From d37285960f4096d0c9e06e4f9961a80d99bf516c Mon Sep 17 00:00:00 2001
From: scientificworld <scientificworld@users.noreply.github.com>
Date: Fri, 9 Jan 2026 11:13:05 +0800
Subject: [PATCH] feat: (DAT/TIMELEAP) add support for unencrypted archive used
 in trial edition

---
 ArcFormats/FrontWing/ArcDAT.cs | 47 ++++++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/ArcFormats/FrontWing/ArcDAT.cs b/ArcFormats/FrontWing/ArcDAT.cs
index 9abbb8bb..3a1ce1a1 100644
--- a/ArcFormats/FrontWing/ArcDAT.cs
+++ b/ArcFormats/FrontWing/ArcDAT.cs
@@ -31,6 +31,19 @@ using GameRes.Utility;
 
 namespace GameRes.Formats.FrontWing
 {
+    internal class TimeLeapArchive : ArcFile
+    {
+        private bool m_encrypted;
+
+        public bool IsEncrypted { get { return m_encrypted; } }
+
+        public TimeLeapArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, bool encrypted)
+            : base (arc, impl, dir)
+        {
+            m_encrypted = encrypted;
+        }
+    }
+
     [Export(typeof(ArchiveFormat))]
     public class DatOpener : ArchiveFormat
     {
@@ -52,7 +65,17 @@ namespace GameRes.Formats.FrontWing
             if (file.MaxOffset < index_size + 4)
                 return null;
             var index = file.View.ReadBytes (file.MaxOffset - 4 - index_size, (uint)index_size);
-            NibbleSwap (index);
+            bool encrypted = false;
+            for (int i = 0; i < 40 && index[i] != 0; i++)
+            {
+                if (index[i] < 0x20 || index[i] >= 0x7f)
+                {
+                    encrypted = true;
+                    break;
+                }
+            }
+            if (encrypted)
+                NibbleSwap (index);
 
             int index_offset = 0;
             var dir = new List<Entry> (count);
@@ -67,7 +90,7 @@ namespace GameRes.Formats.FrontWing
                 index_offset += 0x50;
                 dir.Add (entry);
             }
-            return new ArcFile (file, this, dir);
+            return new TimeLeapArchive (file, this, dir, encrypted);
         }
 
         static readonly byte[] keyTable = {
@@ -80,16 +103,20 @@ namespace GameRes.Formats.FrontWing
 
         public override Stream OpenEntry (ArcFile arc, Entry entry)
         {
-            var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
-            for (int i = 1; i < data.Length; i += 4)
+            var tarc = arc as TimeLeapArchive;
+            var data = tarc.File.View.ReadBytes (entry.Offset, entry.Size);
+            if (tarc.IsEncrypted)
             {
-                data[i] = (byte)(-data[i] & 0xff);
+                for (int i = 1; i < data.Length; i += 4)
+                {
+                    data[i] = (byte)(-data[i] & 0xff);
+                }
+                for (int i = 0; i < data.Length; i += 3)
+                {
+                    data[i] ^= keyTable[i / 5 % 5 + i % 6];
+                }
+                NibbleSwap (data, 2, 6);
             }
-            for (int i = 0; i < data.Length; i += 3)
-            {
-                data[i] ^= keyTable[i / 5 % 5 + i % 6];
-            }
-            NibbleSwap(data, 2, 6);
             return new BinMemoryStream (data);
         }