private static void CreateExtent(Stream extentStream, long size, ExtentType type, long descriptorLength,
out long descriptorStart)
{
if (type == ExtentType.Flat || type == ExtentType.Vmfs)
{
extentStream.SetLength(size);
descriptorStart = 0;
return;
}
if (type == ExtentType.Sparse)
{
CreateSparseExtent(extentStream, size, descriptorLength, out descriptorStart);
}
else if (type == ExtentType.VmfsSparse)
{
ServerSparseExtentHeader header = CreateServerSparseExtentHeader(size);
extentStream.Position = 0;
extentStream.Write(header.GetBytes(), 0, 4 * Sizes.Sector);
byte[] blankGlobalDirectory = new byte[header.NumGdEntries * 4];
extentStream.Write(blankGlobalDirectory, 0, blankGlobalDirectory.Length);
descriptorStart = 0;
}
else
{
throw new NotImplementedException($"Extent type '{ExtentDescriptor.FormatExtentType(type)}' not implemented");
}
}
private SparseStream OpenExtent(ExtentDescriptor extent, long extentStart, SparseStream parent,
Ownership ownsParent)
{
FileAccess access = FileAccess.Read;
FileShare share = FileShare.Read;
if (extent.Access == ExtentAccess.ReadWrite && _access != FileAccess.Read)
{
access = FileAccess.ReadWrite;
share = FileShare.None;
}
if (extent.Type != ExtentType.Sparse && extent.Type != ExtentType.VmfsSparse)
{
if (ownsParent == Ownership.Dispose && parent != null)
{
parent.Dispose();
}
}
switch (extent.Type)
{
case ExtentType.Flat:
case ExtentType.Vmfs:
return(SparseStream.FromStream(
_fileLocator.Open(extent.FileName, FileMode.Open, access, share),
Ownership.Dispose));
case ExtentType.Zero:
return(new ZeroStream(extent.SizeInSectors * Sizes.Sector));
case ExtentType.Sparse:
return(new HostedSparseExtentStream(
_fileLocator.Open(extent.FileName, FileMode.Open, access, share),
Ownership.Dispose,
extentStart,
parent,
ownsParent));
case ExtentType.VmfsSparse:
return(new ServerSparseExtentStream(
_fileLocator.Open(extent.FileName, FileMode.Open, access, share),
Ownership.Dispose,
extentStart,
parent,
ownsParent));
default:
throw new NotSupportedException($"Extent type '{ExtentDescriptor.FormatExtentType(extent.Type)}' not supported");
}
}
