public short AddNode(RadixTreePageBackingObject backingObject, IRadixTreeNode node, int prefixSize, int childCapacity)
{
var size = backingObject.Size;
var nodeSize = GetNodeSize((short)prefixSize, childCapacity);
if (size + nodeSize > _pageManager.PageSize)
{
return(-1);
}
for (short i = 0; i < backingObject.Items.Count; i++)
{
if (backingObject.Items[i] == null)
{
backingObject.Items[i] = node;
return(i);
}
}
if (size + nodeSize + PageFormatter.OnPagePointerSize > _pageManager.PageSize)
{
return(-1);
}
backingObject.Items.Add(node);
return((short)(backingObject.Items.Count - 1));
}
public IRadixTreeNode Fetch(DbItemReference reference)
{
if (DbItemReference.IsNull(reference))
{
return(null);
}
var page = _pageManager.FetchPage(reference.PageIndex);
if (page.BackingObject == null)
{
var obj1 = RadixTreePageBackingObject.FromPage(page);
page = new Page(_pageManager, page.Index, () => Serialize(obj1), obj1);
}
var backingObject = (RadixTreePageBackingObject)page.BackingObject;
var obj = backingObject.Items[reference.ItemIndex];
var result = obj as IRadixTreeNode;
if (result == null)
{
result = NodeFromBytes((byte[])obj);
result.Reference = (DbItemReference)reference.Clone();
backingObject.Items[reference.ItemIndex] = result;
}
return(result);
}
public bool Update(IRadixTreeNode node)
{
var page = _pageManager.FetchPage(node.Reference.PageIndex);
if (page.BackingObject == null)
{
var obj = RadixTreePageBackingObject.FromPage(page);
page = new Page(_pageManager, node.Reference.PageIndex, () => Serialize(obj), obj);
}
var backingObject = (RadixTreePageBackingObject)page.BackingObject;
var oldNodeSize = backingObject.GetNodeSize(node.Reference.ItemIndex);
var newNodeSize = GetNodeSize((short)node.Prefix.Length, node.Entries.Count);
var oldObjectSize = backingObject.Size;
var newObjectSize = oldObjectSize + newNodeSize - oldNodeSize;
if (newObjectSize > _pageManager.PageSize)
{
return(false);
}
backingObject.Items[node.Reference.ItemIndex] = node;
_pageManager.UpdatePage(page);
return(true);
}
public static RadixTreePageBackingObject FromPage(IPage page)
{
var result = new RadixTreePageBackingObject(page.Index);
var items = PageFormatter.ReadVariableSizeItems(page);
foreach (var item in items)
{
result.Items.Add(item);
}
return(result);
}
public IRadixTreeNode Create(int prefixSize, int childCapacity)
{
CheckRoot();
IPage page;
short itemIndex;
var node = NewNode(DbItemReference.Null);
foreach (var pageIndex in _recentPages)
{
page = _pageManager.FetchPage(pageIndex);
if (page.BackingObject == null)
{
var obj = RadixTreePageBackingObject.FromPage(page);
page = new Page(_pageManager, pageIndex, () => Serialize(obj), obj);
}
var backingObject = (RadixTreePageBackingObject)page.BackingObject;
itemIndex = AddNode(backingObject, node, prefixSize, childCapacity);
if (itemIndex != -1)
{
UpdateRecentPage(page.Index);
node.Reference = new DbItemReference(page.Index, itemIndex);
_pageManager.UpdatePage(page);
return(node);
}
}
page = _pageManager.CreatePage();
var obj1 = new RadixTreePageBackingObject(page.Index);
long index1 = page.Index;
page = new Page(_pageManager, index1, () => Serialize(obj1), obj1);
itemIndex = AddNode((RadixTreePageBackingObject)page.BackingObject, node, prefixSize, childCapacity);
if (itemIndex != -1)
{
UpdateRecentPage(page.Index);
node.Reference = new DbItemReference(page.Index, itemIndex);
_pageManager.UpdatePage(page);
return(node);
}
Debug.Fail("Should never get here");
return(null);
}
public void Remove(DbItemReference reference)
{
if (_rootNodeReference.Equals(reference))
{
throw new ArgumentOutOfRangeException(nameof(reference), "Unable to delete the root node");
}
var page = _pageManager.FetchPage(reference.PageIndex);
if (page.BackingObject == null)
{
var obj = RadixTreePageBackingObject.FromPage(page);
page = new Page(_pageManager, reference.PageIndex, () => Serialize(obj), obj);
}
var backingObject = (RadixTreePageBackingObject)page.BackingObject;
if (backingObject.Items.Count == reference.ItemIndex + 1)
{
backingObject.Items.RemoveAt(reference.ItemIndex);
}
else
{
backingObject.Items[reference.ItemIndex] = null;
}
if (backingObject.Items.Any(item => item != null))
{
_pageManager.UpdatePage(page);
}
else
{
_pageManager.RemovePage(page.Index);
if (_recentPages.Contains(page.Index))
{
_recentPages.Remove(page.Index);
}
}
}
private byte[] Serialize(RadixTreePageBackingObject backingObject)
{
var header = new RadixTreeNodesPageHeader();
var page = new Page(_pageManager, backingObject.PageIndex, new byte[_pageManager.PageSize]);
var items = backingObject.Items.Select(item =>
{
if (item is byte[] bytes)
{
return(bytes);
}
if (item == null)
{
return(new byte[0]);
}
return(GetNodeBytes((IRadixTreeNode)item, 0));
}).ToList();
PageFormatter.FormatVariableSizeItemsPage(page, header, items);
return(page.Content);
}