// Copyright (c) 1996-2009 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:

 // f32\sfsrv\cl_ftext.cpp

 // 

 //

 #include "cl_std.h"

 EXPORT_C TFileText::TFileText()

 /**

 Default constructor.

 */

 	{}

 EXPORT_C void TFileText::Set(RFile& aFile)

 /**

 Sets the Unicode file to be read from, or written to.

 This function must be called before 

 Read(), Write() or Seek() can be used.

 @param aFile The file to be used. Must be open.

 @see TFileText::Read

 @see TFileText::Write

 @see TFileText::Seek

 */

 	{

 #ifndef SYMBIAN_ENABLE_64_BIT_FILE_SERVER_API

 	iFile=aFile;

 #else

 	iFile=(RFile64&)aFile;

 #endif

 	iReadBuf.Zero();

 	iNext=(TText*)iReadBuf.Ptr();

 	iEnd=iNext;

 #ifndef SYMBIAN_ENABLE_64_BIT_FILE_SERVER_API

 	TInt pos = 0;

 #else

 	TInt64 pos = 0;

 #endif

 	iFile.Seek(ESeekCurrent,pos);

  	if (pos == 0)

  		iState = EStartOfFile;

  	else

  		iState = ENormal;

 	}

 EXPORT_C TInt TFileText::Read(TDes& aDes)

 /**

 Reads single line text record from a Unicode file into the specified descriptor.

 The read operation begins at the current file position, and ends when

 a line delimiter character is read.

 If the maximum length of the descriptor is insufficient to hold the record, 

 the function returns KErrTooBig and the descriptor is filled to its maximum 

 length.

 If Read() is called when the current position is the end of the file (that 

 is, after the last line delimiter in the file), KErrEof is returned, and the 

 length of the buffer is set to zero.

 @param aDes On return, contains the single record read from the file. Any 

             previous contents are overwritten.

 @return KErrNone if successful, otherwise one of the other system-wide error 

         codes.

 */

 	{

 	TText* pD=(TText*)aDes.Ptr();

 	TInt len=aDes.MaxLength();

 	TInt newLen=0;

 	while (newLen<len)

 		{

 		if (iNext>=iEnd)

 			{

 			TInt r=FillBuffer();

 			if (r!=KErrNone && r!=KErrEof)

 				return(r);

 			if (r==KErrEof)

 				{

 				aDes.SetLength(newLen);

 				return(newLen ? KErrNone : KErrEof);

 				}

 			continue;

 			}

 		TBool terminate=newLen;

 		TInt r=CheckForTerminator(terminate);

 		if (r!=KErrNone || terminate)

 			{

 			aDes.SetLength(newLen);

 			return(r);

 			}

 		*pD++=(*iNext++);

 		newLen++;

 		}

 	aDes.SetLength(newLen);

 	TBool terminate=newLen;

 	TInt r=CheckForTerminator(terminate);

 	if (r!=KErrNone || terminate)

 		return(r);

 	NextRecord();

 	return(KErrTooBig);

 	}

 void TFileText::NextRecord()

 //

 // Move to the start of the next record

 //

 	{

 	FOREVER

 		{

 		TBool terminate=EFalse;

 		TInt r=CheckForTerminator(terminate);

 		if (r!=KErrNone || terminate)

 			return;

 		iNext++;

 		}

 	}

 static void SwapWords(TText* aStart,TInt aCount)

  	{

  	TUint8* p = (TUint8*)aStart;

  	while (aCount-- > 0)

  		{

  		TUint8 temp = *p;

  		*p = p[1];

  		p[1] = temp;

  		p += 2;

    		}

    	}

 TInt TFileText::FillBuffer()

 //

 // Read the new data from the file

 //

 	{

 	TInt r=iFile.Read(iReadBuf);

 	if (r!=KErrNone)

 		return(r);

 	if (iReadBuf.Length()==0)

 		return(KErrEof);

 	iNext=(const TText*)iReadBuf.Ptr();

 	iEnd=iNext+iReadBuf.Length()/sizeof(TText);

  	// Use any leading byte order marker to determine endianness.

  	if (iState == EStartOfFile)

  		{

  		iState = ENormal;

  		// Ignore an ordinary byte order marker.

  		if (*iNext == 0xFEFF)

  			iNext++;

  		// Set the endianness state to 'reverse' if a reversed byte order marker is found.

  		else if (*iNext == 0xFFFE)

  			{

  			iNext++;

  			iState = EReverse;

  			}

  		if (iNext == iEnd)

  			return KErrEof;

  		}

  	if (iState == EReverse)

 		SwapWords((TText*)iNext,(iEnd - iNext));

 	return(KErrNone);

 	}

 TInt TFileText::CheckForTerminator(TBool& anAnswer)

 //

 // Return ETrue if the next char is a record terminator: PARAGRAPH SEPARATOR (U+2029), LINE SEPARATOR (U+2028),

 // CR-LF (U+000D, U+000A), or LF (U+000A)

 //

 	{

 	if (iNext>=iEnd)

 		{

 		TInt r=FillBuffer();

 		if (r!=KErrNone)

 			{

 			if (r==KErrEof && anAnswer)

 				return(KErrNone);

 			return(r);

 			}

 		}

 	anAnswer=EFalse;

 	const TText* oldNext=iNext;

 	TInt oldBufferLength=iReadBuf.Length();

 	TText c=(*iNext);

 	TBool peek=EFalse;

 	// Check for unambiguous paragraph or line separator.

  	if (c == 0x2029 || c == 0x2028)

  		{

  		iNext++;

  		anAnswer = ETrue;

 		return KErrNone;

  		}

  	// Check for CR-LF or LF.

  	if (c == 0x000D)

 		{

 		iNext++;

 		if (iNext<iEnd)

 			c=(*iNext);

 		else

 			{

 			peek=ETrue;

 			TInt r=FillBuffer();

 			if (r!=KErrNone && r!=KErrEof)

 				return(r);

 			if (r==KErrNone)

 				c=(*iNext);

 			}

 		}

 	if (c == 0x000A)

 		{

 		iNext++;

 		anAnswer=ETrue;

 		return(KErrNone);

 		}

 	iNext=oldNext;

 	if (!peek)

 		return(KErrNone);

 #ifndef SYMBIAN_ENABLE_64_BIT_FILE_SERVER_API

 	TInt pos=(-1)*(oldBufferLength+iReadBuf.Length());

 #else

 	TInt64 pos=(-1)*(oldBufferLength+iReadBuf.Length());

 #endif

 	TInt r=iFile.Seek(ESeekCurrent,pos);

 	if (r==KErrNone)

 		r=FillBuffer();

 	if (r!=KErrNone)

 		return(r);

 	iNext=oldNext;

 	return(KErrNone);

 	}

 EXPORT_C TInt TFileText::Write(const TDesC& aDes)

 /**

 Writes the contents of a descriptor to the end of a Unicode file.

 A line delimiter is appended to the descriptor, and the current file position

 is set to the new end of file.

 If the descriptor contains one or more paragraph delimiters, Read() will treat 

 the contents of the descriptor as more than one record.

 @param aDes The descriptor content to be appended to the file.

 @return KErrNone if successful, otherwise one of the other system-wide error 

         codes.

 @see TFileText::Read

 */

 	{

 	TInt r=Seek(ESeekEnd);

 	if (r!=KErrNone)

 		return(r);

 	TPtrC8 writeBuf((const TUint8*)aDes.Ptr(),aDes.Size());

 	r=iFile.Write(writeBuf);

 	if (r!=KErrNone)

 		return(r);

  	TText lf = 0x000A;

  	TPtrC8 lf8((const TUint8*)&lf,sizeof(TText));

  	r=iFile.Write(lf8);

 	return(r);

 	}

 EXPORT_C TInt TFileText::Seek(TSeek aMode)

 /**

 Seeks to start or end of file.

 It is only necessary to call this function before 

 using Read() because Write() always seeks to the end of the file

 before writing.

 @param aMode ESeekStart to seek to the start of the file;

              ESeekEnd to seek to the end.

 @return KErrNone if successful, otherwise one of the other system-wide error 

         codes.

 @panic FSCLIENT 5 if aMode is neither ESeekStart nor ESeekEnd.

 @see TFileText::Read

 @see TFileText::Write

 */

 	{

 	__ASSERT_ALWAYS(aMode==ESeekStart || aMode==ESeekEnd,Panic(EFTextIllegalSeekMode));

 #ifndef	SYMBIAN_ENABLE_64_BIT_FILE_SERVER_API

 	TInt pos=0;

 #else

 	TInt64 pos = 0;

 #endif

 	TInt ret=iFile.Seek(aMode,pos);

  	if (ret == 0 && aMode == ESeekStart)

  		iState = EStartOfFile;

 	iNext = (TText*)iReadBuf.Ptr();

  	iEnd = iNext;

 	return ret;

 	}