private void AllocateGrains(int grainTable, int grain, int count)
{
// Calculate start pos for new grain
long grainStartPos = (long)_serverHeader.FreeSector * Sizes.Sector;
// Copy-on-write semantics, read the bytes from parent and write them out to this extent.
_parentDiskStream.Position = _diskOffset +
(grain + _header.NumGTEsPerGT * grainTable) * _header.GrainSize *
Sizes.Sector;
byte[] content = StreamUtilities.ReadExact(_parentDiskStream, (int)(_header.GrainSize * Sizes.Sector * count));
_fileStream.Position = grainStartPos;
_fileStream.Write(content, 0, content.Length);
// Update next-free-sector in disk header
_serverHeader.FreeSector += (uint)MathUtilities.Ceil(content.Length, Sizes.Sector);
byte[] headerBytes = _serverHeader.GetBytes();
_fileStream.Position = 0;
_fileStream.Write(headerBytes, 0, headerBytes.Length);
LoadGrainTable(grainTable);
for (int i = 0; i < count; ++i)
{
SetGrainTableEntry(grain + i, (uint)(grainStartPos / Sizes.Sector + _header.GrainSize * i));
}
WriteGrainTable();
}
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);
return;
}
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;
return;
}
else
{
throw new NotImplementedException("Extent type not implemented");
}
}
internal override List <BuilderExtent> FixExtents(out long totalLength)
{
List <BuilderExtent> extents = new List <BuilderExtent>();
ServerSparseExtentHeader header = DiskImageFile.CreateServerSparseExtentHeader(_content.Length);
GlobalDirectoryExtent gdExtent = new GlobalDirectoryExtent(header);
long grainTableStart = (header.GdOffset * Sizes.Sector) + gdExtent.Length;
long grainTableCoverage = header.NumGTEsPerGT * header.GrainSize * Sizes.Sector;
foreach (var grainTableRange in StreamExtent.Blocks(_content.Extents, grainTableCoverage))
{
for (int i = 0; i < grainTableRange.Count; ++i)
{
long grainTable = grainTableRange.Offset + i;
long dataStart = grainTable * grainTableCoverage;
GrainTableExtent gtExtent = new GrainTableExtent(grainTableStart, new SubStream(_content, dataStart, Math.Min(grainTableCoverage, _content.Length - dataStart)), header);
extents.Add(gtExtent);
gdExtent.SetEntry((int)grainTable, (uint)(grainTableStart / Sizes.Sector));
grainTableStart += gtExtent.Length;
}
}
extents.Insert(0, gdExtent);
header.FreeSector = (uint)(grainTableStart / Sizes.Sector);
byte[] buffer = header.GetBytes();
extents.Insert(0, new BuilderBufferExtent(0, buffer));
totalLength = grainTableStart;
return(extents);
}