/// <summary>
/// Removes redundant nodes (that contain only an 'End' entry).
/// </summary>
/// <param name="entryIndex">The index of the entry that may have a redundant child</param>
/// <returns>An entry that needs to be promoted to the parent node (if any)</returns>
private IndexEntry LiftNode(int entryIndex)
{
if ((_entries[entryIndex].Flags & IndexEntryFlags.Node) != 0)
{
IndexNode childNode = _index.GetSubBlock(_entries[entryIndex]).Node;
if (childNode._entries.Count == 1)
{
long freeBlock = _entries[entryIndex].ChildrenVirtualCluster;
_entries[entryIndex].Flags = (_entries[entryIndex].Flags & ~IndexEntryFlags.Node) | (childNode._entries[0].Flags & IndexEntryFlags.Node);
_entries[entryIndex].ChildrenVirtualCluster = childNode._entries[0].ChildrenVirtualCluster;
_index.FreeBlock(freeBlock);
}
if ((_entries[entryIndex].Flags & (IndexEntryFlags.Node | IndexEntryFlags.End)) == 0)
{
IndexEntry entry = _entries[entryIndex];
_entries.RemoveAt(entryIndex);
IndexNode nextNode = _index.GetSubBlock(_entries[entryIndex]).Node;
return(nextNode.AddEntry(entry));
}
}
return(null);
}
