Added write support for binary files!

Holy cow, this took a lot of work. I think I may need to do a few more
things before I consider this a 1.0 release, but I'm glad to have
finally overcome this hurdle!

BinaryFormat/Chunks/INST.cs

@@ -1,40 +1,111 @@
-namespace RobloxFiles.BinaryFormat.Chunks
+using System.Collections.Generic;
+using System.Linq;
+
+namespace RobloxFiles.BinaryFormat.Chunks
 {
-    public class INST
+    public class INST : IBinaryFileChunk
     {
-        public readonly int TypeIndex;
-        public readonly string TypeName;
-        public readonly bool IsService;
-        public readonly int NumInstances;
-        public readonly int[] InstanceIds;
+        public int TypeIndex { get; internal set; }
+        public string TypeName { get; internal set; }
+
+        public bool IsService { get; internal set; }
+        public List<bool> RootedServices { get; internal set; }
+
+        public int NumInstances { get; internal set; }
+        public List<int> InstanceIds { get; internal set; }
 
         public override string ToString()
         {
             return TypeName;
         }
 
-        public INST(BinaryRobloxFileChunk chunk)
+        public void LoadFromReader(BinaryRobloxFileReader reader)
         {
-            using (BinaryRobloxFileReader reader = chunk.GetDataReader())
-            {
-                TypeIndex = reader.ReadInt32();
-                TypeName = reader.ReadString();
-                IsService = reader.ReadBoolean();
+            BinaryRobloxFile file = reader.File;
 
-                NumInstances = reader.ReadInt32();
-                InstanceIds = reader.ReadInstanceIds(NumInstances);
+            TypeIndex = reader.ReadInt32();
+            TypeName = reader.ReadString();
+            IsService = reader.ReadBoolean();
+
+            NumInstances = reader.ReadInt32();
+            InstanceIds = reader.ReadInstanceIds(NumInstances);
+
+            if (IsService)
+            {
+                RootedServices = new List<bool>();
+
+                for (int i = 0; i < NumInstances; i++)
+                {
+                    bool isRooted = reader.ReadBoolean();
+                    RootedServices.Add(isRooted);
+                }
             }
-        }
 
-        public void Allocate(BinaryRobloxFile file)
-        {
-            foreach (int instId in InstanceIds)
+            for (int i = 0; i < NumInstances; i++)
             {
-                Instance inst = new Instance() { ClassName = TypeName };
+                int instId = InstanceIds[i];
+
+                var inst = new Instance()
+                {
+                    ClassName = TypeName,
+                    IsService = IsService,
+                    Referent = instId.ToString()
+                };
+
+                if (IsService)
+                {
+                    bool rooted = RootedServices[i];
+                    inst.IsRootedService = rooted;
+                }
+
                 file.Instances[instId] = inst;
             }
 
             file.Types[TypeIndex] = this;
         }
+
+        public BinaryRobloxFileChunk SaveAsChunk(BinaryRobloxFileWriter writer)
+        {
+            writer.StartWritingChunk(this);
+
+            writer.Write(TypeIndex);
+            writer.WriteString(TypeName);
+
+            writer.Write(IsService);
+            writer.Write(NumInstances);
+            writer.WriteInstanceIds(InstanceIds);
+
+            if (IsService)
+            {
+                BinaryRobloxFile file = writer.File;
+
+                foreach (int instId in InstanceIds)
+                {
+                    Instance service = file.Instances[instId];
+                    writer.Write(service.IsRootedService);
+                }
+            }
+
+            return writer.FinishWritingChunk();
+        }
+
+        internal static void ApplyTypeMap(BinaryRobloxFileWriter writer)
+        {
+            BinaryRobloxFile file = writer.File;
+            file.Instances = writer.Instances.ToArray();
+
+            var types = writer.TypeMap
+                .OrderBy(type => type.Key)
+                .Select(type => type.Value)
+                .ToArray();
+
+            for (int i = 0; i < types.Length; i++, file.NumTypes++)
+            {
+                INST type = types[i];
+                type.TypeIndex = i;
+            }
+
+            file.Types = types;
+        }
     }
 }