protected bool ReadBootSector()
{
valid = false;
if (blockSize != 512) // only going to work with 512 sector sizes (for now)
{
return(false);
}
BinaryFormat bootSector = new BinaryFormat(partition.ReadBlock(0, 1));
byte bootSignature = bootSector.GetByte(BootSector.ExtendedBootSignature);
if ((bootSignature != 0x29) && (bootSignature != 0x28))
{
return(false);
}
//TextMode.Write ("EOM NAME: ");
//for (uint i = 0; i < 8; i++)
// TextMode.WriteChar (bootsector.GetByte (BootSector.EOMName + i));
//TextMode.WriteLine ();
bytesPerSector = bootSector.GetUShort(BootSector.BytesPerSector);
sectorsPerCluster = bootSector.GetByte(BootSector.SectorsPerCluster);
reservedSectors = bootSector.GetByte(BootSector.ReservedSectors);
nbrFats = bootSector.GetByte(BootSector.FatAllocationTables);
rootEntries = bootSector.GetUShort(BootSector.MaxRootDirEntries);
uint sectorsPerFat16 = bootSector.GetUShort(BootSector.SectorsPerFAT);
uint sectorsPerFat32 = bootSector.GetUInt(BootSector.FAT32_SectorPerFAT);
uint totalSectors16 = bootSector.GetUShort(BootSector.TotalSectors);
uint totalSectors32 = bootSector.GetUInt(BootSector.FAT32_TotalSectors);
uint sectorsPerFat = (sectorsPerFat16 != 0) ? sectorsPerFat16 : sectorsPerFat32;
uint fatSectors = nbrFats * sectorsPerFat;
clusterSizeInBytes = sectorsPerCluster * blockSize;
rootDirSectors = (((rootEntries * 32) + (bytesPerSector - 1)) / bytesPerSector);
firstDataSector = reservedSectors + (nbrFats * sectorsPerFat) + rootDirSectors;
if (totalSectors16 != 0)
{
totalSectors = totalSectors16;
}
else
{
totalSectors = totalSectors32;
}
dataSectors = totalSectors - (reservedSectors + (nbrFats * sectorsPerFat) + rootDirSectors);
totalClusters = dataSectors / sectorsPerCluster;
entriesPerSector = (bytesPerSector / 32);
firstRootDirectorySector = reservedSectors + fatSectors;
dataAreaStart = firstRootDirectorySector + rootDirSectors;
fatStart = reservedSectors;
if (totalClusters < 4085)
{
fatType = FATType.FAT12;
}
else if (totalClusters < 65525)
{
fatType = FATType.FAT16;
}
else
{
fatType = FATType.FAT32;
}
if (fatType == FATType.FAT12)
{
reserved = 0xFF0;
last = 0x0FF8;
bad = 0x0FF7;
fatMask = 0xFFFFFFFF;
fatEntries = sectorsPerFat * 3 * blockSize / 2;
}
else if (fatType == FATType.FAT16)
{
reserved = 0xFFF0;
last = 0xFFF8;
bad = 0xFFF7;
fatMask = 0xFFFFFFFF;
fatEntries = sectorsPerFat * blockSize / 2;
}
else // if (type == FatType.FAT32) {
{
reserved = 0xFFF0;
last = 0x0FFFFFF8;
bad = 0x0FFFFFF7;
fatMask = 0x0FFFFFFF;
fatEntries = sectorsPerFat * blockSize / 4;
}
// some basic checks
if ((nbrFats == 0) || (nbrFats > 2))
{
valid = false;
}
else if (totalSectors == 0)
{
valid = false;
}
else if (sectorsPerFat == 0)
{
valid = false;
}
else if (!((fatType == FATType.FAT12) || (fatType == FATType.FAT16))) // no support for Fat32 yet
{
valid = false;
}
else
{
valid = true;
}
if (valid)
{
base.volumeLabel = bootSector.GetString(fatType != FATType.FAT32 ? BootSector.VolumeLabel : BootSector.FAT32_VolumeLabel, 11);
base.serialNbr = bootSector.GetBytes(fatType != FATType.FAT32 ? BootSector.IDSerialNumber : BootSector.FAT32_IDSerialNumber, 4);
}
return(valid);
}
