/*

* Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "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: 

* Definition of the Swi::Sis::CField

*

*/

/**

 @file 

 @released

 @internalTechnology

*/

#ifndef __SISFIELD_H__

#define __SISFIELD_H__

#include <e32base.h>

#include <e32def.h>

#include <f32file.h>

#include "sisinstallerrors.h"

#include "sisfieldtypes.h"

#include "sisdataprovider.h"

#include "sisptrprovider.h"

namespace Swi

{

namespace Sis

 {

/**

 * Controls whether the field type is read from the stream and checked

 * or whether we know the field type already.

 *

 * @released

 * @publishedPartner

 */

enum TReadTypeBehaviour 

	{

	EReadType,

	EAssumeType

	};

/**

 * This class represents a Field. Field is a basic structure found in  files.

 * It is described in SGL.GT0188.251.

 *

 * @released

 * @internalTechnology

 */

class CField : public CBase

	{

public:

	enum TArrayStatus { EInArray, ENotInArray };

	virtual ~CField();

protected:

	CField();

	/**

	 * The second phase constructor.

	 *

	 * @param aDataProvider 	 An instance of a MSisDataProvider to read the entity from.

	 * @param aFieldType 		 The field type we are attempting to read.

	 * @param aTypeReadBehaviour Whether we need to check the sis type or not.

	 */

	void ConstructL(MSisDataProvider& aDataProvider, TFieldType aFieldType, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

	/**

	 * The second phase in place constructor.

	 *

	 * @param aDataProvider 	 An instance of a TPtrProvider to read the entity from.

	 * @param aFieldType 		 The field type we are attempting to read.

	 * @param aTypeReadBehaviour Whether we need to check the sis type or not.

	 */

	void ConstructL(TPtrProvider& aDataProvider, TFieldType aFieldType, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

public:

	/**

	 * This function returns the value of the Length part of the Field.

	 */

	IMPORT_C TFieldLength Length() const;

	/**

	  * Each SISField has and header comprising its type and its length.

	  * This last attribute has variable size.

	  * This method can be used to ascertain the size of the header.

	  *

	  * @return The size of the SISField header in bytes.

	  */	

	TInt HeaderSize(TArrayStatus aInArray = ENotInArray) const;

	/**

	  * SISFields can be padded, use this function to learn how many padding

	  * bytes are used in this SISField.

	  *

	  * @return The number of padding bytes for this SISField

	  */

	TInt PaddingSize() const;

	/**

	 * This function returns the value of the Type part of the Field.

	 */

	TFieldType FieldType() const;

protected:

	// Ensures alignment to 4 bytes after reading the field

	void EnsureAlignedL(MSisDataProvider& aDataProvider, TInt64 aBytesConsumed, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

	static void CheckedReadL(MSisDataProvider& aDataProvider, TDes8& aBuffer, TInt64& aBytesRead);

	static void CheckedReadL(MSisDataProvider& aDataProvider, TDes8& aBuffer, TInt aSize, TInt64& aBytesRead);

	// Skip unknown fields, used to skip unknown fields at the end of a SISField

	void SkipUnknownFieldsL(MSisDataProvider& aDataProvider, TInt64 aBytesConsumed, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

	// Read an array into a member variable

	template <typename T>

	void ReadMemberArrayL(MSisDataProvider& aDataProvider, RPointerArray<T>& aArray, TFieldType aExpectedInternalField, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour = EReadType);

	// Read a collection into a member variable

	template <typename T>

	void ReadMemberCollectionL(MSisDataProvider& aDataProvider, RPointerArray<T>& aArray, TFieldType aExpectedInternalField, TFieldType aTerminatingInternalFieldType, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour = EReadType);

	template<typename T>

	static inline void ReadTTypeL(MSisDataProvider& aDataProvider,T& aValue, TInt64& aBytesRead);

	template<typename EnumType, typename StoredType>

	static inline void ReadEnumL(MSisDataProvider& aDataProvider,EnumType& aValue, TInt64& aBytesRead);

	// fill the supplied buffer with the header for the given field type and length

	static void CreateHeader(TFieldType aFieldType, TFieldLength aFieldLength, TDes8& aHeader);

	// called by derived classes to calculate the CRC of their data

	static void CalculateCrcL(MSisDataProvider& aDataProvider, const TInt64 aLength, TUint16& aCrc);

	// -----------

	// in place readers

	// -----------

	void EnsureAlignedL(TPtrProvider& aDataProvider, TInt64 aBytesConsumed, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

	void SkipUnknownFieldsL(TPtrProvider& aDataProvider, TInt64 aBytesConsumed, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

	// Read an array into a member variable

	template <typename T>

	void ReadMemberArrayL(TPtrProvider& aDataProvider, RPointerArray<T>& aArray, TFieldType aExpectedInternalField, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour = EReadType);

	template<typename T>

	static inline void ReadTTypeL(TPtrProvider& aDataProvider,T& aValue, TInt64& aBytesRead);

	template<typename EnumType, typename StoredType>

	static inline void ReadEnumL(TPtrProvider& aDataProvider,EnumType& aValue, TInt64& aBytesRead);

	template <typename T>

	void ReadMemberCollectionL(TPtrProvider& aDataProvider, RPointerArray<T>& aArray, TFieldType aExpectedInternalField, TFieldType aTerminatingInternalFieldType, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour = EReadType);

private:

	/// protected copy constructor to prevent copying of derived classes

	CField(const CField& aField);

	/// protected assignment operator to prevent copying of derived classes

	CField& operator=(const CField& aField);

	void ReadLengthL(MSisDataProvider& aDataProvider, TInt64& aBytesRead);

	void ReadTypeL(MSisDataProvider& aDataProvider, TFieldType aFieldType, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

	void ReadLengthL(TPtrProvider& aDataProvider, TInt64& aBytesRead);

	void ReadTypeL(TPtrProvider& aDataProvider, TFieldType aFieldType, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour);

private:

	/// Length of the SISField Value (Not including Type, Length fields)

	TFieldLength iLength;

	/// Type of the SISField

	TFieldType iType;

	/**

	 * Size of the SISField header if it were not stored in an array

	 * so 12 if length is stored in 8 bytes and 8 if length is stored

	 * in 4 bytes

	 */

	TInt iHeaderSize;

	};

// template functions from CField

template<typename T>

void CField::ReadTTypeL(MSisDataProvider& aDataProvider,T& aValue, TInt64& aBytesRead)

	{

	TPckg<T> package(aValue);

	CField::CheckedReadL(aDataProvider, package, aBytesRead);

	}

template<typename EnumType, typename StoredType>

void CField::ReadEnumL(MSisDataProvider& aDataProvider,EnumType& aValue, TInt64& aBytesRead)

	{

	StoredType storedValue=0;

	CField::ReadTTypeL(aDataProvider, storedValue, aBytesRead);

	aValue=EnumType(storedValue);			

	}

template <typename T>

void CField::ReadMemberArrayL(MSisDataProvider& aDataProvider, 

			      RPointerArray<T>& aArray, 

			      TFieldType aExpectedInternalFieldType, 

			      TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour)

	{

	// Arrays are stored as 

	// T = EFieldTypeArray, L = Length , V=

	// {

	//   TUint32 internalFieldType

	//   

	//   Item 1   (stored without Type T)

	//   ....

	//   Item N   (stored without Type T)

	// }	

	TInt64 fieldOffset = aBytesRead;

	aArray.ResetAndDestroy();

	CField* field=new (ELeave) CField();

	CleanupStack::PushL(field);

	TInt64 bytesRead=aBytesRead;

	field->ReadTypeL(aDataProvider, EFieldTypeArray, aBytesRead, aTypeReadBehaviour);

	field->ReadLengthL(aDataProvider, aBytesRead);

	TFieldType internalFieldType;

	CField::ReadEnumL<TFieldType,TUint32>(aDataProvider, internalFieldType, aBytesRead);

	if (internalFieldType != aExpectedInternalFieldType)

		{

		User::Leave(KErrSISArrayTypeMismatch);

		}

	TFieldLength lengthRead(sizeof(TUint32)); // Internal field type

	while (lengthRead < field->Length())

		{

		T* value=T::NewLC(aDataProvider, aBytesRead, EAssumeType);

		if (value->FieldType() != internalFieldType)

			{

			User::Leave(KErrSISArrayTypeMismatch);

			}

		User::LeaveIfError(aArray.Append(value));

		CleanupStack::Pop(value);

		lengthRead+=value->HeaderSize(EInArray); 

		lengthRead+=value->Length();

		lengthRead+=value->PaddingSize();

		}

	if (lengthRead!=field->Length())

		{

		User::Leave(KErrSISArrayReadError);

		}

	field->SkipUnknownFieldsL(aDataProvider, aBytesRead - fieldOffset, aBytesRead , EReadType);

	field->EnsureAlignedL(aDataProvider, aBytesRead - fieldOffset, aBytesRead, aTypeReadBehaviour);

	CleanupStack::PopAndDestroy(field);

	}

template <typename T>

	void CField::ReadMemberCollectionL(MSisDataProvider& aDataProvider, 

					RPointerArray<T>& aArray, 

					TFieldType aExpectedInternalFieldType, 

					TFieldType aTerminatingInternalFieldType,

					TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour)

	{

	// Collections are sequences of SISFields all of the same type

	// another different SISfield is used to terminate the collection

	TFieldType fieldType;

	// Setup field type, read if necessary, otherwise just set it

	if (aTypeReadBehaviour==EReadType)

		{

		CField::ReadEnumL<TFieldType, TInt32>(aDataProvider, fieldType, aBytesRead);

		}

	else if (aTypeReadBehaviour==EAssumeType)

		{

		fieldType=aExpectedInternalFieldType;

		}

	// while the next field is the type we're expecting, collection is continued	

	while (fieldType==aExpectedInternalFieldType)

		{

		// read the current field

		T* value=T::NewLC(aDataProvider, aBytesRead, EAssumeType);

		User::LeaveIfError(aArray.Append(value));

		CleanupStack::Pop(value);

		// read the next field's type

		CField::ReadEnumL<TFieldType, TInt32>(aDataProvider, fieldType, aBytesRead);

		}

	// Check the terminating field's type is as expected

	if (fieldType!=aTerminatingInternalFieldType)

		{

		User::Leave(KErrSISUnexpectedFieldType);

		}

	}

template <typename T>

	void CField::ReadMemberArrayL(TPtrProvider& aDataProvider, RPointerArray<T>& aArray, TFieldType aExpectedInternalField, TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour)

	{

	TInt64 fieldOffset = aBytesRead;

	aArray.ResetAndDestroy();

	CField* field=new (ELeave) CField;

	CleanupStack::PushL(field);

	TInt64 bytesRead=aBytesRead;

	field->ReadTypeL(aDataProvider, EFieldTypeArray, aBytesRead, aTypeReadBehaviour);

	field->ReadLengthL(aDataProvider, aBytesRead);

	TFieldType internalFieldType;

	CField::ReadEnumL<TFieldType,TUint32>(aDataProvider, internalFieldType, aBytesRead);

	if (internalFieldType != aExpectedInternalField)

		{

		User::Leave(KErrSISArrayTypeMismatch);

		}

	TFieldLength lengthRead(sizeof(TUint32)); // Internal field type

	while (lengthRead < field->Length())

		{

		T* value=T::NewLC(aDataProvider, aBytesRead, EAssumeType);

		if (value->FieldType() != internalFieldType)

			{

			User::Leave(KErrSISArrayTypeMismatch);

			}

		User::LeaveIfError(aArray.Append(value));

		CleanupStack::Pop(value);

		lengthRead+=value->HeaderSize(EInArray); 

		lengthRead+=value->Length();

		lengthRead+=value->PaddingSize();

		}

	if (lengthRead!=field->Length())

		{

		User::Leave(KErrSISArrayReadError);

		}

	field->SkipUnknownFieldsL(aDataProvider, aBytesRead - fieldOffset, aBytesRead , EReadType);

	field->EnsureAlignedL(aDataProvider, aBytesRead - fieldOffset, aBytesRead, aTypeReadBehaviour);

	CleanupStack::PopAndDestroy(field);	

	}

template <typename T>

	void CField::ReadMemberCollectionL(TPtrProvider& aDataProvider, 

					RPointerArray<T>& aArray, 

					TFieldType aExpectedInternalFieldType, 

					TFieldType aTerminatingInternalFieldType,

					TInt64& aBytesRead, TReadTypeBehaviour aTypeReadBehaviour)

	{

	// Collections are sequences of SISFields all of the same type

	// another different SISfield is used to terminate the collection

	TFieldType fieldType;

	// Setup field type, read if necessary, otherwise just set it

	if (aTypeReadBehaviour==EReadType)

		{

		CField::ReadEnumL<TFieldType, TInt32>(aDataProvider, fieldType, aBytesRead);

		}

	else if (aTypeReadBehaviour==EAssumeType)

		{

		fieldType=aExpectedInternalFieldType;

		}

	// while the next field is the type we're expecting, collection is continued	

	while (fieldType==aExpectedInternalFieldType)

		{

		// read the current field

		T* value=T::NewLC(aDataProvider, aBytesRead, EAssumeType);

		User::LeaveIfError(aArray.Append(value));

		CleanupStack::Pop(value);

		// read the next field's type

		CField::ReadEnumL<TFieldType, TInt32>(aDataProvider, fieldType, aBytesRead);

		}

	// Check the terminating field's type is as expected

	if (fieldType!=aTerminatingInternalFieldType)

		{

		User::Leave(KErrSISUnexpectedFieldType);

		}

	}

template<typename T>

	void CField::ReadTTypeL(TPtrProvider& aDataProvider,T& aValue, TInt64& aBytesRead)

	{

	TPckg<T> package(aValue);

	package.Copy(aDataProvider.ReadL(package.Length()));

	aBytesRead += package.Length();

	}

template<typename EnumType, typename StoredType>

	void CField::ReadEnumL(TPtrProvider& aDataProvider,EnumType& aValue, TInt64& aBytesRead)

	{

	StoredType storedValue=0;

	CField::ReadTTypeL(aDataProvider, storedValue, aBytesRead);

	aValue=EnumType(storedValue);	

	}

inline TInt CField::HeaderSize(TArrayStatus aInArray) const

	{

	// Arrays do not store the type so take the size off for this case

	return iHeaderSize - (aInArray==EInArray ? sizeof(TInt32) : 0); 

	}

inline TInt CField::PaddingSize() const

	{

	return (4 - (I64LOW(Length()) & 0x3)) & 0x3;

	};

 } // namespace Sis

} // namespace Swi

#endif