// 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\sfat\sl_vfat.cpp

// 

//

#include "sl_std.h"

#include "sl_cache.h"

#include <e32svr.h>

#include <e32math.h>

IMPORT_C const TFatUtilityFunctions* GetFatUtilityFunctions();

const TInt KMaxLengthWithoutTilde = 8;

const TUint8 KLeadingE5Replacement = 0x05;

// use second half of ISO Latin 1 character set for extended chars

const TUint KExtendedCharStart=0x80;

const TUint KExtendedCharEnd=0xff;

LOCAL_C TBool IsLegalChar(TChar aCharacter,TBool aAllowWildChars,TBool aUseExtendedChars=EFalse,TBool aInScanDrive=EFalse)

//

// Returns ETrue if aCharacter is legal inside a dos filename

//

	{

	if ((aCharacter==KMatchOne) || (aCharacter==KMatchAny))

		return(aAllowWildChars);

	if ((TUint)aCharacter < 0x20)

	    return EFalse;

   	// Don't check illegal ascii char because some non-English char value may

   	// fall in this area

    if (aInScanDrive)

    	return ETrue;

	return LocaleUtils::IsLegalShortNameCharacter(aCharacter,aUseExtendedChars);

	}

LOCAL_C void ReplaceFirstCharacterIfClashesWithE5L(TDes8& aShortName)

	{

	if (0 < aShortName.Length() && aShortName[0] == KEntryErasedMarker)

		{

		aShortName[0] = KLeadingE5Replacement;

		}

	}

LOCAL_C void ReplaceIllegalCharactersL(TDes& aLongName, TUint aCharacterToReplaceWith)

	{

	TBool alreadyFoundExtensionDelimiter=EFalse;

	TInt LongNameLen = aLongName.Length();

	TInt extDelimiterIndex = aLongName.LocateReverse(KExtDelimiter);

	for (TInt i=LongNameLen-1; i>=0; --i) // iterate backwards as aLongName may change length during the loop, and also because we want to leave the *right-most* occurrence of KExtDelimiter unchanged

		{

		TUint character=aLongName[i];

		if (character==(TUint)KExtDelimiter)

			{

			if (alreadyFoundExtensionDelimiter)

				{

				aLongName[i]=(TText)aCharacterToReplaceWith; // A.B.C becomes A_B.C

				}

			alreadyFoundExtensionDelimiter=ETrue;

			}

		else

			{

			// the code below doesn't need any #if defined(_UNICODE) stuff as a narrow-build aLongName would not contain values above 0xff (which is well below the surrogates area in Unicode 0xd800-0xdfff)

			TBool isSurrogatePair=EFalse;

			// LAST character in file name or file ext CAN NOT be HIGH surrogate

			if (i==LongNameLen-1 || i==extDelimiterIndex-1)

				{

				if (IsHighSurrogate((TText16)character))

					{

					// Corrupt surrogate

					User::Leave(KErrBadName);

					}

				}

			// FIRST character in file name or file ext CAN NOT be LOW surrogate

			if (i==0 || i==extDelimiterIndex+1)

				{

				if (IsLowSurrogate((TText16)character))

					{

					// Corrupt surrogate

					User::Leave(KErrBadName);

					}

				}

			// if LOW Surrogate

			if (IsLowSurrogate((TText16)character))

				{

				// check for HIGH surrogate

				if (!IsHighSurrogate(aLongName[--i]))

					{

					// Corrupt surrogate

					User::Leave(KErrBadName);

					}

				// surrogate pair found

				character&=~0xdc00;

				character|=((aLongName[i]&~0xd800)<<10);

				character+=0x00010000; // this must be added - it cannot be bitwise-"or"-ed

				isSurrogatePair=ETrue;

				}

			// if High Surrogate

			if (!isSurrogatePair && IsHighSurrogate((TText16)character))

				{

				// Corrupt surrogate

				User::Leave(KErrBadName);

				}

			if (!IsLegalChar(character, EFalse))

				{

				if (isSurrogatePair)

					{

					aLongName.Delete(i+1, 1);

					}

				aLongName[i]=(TText)aCharacterToReplaceWith;

				}

			}

		}

	}

TShortName DoGenerateShortNameL(const TDesC& aLongName,TInt& aNum,TBool aUseTildeSelectively)

//

// Create a legal shortname from aLongName

//

	{

	TFileName longName(aLongName);

	longName.UpperCase();

	ReplaceIllegalCharactersL(longName, '_');

	TPtrC longNameWithoutExtension(longName);

	TPtrC longNameExtension(KNullDesC);

	const TInt positionOfExtension=longName.LocateReverse(KExtDelimiter);

	if (positionOfExtension==0)

		{

		// No filename specified, so use the extension as the basis of the shortname.

		// Make sure we always append a tilde+number in this case to avoid generating the same 

		// short filename as one of the protected folders ("\SYS", "\RESOURCE","\PRIVATE")

		longNameWithoutExtension.Set(longName.Mid(positionOfExtension+1));

		aUseTildeSelectively = EFalse;

		if (aNum < 0)

			aNum = 1;

		}

	else if (positionOfExtension!=KErrNotFound)

		{

		longNameWithoutExtension.Set(longName.Left(positionOfExtension));

		longNameExtension.Set(longName.Mid(positionOfExtension+1));

		}

	// Converts the original file name main part into 8-bit character string

	TShortName tempShortName(0);

	LocaleUtils::ConvertFromUnicodeL(tempShortName, longNameWithoutExtension);

	const TInt originalNameLength = tempShortName.Length();

	// Converts the original file name extension part into 8-bit character string

	TShortName tempShortNameExt(0);

	LocaleUtils::ConvertFromUnicodeL(tempShortNameExt, longNameExtension);

	const TInt extensionNameLength = tempShortNameExt.Length();

	// // const TInt extensionNameLength = tempShortNameExt.Length();

	// Checks the length of both original file name main part and original file name extension part

	if(aUseTildeSelectively)

		{

		// don't append ~<aNum>

		if(originalNameLength<=KMaxLengthWithoutTilde && extensionNameLength<=KMaxFatFileNameExt)

			aNum=-1;

		}

	// Applies tilde and number if necessary

	TBuf8<5> tildeAndNumber;

	if (aNum>=0)

		{

		tildeAndNumber.Append('~');

		tildeAndNumber.AppendNumUC(aNum,EHex);

		}

	const TInt lengthOfTildeAndNumber=tildeAndNumber.Length();

	// Creates actual shortname from longname of the original file

	TShortName shortName(11);

#if defined(_DEBUG)

	shortName.Fill(0x01); // fill shortName with garbage to ensure that every byte is written to by this function

#endif

	// Fills the main part of the shortname of the original file

	const TInt numberOfBytesFreeBeforeTilde=KMaxFatFileNameWithoutExt-lengthOfTildeAndNumber;

	TPtr8 portionOfShortNameBeforeTilde((TUint8*)shortName.Ptr(), 0, numberOfBytesFreeBeforeTilde);

	TInt lengthOfPortionOfShortNameBeforeTilde = 

				(originalNameLength < numberOfBytesFreeBeforeTilde) ? originalNameLength : numberOfBytesFreeBeforeTilde;

	portionOfShortNameBeforeTilde.Copy((TUint8*)tempShortName.Ptr(), lengthOfPortionOfShortNameBeforeTilde);

	if( lengthOfPortionOfShortNameBeforeTilde != originalNameLength)

		{

		for( int i = 0; i<lengthOfPortionOfShortNameBeforeTilde; i++)

			{

			if(portionOfShortNameBeforeTilde[i] >= 0x80) //leading byte found

				{

				if( i == lengthOfPortionOfShortNameBeforeTilde - 1) //leading byte found on the edge

					{

					lengthOfPortionOfShortNameBeforeTilde -= 1;

					break;

					}

				else

					{

					i++;

					}

				}

			}

		}

	Mem::Copy(((TUint8*)shortName.Ptr())+lengthOfPortionOfShortNameBeforeTilde, tildeAndNumber.Ptr(), lengthOfTildeAndNumber);

	TInt i;

	for (i=lengthOfPortionOfShortNameBeforeTilde+lengthOfTildeAndNumber; i<KMaxFatFileNameWithoutExt; ++i)

		{

		shortName[i]=' ';

		}

	// Fills the extension part of the shortname of the original file

	TInt lengthOfExt = 

				(extensionNameLength < KMaxFatFileNameExt) ? extensionNameLength : KMaxFatFileNameExt;

	if( lengthOfExt != extensionNameLength)

		{

		for( int i = 0; i<lengthOfExt; i++)

			{

			if(tempShortNameExt[i] >= 0x80)

				{

				if( i == lengthOfExt - 1)

					{

					lengthOfExt -= 1;

					break;

					}

				else

					{

					i++;

					}

				}

			}

		}			

	Mem::Copy(((TUint8*)shortName.Ptr()) + KMaxFatFileNameWithoutExt, tempShortNameExt.Ptr(), lengthOfExt);

	for (i = KMaxFatFileNameWithoutExt + lengthOfExt; i<KMaxFatFileNameWithoutExt+KMaxFatFileNameExt; ++i)

		{

		shortName[i]=' ';

		}

	ReplaceFirstCharacterIfClashesWithE5L(shortName);		

	return shortName;

	}

/**

Check whether a Dos name is legal or not.

@param aName                The entry name to be analysed (may be represented as TDes16& or TDes8&)

@param anAllowWildCards	    Flag to indicate whether to allow wildcards in name or not

@param aUseExtendedChars    Flag to indicate if extended characters are allowed

@param aInScanDrive         Flag to indicate whether called when scanning drive

@param aAllowLowerCase      ETrue to allow lower case in the analysed DOS name

@return ETrue if the name is a legal DOS one.

*/

static TBool DoCheckLegalDosName(const TDesC& aName, TBool anAllowWildCards, TBool aUseExtendedChars, TBool aInScanDrive, TBool aAllowLowerCase, TBool aIsForFileCreation)

	{

    const TInt count=aName.Length();

	if (count==0)

		return EFalse;

	TInt valid=0;

	TInt i=0;

    //-- check the entry name

	while (i<count)

		{

		TChar c=aName[i++];

		if (c==KExtDelimiter)

			{

			// DOS entry names must contain at least one valid character before the extension

			if (i == 1)

				return EFalse;

			break;

			}

          if(!aAllowLowerCase && c.IsLower())

            return EFalse; //-- low case is not allowed

		if (!IsLegalChar(c,anAllowWildCards,aUseExtendedChars,aInScanDrive))

		    {

			return EFalse;

		    }

		if (aIsForFileCreation)

			{

			if ((aUseExtendedChars && (TUint) c > KExtendedCharEnd) || 

					(!aUseExtendedChars && (TUint) c > KExtendedCharStart))

				{

				return EFalse;

				}

			}

		if (c!=KMatchAny)

			if (++valid>KMaxFatFileNameWithoutExt)

				return EFalse;

		}

	//-- check entry extension

    valid=0;

	while (i<count)

		{

		TChar c=aName[i++];

		if (c==KExtDelimiter)

			return EFalse;

        if(!aAllowLowerCase && c.IsLower())

            return EFalse; //-- low case is not allowed

		if (!IsLegalChar(c,anAllowWildCards,aUseExtendedChars,aInScanDrive))

			return EFalse;

		if (aIsForFileCreation)

			{

			if ((aUseExtendedChars && (TUint) c > KExtendedCharEnd) || 

					(!aUseExtendedChars && (TUint) c > KExtendedCharStart))

				{

				return EFalse;

				}

			}

		if (c!=KMatchAny)

			if (++valid>KMaxFatFileNameExt)

				return EFalse;

		}

	// Unicode file name checking for file opening.

	if (!aIsForFileCreation && GetFatUtilityFunctions())

		{

		TBuf8<KMaxFileName*2> convertedName8;

		TRAPD(err, LocaleUtils::ConvertFromUnicodeL(convertedName8, aName, TFatUtilityFunctions::EOverflowActionLeave));

		if (err != KErrNone)

			return EFalse;

		const TInt len8 = convertedName8.Length();

		TInt j = 0; 

		TInt nonWildChar = 0;

		while (j < len8)

			{

			const TUint8 c8 = convertedName8[j++];

			if (c8 == KExtDelimiter)

				break;

			if (c8 == '*' && !anAllowWildCards)

				return EFalse;

			if (c8 == '*' && anAllowWildCards)

				continue;

			if (++nonWildChar > KMaxFatFileNameWithoutExt)

				return EFalse;

			}

		// check extension part

		nonWildChar = 0;

		while (j < len8)

			{

			const TUint8 c8 = convertedName8[j++];

			if (c8 == KExtDelimiter)

				return EFalse;

			if (c8 == '*' && !anAllowWildCards)

				return EFalse;

			if (c8 == '*' && anAllowWildCards)

				continue;

			if (++nonWildChar > KMaxFatFileNameExt)

				return EFalse;

			}

		}

	return ETrue;

	}

/**

    Check whether a Dos name is legal or not. Unicode version

    parameters and return value absolutely the same as in DoCheckLegalDosName()

*/

TBool IsLegalDosName(const TDesC16& aName, TBool anAllowWildCards, TBool aUseExtendedChars, TBool aInScanDrive, TBool aAllowLowerCase, TBool aIsForFileCreation)

	{

	__PRINT(_L("IsLegalDosName 16"));

    return DoCheckLegalDosName(aName, anAllowWildCards, aUseExtendedChars, aInScanDrive, aAllowLowerCase, aIsForFileCreation);	

	}

TBool CFatMountCB::FindShortNameL(const TShortName& aName,TEntryPos& anEntryPos)

//

// Returns ETrue and the entryPos of aName if found or EFalse

//

	{

	__PRINT(_L("VFAT::CFatMountCB::FindShortNameL"));	

	TFatDirEntry fatEntry;

	TInt count=0;

	FOREVER

		{

		count++;

		ReadDirEntryL(anEntryPos,fatEntry);

		MoveToDosEntryL(anEntryPos,fatEntry);

		if (fatEntry.IsEndOfDirectory())

			break;

		if (IsRootDir(anEntryPos)&&(anEntryPos.iPos+StartOfRootDirInBytes()==(RootDirEnd()-KSizeOfFatDirEntry)))	

			if (fatEntry.IsErased())

				break;//Allows maximum number of entries in root directory

		if (fatEntry.Name()==aName)

			return ETrue;

		MoveToNextEntryL(anEntryPos);

		if (IsRootDir(anEntryPos)&&(StartOfRootDirInBytes()+anEntryPos.iPos==RootDirEnd()))

			break;//Allows maximum number of entries in root directory

		}

	return EFalse;

	}

TBool CFatMountCB::IsUniqueNameL(const TShortName& aName,TInt aDirCluster)

//

// Returns ETrue if aName is unique, EFalse if a matching name is found.

//

	{

	__PRINT(_L("VFAT::CFatMountCB::IsUniqueNameL"));	

	TEntryPos entryPos(aDirCluster,0);

	if (FindShortNameL(aName,entryPos))

		return(EFalse);

	return(ETrue);

	}

void CFatMountCB::ReplaceClashingNameL(const TShortName& aNewName,const TEntryPos& anEntryPos)

//

// A legal dos name has been typed that clashes with a computer generated shortname

// Change the shortname to something else.

//

	{

	__PRINT(_L("VFAT::CFatMountCB::ReplaceClashingNameL"));	

	TFatDirEntry entry;

	ReadDirEntryL(anEntryPos,entry);

	__ASSERT_ALWAYS(entry.IsEndOfDirectory()==EFalse,User::Leave(KErrCorrupt));

	entry.SetName(aNewName);

	WriteDirEntryL(anEntryPos,entry);

//	We now need to fix up VFAT entries with a new checksum reflecting new shortname

//	Calculate new checksum

	TUint8 checksum=CalculateShortNameCheckSum(aNewName);

//	Now go back and adjust all VFAT entries corresponding to this shortname

	TEntryPos entryPos=anEntryPos;

	FOREVER

		{

		entryPos.iPos-=KSizeOfFatDirEntry;	

		ReadDirEntryL(entryPos,entry);

		entry.iData[0x0D]=checksum;

		if (entry.iData[0]&0x40)

			break;

		}

	}

TBool CFatMountCB::GenerateShortNameL(TInt aDirCluster,const TDesC& aName,TShortName& aGeneratedName, TBool aForceRandomize)

//

// Generate a legal dos filename as an alias for aName.

// Returns ETrue if aName is a legal dos name.

//

	{

	__PRINT(_L("VFAT::CFatMountCB::GenerateShortNameL"));

	// Given the long file-name "ABCDEFGHI.TXT", EPOC used to generate short 

	// file-names in the following pecking order:

	//     "ABCDEFGH.TXT",

	//     "ABCDEF~0.TXT",

	//     "ABCDEF~1.TXT",

	//     "ABCDEF~2.TXT",

	//     etc.

	// Now, however, EPOC behaves in a more Windows-like manner and 

	// generates short file-names in this pecking order:

	//     "ABCDEF~1.TXT",

	//     "ABCDEF~2.TXT",

	//     "ABCDEF~3.TXT",

	//     "ABCDEF~4.TXT",

	// After failing to find an unused short name 4 times in a row, 

	// a random number is used to speed up the process. So subsequent

	// short-file names become

	//     "ABC~nnnn.TXT"	where nnnn is a random number

	//    

	TBool useTildeSelectively = ETrue;

	TInt endNum = KMaxDuplicateShortName;	//	0xFFFF

	const TInt KMaxNonRandomShortFileNames = 4;

	TInt i = 1;

	TBool randomize = aForceRandomize;

	if (randomize)

		{

		i = (TInt) (Math::Random() & KMaxDuplicateShortName);

		endNum = (i - 1) & KMaxDuplicateShortName;

		}

	while(i != endNum)

		{

		aGeneratedName=DoGenerateShortNameL(aName,i,useTildeSelectively);

		if (IsUniqueNameL(aGeneratedName,aDirCluster))

			break;

		if (i == KMaxNonRandomShortFileNames && !randomize)

			{

			randomize = ETrue;

			i = (TInt) (Math::Random() & KMaxDuplicateShortName);

			endNum = (i - 1) & KMaxDuplicateShortName;

			}

		else if (i == -1)

			{

			useTildeSelectively=EFalse;

			i = 1;

			}