Replace BinaryFormatter with DataContractSerializer (#641)

* Replace BinaryFormatter with DataContractSerializer

BinaryFormatter is deprecated in future .NET versions and may prevent
assemblies from unloading or return incorrect results.

Replaced with System.Runtime.Serialization.DataContractSerializer as
recommended for compatibility.

Changes:
- KdTree.cs: Replaced BinaryFormatter with DataContractSerializer in
  SaveToFile and LoadFromFile methods
- KdTreeNode.cs: Added DataContract and DataMember attributes
- Added [DataContract] and [DataMember] attributes to all serialized classes

Related to SCP-1555

* Use binary XML format for DataContractSerializer

Switch from text XML to binary XML format using XmlDictionaryWriter.CreateBinaryWriter()
and XmlDictionaryReader.CreateBinaryReader(). This provides:
- Binary format similar to BinaryFormatter (more compact and efficient)
- Better performance for large KdTree data structures
- Still uses DataContractSerializer for CoreCLR compatibility

Note: This changes the file format. Existing serialized KdTree files will need to be regenerated.

---------

Co-authored-by: thomas-tu <45040865+thomas-tu@users.noreply.github.com>

Author: MiroBrodlovaUnityGit

External/KdTree/KdTreeLib/KdTree.cs

@@ -3,8 +3,9 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.Serialization.Formatters.Binary;
+using System.Runtime.Serialization;
 using System.Text;
+using System.Xml;
 
 namespace UnityEngine.ProBuilder.KdTree
 {
@@ -25,6 +26,7 @@ public DuplicateNodeError()
 	}
 
 	[Serializable]
+	[DataContract]
 	class KdTree<TKey, TValue> : IKdTree<TKey, TValue>
 	{
 		public KdTree(int dimensions, ITypeMath<TKey> typeMath)
@@ -40,12 +42,16 @@ public KdTree(int dimensions, ITypeMath<TKey> typeMath, AddDuplicateBehavior add
 			AddDuplicateBehavior = addDuplicateBehavior;
 		}
 
+		[DataMember]
 		private int dimensions;
 
+		[DataMember]
 		private ITypeMath<TKey> typeMath = null;
 
+		[DataMember]
 		private KdTreeNode<TKey, TValue> root = null;
 
+		[DataMember]
 		public AddDuplicateBehavior AddDuplicateBehavior { get; private set; }
 
 		public bool Add(TKey[] point, TValue value)
@@ -370,7 +376,8 @@ public KdTreeNode<TKey, TValue>[] RadialSearch(TKey[] center, TKey radius, int c
 			return neighbourArray;
 		}
 
-		public int Count { get; private set; }
+		[DataMember]
+	public int Count { get; private set; }
 
 		public bool TryFindValueAt(TKey[] point, out TValue value)
 		{
@@ -578,20 +585,22 @@ public void Clear()
 
 		public void SaveToFile(string filename)
 		{
-			BinaryFormatter formatter = new BinaryFormatter();
+			var serializer = new DataContractSerializer(typeof(KdTree<TKey, TValue>));
 			using (FileStream stream = File.Create(filename))
+			using (var writer = XmlDictionaryWriter.CreateBinaryWriter(stream))
 			{
-				formatter.Serialize(stream, this);
-				stream.Flush();
+				serializer.WriteObject(writer, this);
+				writer.Flush();
 			}
 		}
 
 		public static KdTree<TKey, TValue> LoadFromFile(string filename)
 		{
-			BinaryFormatter formatter = new BinaryFormatter();
+			var serializer = new DataContractSerializer(typeof(KdTree<TKey, TValue>));
 			using (FileStream stream = File.Open(filename, FileMode.Open))
+			using (var reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max))
 			{
-				return (KdTree<TKey, TValue>)formatter.Deserialize(stream);
+				return (KdTree<TKey, TValue>)serializer.ReadObject(reader);
 			}
 
 		}

External/KdTree/KdTreeLib/KdTreeNode.cs

@@ -2,10 +2,12 @@
 using System.Text;
 using System.Linq;
 using System.Collections.Generic;
+using System.Runtime.Serialization;
 
 namespace UnityEngine.ProBuilder.KdTree
 {
 	[Serializable]
+	[DataContract]
 	class KdTreeNode<TKey, TValue>
 	{
 		public KdTreeNode()
@@ -18,11 +20,16 @@ public KdTreeNode(TKey[] point, TValue value)
 			Value = value;
 		}
 
+		[DataMember]
 		public TKey[] Point;
+		[DataMember]
 		public TValue Value = default(TValue);
+		[DataMember]
 		public List<TValue> Duplicates = null;
 
+		[DataMember]
 		internal KdTreeNode<TKey, TValue> LeftChild = null;
+		[DataMember]
 		internal KdTreeNode<TKey, TValue> RightChild = null;
 
 		internal KdTreeNode<TKey, TValue> this[int compare]