public void Create_CreateFileSystemAndReadFile_Success()
{
// The minimum number of clusters for Fat32 is 65525.
const int amountOfClusters = 65525;
using (MemoryStream disk = new MemoryStream())
{
BootSector boot = new BootSector();
boot.FatSize = (uint)Math.Ceiling(amountOfClusters / (double)boot.BytesPerSector);
boot.Sectors = (uint)boot.SectorsPerCluster * amountOfClusters + boot.ReservedSectors + boot.FatSize;
Fat32FileSystem.Create(disk, boot);
byte[] bytes = new byte[4600]; // Use multiple clusters.
Random random = new Random();
random.NextBytes(bytes);
using (MemoryStream expected = new MemoryStream(bytes))
{
Fat32FileSystem system = new Fat32FileSystem(disk);
system.Create("Data.bin");
using (Stream file = system.Open("Data.bin"))
{
expected.CopyTo(file);
file.Flush();
}
using (Stream file = system.Open("Data.bin"))
FileAssert.AreEqual(expected, file);
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Fat32FileSystem"/> class.
/// </summary>
/// <param name="stream">The stream containing the image of the file system.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="stream"/> is null.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="stream"/> cannot be read or written or seeked.
/// </exception>
public Fat32FileSystem(Stream stream) : base(stream)
{
boot = ReadStructure <BootSector>(0);
info = ReadStructure <FileSystemInfo>(boot.FileSystemInfoSector * boot.BytesPerSector);
if (!info.IsFileSystemInfo)
{
throw new ArgumentException("File System Info is corrupted.", nameof(stream));
}
}
/// <summary>
/// Creates Fat32 file system on the <paramref name="stream"/>.
/// </summary>
/// <param name="stream">The stream the file system is written on.</param>
/// <param name="boot">The boot sector of the file system.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="stream"/> or <paramref name="boot"/> is null.
/// </exception>
public static void Create(Stream stream, BootSector boot)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (boot == null)
{
throw new ArgumentNullException(nameof(boot));
}
if (boot.Fats != 1)
{
throw new ArgumentOutOfRangeException(nameof(boot), "This must be 1.");
}
byte[] bytes = Structures.ToBytes(boot);
stream.Position = 0;
stream.Write(bytes, 0, bytes.Length);
bytes = Structures.ToBytes(new FileSystemInfo());
stream.Position = boot.FileSystemInfoSector * boot.BytesPerSector;
stream.Write(bytes, 0, bytes.Length);
FileEntry volume = new FileEntry();
volume.ShortName = "SD Card";
volume.Attributes = FileAttributes.VolumeId;
uint firstDataSector = boot.ReservedSectors + (boot.Fats * boot.FatSize);
uint firstByteOfRootCluster = ((boot.RootCluster - 2) * boot.SectorsPerCluster) + firstDataSector;
bytes = Structures.ToBytes(volume);
stream.Position = firstByteOfRootCluster;
stream.Write(bytes, 0, bytes.Length);
// Allocate the root cluster.
bytes = BitConverter.GetBytes(0xFFFFFFFF);
stream.Position = boot.ReservedSectors * boot.BytesPerSector + boot.RootCluster * 4;
stream.Write(bytes, 0, bytes.Length);
// Place signature.
bytes = BitConverter.GetBytes((ushort)0xAA55);
stream.Position = 510;
stream.Write(bytes, 0, bytes.Length);
// Reach the end of the disk to allocated it.
stream.Position = boot.Sectors * boot.BytesPerSector;
stream.WriteByte(0);
}