// Copyright (c) 2001-2009 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:

//

#include <s32file.h>

#include "CHtmlToCrtConvCharsetConvert.h"

#include "CHtmlToCrtConvBuffer.h"

#include "CHtmlToCrtConverter.h"

#include "MHtmlToCrtConvResourceFile.h"

#include <chtmltocrtconverter.rsg>

const TInt KSampleBufferSize = 256;

const TInt KMetaTagCharsetValueBufferLength	= 40;

const TInt KMimimumConfidenceLevel = 50;

CHtmlToCrtConvCharsetConvert* CHtmlToCrtConvCharsetConvert::NewL(CHtmlToCrtConvBuffer& aBuffer, RFs& aFsSession, CCnvCharacterSetConverter& aCnvCharacterSetConverter, MHtmlToCrtConvResourceFile& aResourceFile, MConverterUiObserver* aObserver)

	{

	CHtmlToCrtConvCharsetConvert* self=new(ELeave) CHtmlToCrtConvCharsetConvert(aBuffer, aObserver, aFsSession, aCnvCharacterSetConverter, aResourceFile);

	CleanupStack::PushL(self);

	self->ConstructL();

	CleanupStack::Pop(self);

	return self;

	}

void CHtmlToCrtConvCharsetConvert::ConstructL()

	{

	iArrayOfCharacterSetsAvailable=CCnvCharacterSetConverter::CreateArrayOfCharacterSetsAvailableL(iFsSession);

	}

CHtmlToCrtConvCharsetConvert::CHtmlToCrtConvCharsetConvert(CHtmlToCrtConvBuffer& aBuffer, MConverterUiObserver* aObserver, RFs& aFsSession, CCnvCharacterSetConverter& aCnvCharacterSetConverter, MHtmlToCrtConvResourceFile& aResourceFile)

:iCnvCharacterSetConverter(aCnvCharacterSetConverter)

,iBuffer(aBuffer)

,iObserver(aObserver)

,iResourceFile(aResourceFile)

,iFsSession(aFsSession)

	{

	}

CHtmlToCrtConvCharsetConvert::~CHtmlToCrtConvCharsetConvert()

	{

	delete iArrayOfCharacterSetsAvailable;

	}

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

//GetCharSetFromPasswordL - uses MConverterUiObserver::QueryPasswordL

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

TBool CHtmlToCrtConvCharsetConvert::GetCharSetFromPasswordL()

	{

	if(iObserver)

		{

		HBufC16* unicodeCharsetName=iObserver->QueryPasswordL(KHtmlToCrtRequestCharset);

		if(unicodeCharsetName)

			{

			//convert from unicode

			HBufC8* charsetName=HBufC8::NewLC(unicodeCharsetName->Length());

			ConvertFromUnicodeL(*unicodeCharsetName, *charsetName);		

			//convert standard name of character set to TUint identifier

			iCharacterSetIdentifier=iCnvCharacterSetConverter.ConvertStandardNameOfCharacterSetToIdentifierL(*(charsetName), iFsSession);

			CleanupStack::PopAndDestroy(charsetName);

			}

		}

	return iCharacterSetIdentifier;

	}

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

//GetCharSetFromMetaTagL - searches for META tag, then extracts charset value

//<META http-equiv="Content-Type" content="text/html; charset = us-ascii">

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

TBool CHtmlToCrtConvCharsetConvert::GetCharSetFromMetaTagL()

	{

	HBufC8* temp=HBufC8::NewLC(KSampleBufferSize);

	TPtr8 buffer(temp->Des());

	TInt offset=0;

	iBuffer.GetSampleOfTextFromFileL(buffer, KSampleBufferSize, offset);

	_LIT8(KMeta, "<meta");

	_LIT8(KClosingTagIndicator, ">");

	_LIT8(KCharset, "charset");

	_LIT8(KEquals, "=");

	offset=FindAndDeleteString(buffer, KMeta);

	if(offset>=0)//meta found

		{

		//find >

		TInt offset=buffer.FindF(KClosingTagIndicator);		

		if(offset>=0)//> found

			{

			//delete > onwards - Delete() adjusts length so as not to delete beyond end of buffer

			buffer.Delete(offset, buffer.Length());

			//now buffer only contains META tag

			offset=FindAndDeleteString(buffer, KCharset);

			if(offset>=0)//charset found

				{

				offset=FindAndDeleteString(buffer, KEquals);

				if(offset>=0)//= found

					{

					ParseCharsetValue(buffer);

					//ConvertStandardNameOfCharacterSetToIdentifierL returns the UID of a 

					//character set for a given Internet-standard name

					//zero is returned if none found

					iCharacterSetIdentifier=iCnvCharacterSetConverter.ConvertStandardNameOfCharacterSetToIdentifierL(buffer, iFsSession);

					}

				}

			}

		}

	CleanupStack::PopAndDestroy(temp);

	return iCharacterSetIdentifier;

	}

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

//FindAndDeleteString - deletes up to and including string

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

TInt CHtmlToCrtConvCharsetConvert::FindAndDeleteString(TDes8& aBuffer, const TDesC8& aString)

	{

	TInt offset=aBuffer.FindF(aString);

	TInt length=aString.Length();

	if(offset>=0)//string found

		{

		//delete up to and including string

		ASSERT(offset+length <= aBuffer.Length());

		aBuffer.Delete(0, offset+length);

		}

	return offset;

	}

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

//ParseCharsetValue - charset value read until " or white space character seen

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

void CHtmlToCrtConvCharsetConvert::ParseCharsetValue(TDes8& aBuffer)

	{

	aBuffer.TrimLeft();

	TInt length=aBuffer.Length();

	if(length)

		{

		TChar character;

		TBuf8<KMetaTagCharsetValueBufferLength> charsetBuffer;

		TBool finishedReadingValue=EFalse;

		TInt ii=0;

		while(ii<length && !finishedReadingValue)

			{

			character=aBuffer[ii++];

			if(character.IsSpace() || character=='"')

				{

				finishedReadingValue=ETrue;

				}

			else

				{

				if(charsetBuffer.Length()<KMetaTagCharsetValueBufferLength)

					{

					charsetBuffer.Append(character);

					}

				else

					{

					ii=length;

					}

				}

			}

		aBuffer.Copy(charsetBuffer);

		}

	}

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

//GetCharSetUsingAutoDetectL

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

TBool CHtmlToCrtConvCharsetConvert::GetCharSetUsingAutoDetectL()

	{

	HBufC8* temp=HBufC8::NewLC(KSampleBufferSize);

	TPtr8 buffer(temp->Des());

	TInt offset=256;

	//it's likely that the start of the file will contain the header, so offset

	//is used to read from a position within the file

	iBuffer.GetSampleOfTextFromFileL(buffer, KSampleBufferSize, offset);

	TInt confidence=0;

	if(buffer.Length())

		{

		iCnvCharacterSetConverter.AutoDetectCharacterSetL(confidence, iCharacterSetIdentifier, *iArrayOfCharacterSetsAvailable, buffer);

		}

	CleanupStack::PopAndDestroy(temp);

	if(iCharacterSetIdentifier == KCharacterSetIdentifierAscii)

		{

		//In order to support Latin letters, the character set needs to 

		//be widened from ASCII to Code Page 1252

		iCharacterSetIdentifier = KCharacterSetIdentifierCodePage1252;

		}

	//confidence in range 0-100

	if(confidence<KMimimumConfidenceLevel)

		{

		//low level of confidence in the chosen character set, so reset

		// - this method of determining character set not successful

		iCharacterSetIdentifier=0;

		return EFalse;

		}

	else

		return ETrue;

	}

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

//PrepareForConvertToUnicodeL

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

void CHtmlToCrtConvCharsetConvert::PrepareForConvertToUnicodeL()

	{

	if(!iCharacterSetIdentifier)

		{

		//get default character set for locale from resource file

		HBufC* unicodeDefaultCharacterSet=iResourceFile.ReadResourceHBufCLC(R_CNV_DEFAULT_CHARACTER_SET);

		//convert from unicode

		HBufC8* defaultCharacterSet=HBufC8::NewLC(unicodeDefaultCharacterSet->Length());

		ConvertFromUnicodeL(*unicodeDefaultCharacterSet, *defaultCharacterSet);

		//convert standard name of character set to TUint identifier

		iCharacterSetIdentifier=iCnvCharacterSetConverter.ConvertStandardNameOfCharacterSetToIdentifierL(*(defaultCharacterSet), iFsSession);

		CleanupStack::PopAndDestroy(2); //defaultCharacterSet, unicodeDefaultCharacterSet

		}

	iCnvCharacterSetConverter.PrepareToConvertToOrFromL(iCharacterSetIdentifier, *iArrayOfCharacterSetsAvailable, iFsSession);

	}

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

//ConvertFromUnicodeL

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

void CHtmlToCrtConvCharsetConvert::ConvertFromUnicodeL(const TDesC& aUnicode, HBufC8& aNarrow)

	{

	TPtr8 ptrNarrow(aNarrow.Des());	

	iCnvCharacterSetConverter.PrepareToConvertToOrFromL(KCharacterSetIdentifierAscii, *iArrayOfCharacterSetsAvailable, iFsSession);

	iCnvCharacterSetConverter.ConvertFromUnicode(ptrNarrow, aUnicode);

	}