/*

* Copyright (c) 2003, 2004 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:  Exif data parser, that can parse both Little and Big endian 

*                formats

*

*/

// INCLUDE FILES

#include "ExifEndian.h"

#include "ExifCommon.h"

// ============================ CLASS CExifEndianBase ==========================

// ============================ MEMBER FUNCTIONS ===============================

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

// CExifEndianBase::CExifEndianBase

// C++ default constructor can NOT contain any code, that

// might leave.

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

//

CExifEndianBase::CExifEndianBase()

    {

    }

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

// CExifEndianBase::ConstructL

// Symbian 2nd phase constructor can leave.

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

//

void CExifEndianBase::ConstructL()

    {

    }

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

// CExifEndianBase::NewBaseL

// Two-phased constructor. Instantiates and returns relevant derived class.

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

//

CExifEndianBase* CExifEndianBase::NewBaseL( 

    const TUint8* aExifDataPtr, 

    TUint aDataLength, 

    TBool aIsExif )

    {

    // 

    // Parse header. 

    // Find SOI (FFD8 )

    // ptr = SOI pos.

    // Then check the following 10 bytes:

    // APP1 Marker (FFE1) + APP1 Length (no check) + Identifier ("Exif"00) + 

    // Pad (00) (no check)

    //TUint8* dataStartPtr = CONST_CAST( TUint8*, aExifData.Ptr() ); 

    if ( !aExifDataPtr )

        {

        User::Leave( KErrGeneral );

        }

    TUint8* ptr = CONST_CAST( TUint8*, aExifDataPtr ) - 1;

    TUint8 *pE = CONST_CAST( TUint8*, aExifDataPtr ) + aDataLength; 

    // Locate the SOI marker.

    do

        {

        if ( ptr == pE )

            {

            User::Leave( KErrCorrupt );

            }

        } 

    while ( *++ptr != KMarkerStart );

    if ( *( ptr + 1 ) != KSoiEnd )

        {

        User::Leave( KErrCorrupt );

        }

    // ptr is now at SOI.

    // If original is Exif, check whether it is Little- or Big-endian.

    // Otherwise create Little-endian reader.

    if ( aIsExif )

        {

        // Locate the APP1 marker

        do

            {

            do

                {

                if ( ptr == pE )

                    {

                    User::Leave( KErrCorrupt );

                    }

                } 

            while ( *++ptr != KMarkerStart );

            } 

        while ( *( ptr + 1 ) != KApp1End );

        // ptr is now at APP1

        // Skip App1 length.

        ptr += 4;

        // Check the APP1 and Exif header.

        if ( TExifCommon::Uint32L( ptr ) != KExifIdentifierRev ) 

            {

            User::Leave( KErrCorrupt );

            }

        ptr += 4;

        // Padding 0 after 8 bytes of data. No need to check, skip.

        //if ( ( *ptr ) != 0)

        //    {

        //    User::Leave( KErrCorrupt );

        //    }

        ptr += 2;

        // Check if little- or big- endian, and create the reader.

        if ( TExifCommon::Uint16L( ptr ) == KLittleEndian )

            {

            return CExifLittleEndian::NewL( aExifDataPtr, ptr, pE, aIsExif );

            }

        else if ( TExifCommon::Uint16L( ptr ) == KBigEndian )

            {

            return CExifBigEndian::NewL( aExifDataPtr, ptr, pE, aIsExif );

            }

        else // None of the formats match!!

            {

            User::Leave( KErrCorrupt );

            }

        }

    else

        {

        return CExifLittleEndian::NewL( aExifDataPtr, ptr, pE, aIsExif );

        }

    return NULL;

    }

// Destructor

CExifEndianBase::~CExifEndianBase()

    {

    }

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

// CExifEndianBase::CopyBufferL

// Copies the data from the location, which starts and ends with the given 

// Jpeg Markers.

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

//

void CExifEndianBase::CopyBufferL( 

    TUint16 aStartMarker, 

    TUint16 aEndMarker, 

    HBufC8*& aDestBuffer, 

    TBool aIncludeEnd )

    {

    TUint32 startOffset = 0;

    if ( LocateJpegMarker( aStartMarker, startOffset ) )

        {

        User::Leave( KErrCorrupt );

        }

    TUint32 endOffset = 0;

    if ( LocateJpegMarker( aEndMarker, endOffset ) )

        {

        User::Leave( KErrCorrupt );

        }

    TUint32 size =  endOffset - startOffset;

    if ( aIncludeEnd )

        {

        size += 2;

        }

    aDestBuffer = HBufC8::NewL( size );

    CleanupStack::PushL( aDestBuffer );

    iPosOffset = startOffset;

    CopyBuffer( size, 1 , aDestBuffer );

    CleanupStack::Pop();

    }

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

// CExifEndianBase::ReadUint8

// Gets the next 8-bit unsigned integer from the data.

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

//

TInt CExifEndianBase::ReadUint8( TUint8& aInt8 )

    {

    if ( iPosOffset + 1 >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    aInt8 = *( iDataStartPtr + iPosOffset );

    ++iPosOffset;

    return KErrNone;

    }

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

// CExifEndianBase::MoveTo

// Moves to the specified offset.

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

//

TInt CExifEndianBase::MoveTo( TUint aOffset )

    {

    if ( iExifStartOffset + aOffset >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    iPosOffset = iExifStartOffset + aOffset;

    return KErrNone;

    }

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

// CExifEndianBase::Skip

// Moves the current position forward by the given number of bytes.

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

//

TInt CExifEndianBase::Skip( TUint aNoBytes )

    {

    if ( iPosOffset + aNoBytes >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    iPosOffset += aNoBytes;

    return KErrNone;

    }

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

// CExifEndianBase::Locate8

// Locates the offset of the next specified 8-bit unsigned integer 

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

//

TInt CExifEndianBase::Locate8( TUint8 aSearch, TUint32& aOffset )

    {

    TUint8 *pBuf = iDataStartPtr + iPosOffset;

    TUint8 *pB = pBuf - 1;

    TUint8* pE = iDataStartPtr + iExifEndOffset;

    do

        {

        if ( pB == pE )

            {

            return KErrCorrupt;

            }

        } 

    while ( *++pB != aSearch );

    aOffset = pB - iDataStartPtr;

    return KErrNone;

    }

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

// CExifEndianBase::LocateJpegMarker

// Locates the offset of the specified Jpeg Marker, which resides after the 

// given offset.

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

//

TInt CExifEndianBase::LocateJpegMarker( 

    TUint16 aMarker, 

    TUint32& aOffset, 

    TUint32 aAfter,

    TUint32 aBefore )

    {

    if ( aAfter < iPosOffset )

        {

        aAfter = iPosOffset;

        }

    TUint8* startPtr = iDataStartPtr + aAfter;

    if ( !aBefore )

        {

        aBefore = iExifEndOffset;

        }

    TUint8* endPtr = iDataStartPtr + aBefore;

    TUint8* pB = TExifCommon::LocateJpegMarkerPtr( 

        aMarker, startPtr, endPtr );

    if ( !pB )

        {

        return KErrCorrupt;

        }

    aOffset = pB - iDataStartPtr;

    return KErrNone;    

    }

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

// CExifEndianBase::LocateJpegMarkerFromEnd

// Locates the offset of the last specified Jpeg Marker.

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

//

TInt CExifEndianBase::LocateJpegMarkerFromEnd( 

    TUint16 aMarker, 

    TUint32& aOffset,

    TUint32 aAfter,

    TUint32 aBefore )

    {

    if ( aAfter < iPosOffset)

        {

        aAfter = iPosOffset;

        }

    TUint8* startPtr = iDataStartPtr + aAfter;

    if ( !aBefore )

        {

        aBefore = iExifEndOffset;

        }

    TUint8* endPtr = iDataStartPtr + aBefore;

    TUint8* pB = TExifCommon::LocateJpegMarkerPtrFromEnd( aMarker, 

        startPtr, endPtr );

    if ( !pB )

        {

        return KErrCorrupt;

        }

    aOffset = pB - iDataStartPtr;

    return KErrNone;    

    }

// ============================ CLASS CExifLittleEndian ========================

// ============================ MEMBER FUNCTIONS ===============================

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

// CExifLittleEndian::NewL

// Two-phased constructor.

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

//

CExifLittleEndian* CExifLittleEndian::NewL( 

    const TUint8* aDataStartPtr, 

    TUint8* aExifStartPtr, 

    TUint8* aExifEndPtr, 

    TBool aIsExif )

    {

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

    CleanupStack::PushL( self );

    self->ConstructL( CONST_CAST( TUint8*, aDataStartPtr ), aExifStartPtr, 

        aExifEndPtr, aIsExif );

    CleanupStack::Pop();

    return self;

    }

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

// CExifLittleEndian::CExifLittleEndian

// C++ default constructor can NOT contain any code, that

// might leave.

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

//

CExifLittleEndian::CExifLittleEndian()

    {

    }

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

// CExifLittleEndian::ConstructL

// Symbian 2nd phase constructor can leave.

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

//

void CExifLittleEndian::ConstructL( 

    TUint8* aDataStartPtr, 

    TUint8* aExifStartPtr, 

    TUint8* aExifEndPtr, 

    TBool aIsExif )

    {

    if ( !aDataStartPtr || !aExifStartPtr || !aExifEndPtr )

        {

        User::Leave( KErrGeneral );

        }

    iDataStartPtr = aDataStartPtr;

    iExifEndOffset = aExifEndPtr - iDataStartPtr;

    if ( aIsExif )

        {

        iExifStartOffset = aExifStartPtr - iDataStartPtr;

        if ( TExifCommon::Uint16L( aExifStartPtr + 2 ) != KExifDummyRev )

            {

            User::Leave( KErrCorrupt );

            }

        TUint32 ifdOffset = TExifCommon::Uint32L( aExifStartPtr + 4 );

        iPosOffset = iExifStartOffset + ifdOffset; //Locate 0th IFD position

        if ( iPosOffset >= iExifEndOffset )

            {

            User::Leave( KErrCorrupt );

            }

        }

    else

        {

        iPosOffset = aExifStartPtr - iDataStartPtr;

        }

    }

// Destructor

CExifLittleEndian::~CExifLittleEndian()

    {

    }

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

// CExifLittleEndian::Locate16

// Locates the offset of the next specified 16-bit unsigned integer.

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

//

TInt CExifLittleEndian::Locate16( TUint16 aSearch, TUint32& aOffset )

    {

    TUint8* pB = iDataStartPtr + iPosOffset - 1;

    TUint16 atHand = *pB;

    TUint8* pE = iDataStartPtr + iExifEndOffset;

    TInt error = KErrNone;

    do

        {

        if ( pB >= pE )

            {

            return KErrCorrupt;

            }

        TRAP( error, atHand =TExifCommon::Uint16L( ++pB ) );

        } 

    while ( ( atHand != aSearch ) && ( error == KErrNone ) );

    if ( error )

        {

        return error;

        }

    aOffset = pB - iDataStartPtr;

    return KErrNone;

    }

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

// CExifLittleEndian::ReadUint16

// Gets the next 16-bit unsigned integer from the data.

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

//

TInt CExifLittleEndian::ReadUInt16( TUint16& aInt16 )

    {

    if ( iPosOffset + 2 >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    TRAPD( error, aInt16 = TExifCommon::Uint16L( iDataStartPtr + iPosOffset ) );

    if ( error )

        {

        return error;

        }

    iPosOffset += 2;

    return KErrNone;

    }

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

// CExifLittleEndian::ReadUint32

// Gets the next 32-bit unsigned integer from the data.

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

//

TInt CExifLittleEndian::ReadUInt32( TUint32& aInt32 )

    {

    if ( iPosOffset + 4 >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    TRAPD( error, aInt32 = TExifCommon::Uint32L( iDataStartPtr + iPosOffset ) );

    if ( error )

        {

        return error;

        }

    iPosOffset += 4;

    return KErrNone;

    }

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

// CExifLittleEndian::CopyBuffer

// Copies the next specified amount of data to the given descriptor.

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

//

TInt CExifLittleEndian::CopyBuffer( 

    TUint32 aCount, 

    TUint8 aWordSize, 

    HBufC8*& aBuffer )

    {

    if ( !aBuffer )

        {

        return KErrCorrupt;

        }

    TUint bufferSize = aCount * aWordSize;

    if ( iPosOffset + bufferSize >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    aBuffer->Des().Copy( iDataStartPtr + iPosOffset, bufferSize );

    iPosOffset += bufferSize;

    return KErrNone;

    }

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

// CExifLittleEndian::CopyBuffer

// Copies the specified amount of data located in the given offset to the 

// given descriptor.

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

//

TInt CExifLittleEndian::CopyBuffer( 

    TUint32 aOffset, 

    TUint32 aCount, 

    TUint8 aWordSize, 

    HBufC8*& aBuffer )

    {

    if ( !aBuffer )

        {

        return KErrCorrupt;

        }

    TUint bufferSize = aCount * aWordSize;

    if ( ( aOffset + iExifStartOffset + bufferSize ) >= iExifEndOffset )

        {

        return KErrCorrupt;

        }

    TUint8* ptr = iDataStartPtr + iExifStartOffset + aOffset;

    aBuffer->Des().Copy( ptr, bufferSize );

    return KErrNone;

    }

// ============================ CLASS CExifBigEndian ===========================

// ============================ MEMBER FUNCTIONS ===============================

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

// CExifBigEndian::NewL

// Two-phased constructor.

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

//