// Copyright (c) 2006-2009 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 "readers.h"

//

// Creates a new CReader object.

//

CReader::CReader(const TDesC8& aBuffer, TReaderType aType)

 :	iBuffer(aBuffer),

 	iType(aType)

	{

	}

//

// Returns ETrue is aPattern is in the buffer, EFalse otherwise.

//

TBool CReader::Match(const TDesC8& aPattern)

	{

	return (iBuffer.Match(aPattern) != KErrNotFound);

	}

//

// Reads aBuf.Length() bytes into a descriptor.

//

void CReader::ReadBytesL(TDes8& aBuf)

	{

	TInt bufLen = aBuf.Length();

	if (!CheckEnoughData(bufLen))

		{

		User::Leave(KErrEof);

		}

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

		{

		aBuf[i] = iBuffer[iBufPos++];

		}

	}

//

// Reads a byte from the buffer.

//

void CReader::ReadByteL(TUint8& aData)

	{

	if (!CheckEnoughData(sizeof(TUint8)))

		{

		User::Leave(KErrEof);

		}

	aData = iBuffer[iBufPos++];

	}

//

// Reads 16 bits of data at the current reader position.

// Some formats (mainly those developed by Microsoft) still use little-endian

// encoding of fields. The file format specifications will specify which

// byte-ordering scheme is used.

//

void CReader::Read16L(TUint16& aData, TBool aLittleEndian)

	{

	if (!CheckEnoughData(sizeof(TUint16)))

		{

		User::Leave(KErrEof);

		}

	TUint8 a = iBuffer[iBufPos++];

	TUint8 b = iBuffer[iBufPos++];

	if (aLittleEndian)

		{

		aData = (b << 8) | a;

		}

	else

		{

		aData = (a << 8) | b;

		}

	}

//

// Reads 32 bits of data at the current reader position.

// Some formats (mainly those developed by Microsoft) still use little-endian

// encoding of fields. The file format specifications will specify which

// byte-ordering scheme is used.

//

void CReader::Read32L(TUint32& aData, TBool aLittleEndian)

	{

	if (!CheckEnoughData(sizeof(TUint32)))

		{

		User::Leave(KErrEof);

		}

	TUint8 a = iBuffer[iBufPos++];

	TUint8 b = iBuffer[iBufPos++];

	TUint8 c = iBuffer[iBufPos++];

	TUint8 d = iBuffer[iBufPos++];

	if (aLittleEndian)

		{

		aData = MAKE_INT32(d, c, b, a);

		}

	else

		{

		aData = MAKE_INT32(a, b, c, d);

		}

	}

//

// Reads 64 bits of data at the current reader position.

// Some formats (mainly those developed by Microsoft) still use little-endian

// encoding of fields. The file format specifications will specify which

// byte-ordering scheme is used.

//

void CReader::Read64L(TInt64& aData, TBool aLittleEndian)

	{

	TUint32 high;

	TUint32 low;

	Read32L(high, aLittleEndian);

	Read32L(low, aLittleEndian);

	if (aLittleEndian)

		{

		aData = MAKE_TINT64(low, high);

		}

	else

		{

		aData = MAKE_TINT64(high, low);

		}

	}

//

//

//

TBool CReader::CheckEnoughData(TInt aNeeded)

	{

	return ((iBufPos + aNeeded) <= iBuffer.Length());

	}

//

// Skips forwards or backwards aOffset number of bytes.

//

TInt CReader::Seek(TInt aOffset)

	{

	TInt newBufPos = iBufPos + aOffset;

	if ((newBufPos < 0) || (newBufPos >= iBuffer.Length()))

		{

		// Trying to seek past the bounds of the buffer.

		return KErrUnderflow;

		}

	iBufPos += aOffset;

	return KErrNone;

	}

//

// Skips forwards or backwards aOffset number of bytes.

//

TInt CReader::Seek(TInt64 aOffset)

    {

    TInt64 newBufPos = iBufPos + aOffset;

    if ((newBufPos < 0) || (newBufPos >= iBuffer.Length()))

        {

        // Trying to seek past the bounds of the buffer.

        return KErrUnderflow;

        }

    iBufPos += aOffset;

    return KErrNone;

    }