// 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\sfat32\sl_bpb32.cpp
// Boot sector code, specific for EFat32.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(); //-- it will check SectorsPerCluster etc.

    if(fatType == EInvalid || ReservedSectors() < 1 || NumberOfFats() < 1)
        goto Invalid;
        
    if(fatType == EFat32)
    {
        if(VersionNumber()!= 0 || FatSectors()!=0 || FatSectors32()<1 || RootClusterNum()<KFatFirstSearchCluster ||
           TotalSectors()!=0 || HugeSectors() <5 || RootDirEntries() !=0)
        {
            goto Invalid; //-- these values are not compliant with FAT specs
        }
    }
    else //-- FAT12/16
    {
        if(TotalSectors() >0 && HugeSectors() >0 )
            goto Invalid; //-- values clash

        const TUint32 totSectors = Max(TotalSectors(), HugeSectors());
        const TUint32 rootDirStartSec =  ReservedSectors() + FatSectors()*NumberOfFats(); //-- root directory start sector

        if(FatSectors() < 1 || rootDirStartSec < 3 || RootDirEntries() < 1 || totSectors < 5)
            goto Invalid; //-- these values are not compliant with FAT specs
    }

    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

    if(RootDirEntries() == 0) //-- we have FAT32 volume
    {
        Mem::Copy(&iFatSectors32, &aBuf[pos],4);    pos+=4; // 36 TUint32 iFatSectors32     
        Mem::Copy(&iFATFlags, &aBuf[pos],2);        pos+=2; // 40 TUint16 iFATFlags
        Mem::Copy(&iVersionNumber, &aBuf[pos],2);   pos+=2; // 42 TUint16 iVersionNumber
        Mem::Copy(&iRootClusterNum, &aBuf[pos],4);  pos+=4; // 44 TUint32 iRootClusterNum
        Mem::Copy(&iFSInfoSectorNum, &aBuf[pos],2); pos+=2; // 48 TUint16 iFSInfoSectorNum
        Mem::Copy(&iBkBootRecSector, &aBuf[pos],2);         // 50 TUint16 iBkBootRecSector
        pos+=(2+12);    //extra 12 for the reserved bytes   
    }

    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;

    if(iFatSectors == 0)    
        {
        Mem::Copy(&aBuf[pos], &iFatSectors32,4);    pos+=4;
        Mem::Copy(&aBuf[pos], &iFATFlags, 2);       pos+=2;
        Mem::Copy(&aBuf[pos], &iVersionNumber, 2);  pos+=2;
        Mem::Copy(&aBuf[pos], &iRootClusterNum, 4); pos+=4;
        Mem::Copy(&aBuf[pos], &iFSInfoSectorNum, 2);pos+=2;
        Mem::Copy(&aBuf[pos], &iBkBootRecSector, 2);pos+=2;

        //extra 12 for the reserved bytes   
        ASSERT(aBuf.Size() >= pos+12);
        Mem::FillZ(&aBuf[pos],12);
        pos+=12;
        }

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

    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("Fat32 Sectors:%d"),FatSectors32());
    __PRINT1(_L("Fat32 Flags:%d"),FATFlags());
    __PRINT1(_L("Fat32 Version Number:%d"),VersionNumber());
    __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 fatSz = iFatSectors ? iFatSectors : iFatSectors32;
    const TUint32 totSec = iTotalSectors ? iTotalSectors : iHugeSectors;
    const TUint32 dataSec = totSec - (iReservedSectors + (iNumberOfFats * fatSz) + 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 EFat32;

    }



/** @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));

    const TUint32 firstNonFatSec = ReservedSectors() + TotalFatSectors()*NumberOfFats();

    if(FatType() == EFat32)
    {//-- FAT32 root dir is a file, calculate the position by it's 1st cluster number. FAT[0]+FAT[1] are reserved.
        return (firstNonFatSec + (RootClusterNum()-KFatFirstSearchCluster) * SectorsPerCluster());
    }
    else
    {//-- FAT12/16 root dir starts just after the FATs
        return firstNonFatSec;
    }
}


/** @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 FatSectors() >0 ? (TUint32)FatSectors() : FatSectors32();
}




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

const TUint32   KLeadSignature      = 0x41615252; ///< FSInfo Lead signiture value
const TUint32   KStructureSignature = 0x61417272; ///< FSInfo Structure signiture value
const TUint32   KTrailingSignature  = 0xAA550000; ///< FSInfo Trailing signiture

TFSInfo::TFSInfo()
{
    Initialise();
}
//-------------------------------------------------------------------------------------------------------------------

/** Initialise the data */
void TFSInfo::Initialise()  
{
    Mem::FillZ(this, sizeof(TFSInfo));

    iLeadSig      = KLeadSignature; 
    iStructureSig = KStructureSignature;
    iTrainlingSig = KTrailingSignature;
}

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

/**
    @return ETrue if FSInfo sector contents seems to be valid
*/
TBool TFSInfo::IsValid() const
{
    return (iLeadSig == KLeadSignature && iStructureSig == KStructureSignature && iTrainlingSig == KTrailingSignature);
}

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

/**
    Initialize FSInfo sector object from the given bufer. Does not validate the data.
    @param  aBuf buffer with data.
*/
void TFSInfo::Internalize(const TDesC8& aBuf)
{
    ASSERT((TUint32)aBuf.Size() >= KSizeOfFSInfo);

    TInt pos=0;

    Mem::Copy(&iLeadSig, &aBuf[pos],4);      pos+=(KFSInfoReserved1Size+4);
    Mem::Copy(&iStructureSig, &aBuf[pos],4); pos+=4;
    Mem::Copy(&iFreeCount,&aBuf[pos],4);     pos+=4;
    Mem::Copy(&iNextFree,&aBuf[pos],4);      pos+=(4+KFSInfoReserved2Size);
    Mem::Copy(&iTrainlingSig,&aBuf[pos],4);
}

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

/**
    Externalize FSInfo sector object to the given data buffer.
    @param  aBuf buffer to externalize.
*/
void TFSInfo::Externalize(TDes8& aBuf) const
{
    ASSERT((TUint32)aBuf.MaxSize() >= KSizeOfFSInfo);
    
    aBuf.SetLength(KSizeOfFSInfo);
    aBuf.FillZ();
    
    TInt pos=0;

    Mem::Copy(&aBuf[pos],&KLeadSignature,4);        pos+=4; 
                                                    pos+=KFSInfoReserved1Size;
    Mem::Copy(&aBuf[pos],&KStructureSignature,4);   pos+=4;
    Mem::Copy(&aBuf[pos],&iFreeCount,4);            pos+=4;
    Mem::Copy(&aBuf[pos],&iNextFree,4);             pos+=4;
                                                    pos+=KFSInfoReserved2Size;
    Mem::Copy(&aBuf[pos],&KTrailingSignature,4);
}

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

/** 
    Print out the FSInfo sector info.
*/
void TFSInfo::PrintDebugInfo() const
{
    __PRINT(_L("\n==== FSInfoSector : ===="));
    __PRINT1(_L("FSI_LeadSig:   0x%x"),iLeadSig);
    __PRINT1(_L("FSI_StrucSig:  0x%x"),iStructureSig);
    __PRINT1(_L("FSI_FreeCount: 0x%x"),iFreeCount);
    __PRINT1(_L("FSI_NxtFree:   0x%x"),iNextFree);
    __PRINT1(_L("FSI_TrailSig:  0x%x"),iTrainlingSig);
    __PRINT(_L("========================\n"));
}