// 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;

	}