public RootStructure(byte[] buffer, int offset)
{
ibFileEOF = LittleEndianConverter.ToUInt64(buffer, offset + 4);
ibAMapLast = LittleEndianConverter.ToUInt64(buffer, offset + 12);
cbAMapFree = LittleEndianConverter.ToUInt64(buffer, offset + 20);
cbPMapFree = LittleEndianConverter.ToUInt64(buffer, offset + 28);
BREFNBT = new BlockRef(buffer, offset + 36);
BREFBBT = new BlockRef(buffer, offset + 52);
fAMapValid = ByteReader.ReadByte(buffer, offset + 68);
bReserved = ByteReader.ReadByte(buffer, offset + 69);
wReserved = LittleEndianConverter.ToUInt16(buffer, offset + 70);
}
public static BTreePage ReadFromStream(Stream stream, BlockRef blockRef)
{
long offset = (long)blockRef.ib;
stream.Seek(offset, SeekOrigin.Begin);
byte[] buffer = new byte[Length];
stream.Read(buffer, 0, Length);
PageTypeName ptype = (PageTypeName)buffer[PageTrailer.OffsetFromPageStart + 0];
BTreePage page;
byte cLevel = buffer[491];
if (cLevel > 0)
{
// If cLevel is greater than 0, then each entry in the array is of type BTENTRY.
page = new BTreeIndexPage(buffer);
}
else
{
// If cLevel is 0, then each entry is either of type BBTENTRY or NBTENTRY, depending on the ptype of the page.
if (ptype == PageTypeName.ptypeBBT)
{
page = new BlockBTreeLeafPage(buffer);
}
else if (ptype == PageTypeName.ptypeNBT)
{
page = new NodeBTreeLeafPage(buffer);
}
else
{
throw new ArgumentException("BTreePage has incorrect ptype");
}
}
page.Offset = (ulong)blockRef.ib;
if (blockRef.bid.Value != page.BlockID.Value)
{
throw new InvalidBlockIDException();
}
uint crc = PSTCRCCalculation.ComputeCRC(buffer, PageTrailer.OffsetFromPageStart);
if (page.pageTrailer.dwCRC != crc)
{
throw new InvalidChecksumException();
}
uint signature = BlockTrailer.ComputeSignature(blockRef.ib, blockRef.bid.Value);
if (page.pageTrailer.wSig != signature)
{
throw new InvalidChecksumException();
}
return(page);
}
public BTreePage GetPage(BlockRef blockRef)
{
ulong blockID = blockRef.bid.Value;
if (m_pageBuffer.ContainsKey(blockID))
{
return(m_pageBuffer[blockID]);
}
else
{
BTreePage page = BTreePage.ReadFromStream(m_file.BaseStream, blockRef);
m_pageBuffer.Add(blockRef.bid.Value, page);
return(page);
}
}
public BTreeIndexEntry(byte[] buffer, int offset)
{
btkey = LittleEndianConverter.ToUInt64(buffer, offset + 0);
BREF = new BlockRef(buffer, offset + 8);
}
public BTreeIndexEntry()
{
BREF = new BlockRef();
}
public static Block ReadFromStream(Stream stream, BlockRef blockRef, int dataLength, bCryptMethodName bCryptMethod)
{
long offset = (long)blockRef.ib;
int totalLength = GetTotalBlockLength(dataLength);
stream.Seek(offset, SeekOrigin.Begin);
byte[] buffer = new byte[totalLength];
stream.Read(buffer, 0, totalLength);
BlockTrailer trailer = BlockTrailer.ReadFromEndOfBuffer(buffer);
Block block;
if (trailer.bid.Internal)
{
// XBlock or XXBlock
byte btype = buffer[0];
byte cLevel = buffer[1];
if (btype == (byte)BlockType.XBlock && cLevel == 0x01)
{
// XBLOCK
block = new XBlock(buffer);
}
else if (btype == (byte)BlockType.XXBlock && cLevel == 0x02)
{
// XXBLOCK
block = new XXBlock(buffer);
}
else if (btype == (byte)BlockType.SLBLOCK && cLevel == 0x00)
{
// SLBLock
block = new SubnodeLeafBlock(buffer);
}
else if (btype == (byte)BlockType.SIBLOCK && cLevel == 0x01)
{
// SIBLock
block = new SubnodeIntermediateBlock(buffer);
}
else
{
throw new Exception("Internal block, but not XBLOCK, XXBlock, SLBLOCK or SIBLOCK");
}
}
else
{
block = new DataBlock(buffer, bCryptMethod);
}
// See question 3 at:
// http://social.msdn.microsoft.com/Forums/en-CA/os_binaryfile/thread/923f5964-4a89-4811-86c2-06a553c34510
// However, so far all tests suggest that there should be no problem to use BlockID.Value for both arguments
if (blockRef.bid.LookupValue != block.BlockID.LookupValue)
{
throw new InvalidBlockIDException();
}
if (dataLength != trailer.cb)
{
throw new Exception("Invalid block length");
}
uint crc = PSTCRCCalculation.ComputeCRC(buffer, dataLength);
if (block.BlockTrailer.dwCRC != crc)
{
throw new InvalidChecksumException();
}
uint signature = BlockTrailer.ComputeSignature(blockRef.ib, blockRef.bid.Value);
if (block.BlockTrailer.wSig != signature)
{
throw new InvalidChecksumException();
}
return(block);
}
public BlockBTreeEntry(byte[] buffer, int offset)
{
BREF = new BlockRef(buffer, offset + 0);
cb = LittleEndianConverter.ToUInt16(buffer, offset + 16);
cRef = LittleEndianConverter.ToUInt16(buffer, offset + 18);
}
public ushort cRef; // Reference count: indicating the count of references to this block.
//public uint dwPadding
public BlockBTreeEntry()
{
BREF = new BlockRef();
}