private bool ReadMasterBootBlock()
{
valid = false;
if (diskDevice.BlockSize != 512) // only going to work with 512 sector sizes
{
return(false);
}
BinaryFormat masterboot = new BinaryFormat(diskDevice.ReadBlock(0, 1));
ushort mbrsignature = masterboot.GetUShort(MasterBootRecord.MBRSignature);
diskSignature = masterboot.GetUInt(MasterBootRecord.DiskSignature);
valid = (mbrsignature == MasterBootConstants.MBRSignature);
if (valid)
{
for (uint index = 0; index < MaxMBRPartitions; index++)
{
uint offset = MasterBootRecord.PrimaryPartitions + (index * 16);
GenericPartition partition = new GenericPartition(index);
partition.Bootable = masterboot.GetByte(offset + PartitionRecord.Status) == 0x80;
partition.PartitionType = masterboot.GetByte(offset + PartitionRecord.PartitionType);
partition.StartLBA = masterboot.GetUInt(offset + PartitionRecord.LBA);
partition.TotalBlocks = masterboot.GetUInt(offset + PartitionRecord.Sectors);
partitions[index] = partition;
}
//TODO: Extended Partitions
}
code = new byte[MasterBootConstants.CodeAreaSize];
for (uint index = 0; index < MasterBootConstants.CodeAreaSize; index++)
{
code[index] = masterboot.GetByte(index);
}
return(valid);
}
private bool ReadMasterBootBlock ()
{
valid = false;
if (diskDevice.BlockSize != 512) // only going to work with 512 sector sizes
return false;
BinaryFormat masterboot = new BinaryFormat (diskDevice.ReadBlock (0, 1));
ushort mbrsignature = masterboot.GetUShort (MasterBootRecord.MBRSignature);
diskSignature = masterboot.GetUInt (MasterBootRecord.DiskSignature);
valid = (mbrsignature == MasterBootConstants.MBRSignature);
if (valid) {
for (uint index = 0; index < MaxMBRPartitions; index++) {
uint offset = MasterBootRecord.PrimaryPartitions + (index * 16);
GenericPartition partition = new GenericPartition (index);
partition.Bootable = masterboot.GetByte (offset + PartitionRecord.Status) == 0x80;
partition.PartitionType = masterboot.GetByte (offset + PartitionRecord.PartitionType);
partition.StartLBA = masterboot.GetUInt (offset + PartitionRecord.LBA);
partition.TotalBlocks = masterboot.GetUInt (offset + PartitionRecord.Sectors);
partitions[index] = partition;
}
//TODO: Extended Partitions
}
code = new byte[MasterBootConstants.CodeAreaSize];
for (uint index = 0; index < MasterBootConstants.CodeAreaSize; index++)
code[index] = masterboot.GetByte (index);
return valid;
}
public bool Compare (byte[] data, uint offset, FATType type)
{
BinaryFormat entry = new BinaryFormat (data);
byte first = entry.GetByte (offset + Entry.DOSName);
if (first == FileNameAttribute.LastEntry)
return false;
if ((first == FileNameAttribute.Deleted) | (first == FileNameAttribute.Dot))
return false;
if (first == FileNameAttribute.Escape)
return false;
uint startcluster = FAT.GetClusterEntry (data, offset, type);
if (startcluster == cluster)
return true;
return false;
}
public DirectoryEntryLocation FindEntry (FAT.ICompare compare, uint startCluster)
{
uint activeSector = (startCluster == 0) ? firstRootDirectorySector : (startCluster * this.sectorsPerCluster);
uint increment = 0;
for (; ; ) {
BinaryFormat directory = new BinaryFormat (partition.ReadBlock (activeSector, 1));
for (uint index = 0; index < entriesPerSector; index++) {
if (directory.GetByte ((index * Entry.EntrySize) + Entry.DOSName) == FileNameAttribute.LastEntry)
return new DirectoryEntryLocation ();
FileAttributes attribute = (FileAttributes)directory.GetByte ((index * Entry.EntrySize) + Entry.FileAttributes);
if (compare.Compare (directory.Data, index * 32, fatType))
return new DirectoryEntryLocation (GetClusterEntry (directory.Data, index, fatType), activeSector, index, (attribute & FileAttributes.SubDirectory) != 0);
}
++increment;
if (startCluster == 0) {
// root directory
if (increment >= rootDirSectors)
return new DirectoryEntryLocation ();
activeSector = startCluster + increment;
continue;
}
else {
// subdirectory
if (increment < sectorsPerCluster) {
// still within cluster
activeSector = startCluster + increment;
continue;
}
// exiting cluster
// goto next cluster (if any)
uint cluster = GetClusterBySector (startCluster);
if (cluster == 0)
return new DirectoryEntryLocation ();
uint nextCluster = GetClusterEntryValue (cluster);
if ((IsClusterLast (nextCluster)) || (IsClusterBad (nextCluster)) || (IsClusterFree (nextCluster)) || (IsClusterReserved (nextCluster)))
return new DirectoryEntryLocation ();
activeSector = (uint)(dataAreaStart + (nextCluster - 1 * sectorsPerCluster));
continue;
}
}
}
public static string ExtractFileName (byte[] directory, uint index)
{
BinaryFormat entry = new BinaryFormat (directory);
char[] name = new char[12];
for (uint i = 0; i < 8; i++)
name[i] = (char)entry.GetByte (index + i + Entry.DOSName);
int len = 8;
for (int i = 7; i > 0; i--)
if (name[i] == ' ')
len--;
else
break;
// special case where real character is same as the delete
if ((len >= 1) && (name[0] == (char)FileNameAttribute.Escape))
name[0] = (char)FileNameAttribute.Deleted;
name[len] = '.';
len++;
for (uint i = 0; i < 3; i++)
name[len + i] = (char)entry.GetByte (index + i + Entry.DOSExtension);
len = len + 3;
int spaces = 0;
for (int i = len - 1; i >= 0; i--)
if (name[i] == ' ')
spaces++;
else
break;
if (spaces == 3)
spaces = 4;
len = len - spaces;
string result = SharpOS.Kernel.Foundation.Convert.ToString (name, 0, len);
//Runtime.Free (name);
return result;
}
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;
}
public bool Compare (byte[] data, uint offset, FATType type)
{
BinaryFormat entry = new BinaryFormat (data);
byte first = entry.GetByte (offset + Entry.DOSName);
if (first == FileNameAttribute.LastEntry)
return false;
if ((first == FileNameAttribute.Deleted) | (first == FileNameAttribute.Dot))
return false;
if (first == FileNameAttribute.Escape)
return false;
string entryname = FAT.ExtractFileName (data, offset);
if (entryname == name)
return true;
return false;
}
