

		}

	else if(aParentElement == KSMILDTDEltsmil)

		{

		retVal = CheckValidChildren(SMILDTDSmilChildStates, KSMILDTDSmilChildStateTranCount, aChildElements);

		}

	else if(aParentElement == KSMILDTDEltswitch)

		{

		retVal = CheckValidChildren(SMILDTDSwitchChildStates, KSMILDTDSwitchChildStateTranCount, aChildElements);

		}

	return retVal;

	}

TBool CSMILDtd::CheckValidChildren(const TSMILDTDChildStateType aStateTrans[],TInt aStateCount, const CDesCArray& aChildElements) const

//

// Checks child element ownership based on a Finite State Machine

// @param aFirstChild - pointer to first child element

// @param aStateTrans - Array of state transition elements.

//        The elements must be ordered by tag name first and then starting state

//        as this routine uses the ordering to drive an efficient search.

// @param aStateCount - the number of state transitions in the array

// @return true if the list of children matches the defined state machine

//

	{

	// This routine works by considering the allowed set of child elements as a Finite State

	// Machine.  When tracing through the list of children, each child encountered causes

	// a state transition.  The actual states are 'between' elements.  The states are

	// simply referred to by numbers, 0 is the starting state, the legal final state is

	// state -1, other states are positive integers (the actual values have no significance,

	// only the transitions and the start and end are of importance.

	// When the list of children ends, a special 'empty tag' element is considered to be

	// found.  If this empty tag element causes a transition to the final state then the list

	// has been successfully traversed.

	// If, at any point, a child element is encountered which does not lead to a valid

	// transition from the current state then the list is invalid.  By considering the

	// empty tag element to be on the end of the list we handle the requirements for valid

	// completion.

	// This routine is general - it just needs to be fed a set of state transitions for a specific

	// element type.

	TBool returnValue = true; // We are successful until proved otherwise

	if( aStateCount < 1 )

		{

		returnValue = false; // Just check for a duff count

		}

	TInt fromState=KSMILDTDStartState; // Current state - the one we are looking for a transition from

	TInt toState=KSMILDTDEndState;   // State to which this tag leads us - initialised to avoid warning

	TInt midPoint= aStateCount / 2; // Middle of the state array, used for binary search

	TInt initJump = midPoint / 2; // Size of initial jump for binary search

	TInt tranArrInd; // Index into the state transition array

	// Prime the search with the initial state and the tag for the first element

	// We skip nodes which are not elements (e.g. text, comments or processing instructions)

	for (TInt i = 0; i<aChildElements.Count(); i++)

	  {

		// Check for the 'empty tag'.  We could take a local copy but that would

		// not be most efficient so we have slightly more complex code.

			{

			// Given a current state and tag, find a valid transition.

			// Use a binary search - the array is sorted on tag name first and then

			// from state.  We binary chop to a suitable level and then do a linear

			// search until we hit pay-dirt or find an element which proves.  We

			// only bother to binary search based on the tag name.

			// This is a home baked binary chop and could potentially be made more elegant.

			tranArrInd = midPoint;

			TInt jump = initJump;

			TBool keepChopping = true;

			TInt compVal;

			TPtrC tranTag;

			while(keepChopping)

				{

				tranTag.Set( aStateTrans[tranArrInd].TagName, aStateTrans[tranArrInd].TagLength);

				compVal = aChildElements[i].Compare(tranTag);

				if(compVal < 0)

					{

					tranArrInd -= jump;

					}

				else if(compVal > 0)

					{

					tranArrInd += jump;

					}

				jump = jump / 2;

				if((compVal == 0) || (jump < KSMILDTDMinJump))

					{

					keepChopping = false;

					}

				}// endwhile

			// We have now finished binary chopping, either because we matched the tag or because

			// We got to a small jump size.  Now do a linear scan, up or down, to fimd a match.

			TBool up = true; // Direction of scan

			tranTag.Set( aStateTrans[tranArrInd].TagName, aStateTrans[tranArrInd].TagLength);

			compVal = aChildElements[i].Compare(tranTag);

			if((compVal < 0) ||

			   ((compVal == 0) && (fromState < aStateTrans[tranArrInd].FromState)))

				{

				up = false;

				}

			if( up )

				{

				while((tranArrInd < aStateCount) &&

					  ((compVal > 0) ||

					   ((compVal == 0) && (fromState > aStateTrans[tranArrInd].FromState))))

					{

					tranArrInd ++;

					tranTag.Set( aStateTrans[tranArrInd].TagName, aStateTrans[tranArrInd].TagLength);

					if(tranArrInd < aStateCount)

						{

						compVal = aChildElements[i].Compare(tranTag);

						}

					}// endwhile stepping up

				}

			else

				{

				while((tranArrInd >= 0) &&

					  ((compVal < 0) ||

					   ((compVal == 0) && (fromState < aStateTrans[tranArrInd].FromState))))

					{

					tranArrInd --;

					tranTag.Set( aStateTrans[tranArrInd].TagName, aStateTrans[tranArrInd].TagLength);

					if(tranArrInd >= 0)

						{

						compVal = aChildElements[i].Compare(tranTag);

						}

					}// endwhile stepping down

				}

			// If we have a match, fine, else this is an illegal transition

			if((tranArrInd >= 0) && (tranArrInd < aStateCount) &&

			   (compVal == 0) && (fromState == aStateTrans[tranArrInd].FromState))

				{

				toState = aStateTrans[tranArrInd].ToState;

				}

			else

				{

				returnValue = false;

				break;

				}

			}//end else not reached end of list of children

		fromState = toState;

		}// endfor

		if(returnValue)

			{

			tranArrInd = 0;

			while((tranArrInd < aStateCount) &&

				  (aStateTrans[tranArrInd].FromState != fromState) &&

				  (aStateTrans[tranArrInd].TagLength == 0))

				{

				tranArrInd++;

				}

			if((tranArrInd < aStateCount) &&

			   (aStateTrans[tranArrInd].FromState == fromState) &&

			   (aStateTrans[tranArrInd].TagLength == 0))

				{

				toState = aStateTrans[tranArrInd].ToState ; // Better be the final state!

				}

			else

				{

				returnValue = false ; // No legal transition

				}

			}

	return returnValue;

	}