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ryujinx-final/Ryujinx.Common/Collections/IntervalTree.cs

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using System;
using System.Collections.Generic;
using System.Linq;
namespace Ryujinx.Common.Collections
{
/// <summary>
/// An Augmented Interval Tree based off of the "TreeDictionary"'s Red-Black Tree. Allows fast overlap checking of ranges.
/// </summary>
/// <typeparam name="K">Key</typeparam>
/// <typeparam name="V">Value</typeparam>
public class IntervalTree<K, V> : IntrusiveRedBlackTreeImpl<IntervalTreeNode<K, V>> where K : IComparable<K>
{
private const int ArrayGrowthSize = 32;
#region Public Methods
/// <summary>
/// Gets the values of the interval whose key is <paramref name="key"/>.
/// </summary>
/// <param name="key">Key of the node value to get</param>
/// <param name="overlaps">Overlaps array to place results in</param>
/// <returns>Number of values found</returns>
/// <exception cref="ArgumentNullException"><paramref name="key"/> is null</exception>
public int Get(K key, ref V[] overlaps)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
IntervalTreeNode<K, V> node = GetNode(key);
if (node == null)
{
return 0;
}
if (node.Values.Count > overlaps.Length)
{
Array.Resize(ref overlaps, node.Values.Count);
}
int overlapsCount = 0;
foreach (RangeNode<K, V> value in node.Values)
{
overlaps[overlapsCount++] = value.Value;
}
return overlapsCount;
}
/// <summary>
/// Returns the values of the intervals whose start and end keys overlap the given range.
/// </summary>
/// <param name="start">Start of the range</param>
/// <param name="end">End of the range</param>
/// <param name="overlaps">Overlaps array to place results in</param>
/// <param name="overlapCount">Index to start writing results into the array. Defaults to 0</param>
/// <returns>Number of values found</returns>
/// <exception cref="ArgumentNullException"><paramref name="start"/> or <paramref name="end"/> is null</exception>
public int Get(K start, K end, ref V[] overlaps, int overlapCount = 0)
{
if (start == null)
{
throw new ArgumentNullException(nameof(start));
}
if (end == null)
{
throw new ArgumentNullException(nameof(end));
}
GetValues(Root, start, end, ref overlaps, ref overlapCount);
return overlapCount;
}
/// <summary>
/// Adds a new interval into the tree whose start is <paramref name="start"/>, end is <paramref name="end"/> and value is <paramref name="value"/>.
/// </summary>
/// <param name="start">Start of the range to add</param>
/// <param name="end">End of the range to insert</param>
/// <param name="value">Value to add</param>
/// <exception cref="ArgumentNullException"><paramref name="start"/>, <paramref name="end"/> or <paramref name="value"/> are null</exception>
public void Add(K start, K end, V value)
{
if (start == null)
{
throw new ArgumentNullException(nameof(start));
}
if (end == null)
{
throw new ArgumentNullException(nameof(end));
}
if (value == null)
{
throw new ArgumentNullException(nameof(value));
}
Insert(start, end, value);
}
/// <summary>
/// Removes the given <paramref name="value"/> from the tree, searching for it with <paramref name="key"/>.
/// </summary>
/// <param name="key">Key of the node to remove</param>
/// <param name="value">Value to remove</param>
/// <exception cref="ArgumentNullException"><paramref name="key"/> is null</exception>
/// <returns>Number of deleted values</returns>
public int Remove(K key, V value)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
int removed = Delete(key, value);
Count -= removed;
return removed;
}
/// <summary>
/// Adds all the nodes in the dictionary into <paramref name="list"/>.
/// </summary>
/// <returns>A list of all RangeNodes sorted by Key Order</returns>
public List<RangeNode<K, V>> AsList()
{
List<RangeNode<K, V>> list = new List<RangeNode<K, V>>();
AddToList(Root, list);
return list;
}
#endregion
#region Private Methods (BST)
/// <summary>
/// Adds all RangeNodes that are children of or contained within <paramref name="node"/> into <paramref name="list"/>, in Key Order.
/// </summary>
/// <param name="node">The node to search for RangeNodes within</param>
/// <param name="list">The list to add RangeNodes to</param>
private void AddToList(IntervalTreeNode<K, V> node, List<RangeNode<K, V>> list)
{
if (node == null)
{
return;
}
AddToList(node.Left, list);
list.AddRange(node.Values);
AddToList(node.Right, list);
}
/// <summary>
/// Retrieve the node reference whose key is <paramref name="key"/>, or null if no such node exists.
/// </summary>
/// <param name="key">Key of the node to get</param>
/// <returns>Node reference in the tree</returns>
/// <exception cref="ArgumentNullException"><paramref name="key"/> is null</exception>
private IntervalTreeNode<K, V> GetNode(K key)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
IntervalTreeNode<K, V> node = Root;
while (node != null)
{
int cmp = key.CompareTo(node.Start);
if (cmp < 0)
{
node = node.Left;
}
else if (cmp > 0)
{
node = node.Right;
}
else
{
return node;
}
}
return null;
}
/// <summary>
/// Retrieve all values that overlap the given start and end keys.
/// </summary>
/// <param name="start">Start of the range</param>
/// <param name="end">End of the range</param>
/// <param name="overlaps">Overlaps array to place results in</param>
/// <param name="overlapCount">Overlaps count to update</param>
private void GetValues(IntervalTreeNode<K, V> node, K start, K end, ref V[] overlaps, ref int overlapCount)
{
if (node == null || start.CompareTo(node.Max) >= 0)
{
return;
}
GetValues(node.Left, start, end, ref overlaps, ref overlapCount);
bool endsOnRight = end.CompareTo(node.Start) > 0;
if (endsOnRight)
{
if (start.CompareTo(node.End) < 0)
{
// Contains this node. Add overlaps to list.
foreach (RangeNode<K,V> overlap in node.Values)
{
if (start.CompareTo(overlap.End) < 0)
{
if (overlaps.Length >= overlapCount)
{
Array.Resize(ref overlaps, overlapCount + ArrayGrowthSize);
}
overlaps[overlapCount++] = overlap.Value;
}
}
}
GetValues(node.Right, start, end, ref overlaps, ref overlapCount);
}
}
/// <summary>
/// Inserts a new node into the tree with a given <paramref name="start"/>, <paramref name="end"/> and <paramref name="value"/>.
/// </summary>
/// <param name="start">Start of the range to insert</param>
/// <param name="end">End of the range to insert</param>
/// <param name="value">Value to insert</param>
private void Insert(K start, K end, V value)
{
IntervalTreeNode<K, V> newNode = BSTInsert(start, end, value);
RestoreBalanceAfterInsertion(newNode);
}
/// <summary>
/// Propagate an increase in max value starting at the given node, heading up the tree.
/// This should only be called if the max increases - not for rebalancing or removals.
/// </summary>
/// <param name="node">The node to start propagating from</param>
private void PropagateIncrease(IntervalTreeNode<K, V> node)
{
K max = node.Max;
IntervalTreeNode<K, V> ptr = node;
while ((ptr = ptr.Parent) != null)
{
if (max.CompareTo(ptr.Max) > 0)
{
ptr.Max = max;
}
else
{
break;
}
}
}
/// <summary>
/// Propagate recalculating max value starting at the given node, heading up the tree.
/// This fully recalculates the max value from all children when there is potential for it to decrease.
/// </summary>
/// <param name="node">The node to start propagating from</param>
private void PropagateFull(IntervalTreeNode<K, V> node)
{
IntervalTreeNode<K, V> ptr = node;
do
{
K max = ptr.End;
if (ptr.Left != null && ptr.Left.Max.CompareTo(max) > 0)
{
max = ptr.Left.Max;
}
if (ptr.Right != null && ptr.Right.Max.CompareTo(max) > 0)
{
max = ptr.Right.Max;
}
ptr.Max = max;
} while ((ptr = ptr.Parent) != null);
}
/// <summary>
/// Insertion Mechanism for the interval tree. Similar to a BST insert, with the start of the range as the key.
/// Iterates the tree starting from the root and inserts a new node where all children in the left subtree are less than <paramref name="start"/>, and all children in the right subtree are greater than <paramref name="start"/>.
/// Each node can contain multiple values, and has an end address which is the maximum of all those values.
/// Post insertion, the "max" value of the node and all parents are updated.
/// </summary>
/// <param name="start">Start of the range to insert</param>
/// <param name="end">End of the range to insert</param>
/// <param name="value">Value to insert</param>
/// <returns>The inserted Node</returns>
private IntervalTreeNode<K, V> BSTInsert(K start, K end, V value)
{
IntervalTreeNode<K, V> parent = null;
IntervalTreeNode<K, V> node = Root;
while (node != null)
{
parent = node;
int cmp = start.CompareTo(node.Start);
if (cmp < 0)
{
node = node.Left;
}
else if (cmp > 0)
{
node = node.Right;
}
else
{
node.Values.Add(new RangeNode<K, V>(start, end, value));
if (end.CompareTo(node.End) > 0)
{
node.End = end;
if (end.CompareTo(node.Max) > 0)
{
node.Max = end;
PropagateIncrease(node);
}
}
Count++;
return node;
}
}
IntervalTreeNode<K, V> newNode = new IntervalTreeNode<K, V>(start, end, value, parent);
if (newNode.Parent == null)
{
Root = newNode;
}
else if (start.CompareTo(parent.Start) < 0)
{
parent.Left = newNode;
}
else
{
parent.Right = newNode;
}
PropagateIncrease(newNode);
Count++;
return newNode;
}
/// <summary>
/// Removes instances of <paramref name="value"> from the dictionary after searching for it with <paramref name="key">.
/// </summary>
/// <param name="key">Key to search for</param>
/// <param name="value">Value to delete</param>
/// <returns>Number of deleted values</returns>
private int Delete(K key, V value)
{
IntervalTreeNode<K, V> nodeToDelete = GetNode(key);
if (nodeToDelete == null)
{
return 0;
}
int removed = nodeToDelete.Values.RemoveAll(node => node.Value.Equals(value));
if (nodeToDelete.Values.Count > 0)
{
if (removed > 0)
{
nodeToDelete.End = nodeToDelete.Values.Max(node => node.End);
// Recalculate max from children and new end.
PropagateFull(nodeToDelete);
}
return removed;
}
IntervalTreeNode<K, V> replacementNode;
if (LeftOf(nodeToDelete) == null || RightOf(nodeToDelete) == null)
{
replacementNode = nodeToDelete;
}
else
{
replacementNode = PredecessorOf(nodeToDelete);
}
IntervalTreeNode<K, V> tmp = LeftOf(replacementNode) ?? RightOf(replacementNode);
if (tmp != null)
{
tmp.Parent = ParentOf(replacementNode);
}
if (ParentOf(replacementNode) == null)
{
Root = tmp;
}
else if (replacementNode == LeftOf(ParentOf(replacementNode)))
{
ParentOf(replacementNode).Left = tmp;
}
else
{
ParentOf(replacementNode).Right = tmp;
}
if (replacementNode != nodeToDelete)
{
nodeToDelete.Start = replacementNode.Start;
nodeToDelete.Values = replacementNode.Values;
nodeToDelete.End = replacementNode.End;
nodeToDelete.Max = replacementNode.Max;
}
PropagateFull(replacementNode);
if (tmp != null && ColorOf(replacementNode) == Black)
{
RestoreBalanceAfterRemoval(tmp);
}
return removed;
}
#endregion
protected override void RotateLeft(IntervalTreeNode<K, V> node)
{
if (node != null)
{
base.RotateLeft(node);
PropagateFull(node);
}
}
protected override void RotateRight(IntervalTreeNode<K, V> node)
{
if (node != null)
{
base.RotateRight(node);
PropagateFull(node);
}
}
public bool ContainsKey(K key)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
return GetNode(key) != null;
}
}
/// <summary>
/// Represents a value and its start and end keys.
/// </summary>
/// <typeparam name="K"></typeparam>
/// <typeparam name="V"></typeparam>
public readonly struct RangeNode<K, V>
{
public readonly K Start;
public readonly K End;
public readonly V Value;
public RangeNode(K start, K end, V value)
{
Start = start;
End = end;
Value = value;
}
}
/// <summary>
/// Represents a node in the IntervalTree which contains start and end keys of type K, and a value of generic type V.
/// </summary>
/// <typeparam name="K">Key type of the node</typeparam>
/// <typeparam name="V">Value type of the node</typeparam>
public class IntervalTreeNode<K, V> : IntrusiveRedBlackTreeNode<IntervalTreeNode<K, V>>
{
/// <summary>
/// The start of the range.
/// </summary>
internal K Start;
/// <summary>
/// The end of the range - maximum of all in the Values list.
/// </summary>
internal K End;
/// <summary>
/// The maximum end value of this node and all its children.
/// </summary>
internal K Max;
/// <summary>
/// Values contained on the node that shares a common Start value.
/// </summary>
internal List<RangeNode<K, V>> Values;
internal IntervalTreeNode(K start, K end, V value, IntervalTreeNode<K, V> parent)
{
Start = start;
End = end;
Max = end;
Values = new List<RangeNode<K, V>> { new RangeNode<K, V>(start, end, value) };
Parent = parent;
}
}
}