/// <summary>
/// Gets the minimal key.
/// </summary>
/// <returns>The minimal key</returns>
public TKey Min()
{
var prefixes = new List <byte[]>();
IRadixTreeNode node = _nodeStorage.FetchRoot();
while (true)
{
prefixes.Add(node.Prefix);
if (node.ValueReference != null)
{
break;
}
if (node.Entries.Any())
{
node = _nodeStorage.Fetch(node.Entries.First().Value);
}
}
using (var ms = new MemoryStream())
{
foreach (var prefix in prefixes.Where(p => p != null))
{
ms.Write(prefix, 0, prefix.Length);
}
return(_keySerializer.Deserialize(ms.ToArray()));
}
}
private List <IRadixTreeNode> CreateNodeChain(byte[] remainingKeyPart)
{
var result = new List <IRadixTreeNode>();
var offset = 0;
IRadixTreeNode previousNode = null;
while (offset < remainingKeyPart.Length)
{
var prefixLength = Math.Min(MaxPrefixLength, remainingKeyPart.Length - offset);
var newNode = _nodeStorage.Create(prefixLength, 1);
newNode.Prefix = new byte[prefixLength];
Buffer.BlockCopy(remainingKeyPart, offset, newNode.Prefix, 0, newNode.Prefix.Length);
if (previousNode != null)
{
previousNode.Entries.Add(new KeyValuePair <byte, DbItemReference>(newNode.Prefix[0], newNode.Reference));
newNode.ParentNodeReference = previousNode.Reference;
}
result.Add(newNode);
previousNode = newNode;
offset += MaxPrefixLength;
if (offset > remainingKeyPart.Length)
{
offset = remainingKeyPart.Length;
}
}
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);
}
private bool CheckNode(IRadixTreeNode node, out string message)
{
message = string.Empty;
if (node.ParentNodeReference != null)
{
if (!node.Entries.Any() && node.ValueReference == null)
{
message = $"Node: {node.Reference} has no value and child nodes";
return(false);
}
if (_nodeStorage.Fetch(node.ParentNodeReference) == null)
{
message = $"Node: {node.Reference} has invalid reference ({node.ParentNodeReference}) to parent node.";
return(false);
}
}
foreach (var entry in node.Entries)
{
var childNode = _nodeStorage.Fetch(entry.Value);
if (childNode == null)
{
message = $"Invalid reference ({entry.Value}) to child in node: {node.Reference}";
return(false);
}
}
return(true);
}
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));
}
private byte[] GetNodeBytes(IRadixTreeNode node, short minimalSize)
{
var prefix = node.Prefix ?? new byte[0];
var prefixLength = (short)prefix.Length;
var valueReference = node.ValueReference ?? DbItemReference.Null;
var parentReference = node.ParentNodeReference ?? DbItemReference.Null;
var size = GetNodeSize(prefixLength, node.Entries.Count);
var result = new byte[Math.Max(size, minimalSize)];
using (var ms = new MemoryStream(result))
{
ms.Write(BitConverter.GetBytes(size), 0, PageFormatter.OnPagePointerSize);
ms.Write(BitConverter.GetBytes(prefixLength), 0, PageFormatter.OnPagePointerSize);
ms.Write(prefix, 0, prefixLength);
valueReference.Write(ms);
parentReference.Write(ms);
ms.Write(BitConverter.GetBytes((short)node.Entries.Count), 0, sizeof(short));
foreach (var entry in node.Entries)
{
ms.WriteByte(entry.Key);
ms.Write(entry.Value.GetBytes(), 0, DbItemReference.BytesLength);
}
return(ms.ToArray());
}
}
private void CheckNode(IRadixTreeNode node)
{
if (!_nodes.ContainsKey(node.Reference.ToString()))
{
throw new ArgumentException("Radix tree node has an invalid index", nameof(node));
}
}
/// <summary>
/// This method is used to guarantee the updating.
/// Use this if the updating node is not increased in size.
/// </summary>
/// <param name="node"></param>
private void UpdateOrFail(IRadixTreeNode node)
{
if (!_nodeStorage.Update(node))
{
throw new DataTankerException("Update failed. Node should be reallocated");
}
}
public bool Update(IRadixTreeNode node)
{
CheckNode(node);
_nodes[node.Reference.ToString()] = node;
return(true);
}
/// <summary>
/// Determines if the specified key has subkeys.
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public bool HasSubkeys(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out _, out _, out isFullMatch);
return(isFullMatch && node.Entries.Any());
}
private IRadixTreeNode GetChildPreviousTo(IRadixTreeNode node, byte b)
{
int index;
FindSuitableEntry(node.Entries, b, out index);
if (index <= 0 || index > node.Entries.Count)
{
return(null);
}
return(_nodeStorage.Fetch(node.Entries[index - 1].Value));
}
/// <summary>
/// Retrieves a segment of binary representation
/// of the value referenced by the specified key.
/// </summary>
/// <param name="key">The key</param>
/// <param name="startIndex">The index in binary representation where the specified segment starts</param>
/// <param name="endIndex">The index in binary representation where the specified segment ends</param>
/// <returns></returns>
public byte[] GetRawDataSegment(TKey key, long startIndex, long endIndex)
{
var binaryKey = _keySerializer.Serialize(key);
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out _, out _, out isFullMatch);
if (!isFullMatch)
{
return(null);
}
return(node.ValueReference != null?_valueStorage.GetRawDataSegment(node.ValueReference, startIndex, endIndex) : null);
}
private void Count(IRadixTreeNode node, ref long count)
{
if (node.ValueReference != null)
{
count++;
}
foreach (var entry in node.Entries)
{
var child = _nodeStorage.Fetch(entry.Value);
Count(child, ref count);
}
}
/// <summary>
/// Computes the number of child key-value pairs for a given key.
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public long SubkeysCount(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out _, out _, out isFullMatch);
long result = 0;
if (isFullMatch)
{
Count(node, ref result);
}
return(result);
}
private void AdjustLinksInChildNodes(IRadixTreeNode node, bool update)
{
if (node.Entries.Any())
{
foreach (var entry in node.Entries)
{
var child = _nodeStorage.Fetch(entry.Value);
child.ParentNodeReference = node.Reference;
if (update)
{
UpdateOrFail(child);
}
}
}
}
/// <summary>
/// Cheks if key-value pair exists in tree.
/// </summary>
/// <param name="key">The key</param>
/// <returns>True if key-value pair exists, false otherwise</returns>
public bool Exists(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out _, out _, out isFullMatch);
if (isFullMatch)
{
if (node.ValueReference != null)
{
return(true);
}
}
return(false);
}
/// <summary>
/// Retrieves the length (in bytes) of binary representation
/// of the value referenced by the specified key.
/// </summary>
/// <param name="key">The key</param>
/// <returns>The length of binary representation</returns>
public long GetRawDataLength(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out _, out _, out isFullMatch);
if (isFullMatch)
{
if (node.ValueReference != null)
{
return(_valueStorage.GetRawDataLength(node.ValueReference));
}
}
return(0);
}
private IRadixTreeNode GetChildNextTo(IRadixTreeNode node, byte b)
{
int index;
var entry = FindSuitableEntry(node.Entries, b, out index);
if (entry != null)
{
index++;
}
if (index < 0 || index >= node.Entries.Count)
{
return(null);
}
return(_nodeStorage.Fetch(node.Entries[index].Value));
}
private void AdjustParentNodeLink(IRadixTreeNode node, bool updateNode)
{
var parentNode = _nodeStorage.Fetch(node.ParentNodeReference);
var b = node.Prefix[0];
int index;
if (FindSuitableEntry(parentNode.Entries, b, out index).HasValue)
{
parentNode.Entries[index] = new KeyValuePair <byte, DbItemReference>(b, (DbItemReference)(node.Reference.Clone()));
if (updateNode)
{
UpdateOrFail(parentNode);
}
}
}
/// <summary>
/// Gets the value by its key.
/// </summary>
/// <param name="key">The key</param>
/// <returns>The value corresponding to the given key</returns>
public TValue Get(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out _, out _, out isFullMatch /*, treeNode => references.Add(treeNode.Reference)*/);
if (isFullMatch)
{
if (node.ValueReference != null)
{
return(_valueStorage.Fetch(node.ValueReference));
}
}
return(default(TValue));
}
/// <summary>
/// Gets the value corresponing to the maximal key.
/// </summary>
/// <returns>The value corresponding to the maximal key</returns>
public TValue MaxValue()
{
IRadixTreeNode node = _nodeStorage.FetchRoot();
while (true)
{
if (node.Entries.Any())
{
node = _nodeStorage.Fetch(node.Entries.Last().Value);
}
else
{
break;
}
}
return(_valueStorage.Fetch(node.ValueReference));
}
/// <summary>
/// Gets a value corresponing to the minimal key.
/// </summary>
/// <returns>The value corresponding to the minimal key</returns>
public TValue MinValue()
{
IRadixTreeNode node = _nodeStorage.FetchRoot();
while (true)
{
if (node.ValueReference != null)
{
break;
}
if (node.Entries.Any())
{
node = _nodeStorage.Fetch(node.Entries.First().Value);
}
}
return(_valueStorage.Fetch(node.ValueReference));
}
private TKey BuildKeyForNode(IRadixTreeNode node)
{
var prefixes = new List <byte[]>();
while (!DbItemReference.IsNull(node.ParentNodeReference))
{
prefixes.Add(node.Prefix);
node = _nodeStorage.Fetch(node.ParentNodeReference);
}
prefixes.Reverse();
using (var ms = new MemoryStream())
{
foreach (var prefix in prefixes.Where(p => p != null))
{
ms.Write(prefix, 0, prefix.Length);
}
return(_keySerializer.Deserialize(ms.ToArray()));
}
}
private IRadixTreeNode UpdateOrReallocateNode(IRadixTreeNode node, out bool reallocated)
{
if (!_nodeStorage.Update(node))
{
reallocated = true;
_nodeStorage.Remove(node.Reference);
var reallocatedNode = _nodeStorage.Create(node.Prefix.Length, node.Entries.Count);
reallocatedNode.Prefix = node.Prefix;
reallocatedNode.ValueReference = node.ValueReference;
reallocatedNode.ParentNodeReference = node.ParentNodeReference;
foreach (var entry in node.Entries)
{
reallocatedNode.Entries.Add(entry);
}
_nodeStorage.Update(reallocatedNode);
return(reallocatedNode);
}
reallocated = false;
return(node);
}
private static IEnumerable <KeyValuePair <byte, DbItemReference> > GetChildLinks(IRadixTreeNode node1, IRadixTreeNode node2)
{
KeyValuePair <byte, DbItemReference>[] result;
if (node1 != null)
{
result = new[]
{
new KeyValuePair <byte, DbItemReference>(node2.Prefix[0], (DbItemReference)(node2.Reference.Clone())),
new KeyValuePair <byte, DbItemReference>(node1.Prefix[0], (DbItemReference)(node1.Reference.Clone()))
};
if (node2.Prefix[0] > node1.Prefix[0])
{
Array.Reverse(result);
}
}
else
{
result = new[]
{
new KeyValuePair <byte, DbItemReference>(node2.Prefix[0], (DbItemReference)(node2.Reference.Clone()))
}
};
return(result);
}
/// <summary>
/// Gets the key next to the specified key.
/// The existence of the specified key is not required.
/// </summary>
/// <returns>The key next to specified key</returns>
public TKey NextTo(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
int keyOffset;
int nodePrefixOffset;
bool isFullMatch;
IRadixTreeNode targetNode = FindMostSuitableNode(binaryKey, out keyOffset, out nodePrefixOffset, out isFullMatch);
if (isFullMatch || keyOffset == binaryKey.Length)
{
if (targetNode.Entries.Any())
{
targetNode = _nodeStorage.Fetch(targetNode.Entries.First().Value);
}
else
{
while (!DbItemReference.IsNull(targetNode.ParentNodeReference))
{
var parent = _nodeStorage.Fetch(targetNode.ParentNodeReference);
targetNode = GetChildNextTo(parent, targetNode.Prefix[0]);
if (targetNode != null)
{
break;
}
targetNode = parent;
}
}
}
else
{
byte b = binaryKey[keyOffset];
while (true)
{
var child = GetChildNextTo(targetNode, b);
if (child != null)
{
targetNode = child;
break;
}
if (DbItemReference.IsNull(targetNode.ParentNodeReference))
{
break;
}
b = targetNode.Prefix[0];
targetNode = _nodeStorage.Fetch(targetNode.ParentNodeReference);
}
}
if (DbItemReference.IsNull(targetNode.ParentNodeReference))
{
return(default(TKey));
}
while (DbItemReference.IsNull(targetNode.ValueReference) && targetNode.Entries.Any())
{
targetNode = _nodeStorage.Fetch(targetNode.Entries.First().Value);
}
return(BuildKeyForNode(targetNode));
}
/// <summary>
/// Removes key-value pair by key.
/// </summary>
/// <param name="key">The key</param>
public void Remove(TKey key)
{
var binaryKey = _keySerializer.Serialize(key);
int keyOffset;
int nodePrefixOffset;
bool isFullMatch;
IRadixTreeNode node = FindMostSuitableNode(binaryKey, out keyOffset, out nodePrefixOffset, out isFullMatch);
if (isFullMatch)
{
_valueStorage.Free(node.ValueReference);
node.ValueReference = null;
if (node.Entries.Any())
{
if (node.Prefix != null && node.Entries.Count == 1)
{
var child = _nodeStorage.Fetch(node.Entries[0].Value);
var newPrefixLength = node.Prefix.Length + child.Prefix.Length;
if (newPrefixLength <= MaxPrefixLength)
{
var newPrefix = new byte[newPrefixLength];
Buffer.BlockCopy(node.Prefix, 0, newPrefix, 0, node.Prefix.Length);
Buffer.BlockCopy(child.Prefix, 0, newPrefix, node.Prefix.Length, child.Prefix.Length);
child.Prefix = newPrefix;
child.ParentNodeReference = node.ParentNodeReference;
_nodeStorage.Remove(node.Reference);
bool reallocated;
child = UpdateOrReallocateNode(child, out reallocated);
var parent = _nodeStorage.Fetch(child.ParentNodeReference);
int index;
FindSuitableEntry(parent.Entries, child.Prefix[0], out index);
parent.Entries[index] = new KeyValuePair <byte, DbItemReference>(child.Prefix[0], child.Reference);
UpdateOrFail(parent);
}
else
{
UpdateOrFail(node);
}
}
else
{
UpdateOrFail(node);
}
}
else
{
while (!DbItemReference.IsNull(node.ParentNodeReference))
{
var parentNode = _nodeStorage.Fetch(node.ParentNodeReference);
int index;
FindSuitableEntry(parentNode.Entries, node.Prefix[0], out index);
parentNode.Entries.RemoveAt(index);
_nodeStorage.Remove(node.Reference);
if (parentNode.Entries.Any() || parentNode.ValueReference != null ||
DbItemReference.IsNull(parentNode.ParentNodeReference))
{
UpdateOrFail(parentNode);
break;
}
node = parentNode;
}
}
}
}
/// <summary>
/// Inserts or updates key value pair.
/// </summary>
/// <param name="key">The key</param>
/// <param name="value">The value</param>
public void Set(TKey key, TValue value)
{
var binaryKey = _keySerializer.Serialize(key);
int keyOffset;
int nodePrefixOffset;
bool isFullMatch;
IRadixTreeNode targetNode = FindMostSuitableNode(binaryKey, out keyOffset, out nodePrefixOffset, out isFullMatch);
if (isFullMatch)
{
// here we needn't any manipulation with key prefixes
// simply update the existing or allocate a new value
targetNode.ValueReference =
targetNode.ValueReference != null
? _valueStorage.Reallocate(targetNode.ValueReference, value)
: _valueStorage.AllocateNew(value);
UpdateOrFail(targetNode);
return;
}
// we have a partial match
var remainingKeyPart = new byte[binaryKey.Length - keyOffset];
var nodeChain = new List <IRadixTreeNode>();
if (remainingKeyPart.Length > 0)
{
Buffer.BlockCopy(binaryKey, keyOffset, remainingKeyPart, 0, remainingKeyPart.Length);
// the remaining prefix may exceed the _maxPrefixLength
// we must create a chain of nodes, where each node
// contain part of the prefix remaining
nodeChain = CreateNodeChain(remainingKeyPart);
}
if (targetNode.Prefix != null && nodePrefixOffset < targetNode.Prefix.Length)
{
// we got into splitting update:
// the targetNode is split into newParentNode and targetNode itself
// nodeChain (if has any items) is attached to newParentNode as a child
// split prefix
byte[] remainingPrefix;
byte[] prefixForNewParent;
SplitPrefix(targetNode.Prefix, nodePrefixOffset, out prefixForNewParent, out remainingPrefix);
targetNode.Prefix = remainingPrefix;
var newParentNode = _nodeStorage.Create(prefixForNewParent.Length, 2);
newParentNode.Prefix = prefixForNewParent;
newParentNode.ParentNodeReference = targetNode.ParentNodeReference;
targetNode.ParentNodeReference = newParentNode.Reference;
var valueReference = _valueStorage.AllocateNew(value);
if (nodeChain.Any())
{
nodeChain.First().ParentNodeReference = newParentNode.Reference;
nodeChain.Last().ValueReference = valueReference;
}
else
{
newParentNode.ValueReference = valueReference;
}
// add links to child nodes
foreach (var item in GetChildLinks(nodeChain.FirstOrDefault(), targetNode))
{
newParentNode.Entries.Add(item);
}
if (nodeChain.Any())
{
foreach (var node in nodeChain)
{
UpdateOrFail(node);
}
}
UpdateOrFail(newParentNode);
UpdateOrFail(targetNode);
// change link in parent node if needed
if (!DbItemReference.IsNull(newParentNode.ParentNodeReference))
{
AdjustParentNodeLink(newParentNode, true);
}
}
else
{
// here is keeping update
// all nodes above remain intact
byte b = remainingKeyPart[0];
int index;
FindSuitableEntry(targetNode.Entries, b, out index);
targetNode.Entries.Insert(index, new KeyValuePair <byte, DbItemReference>(b, (DbItemReference)(nodeChain.First().Reference.Clone())));
bool reallocated;
targetNode = UpdateOrReallocateNode(targetNode, out reallocated);
if (reallocated)
{
AdjustParentNodeLink(targetNode, true);
AdjustLinksInChildNodes(targetNode, true);
}
nodeChain.First().ParentNodeReference = targetNode.Reference;
nodeChain.Last().ValueReference = _valueStorage.AllocateNew(value);
foreach (var node in nodeChain)
{
UpdateOrFail(node);
}
}
}
