/*

* Copyright (c) 2002 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: 

*

*/

#include "RegularExpression.h"

#define KNumOfRecognisedChars 13

// Panic is implemented in NumberGrouping.cpp

GLDEF_C void Panic(TNumberGroupingPanic aPanic);

CRegularExpression::CRegularExpression()

{

}

CRegularExpression* CRegularExpression::NewL(RPointerArray<TDesC>* aPatterns)

{

	CRegularExpression* s = NewLC(aPatterns);

	CleanupStack::Pop();

	return s;

}

CRegularExpression* CRegularExpression::NewLC(RPointerArray<TDesC>* aPatterns)

{

	CRegularExpression* s = new(ELeave)CRegularExpression();

	CleanupStack::PushL(s);

	s->ConstructL(aPatterns);

	return s;

}

void CRegularExpression::ConstructL(RPointerArray<TDesC>* aPatterns)

{

	GenerateStateTablesL(aPatterns);

}

CRegularExpression::~CRegularExpression()

{

	for(TInt i = 0; i < iStateMachines.Count(); i++)

		delete iStateMachines[i];

	iStateMachines.Close();

}

TInt CRegularExpression::Search(const TDesC& aString)

{

	return SearchFrom(0, aString);

}

TInt CRegularExpression::SearchFrom(TInt aIndex, const TDesC& aString)

{

	for(TInt i = aIndex; i < iStateMachines.Count(); ++i)

	{

		if(iStateMachines[i]->Matches(aString))

			return i;

	}

	return KErrNotFound;

}

// Do the parsing

void CRegularExpression::GenerateStateTablesL(RPointerArray<TDesC>* aPatterns)

{	

	for(TInt nPatternCount = 0; nPatternCount < aPatterns->Count(); ++nPatternCount)

	{

		const TDesC& desPattern = *((*aPatterns)[nPatternCount]) ;	// I know it looks horrific, but it makes the

																	// rest of the method _so_ much easier to read

		CStateMachine* StateMachine = CStateMachine::NewLC(KNumOfRecognisedChars, desPattern.Length());

		User::LeaveIfError(iStateMachines.Append(StateMachine));

		CleanupStack::Pop(); // now the ownership transfers to iStateMachines

		// parse the desPattern

		enum TParseState

		{

			EAny,

			EOpenBracketFound,

			EChoiceOrRange,

			EChoice,

			ERange,

			ELookingForCloseBracket

		};

		TParseState	parseState = EAny;

		TInt		nPatternIndex = 0;

		TInt		nState = 0;

		TBuf<10>	bufChoice;

		bufChoice.Zero();

		TBuf<20>	bufParsingError = _L("Parsing syntax error");

		while(nPatternIndex < desPattern.Length() )

		{

			TChar cChar = desPattern[nPatternIndex];

			TBool bEndOfParse = EFalse;

			if(nPatternIndex == desPattern.Length() - 1) // end of the parse

				bEndOfParse = ETrue;

			switch(cChar)

			{

			case '1':

			case '2':

			case '3':

			case '4':

			case '5':

			case '6':

			case '7':

			case '8':

			case '9':

			case '0':

				switch(parseState)

				{

				case EAny:

					iStateMachines[nPatternCount]->AddStateTransistionL(cChar, nState, bEndOfParse?

																					KStateMatched:

																					(nState + 1)); 

					++nState;

					break;

				case EOpenBracketFound:

					bufChoice.Append(cChar);

					parseState = EChoiceOrRange;					

					break;

				case EChoiceOrRange:

				case EChoice:

					bufChoice.Append(cChar);

					parseState = EChoice;

					break;

				case ERange:

					bufChoice.Append(cChar);

					parseState = ELookingForCloseBracket;

					break;

				//case ELookingForCloseBracket:						

				default:

					User::Panic(bufParsingError, KErrSyntaxError);

					break;

				}

				break;

			case '[':

				switch(parseState)

				{

				case EAny:						

					bufChoice.Zero();

					parseState = EOpenBracketFound;

					break;

				//case EOpenBracketFound:			

				//case EChoiceOrRange:			

				//case EChoice:					

				//case ERange:					

				//case ELookingForCloseBracket:	

				default:

					User::Panic(bufParsingError, KErrSyntaxError);

					break;

    			}	

				break;

			case ']':

				switch(parseState)

				{

				case EChoice:

					{

						for(TInt i = 0; i < bufChoice.Length(); ++i)

						{

							TChar cChar = bufChoice[i];

							iStateMachines[nPatternCount]->AddStateTransistionL(cChar.GetNumericValue(), 

																				nState, 

																				bEndOfParse?

																					KStateMatched:

																					(nState + 1));

						}

						++nState;

						parseState = EAny;

					}

					break;

				case ELookingForCloseBracket:

					{

						TChar cTopOfRange = bufChoice[1];

						TChar cBottomOfRange = bufChoice[0];

						TInt nTopOfRange = cTopOfRange.GetNumericValue();		// if they're not there then something

						TInt nBottomOfRange = cBottomOfRange.GetNumericValue();	// is seriously amiss...

						if(nTopOfRange < nBottomOfRange)

							User::Panic(bufParsingError, KErrSyntaxError);

						for(TInt i = nBottomOfRange; i <= nTopOfRange; ++i)

						{

							iStateMachines[nPatternCount]->AddStateTransistionL(i, nState, bEndOfParse?

																							KStateMatched:

																							(nState + 1));

						}

						++nState;

						parseState = EAny;

					}

					break;

				//case EAny:						

				//case EOpenBracketFound:			

				//case EChoiceOrRange:			

				//case ERange:		

				default:

					User::Panic(bufParsingError, KErrSyntaxError);

					break;

				}	

				break;

			case '-':

				switch(parseState)

				{

				case EChoiceOrRange:			

					parseState = ERange;

					break;	

				//case EAny:						

				//case EOpenBracketFound:			

				//case ELookingForCloseBracket:	

				//case ERange:					

				//case EChoice:

				default:

					User::Panic(bufParsingError, KErrSyntaxError);

					break;

				}

				break;

			case '.':

			case '+':

				switch(parseState)

				{

				case EAny:						

					iStateMachines[nPatternCount]->AddStateTransistionL(cChar, nState, bEndOfParse?

																					KStateMatched:

																					(nState + 1));

					++nState;

					break;

				//case EOpenBracketFound:			

				//case EChoiceOrRange:			

				//case ELookingForCloseBracket:	

				//case ERange:					

				//case EChoice:

				default:

					User::Panic(bufParsingError, KErrSyntaxError);

					break;					

				}

				break;

			default:

				User::Panic(bufParsingError, KErrSyntaxError);

				break;

			}

			++nPatternIndex;

		}

		if(parseState != EAny)

			User::Panic(bufParsingError, KErrSyntaxError);

	}

}

void CRegularExpression::GetWildcardVersionOfPattern( 

    TInt aPatternIndex, TText aWildcard, TDes& aWildcardedPattern) const

    {

    __ASSERT_ALWAYS( (0 <= aPatternIndex) && (aPatternIndex < iStateMachines.Count()),

        Panic(ENumberGroupingNoSuchStateMachine) );

    iStateMachines[aPatternIndex]->GetWildcardVersionOfPattern( aWildcard, aWildcardedPattern );

    }

// End of File