public DfsFileStream(DragonFs fs, DfsDirectoryEntry root, FileAccess access)
{
_Fs = fs;
_Root = root;
if (root.FilePointer != 0)
{
if ((access == FileAccess.Write) || (access == FileAccess.ReadWrite))
{
throw new NotSupportedException("Writing an existing file is not supported");
}
// Create MemoryStream from existing data
_MemStream = new MemoryStream((int)(_Root.Flags & ~DfsDirectoryEntry.FLAG_MASK));
int remainingBytes = (int)Length;
uint offset = root.FilePointer;
while (remainingBytes > 0)
{
// Fetch a sector and write to the stream
DfsSector sector = _Fs.FindSector(offset);
int sectorBytes = (int)DfsSector.SECTOR_SIZE;
if (sectorBytes >= remainingBytes)
{
sectorBytes = remainingBytes;
}
_MemStream.Write(sector.Buffer, 0, sectorBytes);
remainingBytes -= sectorBytes;
offset += DfsSector.SECTOR_SIZE;
}
_MemStream.Seek(0, SeekOrigin.Begin);
}
else
{
if (access == FileAccess.Read)
{
throw new NotSupportedException("Cannot read file without content");
}
// Create MemoryStream for all file operations
_MemStream = new MemoryStream();
}
switch (access)
{
case FileAccess.Read:
_CanRead = true;
break;
case FileAccess.ReadWrite:
_CanRead = true;
_CanWrite = true;
break;
case FileAccess.Write:
_CanWrite = true;
break;
}
}
public static DragonFs CreateFromStream(Stream source)
{
DragonFs newFs = new DragonFs();
DfsSector sector = new DfsSector(0);
source.Read(sector.Buffer, 0, (int)DfsSector.SECTOR_SIZE);
DfsDirectoryEntry root = new DfsDirectoryEntry(sector);
bool checkValid = true;
if ((root.Flags != ROOT_FLAGS) || (root.NextEntry != ROOT_NEXTENTRY))
{
checkValid = false;
}
else
{
// Check DFS version string
if (!root.Path.Equals(DragonFs.ROOT_PATH))
{
checkValid = false;
}
}
if (checkValid == false)
{
throw new ArgumentException("source", "The stream does not contain a valid DFS 2.0 image");
}
while (source.Position != source.Length)
{
sector = newFs.NewSector();
source.Read(sector.Buffer, 0, (int)DfsSector.SECTOR_SIZE);
}
// The virtual root directory entry needs to point to the first sector
// TODO: Can this be done better?
newFs._RootDirectory.FilePointer = DfsSector.SECTOR_SIZE;
return(newFs);
}