// 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_bpb.cpp

// Boot sector code, specific for EFat.fsy

// 

//

/**

 @file

 @internalTechnology

*/

#include "sl_std.h"

//-------------------------------------------------------------------------------------------------------------------

TFatBootSector::TFatBootSector()

    {

    Initialise();    

    }

/** initialises the boot sector data */

void TFatBootSector::Initialise()

    {

    Mem::FillZ(this, sizeof(TFatBootSector));

    }

//-------------------------------------------------------------------------------------------------------------------

/**

    @return ETrue if the boot sector contents seems to be valid

*/

TBool TFatBootSector::IsValid() const

    {

    const TFatType fatType = FatType();

    const TUint32 totSectors = Max(TotalSectors(), HugeSectors());

    const TUint32 rootDirStartSec =  ReservedSectors() + FatSectors()*NumberOfFats(); //-- root directory start sector

    if(fatType == EInvalid || ReservedSectors() < 1 || NumberOfFats() < 1 || FatSectors() < 1 || rootDirStartSec < 3 ||

       RootDirEntries() < 1 || totSectors < 5)

        goto Invalid;

    if(TotalSectors() >0 && HugeSectors() >0 )

        goto Invalid; //-- values clash

    return ETrue;

    Invalid:

        __PRINT(_L("TFatBootSector::IsValid() failed!"));

    return EFalse;

    }

//-------------------------------------------------------------------------------------------------------------------

/**

    Initialize boot sector object from the given bufer. Does not validate the data.

    @param  aBuf buffer with data.

*/

void TFatBootSector::Internalize(const TDesC8& aBuf)

    {

    ASSERT(aBuf.Size() >= KSizeOfFatBootSector);

    Initialise();

    TInt pos=0;

    Mem::Copy(&iJumpInstruction, &aBuf[pos],3);     pos+=3; // 0    TUint8 iJumpInstruction[3]

    Mem::Copy(&iVendorId,&aBuf[pos],KVendorIdSize); pos+=KVendorIdSize; // 3    TUint8 iVendorId[KVendorIdSize]

    Mem::Copy(&iBytesPerSector,&aBuf[pos],2);       pos+=2; // 11   TUint16 iBytesPerSector

    Mem::Copy(&iSectorsPerCluster,&aBuf[pos],1);    pos+=1; // 13   TUint8 iSectorsPerCluster   

    Mem::Copy(&iReservedSectors,&aBuf[pos],2);      pos+=2; // 14   TUint16 iReservedSectors

    Mem::Copy(&iNumberOfFats,&aBuf[pos],1);         pos+=1; // 16   TUint8 iNumberOfFats

    Mem::Copy(&iRootDirEntries,&aBuf[pos],2);       pos+=2; // 17   TUint16 iRootDirEntries

    Mem::Copy(&iTotalSectors,&aBuf[pos],2);         pos+=2; // 19   TUint16 iTotalSectors

    Mem::Copy(&iMediaDescriptor,&aBuf[pos],1);      pos+=1; // 21   TUint8 iMediaDescriptor

    Mem::Copy(&iFatSectors,&aBuf[pos],2);           pos+=2; // 22   TUint16 iFatSectors

    Mem::Copy(&iSectorsPerTrack,&aBuf[pos],2);      pos+=2; // 24   TUint16 iSectorsPerTrack

    Mem::Copy(&iNumberOfHeads,&aBuf[pos],2);        pos+=2; // 26   TUint16 iNumberOfHeads

    Mem::Copy(&iHiddenSectors,&aBuf[pos],4);        pos+=4; // 28   TUint32 iHiddenSectors

    Mem::Copy(&iHugeSectors,&aBuf[pos],4);          pos+=4; // 32   TUint32 iHugeSectors

    Mem::Copy(&iPhysicalDriveNumber,&aBuf[pos],1);  pos+=1;// 36|64 TUint8 iPhysicalDriveNumber

    Mem::Copy(&iReserved,&aBuf[pos],1);             pos+=1;// 37|65 TUint8 iReserved

    Mem::Copy(&iExtendedBootSignature,&aBuf[pos],1);pos+=1;// 38|66 TUint8 iExtendedBootSignature

    Mem::Copy(&iUniqueID,&aBuf[pos],4);             pos+=4;// 39|67 TUint32 iUniqueID

    Mem::Copy(&iVolumeLabel,&aBuf[pos],KVolumeLabelSize);  // 43|71 TUint8 iVolumeLabel[KVolumeLabelSize]

    pos+=KVolumeLabelSize;

    // 54|82    TUint8 iFileSysType[KFileSysTypeSize]

    ASSERT(aBuf.Size() >= pos+KFileSysTypeSize);

    Mem::Copy(&iFileSysType,&aBuf[pos],KFileSysTypeSize);

    }

//-------------------------------------------------------------------------------------------------------------------

/**

    Externalize boot sector object to the given data buffer.

    @param  aBuf buffer to externalize.

*/

void TFatBootSector::Externalize(TDes8& aBuf) const

    {

    ASSERT(aBuf.MaxSize() >= KSizeOfFatBootSector);

    if(aBuf.Size() < KSizeOfFatBootSector)

        aBuf.SetLength(KSizeOfFatBootSector);

    TInt pos=0;

    Mem::Copy(&aBuf[pos],&iJumpInstruction,3);      pos+=3;

    Mem::Copy(&aBuf[pos],&iVendorId,KVendorIdSize); pos+=8;

    Mem::Copy(&aBuf[pos],&iBytesPerSector,2);       pos+=2;

    Mem::Copy(&aBuf[pos],&iSectorsPerCluster,1);    pos+=1;

    Mem::Copy(&aBuf[pos],&iReservedSectors,2);      pos+=2;

    Mem::Copy(&aBuf[pos],&iNumberOfFats,1);         pos+=1;

    Mem::Copy(&aBuf[pos],&iRootDirEntries,2);       pos+=2;

    Mem::Copy(&aBuf[pos],&iTotalSectors,2);         pos+=2;

    Mem::Copy(&aBuf[pos],&iMediaDescriptor,1);      pos+=1;

    Mem::Copy(&aBuf[pos],&iFatSectors,2);           pos+=2;

    Mem::Copy(&aBuf[pos],&iSectorsPerTrack,2);      pos+=2;

    Mem::Copy(&aBuf[pos],&iNumberOfHeads,2);        pos+=2;

    Mem::Copy(&aBuf[pos],&iHiddenSectors,4);        pos+=4;

    Mem::Copy(&aBuf[pos],&iHugeSectors,4);          pos+=4;

    Mem::Copy(&aBuf[pos],&iPhysicalDriveNumber,1);  pos+=1;

    Mem::FillZ(&aBuf[pos],1);                       pos+=1;

    Mem::Copy(&aBuf[pos],&iExtendedBootSignature,1);pos+=1;

    Mem::Copy(&aBuf[pos],&iUniqueID,4);             pos+=4;

    Mem::Copy(&aBuf[pos],&iVolumeLabel,KVolumeLabelSize); 

    pos+=KVolumeLabelSize;

    ASSERT(aBuf.MaxSize() >= pos+KFileSysTypeSize);

    Mem::Copy(&aBuf[pos],&iFileSysType,KFileSysTypeSize);

    }

//-------------------------------------------------------------------------------------------------------------------

#ifdef _DEBUG

/** replaces all non-printable characters in a buffer with spaces */

static void FixDes(TDes& aDes)

{

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

    {

        TChar ch=aDes[i];

        if(!ch.IsPrint())

            aDes[i]=' ';    

    }

}

#endif

/** 

    Print out the boot sector info.

*/

void TFatBootSector::PrintDebugInfo() const

    {

#ifdef _DEBUG

    __PRINT(_L("\n======== BootSector info: =======\n"));

    TBuf<40> buf;

    buf.Copy(FileSysType()); FixDes(buf);    

    __PRINT1(_L("FAT type:%S"), &buf);

    buf.Copy(VendorId()); FixDes(buf);    

    __PRINT1(_L("Vendor ID:%S"), &buf);

    __PRINT1(_L("BytesPerSector:%d"),BytesPerSector());

    __PRINT1(_L("SectorsPerCluster:%d"),SectorsPerCluster());

    __PRINT1(_L("ReservedSectors:%d"),ReservedSectors());

    __PRINT1(_L("NumberOfFats:%d"),NumberOfFats());

    __PRINT1(_L("RootDirEntries:%d"),RootDirEntries());

    __PRINT1(_L("Total Sectors:%d"),TotalSectors());

    __PRINT1(_L("MediaDescriptor:0x%x"),MediaDescriptor());

    __PRINT1(_L("FatSectors:%d"),FatSectors());

    __PRINT1(_L("SectorsPerTrack:%d"),SectorsPerTrack());

    __PRINT1(_L("NumberOfHeads:%d"),NumberOfHeads());

    __PRINT1(_L("HugeSectors:%d"),HugeSectors());

    __PRINT1(_L("Root Cluster Number:%d"),RootClusterNum());

    __PRINT1(_L("FSInfo Sector Number:%d"),FSInfoSectorNum());

    __PRINT1(_L("Backup Boot Rec Sector Number:%d"),BkBootRecSector());

    __PRINT1(_L("PhysicalDriveNumber:%d"),PhysicalDriveNumber());

    __PRINT1(_L("ExtendedBootSignature:%d"),ExtendedBootSignature());

    __PRINT1(_L("UniqueID:0x%x"),UniqueID());

    buf.Copy(VolumeLabel()); FixDes(buf);    

    __PRINT1(_L("VolumeLabel:%S"), &buf);

    __PRINT(_L("=============================\n"));

#endif

    }

//-------------------------------------------------------------------------------------------------------------------

/**

    Determine FAT type according to the information from boot sector, see FAT32 specs.

    @return  FAT type. 

*/

TFatType TFatBootSector::FatType(void) const

    {

    //-- check iBytesPerSector validity; it shall be one of: 512,1024,2048,4096

    if(!IsPowerOf2(iBytesPerSector) || iBytesPerSector < 512 ||  iBytesPerSector > 4096)

        return EInvalid; //-- invalid iBytesPerSector value

    //-- check iSectorsPerCluster validity, it shall be one of: 1,2,4,8...128

    if(!IsPowerOf2(iSectorsPerCluster) || iSectorsPerCluster > 128)

        return EInvalid; //-- invalid iSectorsPerCluster value

    const TUint32 rootDirSectors = (iRootDirEntries*KSizeOfFatDirEntry + (iBytesPerSector-1)) / iBytesPerSector;

    const TUint32 totSec = iTotalSectors ? iTotalSectors : iHugeSectors;

    const TUint32 dataSec = totSec - (iReservedSectors + (iNumberOfFats * iFatSectors) + rootDirSectors);

    const TUint32 clusterCnt = dataSec / iSectorsPerCluster;

    //-- magic. see FAT specs for details.

    if(clusterCnt < 4085)

        return EFat12;

    else if(clusterCnt < 65525)

        return EFat16;

    else

        return EInvalid; //-- FAT32 is not supported by this fsy

    }

//-------------------------------------------------------------------------------------------------------------------

/** @return The first Fat sector number */

TInt TFatBootSector::FirstFatSector() const

    {

    __ASSERT_DEBUG(IsValid(), Fault(EFatBadBootSectorParameter));

    return ReservedSectors();

    }

/**

    @return Number of sectors in root directory. 0 for FAT32

*/

TUint32 TFatBootSector::RootDirSectors() const

    {

    __ASSERT_DEBUG(IsValid(), Fault(EFatBadBootSectorParameter));

    return ( (RootDirEntries()*KSizeOfFatDirEntry + (BytesPerSector()-1)) / BytesPerSector() );

    }

/** @return Start sector number of the root directory */

TInt TFatBootSector::RootDirStartSector()  const

    {

    __ASSERT_DEBUG(IsValid(), Fault(EFatBadBootSectorParameter));

    //-- FAT12/16 root dir starts just after the FATs

    return ReservedSectors() + TotalFatSectors()*NumberOfFats();

    }

/** @return first data sector number. for FAT32 it includes the root directory */

TInt TFatBootSector::FirstDataSector() const

    {

    return( ReservedSectors() + NumberOfFats()*TotalFatSectors() + RootDirSectors() );

    }

/** @return FAT-type independent sector count on the volume */

TUint32 TFatBootSector::VolumeTotalSectorNumber() const

    {

    __ASSERT_DEBUG(IsValid(), Fault(EFatBadBootSectorParameter));

    return TotalSectors() >0 ? (TUint32)TotalSectors() : (TUint32)HugeSectors();

    }

/** @return FAT-type independent number of sectors in one FAT */

TUint32 TFatBootSector::TotalFatSectors() const

    {

    __ASSERT_DEBUG(IsValid(), Fault(EFatBadBootSectorParameter));

    return (TUint32)FatSectors();

    }