// Copyright (c) 1997-2009 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:
// This file contains the implementation of the TWapTextMessage.
// TWapTextMessage encodes and decodes 7-bit WAP text headers
// 
//

/**
 @file
*/

#include <e32std.h>
#include "wapthdr.h"
#include "ws_main.h"

const TInt TWapTextMessage::KHeaderCount = 6;

_LIT8(KSCKHeaderLong, "//SCKL"); // standard NBS header for 16-bit adresses
_LIT8(KSCKHeaderShort,"//SCK");  // standard NBS header for 8-bit adresses


/**
 *  Indices into different types header for each of the header elements
 *  (dest port, source port, reference, total segments, current segment)
 */
const TWapTextMessage::TIndexInfo TWapTextMessage::KElemIndexes[TWapTextMessage::KHeaderCount] =
{
// Long header ("//SCKL") indices
// destination port (, other header)
	{ 1,{ 6, 10, 0, 0, 0, 0} },
// destination port, source port (, other header)
	{ 2,{ 6, 10, 14, 0, 0, 0} },
// destination port, source port,
// reference, total segments, current segment(, other header)
	{ 5,{ 6, 10, 14, 16, 18, 20}},

// Short header ("//SCK") indices
// destination port (, other header)
	{ 1, { 5, 7, 0, 0, 0, 0}},
// destination port, source port (, other header)
	{ 2, { 5, 7, 9, 0, 0, 0}},
// destination port, source port,
// reference, total segments, current segment(, other header)
	{ 5,{ 5, 7, 9, 11, 13, 15}},
};


/**
 *  C'tor
 *  
 *  @param aWapMessage WAP message to decode/encode
 *  @note simply use KNullDesC8, if you are going to encode.
 */
TWapTextMessage::TWapTextMessage(const TDesC8& aWapMessage)
	:iIsWapTextMessage(EFalse)
	,iWAPMessage(aWapMessage)
	,iIs16Bit(EFalse)
	,iDestinationPort(-1)
	,iSourcePort(-1)
	,iReference(0)
	,iTotalSegments(0)
	,iSegmentNumber(0)
	,iOtherHeader(0)
	,iOtherHeaderLength(0)
	,iData(0)
	,iDataLength(0)
	,iRefOtherHeader(KNullDesC8)
	,iRefData(KNullDesC8)
	{
	} // TWapTextMessage::TWapTextMessage


/**
 *  Panic is raised, if the header with other header and terminating
 *  ' ' is > 159 characters. Then 1 byte is left for payload !
 *  what will be the array element type ?
 */
void TWapTextMessage::EncodeSegmentsL(CArrayPtr<HBufC8>& aSegmentArray)
	{
	TBuf8<KMaxSmsChars>  header;        // buffer for a modifiable header
	TInt        headerLength = 0;
	TInt        segmentNumberIndex = 0; // index of segment number field in the header
	TBuf8<2>    hexSegmentNumber;
	TInt        dataSegmented = 0;

	LOGWAPPROT1("TWapTextMessage::EncodeSegmentsL()");

	iSegmentNumber = 0;
	do
		{
		//
		// Create the segment and add it to the array...
		//
		HBufC8*  segment = HBufC8::NewL(KMaxSmsChars); // 160 characters
		CleanupStack::PushL(segment);
		TPtr8  ptr(segment->Des());
		aSegmentArray.AppendL(segment);
		CleanupStack::Pop(); // segment

		//
		// Calculate length of header and copy it...
		//
		if (iSegmentNumber==0)
			{
			headerLength = CreateHeader(header, segmentNumberIndex);
			}

		ptr.Copy(header);
		if (iTotalSegments>255)
			{
			User::Leave(KErrOverflow);
			}

		//
		// Set segment number...
		//
		if (segmentNumberIndex != 0)
			{
			hexSegmentNumber.NumFixedWidthUC(iSegmentNumber+1, EHex, 2); // two bytes wide
			ptr.Insert(segmentNumberIndex, hexSegmentNumber);
			}

		//
		// Count any escaped characters we can be sure that the converted data
		// size fits inside the remaining length (e.g. so that non-7bit characters
		// when converted by the SMS Stack will still fit).
		//
		TInt  segmentSize = iRefData.Length() - dataSegmented;

		if (segmentSize > KMaxSmsChars - headerLength)
			{
			segmentSize = KMaxSmsChars - headerLength;
			}

		while (segmentSize > 1)
			{
			TPtrC8  segmentData(iRefData.Mid(dataSegmented, segmentSize));
			TInt  non7bitCharEscapes = 0;
			
			//
			// Count all non-7bit characters that will be escaped (many non-7bit
			// characters are not escaped, but converted to "?"). The ones
			// that are known to be escaped are list below:
			//
			//	  12  [Form Feed].
			//	  91  "["
			//	  92  "\"
			//	  93  "]"
			//	  94  "^"
			//	 123  "{"
			//	 124  "|"
			//	 125  "}"
			//	 126  "~"
			//
			for (TInt  ch = 0;  ch < segmentSize;  ch++)
				{
				if (segmentData[ch] == 12  ||
					(segmentData[ch] >= 91  &&  segmentData[ch] <= 94)  ||
					(segmentData[ch] >= 123  &&  segmentData[ch] <= 126))
					{
					non7bitCharEscapes++;
					}
				}
			
			//
			// Can it fit? If so store it, otherwise reduce the size...
			//
			if (segmentData.Length() + non7bitCharEscapes <= KMaxSmsChars - headerLength)
				{
				ptr.Append(segmentData);
				break;
				}
			
			segmentSize--;
			}
		
			dataSegmented += segmentSize;
			iSegmentNumber++;
		}
	while (dataSegmented < iRefData.Length());

	__ASSERT_DEBUG(iTotalSegments == aSegmentArray.Count(), Panic(KPanicEncodingError));
	} // TWapTextMessage::EncodeSegmentsL


/**
 *  Returns true, if the short message starts with
 *  WAP text message header set by SetWapTextMessage.
 */
TBool TWapTextMessage::Parse()
	{
	TInt waplength = iWAPMessage.Length();
	LOGWAPPROT2("TWapTextMessage::Parse [%d bytes]", waplength);
	if(waplength != 0)
		{
		// check whether long or short header
		TInt iBaseIndex = -1;

		// minimum length is 8 "//SCKxx "
		if(waplength >= 8)
			{
			TPtrC8 HeaderIdPart(iWAPMessage.Left(6));
			if(!HeaderIdPart.Compare(KSCKHeaderLong))
				{
				iBaseIndex = 0;
				iIs16Bit = ETrue; // Yes, the ports are 16 bit wide
				}
			else
				HeaderIdPart.Set(iWAPMessage.Left(5));

			if(iBaseIndex == (-1) && !HeaderIdPart.Compare(KSCKHeaderShort) )
				iBaseIndex = 3;
			// else  no match
			}

		if(iBaseIndex >= 0)
			{
			// check which of the TIndexInfos match
			for(TInt i=iBaseIndex; i<iBaseIndex+3; i++)
				{
				// Get length (index) of text header variant
				TInt lastIndex = KElemIndexes[i].iIndexes[KElemIndexes[i].iLastIndex];
				if (iWAPMessage.Length() <= lastIndex)
					{
					// no hope about match, because other variants are longer
					iIsWapTextMessage = EFalse;
					break;
					}

				TInt LastChar = iWAPMessage[lastIndex];
				if (LastChar == '/' || LastChar == ' ' || LastChar == '\n')
					{
					// reinitialize, because following maybe absent
					iTotalSegments = 1;
					iSegmentNumber = 1;
					iIsWapTextMessage = ParseWapTextHeader(KElemIndexes[i]);
					break;
					}

				}

			if (!iIsWapTextMessage)
				{
				LOGWAPPROT1("WARNING! illegal incoming WAP message");
				}
			}
		}

	return iIsWapTextMessage;
	} // TWapTextMessage::Parse


/**
 *  Parses a string of hex characters representing a number
 *  
 *  @param aInValue descriptor containing the number
 *  @param aBigEndian true if number is big endian
 *  @param aRadix Radixbase; 16, 10 etc
 *  @return TInt the parsed number
 *  @leave Panics with KPanicInvalidParseNumber error code, if not a
 *  number. Maximum width of the hex value can be 4.
 *  
 *  TODO use TLex instead
 */
TInt TWapTextMessage::ParseNumber(const TDesC8& aInValue,
								  TBool   aBigEndian,
								  TInt    aRadix)
	{
	LOGWAPPROT2("TWapTextMessage::ParseNumber [%S]", &aInValue);
	// least significant byte first
	TInt Values[4] = {0,0,0,0};
	TInt Temp = 0;
	TInt length = aInValue.Length();
	TInt i = 0;
	TInt Value = 0;

	__ASSERT_DEBUG(length<5,Panic(KPanicInvalidParseNumber));
    if( length >= 5 )
        return KErrNotFound;
	for(i=0; i<length; i++)
		{
		Temp = aInValue[i];
		if (Temp>='0' && Temp<='9')
			Temp-='0';
		else if (Temp>='A' && Temp<='Z')
			Temp = Temp - 'A'+10;
		else if (Temp>='a' && Temp<='z')
			Temp = Temp - 'a'+10;
		else
            return KErrNotFound;
		if (aBigEndian)
			Values[(length-1)-i]=Temp;
		else
			Values[i]=Temp;
		}

	// build the value
	Value=Values[0];
	TInt Base=1;
	for(i=1; i<length; i++)
		{
		Base*=aRadix;
		Value+=(Base)*Values[i];
		}

	return Value;
	} // TWapTextMessage::ParseNumber


/**
 *  parse the WAP text header
 *  
 *  use ElemIndexes to retrieve the index
 *  an starting position of an element in iWapMessage
 *  Length of element is calculated by
 *  subtracting current index value from the next one
 *  except for KOtherHeader and user data, of course
 */
TBool TWapTextMessage::ParseWapTextHeader(const TIndexInfo& aIndexArray)
	{
	LOGWAPPROT2("TWapTextMessage::ParseWapTextHeader: %S", &iWAPMessage );

	TInt ParsedNumber = 0;

	// parse the header
	TInt ElemIndexCount=aIndexArray.iLastIndex+1;
	for(TInt i=0; i<ElemIndexCount; i++)
		{
		if (i<ElemIndexCount-1)
			{
			// all the elems have a length defined in advance
			if (iWAPMessage.Length() >= aIndexArray.iIndexes[i+1])
				{
				// the header fits into the wap datagram
				TPtrC8 Elem(iWAPMessage.Mid(aIndexArray.iIndexes[i],
											aIndexArray.iIndexes[i+1]-
											aIndexArray.iIndexes[i]));

				ParsedNumber = ParseNumber(Elem,ETrue,16);
                if( ParsedNumber == KErrNotFound )
                    return EFalse;
				switch(i)
					{
				  case KIndexDestinationPort:
					  iDestinationPort = ParsedNumber;

					  break;
				  case KIndexSourcePort:
					  iSourcePort = ParsedNumber;
					  break;
				  case KIndexReferenceNumber:
					  iReference = ParsedNumber;
					  break;
				  case KIndexTotalSegments:
					  iTotalSegments = ParsedNumber;
					  break;
				  case KIndexSegmentNumber:
					  iSegmentNumber = ParsedNumber;
					  break;
				  default:
					  LOGWAPPROT2("Hm. unhandled WAP index [%d]", i );
					  break;
					}
				}
			}
		else
			{
			// elems have not a length defined in advance
			iOtherHeader = 0;
			iOtherHeaderLength = 0;

			// Search the terminating character ' '
			iData = iWAPMessage.Locate(' ');
			TInt dataTmp = iWAPMessage.Locate('\n');

			if (iData == KErrNotFound)
				{
				if (dataTmp == KErrNotFound)
					return EFalse;
				else
					iData = dataTmp;
				}
			else if (dataTmp != KErrNotFound)
				iData = Min(iData, dataTmp);

			// check the existence of other header
			// at least "// " should be there
			if (   iWAPMessage.Length() > aIndexArray.iIndexes[i]+2
				   && iWAPMessage[aIndexArray.iIndexes[i]] == '/'
				   && iWAPMessage[aIndexArray.iIndexes[i]+1] == '/')
				{
				iOtherHeader = aIndexArray.iIndexes[i];
				iOtherHeaderLength=iData-iOtherHeader;
				}

			// data: check if any characters after ' '
			iDataLength = 0;
			iData++;
			if (iWAPMessage.Length() > iData)
				{
				iDataLength = iWAPMessage.Length() - iData;
				}

			// That's it
			} // end of other header and data
		}// end of for loop
	return ETrue;
	} // TWapTextMessage::ParseWapTextHeader


/**
 *  Length of header is returned
 *  Sets internally the iTotalSegments
 *  Does not set the segment number into the aFixedHeader
 *  
 *  Length of complete header is returned.
 *  On return the header is not complete, if SAR is needed, because the segment
 *  number is not set. Thus aFixedHeader.Length() != (return value of this function) is true.
 *  The segment number can be set by inserting it into aSegmentNumberIndex position
 *  If SAR is not needed aSegmentNumberIndex = 0 and
 *  aFixedHeader.Length() == (return value of this function) is true
 */
TInt TWapTextMessage::CreateHeader(TDes8& aFixedHeader, TInt& aSegmentNumberIndex)
	{
	LOGWAPPROT1("TWapTextMessage::CreateHeader");

	// Index into KElemIndexes indicating which header elements are present
	TInt elemIndex;
	// Index into Indexes, for current header element
	TInt minorIndex=KIndexDestinationPort;
	TBuf8<4> hexNumber;

	// Segment number length is set, if SAR is needed
	TInt segmentNumberLength = 0;
	aSegmentNumberIndex = 0;

	// Determine whether long or short form is used
	if (iIs16Bit || iSourcePort > 255 || iDestinationPort>255)
		{
		elemIndex = 0;
		aFixedHeader.Copy(KSCKHeaderLong);
		}
	else
		{
		elemIndex = 3;
		aFixedHeader.Copy(KSCKHeaderShort);
		}

	// Set destination port
	hexNumber.NumFixedWidthUC(iDestinationPort,EHex,
							  KElemIndexes[elemIndex].iIndexes[minorIndex+1]-KElemIndexes[elemIndex].iIndexes[minorIndex]);
	aFixedHeader.Append(hexNumber);

	// Don't set the source port,
	// 1) if it is not set or it same as destination port and
	// 2) data (and other header) fits in one segment
	if (!((iSourcePort==-1 || iDestinationPort==iSourcePort)
		  && CalculateTotalSegments(KElemIndexes[elemIndex].iIndexes[minorIndex+1])==1))
		{
		// Source port is present
		elemIndex++;
		minorIndex++;
		if (iSourcePort==-1)
			iSourcePort = iDestinationPort;

		// Set source port
		hexNumber.NumFixedWidthUC(iSourcePort,EHex,
								  KElemIndexes[elemIndex].iIndexes[minorIndex+1]-KElemIndexes[elemIndex].iIndexes[minorIndex]);
		aFixedHeader.Append(hexNumber);

		// Add the SAR info when source port is set
		elemIndex++;

		// Set reference
		minorIndex++;
		hexNumber.NumFixedWidthUC(iReference,EHex,
								  KElemIndexes[elemIndex].iIndexes[minorIndex+1]-KElemIndexes[elemIndex].iIndexes[minorIndex]);
		aFixedHeader.Append(hexNumber);

		// Set fragment count
		minorIndex++;
		CalculateTotalSegments(KElemIndexes[elemIndex].iIndexes[KElemIndexes[elemIndex].iLastIndex]);
		hexNumber.NumFixedWidthUC(iTotalSegments,EHex,
								  KElemIndexes[elemIndex].iIndexes[minorIndex+1]-KElemIndexes[elemIndex].iIndexes[minorIndex]);
		aFixedHeader.Append(hexNumber);

		// Return the index for segment number in the header
		minorIndex++;
		aSegmentNumberIndex = KElemIndexes[elemIndex].iIndexes[minorIndex];
		segmentNumberLength = 2;
		}

	aFixedHeader.Append(iRefOtherHeader);
	aFixedHeader.Append(_L(" "));

	return aFixedHeader.Length()+segmentNumberLength;
	} // TWapTextMessage::CreateHeader


/**
 *  Calculates count of segments to send a used data (based on iRefData)
 *  The values is assigned to iTotalSegments
 *  The affect of terminating ' ' is taken into inside the method
 */
TInt TWapTextMessage::CalculateTotalSegments(TInt aFixedLength)
	{
	LOGWAPPROT2("TWapTextMessage::CalculateTotalSegments [aFixedLength=%d]", aFixedLength);

	// '+1': length of terminating ' '
	TInt  length        = aFixedLength + iRefOtherHeader.Length() + 1;
	TInt  remain        = KMaxSmsChars - length;
	TInt  dataSegmented = 0;

	__ASSERT_DEBUG(remain > 0, Panic(KPanicTextHeaderTooLong));

	iTotalSegments = 0;
	do
		{
		iTotalSegments++;

		//
		// Count any escaped characters we can be sure that the converted data
		// size fits inside the remaining length (e.g. so that non-7bit characters
		// when converted by the SMS Stack will still fit).
		//
		TInt  segmentSize = iRefData.Length() - dataSegmented;

		if (segmentSize > remain)
			{
			segmentSize = remain;
			}

		while (segmentSize > 1)
			{
			TPtrC8  segmentData(iRefData.Mid(dataSegmented, segmentSize));
			TInt  non7bitCharEscapes = 0;
			
			//
			// Count all non-7bit characters that will be escaped (many non-7bit
			// characters are not escaped, but converted to "?"). The ones
			// that are known to be escaped are list below:
			//
			//	  12  [Form Feed].
			//	  91  "["
			//	  92  "\"
			//	  93  "]"
			//	  94  "^"
			//	 123  "{"
			//	 124  "|"
			//	 125  "}"
			//	 126  "~"
			//
			for (TInt  ch = 0;  ch < segmentSize;  ch++)
				{
				if (segmentData[ch] == 12  ||
					(segmentData[ch] >= 91  &&  segmentData[ch] <= 94)  ||
					(segmentData[ch] >= 123  &&  segmentData[ch] <= 126))
					{
					non7bitCharEscapes++;
					}
				}
			
			//
			// Can it fit? If so store it, otherwise reduce the size...
			//
			if (segmentData.Length() + non7bitCharEscapes <= remain)
				{
				break;
				}
			
			segmentSize--;
			}
		
			dataSegmented += segmentSize;
		}
	while (dataSegmented < iRefData.Length());
	
	//
	// At least one fragment is needed...
	//
	if (iTotalSegments == 0)
		{
		iTotalSegments = 1;
		}

	return iTotalSegments;
	} // TWapTextMessage::CalculateTotalSegments

// EOF - WAPTHDR.CPP