/// <summary>
/// Reads a <see cref="Fat"/> as specified by a <see cref="BootSector"/>.
/// </summary>
/// <param name="bs">the boot sector specifying the <see cref="Fat"/> layout</param>
/// <param name="fatNr">the number of the <see cref="Fat"/> to read</param>
/// <returns>the <see cref="Fat"/> that was read</returns>
/// <exception cref="IOException">IOException on read error</exception>
/// <exception cref="ArgumentException">ArgumentException if fatNr is greater than
/// <see cref="BootSector.GetNrFats"/></exception>
public static Fat Read(BootSector bs, int fatNr)
{
if (fatNr > bs.GetNrFats())
{
throw new ArgumentException(
"boot sector says there are only " + bs.GetNrFats() +
" FATs when reading FAT #" + fatNr);
}
var fatOffset = FatUtils.GetFatOffset(bs, fatNr);
var result = new Fat(bs, fatOffset);
result.Read();
return(result);
}
/// <summary>
/// Creates a new <see cref="Fat"/> as specified by a <see cref="BootSector"/>.
/// </summary>
/// <param name="bs">the boot sector specifying the <see cref="Fat"/> layout</param>
/// <param name="fatNr">the number of the <see cref="Fat"/> to create</param>
/// <returns>the <see cref="Fat"/> that was created</returns>
/// <exception cref="IOException">IOException on write error</exception>
/// <exception cref="ArgumentException">ArgumentException if fatNr is greater than
/// <see cref="BootSector.GetNrFats"/></exception>
public static Fat Create(BootSector bs, int fatNr)
{
if (fatNr > bs.GetNrFats())
{
throw new ArgumentException(
"boot sector says there are only " + bs.GetNrFats() +
" FATs when creating FAT #" + fatNr);
}
var fatOffset = FatUtils.GetFatOffset(bs, fatNr);
var result = new Fat(bs, fatOffset);
if (bs.GetDataClusterCount() > result.entries.Length)
{
throw new IOException("FAT too small for device");
}
result.Init(bs.GetMediumDescriptor());
result.Write();
return(result);
}
/// <summary>
/// Flush all changed structures to the device.
/// </summary>
/// <exception cref="IOException">IOException on write error</exception>
public override void Flush()
{
CheckClosed();
if (bs.IsDirty())
{
bs.Write();
}
for (var i = 0; i < bs.GetNrFats(); i++)
{
fat.WriteCopy(FatUtils.GetFatOffset(bs, i));
}
rootDir.Flush();
if (fsiSector != null)
{
fsiSector.SetFreeClusterCount(fat.GetFreeClusterCount());
fsiSector.SetLastAllocatedCluster(fat.GetLastAllocatedCluster());
fsiSector.Write();
}
}
/// <summary>
/// Initializes the boot sector and file system for the device. The file
/// system created by this method will always be in read-write mode.
/// </summary>
/// <returns>the file system that was created</returns>
/// <exception cref="System.IO.IOException">IOException on write error</exception>
public FatFileSystem Format()
{
var sectorSize = device.GetSectorSize();
var totalSectors = (int)(device.GetSize() / sectorSize);
FsInfoSector fsi;
BootSector bs;
if (sectorsPerCluster == 0)
{
throw new Exception();
}
if (fatType == FatType.BaseFat32)
{
bs = new Fat32BootSector(device);
InitBootSector(bs);
var f32Bs = (Fat32BootSector)bs;
f32Bs.SetFsInfoSectorNr(1);
f32Bs.SetSectorsPerFat(SectorsPerFat(0, totalSectors));
var rnd = new Random();
f32Bs.SetFileSystemId(rnd.Next());
f32Bs.SetVolumeLabel(label);
/* create FS info sector */
fsi = FsInfoSector.Create(f32Bs);
}
else
{
bs = new Fat16BootSector(device);
InitBootSector(bs);
var f16Bs = (Fat16BootSector)bs;
var rootDirEntries = RootDirectorySize(
device.GetSectorSize(), totalSectors);
f16Bs.SetRootDirEntryCount(rootDirEntries);
f16Bs.SetSectorsPerFat(SectorsPerFat(rootDirEntries, totalSectors));
if (label != null)
{
f16Bs.SetVolumeLabel(label);
}
fsi = null;
}
// bs.write();
if (fatType == FatType.BaseFat32)
{
var f32Bs = (Fat32BootSector)bs;
/* possibly writes the boot sector copy */
f32Bs.WriteCopy(device);
}
var fat = Fat.Create(bs, 0);
AbstractDirectory rootDirStore;
if (fatType == FatType.BaseFat32)
{
rootDirStore = ClusterChainDirectory.CreateRoot(fat);
fsi.SetFreeClusterCount(fat.GetFreeClusterCount());
fsi.SetLastAllocatedCluster(fat.GetLastAllocatedCluster());
fsi.Write();
}
else
{
rootDirStore = Fat16RootDirectory.Create((Fat16BootSector)bs);
}
var rootDir =
new FatLfnDirectory(rootDirStore, fat, false);
rootDir.Flush();
for (var i = 0; i < bs.GetNrFats(); i++)
{
fat.WriteCopy(FatUtils.GetFatOffset(bs, i));
}
bs.Write();
var fs = FatFileSystem.Read(device, false);
if (label != null)
{
fs.SetVolumeLabel(label);
}
fs.Flush();
return(fs);
}