public BlockBTreeEntry FindBlockEntryByBlockID(ulong blockID)
{
// Readers MUST ignore the reserved bit and treat it as zero before looking up the BID from the BBT
//
// Documented cases where the Reserved bit was set to true:
// 1. PST was created by Outlook 2010 RTM, the hirerarchy table of the 'Top of Personal Folders'
// had a rows subnode, and the entry in the subnode-BTree had the Reserved bit set to true,
// However, both the BBT entry (BREF) and the PageTrailer had the corresponding entry with the bit set to false.
// 2. PST was created by Outlook 2007 RTM, this library created a calendar folder that was modified by Outlook (columns were added)
// The XBlock entry had the reserved bit set to true,
// However, both the BBT entry (BREF) and the PageTrailer had the corresponding entry with the bit set to false.
ulong lookupValue = blockID & 0xFFFFFFFFFFFFFFFEU;
BlockBTreeLeafPage page = (BlockBTreeLeafPage)FindLeafBTreePage(lookupValue);
if (page != null)
{
// page.cLevel is now 0
List <BlockBTreeEntry> blockBTreeEntryList = page.BlockEntryList;
foreach (BlockBTreeEntry entry in blockBTreeEntryList)
{
if (entry.BREF.bid.Value == lookupValue)
{
return(entry);
}
}
}
return(null);
}
/// <summary>
/// Since the PST is immutable, any change will result in a new BBT root page
/// Note: we may leave an empty leaf page
/// </summary>
/// <returns>New BlockBTree root page</returns>
public void DeleteBlockEntry(BlockID blockID)
{
BlockBTreeLeafPage leaf = (BlockBTreeLeafPage)FindLeafBTreePage(blockID.LookupValue);
// Remove the entry
int index = leaf.RemoveEntry(blockID.LookupValue);
if (index == 0)
{
// scanpst.exe report an error if page key does not match the first entry,
// so we want to update the parent
if (leaf.ParentPage != null)
{
if (leaf.BlockEntryList.Count > 0)
{
UpdateIndexEntry(leaf.ParentPage, leaf.BlockID, leaf.PageKey);
}
else
{
DeleteIndexEntry(leaf.ParentPage, leaf.BlockID);
DeletePage(leaf);
return;
}
}
}
// now we have to store the new leaf page, and cascade the changes up to the root page
UpdatePageAndReferences(leaf);
}
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 void UpdateBlockEntry(BlockID blockID, ushort cRef)
{
BlockBTreeLeafPage leaf = (BlockBTreeLeafPage)FindLeafBTreePage(blockID.LookupValue);
int index = leaf.GetIndexOfEntry(blockID.LookupValue);
if (index >= 0)
{
leaf.BlockEntryList[index].cRef = cRef;
// now we have to store the new leaf page, and cascade the changes up to the root page
UpdatePageAndReferences(leaf);
}
}
public void InsertBlockEntry(BlockBTreeEntry entryToInsert)
{
ulong key = entryToInsert.BREF.bid.Value;
BlockBTreeLeafPage page = (BlockBTreeLeafPage)FindLeafBTreePage(key);
if (page.BlockEntryList.Count < BlockBTreeLeafPage.MaximumNumberOfEntries)
{
int insertIndex = page.InsertSorted(entryToInsert);
UpdatePageAndReferences(page);
if (insertIndex == 0 && page.ParentPage != null)
{
// page key has been modified, we must update the parent
UpdateIndexEntry(page.ParentPage, page.BlockID, page.PageKey);
}
}
else
{
// We have to split the tree node
BlockBTreeLeafPage newPage = page.Split();
if (newPage.PageKey < key)
{
newPage.InsertSorted(entryToInsert);
}
else
{
int insertIndex = page.InsertSorted(entryToInsert);
if (insertIndex == 0 && page.ParentPage != null)
{
// page key has been modified, we must update the parent
UpdateIndexEntry(page.ParentPage, page.BlockID, page.PageKey);
}
}
UpdatePageAndReferences(page);
AddPage(newPage);
if (page.ParentPage == null)
{
// this is a root page and it's full, we have to create a new root
CreateNewRoot();
}
InsertIndexEntry(page.ParentPage, newPage.PageKey, newPage.BlockID);
}
}
public BlockBTreeLeafPage Split()
{
int newNodeStartIndex = BlockEntryList.Count / 2;
BlockBTreeLeafPage newPage = new BlockBTreeLeafPage();
// BlockID will be given when the page will be added
newPage.cEntMax = cEntMax;
newPage.cbEnt = cbEnt;
newPage.cLevel = cLevel;
newPage.pageTrailer.ptype = pageTrailer.ptype;
for (int index = newNodeStartIndex; index < BlockEntryList.Count; index++)
{
newPage.BlockEntryList.Add(BlockEntryList[index]);
}
BlockEntryList.RemoveRange(newNodeStartIndex, BlockEntryList.Count - newNodeStartIndex);
return(newPage);
}
