// 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 "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:

// FTP server answer parser

// Author:	Philippe Gabriel

// RFC 959 defines the syntax for answers sent back by FTP servers

// TFTPServerAnswerParser parses these answers 

// RFC says answers are:

// 1) single line answer

// xxx<space><alphadecimal chars><0x0d><0x0a>

// 2) multiline answer

// xxx-<alphadecimal chars><0x0d><0x0a>

// <several lines>

// <0x0d><0x0a>xxx<space><alphadecimal chars><0x0d><0x0a>

// We parse these regular expressions with the class TFTPServerAnswerParser

// implementing an FSM to parse a regular expression

// The parser is called with the method:

// Parse(const TDesC& aBuffer)

// parameter: aBuffer contains an answer to be parsed

// returns:

// 1) True

// a server answer is available 

// Get the answer with: ServerAnswer(TDes& aServerAnswer)

// Get the number of chars from the buffer corresponding to the

// parsed answer with NChars()

// the NChars first chars can be flushed from the buffer

// note: in this case, call the parser again before

// we do any more socket receive operation, to parse the rest of the buffer

// 2)False

// no answer is available yet

// buffer can be completely flushed

// 

//

/**

 @file ANSPARSE.CPP

 @internalComponent

*/

#include "DEBUG.H"

#include "ANSPARSE.H"

//

// Definitions

//

TFTPServerAnswerParser::TFTPServerAnswerParser()

	{

	iState = EIdle;

	}

TBool	TFTPServerAnswerParser::Parse(const TDesC8& aBuffer)

	{

	const TUint8*	c;

	TInt			bufLen;

	iParsingSuccess = FALSE;

	FTPPROTDEBUG(_DBGAnsparse,_L("TFTPServerAnswerParser::Parse -States: "));

	for (iNChars=0,c= aBuffer.Ptr(),bufLen = aBuffer.Length();(!iParsingSuccess && bufLen>0);bufLen--,c++)

		{

		//Log::Printf(_L("<%d>"),iState);

		iNChars++;

		switch (iState)

			{

			case EIdle:

				iDigit.Zero();

				// fall through

			case EState1:

			case EState2:

				// We should have a digit here

				// if not, ignore char and try to be forgiving

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

					{

					FTPPROTDEBUG(_DBGAnsparse,_L("TFTPServerAnswerParser::Parser non digit parsed"));

					continue;

					}

				//Ok we have a digit, store it

				iDigit.Append(*c);

				iState++;

				break;

			case EState3:

				switch (*c)

					{

					case '-':

						// We can have a '-' here for a multiline answer

						iState = EState6;

						break;

					case CR: 

						iState = EState5;

						break;

					default:

						// No '-', just wait for Telnet EOL

							iState = EState4;

						break;

					}

				break;

			// Wait for Telnet EOL

			case EState4:

				// note: this state cannot be collapsed with state3

				// we need this state for the transition from state11

				// Wait for CR

				if(*c ==CR)

					iState = EState5;

				break;

			case EState5:

				// Wait for LF

				if(*c ==LF)

					{

					iState = EIdle;

					iParsingSuccess = TRUE;

					// Update iBufferPos

					}

				else

					iState = EState4;

				break;

			// Parsing multiline answer

			case EState6:

				// Wait for CR

				if(*c ==CR)

					iState = EState7;

				break;

			case EState7:

				// Wait for LF

				if(*c ==LF)

					iState = EState8;

				else

					iState = EState6;

				break;

			// Parsing final line of a multiline answer

			case EState8:

			case EState9:

			case EState10:

				// Wait for a digit

				if(*c ==iDigit[iState-EState8])

					iState++;

				else

					if (*c == CR)

						iState = EState7;

					else

						iState = EState6;

				break;

			case EState11:

				// Finally we want a space

				if(*c ==' ')

					iState = EState4;

				else

					iState = EState6;

				break;

			default:

				__ASSERT_DEBUG(FALSE, User::Panic(_L("TFTPServerAnswerParser"),EPIPanicOutOfState));

			}

		}

	FTPPROTDEBUG(_DBGAnsparse,_L("\n"));

	return iParsingSuccess;

	}