// Copyright (c) 1998-2009 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:

 // e32test\misc\ymodem.cpp

 // 

 //

 #include <e32cmn.h>

 #include <e32cmn_private.h>

 #include "ymodem.h"

 //#include <e32test.h>

 //GLREF_D RTest test;

 const TInt KMaxRetries=10;

 static const TUint16 crcTab[256] =

     {

 	0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,0x8108,0x9129,0xa14a,

 	0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,

 	0x72f7,0x62d6,0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,0x2462,

 	0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,0xa56a,0xb54b,0x8528,0x9509,

 	0xe5ee,0xf5cf,0xc5ac,0xd58d,0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,

 	0x46b4,0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,0x48c4,0x58e5,

 	0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,

 	0x9969,0xa90a,0xb92b,0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,

 	0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,0x6ca6,0x7c87,0x4ce4,

 	0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,

 	0x8d68,0x9d49,0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,0xff9f,

 	0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,0x9188,0x81a9,0xb1ca,0xa1eb,

 	0xd10c,0xc12d,0xf14e,0xe16f,0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,

 	0x6067,0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,0x02b1,0x1290,

 	0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,

 	0xe54f,0xd52c,0xc50d,0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,

 	0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,0x26d3,0x36f2,0x0691,

 	0x16b0,0x6657,0x7676,0x4615,0x5634,0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,

 	0xb98a,0xa9ab,0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,0xcb7d,

 	0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,0x4a75,0x5a54,0x6a37,0x7a16,

 	0x0af1,0x1ad0,0x2ab3,0x3a92,0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,

 	0x8dc9,0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,0xef1f,0xff3e,

 	0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,

 	0x3eb2,0x0ed1,0x1ef0

     };

 YModem::YModem(TBool aG)

 	{

 	iTimeout=2000000;

 	iPacketSize=0;

 	iInitChar=aG?BIGG:BIGC;

 	}

 void YModem::UpdateCrc(const TUint8* aPtr, TInt aLength)

 //

 // Perform a CCITT CRC checksum.

 //

 	{

 	register const TUint8* pB=aPtr;

 	register TUint16 crc=iCrc;

     while (aLength--)

 		crc=TUint16((crc<<8)^crcTab[(crc>>8)^*pB++]);

 	iCrc=crc;

 	}

 TInt YModem::ReadPacket(TDes8& aDest)

 	{

 	TUint8* pD = (TUint8*)aDest.Ptr();

 	TInt r;

 	TPtr8 d(pD, 0, 1);

 	r = ReadBlock(d);

 	if (r != KErrNone)

 		return r;

 	if (d.Length()==0)

 		return KErrZeroLengthPacket;

 	TUint8 b0 = *pD;

 	if (b0==CAN)

 		return KErrAbort;

 	if (b0==EOT)

 		return KErrEof;

 	if (b0==SOH)

 		iBlockSize=128;

 	else if (b0==STX)

 		iBlockSize=1024;

 	else

 		return KErrBadPacketType;

 	iTimeout=5000000;

 	iPacketSize = iBlockSize+5;

 	d.Set(pD+1, 0, iPacketSize-1);

 	r = ReadBlock(d);

 	if (r!=KErrNone && r!=KErrTimedOut)

 		return r;

 	if (d.Length() < iPacketSize-1)

 		return KErrPacketTooShort;

 	TUint8 seq = pD[1];

 	TUint8 seqbar = pD[2];

 	seqbar^=seq;

 	if (seqbar != 0xff)

 		return KErrCorruptSequenceNumber;

 	if (seq==iSeqNum)

 		return KErrAlreadyExists;

 	else

 		{

 		TUint8 nextseq=(TUint8)(iSeqNum+1);

 		if (seq!=nextseq)

 			return KErrWrongSequenceNumber;

 		}

 	iCrc=0;

 	UpdateCrc(pD+3, iBlockSize);

 	aDest.SetLength(iPacketSize);

 	TUint16 rx_crc = (TUint16)((pD[iPacketSize-2]<<8) | pD[iPacketSize-1]);

 	if (rx_crc != iCrc)

 		return KErrBadCrc;

 	++iSeqNum;

 	return KErrNone;

 	}

 TInt YModem::CheckPacket(TUint8* aDest)

 	{

 	const TUint8* p=iPacketBuf.Ptr()+3;

 	if (iState>0)

 		memcpy(aDest, p, iBlockSize);

 	else

 		{

 		// parse packet 0

 		TPtrC8 nameptr(p);

 		TInt nLen=nameptr.Length();

 		if (nLen==0)

 			return KErrSessionClosed;		// batch termination packet

 		iFileName.Copy(nameptr.Left(Min(nLen,iFileName.MaxLength())));

 		p+=nLen+1;

 		iFileSize=0;

 		for (;;)

 			{

 			TUint c=*p++;

 			if (c<'0' || c>'9')

 				break;

 			iFileSize*=10;

 			iFileSize+=c-'0';

 			}

 //		test.Printf(_L("File %S, size %d\n"),&iFileName,iFileSize);

 		}

 	return KErrNone;

 	}

 TInt YModem::ReadPackets(TUint8*& aDest, TInt aLength)

 	{

 	TInt l=0;

 	TInt r=KErrNone;

 	while(l<aLength || iState==0)

 		{

 		TInt retries=0;

 		for(retries=0; retries<KMaxRetries; retries++)

 			{

 			if (iState==0)

 				iTimeout=2000000, WriteC(iInitChar);

 			r=ReadPacket(iPacketBuf);

 //			test.Printf(_L("%d\n"),r);

 			if (r==KErrTimedOut)

 				continue;

 			if (r==KErrNone)

 				r=CheckPacket(aDest);

 			if (r==KErrEof || r==KErrSessionClosed)

 				break;

 			if (r==KErrNone || r==KErrAlreadyExists)

 				{

 				if (r==KErrNone)

 					iState++;

 				if (iState>1)

 					aDest+=iBlockSize;		// don't store packet 0

 				if (iInitChar==BIGC)

 					WriteC(ACK);

 				if (iState==1)

 					WriteC(iInitChar);		// Send another 'C' after ACK

 				if (r==KErrAlreadyExists)

 					continue;

 				break;

 				}

 			if (r==KErrAbort)

 				break;

 			if (iInitChar==BIGG)

 				break;

 			WriteC(NAK);

 			}

 		if (r==KErrNone)

 			{

 			if (iState>1)

 				l+=iBlockSize;

 			}

 		else if (r==KErrSessionClosed)

 			{

 			if (iInitChar==BIGC)

 				WriteC(ACK);

 			break;

 			}

 		else if (r==KErrEof)

 			{

 			WriteC(ACK);					// acknowledge end

 			break;

 			}

 		else if (r!=KErrAbort)

 			{

 			WriteC(CAN);

 			WriteC(CAN);

 			WriteC(CAN);

 			WriteC(CAN);

 			WriteC(CAN);

 			break;

 			}

 		}

 	return r;

 	}

 TInt YModem::StartDownload(TBool aG, TInt& aLength, TDes& aName)

 	{

 	TInt r;

 	iInitChar=aG?BIGG:BIGC;

 	iState=0;

 	iSeqNum=255;

 	TUint8* dummy=NULL;

 	r=ReadPackets(dummy, 0);			// read the file description packet

 	if (r==KErrNone)

 		{

 		aLength=iFileSize;				// return file name and file size

 		aName=iFileName;

 		}

 	return r;

 	}