From ec15a2ad84ac6e0549603ed06746e1febc54bb8f Mon Sep 17 00:00:00 2001
From: scientificworld <scientificworld@users.noreply.github.com>
Date: Thu, 25 Dec 2025 20:26:47 +0800
Subject: [PATCH] feat: add DAT/DUKE format

similar to PAC/CLIO but with encryption.
---
 Legacy/Duke/ArcDAT.cs | 88 +++++++++++++++++++++++++++++++++++++++++++
 Legacy/Legacy.csproj  |  1 +
 2 files changed, 89 insertions(+)
 create mode 100644 Legacy/Duke/ArcDAT.cs

diff --git a/Legacy/Duke/ArcDAT.cs b/Legacy/Duke/ArcDAT.cs
new file mode 100644
index 00000000..2a5d70d3
--- /dev/null
+++ b/Legacy/Duke/ArcDAT.cs
@@ -0,0 +1,88 @@
+//! \file       ArcDAT.cs
+//! \date       2025-12-25
+//! \brief      Duke resource archive.
+//
+// Copyright (C) 2017 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.IO;
+using GameRes.Utility;
+
+namespace GameRes.Formats.Duke
+{
+    [Export(typeof(ArchiveFormat))]
+    public class DatOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "DAT/DUKE"; } }
+        public override string Description { get { return "Duke resource archive"; } }
+        public override uint     Signature { get { return 0; } }
+        public override bool  IsHierarchic { get { return false; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            int count = (int)(file.View.ReadUInt32 (0) ^ 0xfa261efb);
+            if (!file.Name.HasExtension (".dat") || !IsSaneCount (count))
+                return null;
+
+            uint index_offset = 4;
+            uint data_offset = index_offset + (uint)count * 0x28u;
+            var dir = new List<Entry> (count);
+            for (int i = 0; i < count; ++i)
+            {
+                var buffer = file.View.ReadBytes (index_offset, 0x20);
+                for (int counter = 0; counter < 0x20; counter++)
+                {
+                    buffer[counter] = (byte)(buffer[counter] ^ counter * 5 + 172);
+                }
+                var name = Binary.GetCString (buffer, 0);
+                if (string.IsNullOrWhiteSpace (name))
+                    return null;
+                var entry = FormatCatalog.Instance.Create<Entry> (name);
+                entry.Size   = (uint)(file.View.ReadUInt32 (index_offset+0x20) ^ 0xfa261efb);
+                entry.Offset = file.View.ReadUInt32 (index_offset+0x24);
+                if (entry.Offset < data_offset || !entry.CheckPlacement (file.MaxOffset))
+                    return null;
+                dir.Add (entry);
+                index_offset += 0x28;
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
+            var name = Encodings.cp932.GetBytes (entry.Name);
+            int length = name.Length;
+            for (int i = 0; i < entry.Size && i < 0x2c00; i += length)
+            {
+                for (int j = 0; j < length && j < entry.Size - i; j++)
+                {
+                    data[i + j] = (byte)(data[i + j] ^ name[j] + i + j);
+                }
+            }
+            return new BinMemoryStream (data);
+        }
+    }
+}
diff --git a/Legacy/Legacy.csproj b/Legacy/Legacy.csproj
index 19c8f3e5..fadcf734 100644
--- a/Legacy/Legacy.csproj
+++ b/Legacy/Legacy.csproj
@@ -214,6 +214,7 @@
     <Compile Include="Dice\ArcRLZ.cs" />
     <Compile Include="Dice\AudioKWF.cs" />
     <Compile Include="Dice\ImageRBP.cs" />
+    <Compile Include="Duke\ArcDAT.cs" />
     <Compile Include="Electriciteit\ArcDAT.cs" />
     <Compile Include="Eve\ArcGM.cs" />
     <Compile Include="Eve\AudioWV.cs" />