/*

* 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: 

* This file contains the implementation of the General Time ASN1 class.

* Fully support three forms of ASN.1 generalizedTime

* Fraction of second accepts 1,2 or 3 digits input. This is to maximize the tolerance of client input 

*

*/

#include <asn1dec.h>

EXPORT_C TASN1DecGeneralizedTime::TASN1DecGeneralizedTime()

	{

	}

TTime TASN1DecGeneralizedTime::GetTimeL(const TDesC8& aSource)

	{

	// __OFFSET__ Extract corrected time to include offset too.

	// Did this checking ought to be done on creation rather than when we attempt to get the result?

	// I guess we ought to check that the contents we've got are long enough to contain a time!

	if (aSource.Length()<13)

		{

		User::Leave(KErrArgument);

		}

	// Check all digits the main bit of time are valid, YYYY:MM:DD HH:MM

	TInt i;

	for (i=0;i<12;i++)

		{

		TUint8 j;

		j=(TUint8)(aSource[i]-'0');

		if (j>=10)

			{

			User::Leave(KErrArgument);

			}

		}

	//check seconds are valid if present

	i = 12;

	if(aSource.Length() > 13)

		{

			if ((aSource[i] < '0') || (aSource[i] > '9')

					|| (aSource[i+1] < '0') || (aSource[i+1] > '9'))

				User::Leave(KErrArgument);

		}

	i = 14;

	//if the time string is longer 

	if(aSource.Length() > 14)

		{

		TInt countDot = 0;

		TInt countOperator = 0;

		TInt countZ = 0;

		//check if the extra bytes are valid

		while(i < aSource.Length())

			{

				switch(aSource[i])

				{

				case '.': //'.' can't appear more than once and at least one digit should follow

					countDot++;

					if(countDot > 1)

						User::Leave(KErrArgument);

					if(aSource.Length()-1 ==  i) //error, '.' is last char in time string

						User::Leave(KErrArgument);

					else

						{

							if(aSource[i+1] - '0' < 0 || aSource[i+1] - '0' > 9)

								User::Leave(KErrArgument);

						}

					break;

				case '+':

				case '-': // '+' and '-' can't appear more than once and at least four digits should follow

						  // After that, we reach either EOF or 'Z', no more char could follow

					countOperator++;

					if(countOperator > 1)

						User::Leave(KErrArgument);

					if(aSource.Length()-1 < i + 4) //error, not enough digits following operator

						User::Leave(KErrArgument);

					else

						{

						for(TInt j = i+1; j <= i+4; j++)

							if(aSource[j] - '0' < 0 || aSource[j] -'0' > 9)

								User::Leave(KErrArgument);

						if(aSource.Length() > i + 6)//error, unexpected rubbish

							User::Leave(KErrArgument);

						if(aSource.Length() == i + 6 && aSource[i+5] != 'Z')

							User::Leave(KErrArgument);

						}

					break;

				case 'Z': //'Z' can't appear more than once and must be the last char in time string

					countZ++;

					if(countZ > 1)

						User::Leave(KErrArgument);

					if(aSource.Length()-1 > i) //error, something following 'Z'

						User::Leave(KErrArgument);

					break;

				default: //so is this a digit?

					if(aSource[i] -'0' < 0 || aSource[i] -'0' > 9)

						User::Leave(KErrArgument);

				}

				i++;

			}

		}

	// Uh-oh, looks like we're going to have to pull each bit manually and pop it in a TDateTime thing

	TInt Year,Month,Day,Hour,Minute,Second=0;		// Only set seconds to zero 'cos they are optional, everything else is going to be set

	TInt MicroSecond = 0;

	TInt offsetIntHours = 0, offsetIntMinutes = 0;

	TTimeIntervalHours offsetHours = 0;

	TTimeIntervalMinutes offsetMinutes = 0;

	Year=(aSource[0]-'0')*1000+(aSource[1]-'0')*100+(aSource[2]-'0')*10+(aSource[3]-'0');

	Month=(aSource[4]-'0')*10+aSource[5]-'0';

	Month--;										// Because the enum for months starts at 0 not 1

	Day=(aSource[6]-'0')*10+aSource[7]-'0';

	Day--;										// Because the enum for days starts at 0 not 1

	Hour=(aSource[8]-'0')*10+aSource[9]-'0';

	Minute=(aSource[10]-'0')*10+aSource[11]-'0';

	TInt Pos=12;

	if (aSource.Length()>13)

		{

			// seconds

			Second = (aSource[Pos++]-'0')*10;

			Second += aSource[Pos++]-'0';

		}

	// check range for various components

	if (Month<EJanuary || Month>EDecember)

		{

		User::Leave(KErrArgument);

		}

	TMonth month = (TMonth)Month;

	if (	(Day<0 || Day>=Time::DaysInMonth(Year,month))	||

			(Hour<0 || Hour>=24)	||

			(Minute<0 || Minute>=60)	||

			(Second<0 || Second>=60)	)

		{

		User::Leave(KErrArgument);

		}

	//optional 3 bytes fraction of seconds

	//Converts the fraction of seconds to microsecond

	if(aSource.Length() > Pos && aSource[Pos] == '.')

		{

		Pos++;			

		TInt multiplier = 100000;

		// parse fraction of second

		while(Pos <= 17 && Pos < aSource.Length())

			{

			if(!((aSource[Pos] >= '0') && (aSource[Pos] <= '9')))

				break; //fraction ended

			MicroSecond += (aSource[Pos++]-'0') * multiplier;

			multiplier /= 10;

			}			

		}

	if (aSource.Length()>Pos)

		{

		TBool aheadUTC = EFalse;

		switch (aSource[Pos])

			{

		case 'Z':

			// Zulu - nothing more to do

			break;

		case '+':

			//'+' indicates local time is ahead of UTC, need to substract the offset later

			aheadUTC = ETrue;

			// The case fall-through is intentional, both cases have the same functionality, with a different

			// aheadUTC value

		case '-':

			{//brackets are required to prevent armv5 warning and gccxml errors

			//'-' indicates local time is behind of UTC, need to add the offset later

			//if we are in here with '-', aheadUTC has already been set to the correct value

			Pos++;

			//parse

			TInt multiplier = 10;

			for(TInt i = 0; i <= 3; i++)

				{

					if(i < 2)

						offsetIntHours += (aSource[Pos + i]-'0') * multiplier; 

					else

						offsetIntMinutes += (aSource[Pos + i]-'0') * (TInt)multiplier; 

					multiplier = (multiplier == 10)? 1 : 10;

				}

			//expected range,

			//offset hour range: 0-23

			//offset minute range: 0-59

			if(offsetIntHours < 0 || offsetIntHours > 23 || 

					offsetIntMinutes < 0 || offsetIntMinutes > 59)

				User::Leave(KErrArgument);

			offsetHours = aheadUTC ? -offsetIntHours : offsetIntHours ;

			offsetMinutes =  aheadUTC ? -offsetIntMinutes :  offsetIntMinutes;

			break;

			}

		default:

			// Error!

			User::Leave(KErrArgument);

			break;

			}

		}

	TDateTime D(Year, month,Day,Hour,Minute,Second,MicroSecond);

	TTime T(D);

	T = T + offsetHours;

	T = T + offsetMinutes;

	return T;

	}

EXPORT_C TTime TASN1DecGeneralizedTime::DecodeDERL(const TDesC8& aSource,TInt& aPos)

	{

	TPtrC8 Source=aSource.Mid(aPos);

	TASN1DecGeneric gen(Source);

	gen.InitL();

	TTime t = GetTimeL(gen.GetContentDER());

	aPos+=gen.LengthDER();

	return t;

	}

EXPORT_C TTime TASN1DecGeneralizedTime::DecodeDERL(const TASN1DecGeneric& aGen)

	{

	return GetTimeL(aGen.GetContentDER());

	}