Add save/load for FEAT chunk

UndertaleModLib/Models/UndertaleFeatureFlags.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace UndertaleModLib.Models;
+
+/// <summary>
+/// List of feature flag entries in a GameMaker data file, version 2022.8 and above.
+/// </summary>
+[PropertyChanged.AddINotifyPropertyChangedInterface]
+public class UndertaleFeatureFlags : UndertaleObject, IDisposable
+{
+    public UndertaleSimpleListString List { get; set; }
+
+
+    /// <inheritdoc />
+    public void Serialize(UndertaleWriter writer)
+    {
+        List.Serialize(writer);
+    }
+
+    /// <inheritdoc />
+    public void Unserialize(UndertaleReader reader)
+    {
+        List = new UndertaleSimpleListString();
+        List.Unserialize(reader);
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        GC.SuppressFinalize(this);
+
+        List = null;
+    }
+}

UndertaleModLib/UndertaleChunks.cs

@@ -50,6 +50,7 @@ public class UndertaleChunkFORM : UndertaleChunk
         public UndertaleChunkACRV ACRV => Chunks.GetValueOrDefault("ACRV") as UndertaleChunkACRV;
         public UndertaleChunkSEQN SEQN => Chunks.GetValueOrDefault("SEQN") as UndertaleChunkSEQN;
         public UndertaleChunkTAGS TAGS => Chunks.GetValueOrDefault("TAGS") as UndertaleChunkTAGS;
+        public UndertaleChunkFEAT FEAT => Chunks.GetValueOrDefault("FEAT") as UndertaleChunkFEAT;
 
         internal override void SerializeChunk(UndertaleWriter writer)
         {
@@ -1054,4 +1055,34 @@ internal override void UnserializeChunk(UndertaleReader reader)
             base.UnserializeChunk(reader);
         }
     }
+
+    // GMS2022.8+ only
+    public class UndertaleChunkFEAT : UndertaleSingleChunk<UndertaleFeatureFlags>
+    {
+        public override string Name => "FEAT";
+
+        internal override void SerializeChunk(UndertaleWriter writer)
+        {
+            if (writer.undertaleData.GeneralInfo.Major < 2)
+                throw new InvalidOperationException();
+
+            while (writer.Position % 4 != 0)
+                writer.Write((byte)0);
+
+            base.SerializeChunk(writer);
+        }
+
+        internal override void UnserializeChunk(UndertaleReader reader)
+        {
+            if (reader.undertaleData.GeneralInfo.Major < 2)
+                throw new InvalidOperationException();
+
+            // Padding
+            while (reader.Position % 4 != 0)
+                if (reader.ReadByte() != 0)
+                    throw new IOException("Padding error!");
+
+            base.UnserializeChunk(reader);
+        }
+    }
 }

UndertaleModLib/UndertaleData.cs

@@ -269,6 +269,11 @@ public object this[Type resourceType]
         /// </summary>
         public IList<UndertaleSequence> Sequences => FORM.SEQN?.List;
 
+        /// <summary>
+        /// The feature flags stored in the data file.
+        /// </summary>
+        public UndertaleFeatureFlags FeatureFlags => FORM.FEAT?.Object;
+
         /// <summary>
         /// Whether this is an unsupported bytecode version.
         /// </summary>