// Copyright (c) 1994-2009 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:

// e32\euser\us_lex8.cpp

// 

//

#include "us_std.h"

EXPORT_C TLex8::TLex8()

	: iNext(NULL),iBuf(NULL),iEnd(NULL),iMark(NULL)

/**

Default constructor.

Constructs a TLex8, initialising its members to NULL.

*/

	{}

EXPORT_C void TLex8::Assign(const TUint8 *aString)

/**

Assigns a string to this object from another string.

@param aString A pointer to a string to be assigned.

*/

	{

	iMark.iPtr=iNext=iBuf=aString;

	iEnd=iBuf+User::StringLength(aString);

	}

EXPORT_C void TLex8::Assign(const TDesC8 &aDes)

/**

Assigns a string to this object from a descriptor.

@param aDes The descriptor to be assigned.

*/

	{

	iMark.iPtr=iNext=iBuf=aDes.Ptr();

	iEnd=iBuf+aDes.Length();

	}

EXPORT_C void TLex8::UnGet()

/**

Decrements the next character position, allowing a previously "got" character 

to be re-read.

@panic USER 59, if the previous character is before the start of the string.

*/

	{

	__ASSERT_ALWAYS(iNext>iBuf,Panic(ETLex8UnGetUnderflow));

	iNext--;

	}

EXPORT_C void TLex8::UnGetToMark(const TLexMark8 aMark)

/**

Sets the next character position to the supplied extraction mark position.

@param aMark Mark to copy to the next character position.

@panic USER 63, if the extraction mark is before the start or beyond the end

       of the string.

*/

	{

	ValidateMark(aMark);

	iNext=aMark.iPtr;

	}

EXPORT_C void TLex8::Inc(TInt aNumber)

/**

Increments the next character position by aNumber.

@param aNumber The number of characters to increment the next character position 

               by. 

@panic USER 60, if the increment puts the next character position before the

                start or beyond the end of the string.

*/

	{

	iNext+=aNumber;

	__ASSERT_ALWAYS(iNext>=iBuf && iNext<=iEnd,Panic(ETLex8IncOutOfRange));

	}

EXPORT_C void TLex8::Inc()

/**

Increments to the next character position.

@panic USER 60, if the increment puts the next character position beyond the

       end of the string.

*/

	{

	if (!Eos())

		iNext++;

	__ASSERT_ALWAYS(iNext<=iEnd,Panic(ETLex8IncOutOfRange));

	}

EXPORT_C TChar TLex8::Get()

/**

Gets the next character in the string, and increments the next

character position.

@return Next character to be read.0 if at the end of the string.

*/

	{

	if (Eos())

		return(0);

	return(*iNext++);

	}

EXPORT_C TChar TLex8::Peek() const

/**

Shows the next character to be returned by Get().

@return Character to be returned by the next call to Get(). 0 if at the

        end of the string.

@see TLex8::Get

*/

	{

	if (Eos())

		return(0);

	return(*iNext);

	}

EXPORT_C void TLex8::SkipSpace()

/** 

Moves the next character position past any white space (space or separator).

Stops if at the end of string.

*/

	{

	while (!Eos() && Peek().IsSpace())

		iNext++;

	}

EXPORT_C void TLex8::SkipAndMark(TInt aNumber,TLexMark8& aMark)

/**

Moves the next character position a specified number of characters and copies 

it to the specified extraction mark.

@param aNumber Number of characters to skip.  

@param aMark   On return, set to the next character position. 

@panic USER 61, if the skip moves the next character position either to before

       the start or beyond the end of the string.

*/

	{

	iNext+=aNumber;

	__ASSERT_ALWAYS(iNext>=iBuf && iNext<=iEnd,Panic(ETLex8SkipOutOfRange));

	Mark(aMark);

	}

EXPORT_C void TLex8::SkipSpaceAndMark(TLexMark8& aMark)

/**

Moves the next character position past any white space and copies it to the 

specified extraction mark.

Stops if at the end of the string.

@param aMark On return, contains a reference to the next character position.

*/

	{

	SkipSpace();

	Mark(aMark);

	}

EXPORT_C void TLex8::SkipCharacters()

/**

Moves the next character position to the next white space (space or separator). 

Stops if at the end of the string.

*/

	{

	while (!Eos() && !Peek().IsSpace())

		iNext++;

	}

EXPORT_C TInt TLex8::TokenLength(const TLexMark8 aMark) const

/**

Gets the length of the token starting at the specified extraction mark.

@param aMark Extraction mark indicating the start of the token.

@return Length of the token.

@panic USER 63, if the specified mark is before the start or beyond the end

       of the string.

*/

	{

	ValidateMark(aMark);

	return (iNext-aMark.iPtr);

	}

EXPORT_C TPtrC8 TLex8::MarkedToken(const TLexMark8 aMark) const

/**

Extracts the token, starting at the specified mark

@param aMark Extraction mark indicating the start of the token.

@return Extracted token.

@panic USER 63, if the specified mark is before the start or beyond the end

       of the string.

*/

	{

	return(TPtrC8(aMark.iPtr,TokenLength(aMark)));

	}

EXPORT_C TPtrC8 TLex8::MarkedToken() const

//

// Extract the internally marked token

// there is the assumption here that iMark is always valid

/**

Extracts the marked token.

Note that the function assumes that the current extraction mark is valid.

@return Extracted token.

@panic USER 63, if the specified mark is before the start or beyond the end

       of the string.

*/

	{

	return(TPtrC8(iMark.iPtr,TokenLength()));

	}

EXPORT_C TPtrC8 TLex8::NextToken()

/**

Strips any white space and extracts the next token.

@return Extracted token.

*/

	{

	TLexMark8 mark;

	SkipSpaceAndMark(mark);

	SkipCharacters();

	return(TPtrC8(mark.iPtr,TokenLength(mark)));

	}

EXPORT_C TPtrC8 TLex8::Remainder() const

/**

Gets a descriptor containing all the text from the next character position 

to the end of the string.

@return Text from the next character position onwards.

@panic USER 29, if the value of (next character position - extraction mark) is

       negative.

*/

	{

	return(TPtrC8(iNext,iEnd-iNext));

	}

EXPORT_C TPtrC8 TLex8::RemainderFromMark(const TLexMark8 aMark) const

/**

Gets a descriptor containing all the text from the specified extraction mark 

to the end of the string.

@param aMark Extraction mark indicating where remaining text starts.

@return Text from the specified extraction mark onwards.

@panic USER 29, if the value of (next character position - extraction mark) is

       negative.

@panic USER 63, if the specified mark is before the start or beyond the end

       of the string.

*/

	{

	ValidateMark(aMark);

	return(TPtrC8(aMark.iPtr,iEnd-aMark.iPtr));

	}

EXPORT_C TPtrC8 TLex8::RemainderFromMark() const

//

// Return the remainder from iMark

// There is an assumption here that the internal mark will always be valid

//

/**

Gets a descriptor containing all the text from the current extraction mark to the end 

of the string.

The function assumes that the current extraction mark is valid.

@return Text from the extraction mark onwards.

*/

	{

	return(TPtrC8(iMark.iPtr,iEnd-iMark.iPtr));

	}

EXPORT_C TInt TLex8::Offset() const

//

// Return the offset from iNext to the lex start.

//

/**

Gets the offset of the next character position from the start of the string.

@return Offset of next character position.

*/

	{

	return((TUint)(iNext-iBuf));

	}

EXPORT_C TInt TLex8::MarkedOffset(const TLexMark8 aMark) const

/**

Gets the offset of the specified extraction mark from the start of the string.

@param aMark Extraction mark. 

@return The offset of the extraction mark.

@panic USER 63, if the specified mark is before the start or beyond the end

       of the string.

*/

	{

	ValidateMark(aMark);

	return((TUint)(aMark.iPtr-iBuf));

	}

EXPORT_C TInt TLex8::BoundedVal(TUint32 &aVal,TRadix aRadix,TUint aLimit)

/**

Parses the string to extract a 32-bit unsigned integer, using the

specified radix, and checks that it is within the specified limit.

The specified radix is one of binary, octal, decimal, or hexadecimal.

@param aVal   On return, contains the extracted integer.

@param aRadix The radix to use when converting the number.

@param aLimit The upper limit.

@return KErrNone if successful.

        KErrGeneral if the next character position is initially at the end of the string

        or no valid characters found initially.

        KErrOverflow if there is sign overflow, i.e. converted value greater than limit.

        If error codes KErrGeneral or KErrOverflow are returned, the object's

        members are left unaltered.

*/

	{

	TUint l=aLimit/aRadix;

	TUint v=0;

	TUint d=0;

	TLexMark8 mark(iNext);

	while (!Eos())

		{

		TChar c=Peek(); 

		if (!c.IsHexDigit())

			break; 

		c=Get(); 

		if (c.IsAlpha())

			{

			c.UpperCase();

			c-=('A'-10);

			}

		else

			c-='0';

		if (c>=(TUint)aRadix)

			{

			iNext--;

			break;

			}

		if (v>l)

			{

			UnGetToMark(mark);

			return(KErrOverflow);

			}

		TUint o=v;

		v*=aRadix;

		v+=c;

		if (o>v)

			{

			UnGetToMark(mark);

			return(KErrOverflow);

			}

		d++;

		}

	if (d==0)

		{

		UnGetToMark(mark);

		return(KErrGeneral);

		}

	if (v>aLimit)

		{

		UnGetToMark(mark);

		return(KErrOverflow);

		}

	aVal=v;

	return(KErrNone);

	}

EXPORT_C TInt TLex8::BoundedVal(TInt32 &aVal,TInt aLimit)

/**

Parses the string to extract a 32-bit signed integer, and checks that it is

within the specified limit.

@param aVal   On return, contains the extracted integer.

@param aLimit The upper limit.

@return KErrNone if successful.

        KErrGeneral if the next character position is initially at the end of the string

        or no valid characters found initially.

        KErrOverflow if there is sign overflow, i.e. converted value greater than limit.

        If error codes KErrGeneral or KErrOverflow are returned, the object's

        members are left unaltered.

*/

	{

	if (Eos())

		return(KErrGeneral);

	TUint lim=aLimit;

	TLexMark8 mark(iNext);

	TUint s=FALSE;

	TChar c=Peek();

	if (c=='-')

		{

		lim++;

		s++;

		Inc();

		}

	else if (c=='+')

		Inc();

	TUint32 v;

	TInt r=BoundedVal(v,EDecimal,lim);

	if (r==KErrNone)

		{

		if (v>lim)

			r=KErrOverflow;

		else if (s)

			aVal=(-((TInt32)v));