public void Sparse()
{
int fileSize = 1 * 1024 * 1024;
NtfsFileSystem ntfs = FileSystemSource.NtfsFileSystem();
byte[] data = new byte[fileSize];
for (int i = 0; i < fileSize; i++)
{
data[i] = (byte)i;
}
using (SparseStream s = ntfs.OpenFile("file.bin", FileMode.CreateNew))
{
s.Write(data, 0, fileSize);
ntfs.SetAttributes("file.bin", ntfs.GetAttributes("file.bin") | FileAttributes.SparseFile);
s.Position = 64 * 1024;
s.Clear(128 * 1024);
s.Position = fileSize - 64 * 1024;
s.Clear(128 * 1024);
}
using (SparseStream s = ntfs.OpenFile("file.bin", FileMode.Open))
{
Assert.Equal(fileSize + 64 * 1024, s.Length);
List <StreamExtent> extents = new List <StreamExtent>(s.Extents);
Assert.Equal(2, extents.Count);
Assert.Equal(0, extents[0].Start);
Assert.Equal(64 * 1024, extents[0].Length);
Assert.Equal((64 + 128) * 1024, extents[1].Start);
Assert.Equal(fileSize - (64 * 1024) - ((64 + 128) * 1024), extents[1].Length);
s.Position = 72 * 1024;
s.WriteByte(99);
byte[] readBuffer = new byte[fileSize];
s.Position = 0;
s.Read(readBuffer, 0, fileSize);
for (int i = 64 * 1024; i < (128 + 64) * 1024; ++i)
{
data[i] = 0;
}
for (int i = fileSize - (64 * 1024); i < fileSize; ++i)
{
data[i] = 0;
}
data[72 * 1024] = 99;
Assert.Equal(data, readBuffer);
}
}
public override void Clear(int count)
{
using (new NtfsTransaction())
{
_isDirty = true;
_baseStream.Clear(count);
}
}
public override void Clear(int count)
{
if (_wrapped.Position + count > Length)
{
ChangeAttributeResidencyByLength(_wrapped.Position + count);
}
_wrapped.Clear(count);
}
public override void Clear(int count)
{
SparseStream sparse = WrappedStream as SparseStream;
if (sparse != null)
{
sparse.Clear(count);
}
else
{
base.Clear(count);
}
}
private long AllocateSpace(int sizeBytes, bool zero)
{
long pos;
if (!_freeSpace.TryAllocate(sizeBytes, out pos))
{
pos = Utilities.RoundUp(_file.Length, Sizes.OneMiB);
_file.SetLength(pos + sizeBytes);
_freeSpace.ExtendTo(pos + sizeBytes, false);
}
else if (zero)
{
_file.Position = pos;
_file.Clear(sizeBytes);
}
return(pos);
}
public override void Clear(int count)
{
_wrapped.Clear(count);
}
