From 95852ac7297def2efbb55985d453acd16f133e09 Mon Sep 17 00:00:00 2001
From: morkt <morkt@users.noreply.github.com>
Date: Wed, 7 Feb 2018 03:45:07 +0400
Subject: [PATCH] implemented Utage encrypted images.

---
 ArcFormats/ArcFormats.csproj         |   3 +
 ArcFormats/Unity/Utage/ImageUTAGE.cs | 102 +++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 ArcFormats/Unity/Utage/ImageUTAGE.cs

diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index ab72653e..5016f39a 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -91,6 +91,7 @@
     <Compile Include="Abogado\ImageKG.cs" />
     <Compile Include="Actgs\ArcCG.cs" />
     <Compile Include="Actgs\ArcDAT.cs" />
+    <Compile Include="AdvScripter\ArcPAK.cs" />
     <Compile Include="AdvSys\ArcAdvSys3.cs" />
     <Compile Include="AdvSys\ImageGWD.cs" />
     <Compile Include="Ail\ArcLNK2.cs" />
@@ -144,6 +145,7 @@
     <Compile Include="Ikura\ImageTAN.cs" />
     <Compile Include="Ikura\ImageVRS.cs" />
     <Compile Include="ImageMNG.cs" />
+    <Compile Include="Ivory\ArcSG.cs" />
     <Compile Include="KiriKiri\MoreCrypt.cs" />
     <Compile Include="Lambda\ArcLAX.cs" />
     <Compile Include="Lambda\ImageCLS.cs" />
@@ -636,6 +638,7 @@
     <Compile Include="Unity\BundleStream.cs" />
     <Compile Include="Unity\OggStream.cs" />
     <Compile Include="Unity\Texture2D.cs" />
+    <Compile Include="Unity\Utage\ImageUTAGE.cs" />
     <Compile Include="Unity\Vorbis.cs" />
     <Compile Include="Valkyria\ArcDAT.cs" />
     <Compile Include="Valkyria\ArcODN.cs" />
diff --git a/ArcFormats/Unity/Utage/ImageUTAGE.cs b/ArcFormats/Unity/Utage/ImageUTAGE.cs
new file mode 100644
index 00000000..a8458126
--- /dev/null
+++ b/ArcFormats/Unity/Utage/ImageUTAGE.cs
@@ -0,0 +1,102 @@
+//! \file       ImageUTAGE.cs
+//! \date       2018 Feb 05
+//! \brief      Utage engine encrypted image.
+//
+// Copyright (C) 2018 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.ComponentModel.Composition;
+using System.IO;
+using System.Text;
+
+namespace GameRes.Formats.Unity.Utage
+{
+    [Export(typeof(ImageFormat))]
+    public class UtageFormat : ImageFormat
+    {
+        public override string         Tag { get { return "UTAGE"; } }
+        public override string Description { get { return "Utage engine encrypted image"; } }
+        public override uint     Signature { get { return 0x323E3EC0; } }
+
+        public static readonly byte[] KnownKey = Encoding.UTF8.GetBytes ("InputOriginalKey");
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            using (var input = OpenEncryptedStream (file, KnownKey))
+                return Png.ReadMetaData (input);
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            using (var input = OpenEncryptedStream (file, KnownKey))
+                return Png.Read (input, info);
+        }
+
+        internal IBinaryStream OpenEncryptedStream (IBinaryStream file, byte[] key)
+        {
+            var input = new UtageEncryptedStream (file.AsStream, key, true);
+            return new BinaryStream (input, file.Name);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("UtageFormat.Write not implemented");
+        }
+    }
+
+    internal class UtageEncryptedStream : InputProxyStream
+    {
+        byte[]  m_key;
+
+        public UtageEncryptedStream (Stream main, byte[] key, bool leave_open = false)
+            : base (main, leave_open)
+        {
+            m_key = key;
+        }
+
+        public override int Read (byte[] buffer, int offset, int count)
+        {
+            int key_length = m_key.Length;
+            int start_pos = (int)(BaseStream.Position % key_length);
+            int read = BaseStream.Read (buffer, offset, count);
+            for (int i = 0; i < read; ++i)
+            {
+                byte key = m_key[(start_pos + i) % key_length];
+                if (buffer[offset+i] != 0 && buffer[offset+i] != key)
+                    buffer[offset+i] ^= key;
+            }
+            return read;
+        }
+
+        public override int ReadByte ()
+        {
+            long pos = BaseStream.Position;
+            int b = BaseStream.ReadByte();
+            if (b > 0)
+            {
+                byte key = m_key[pos % m_key.Length];
+                if (b != key)
+                    b ^= key;
+            }
+            return b;
+        }
+    }
+}