// Copyright (c) 2000-2009 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 "wapdecoder.h"

const TInt KMaxLongIntSize = 0x1E;	// Long-integer can have maximum 30 OCTETS (WSP Spec)

/**

Extracts a WAP variable length integer from a binary data buffer.

@param	aSource 

Input binary data buffer.

@param	aStartIndex

Position in aSource from which to extract the integer.

@param	aMultiByte

On return, the extracted variable length integer.

@leave	KErrCorrupt

A valid variable length integer was not found in the buffer.

*/

EXPORT_C void TWapBinCodex::ExtractUIntvarL(const TDesC8& aSource, TInt aStartIndex, TWapBinCodex::TUintvar& aMultiByte)

	{

	TUint8 byte = 0, topThreeBits = 0;

	aMultiByte.iValue = 0;

	aMultiByte.iOctetSize = 0;

	TInt lenLeft = aSource.Length() - aStartIndex;

	if (lenLeft <= 0)

		User::Leave(KErrCorrupt);

	// get the first octet

	byte = aSource[aStartIndex];

	// if the topThreeBits are set and we are using all 5 octets, this is corrupt data

	topThreeBits |= byte & 0x70; 

	// copy over the top byte

	aMultiByte.iValue |= byte & ~0x80;

	++aMultiByte.iOctetSize;

	// while the top 'continue' byte is set and we have more data

	while ((byte & 0x80) && (aMultiByte.iOctetSize < 5) && (--lenLeft > 0))

	{

		aMultiByte.iValue <<= 7;

		byte = aSource[aStartIndex + aMultiByte.iOctetSize++];

		aMultiByte.iValue |= byte & ~0x80;

	} 

	// last octet had continue bit set ... NOT allowed or aSource wasn't complete

	if (byte & 0x80)

		User::Leave(KErrCorrupt);

	// this was encoded wrong and the topThreeBits are about to shift off ... NOT allowed

	if (aMultiByte.iOctetSize == 5 && topThreeBits)

		User::Leave(KErrCorrupt);

	}

/**

Extracts a WAP-encoded multi-octet integer from a binary data buffer.

The function will panic if the binary data is corrupt.

@param	aSource

The binary data buffer containing the integer.

@param	aInt

The output argument with the parsed integer.

@panic

The binary data buffer is corrupted (debug only).

@deprecated TWapBinCodex::ParseMultiOctetInteger function.

Use the new 

*/

EXPORT_C void TWapBinCodex::ExtractMultiOctetInteger(const TDesC8& aSource, TInt& aInt)

/* 

 * NOTE - It is a straight copy from CHttpResponse as the function isn't exported, and it is  

 * not possible to change the interface to the Wapplugins dll. 

 */

	{

	// Get num bytes encoding the integer - 

	// we are positioned at that location in the source descriptor

	TUint8 numBytes = aSource[0];

	aInt = 0;

	__ASSERT_DEBUG(numBytes < aSource.Length(), User::Invariant());

	// Loop over the source, taking each byte and shifting it in to the count.  

    for (TInt count = 1; (count <= numBytes); count++)

        aInt = (aInt << 8) + aSource[count];

	}

/**

Extracts a WAP-encoded multi-octet integer from a binary data buffer.

If the integer could not be parsed, then the output argument aInt is not valid.

@param

aSource	The binary data buffer containing the integer.

@param

aInt	The output argument with the parsed integer.

@return

The number of bytes parsed or an error code. A value of KErrCorrupt indicates 

that the data buffer contained a corrupted multi-octet integer.

*/

EXPORT_C TInt TWapBinCodex::ParseMultiOctetInteger(const TDesC8& aSource, TInt& aInt)

	{

	// Get num bytes encoding the integer.

	TUint8 numBytes = aSource[0];

	aInt = 0;

	if( numBytes > aSource.Length() - 1 || numBytes > KMaxLongIntSize )

		return KErrCorrupt;

	// Loop over the source, taking each byte and shifting it in to the count.  

    for (TInt count = 1; (count <= numBytes); ++count)

        aInt = (aInt << 8) + aSource[count];

	return numBytes + 1;

	}