implemented '*_scr.med' archives decryption.

ArcFormats/ArcFormats.csproj

@@ -87,6 +87,9 @@
     <Compile Include="Cri\ImageSPC.cs" />
     <Compile Include="Cri\ImageXTX.cs" />
     <Compile Include="DxLib\ArcMED.cs" />
+    <Compile Include="DxLib\WidgetSCR.xaml.cs">
+      <DependentUpon>WidgetSCR.xaml</DependentUpon>
+    </Compile>
     <Compile Include="elf\ArcVOL.cs" />
     <Compile Include="EmonEngine\ArcEME.cs" />
     <Compile Include="EmonEngine\ImageBMP.cs" />
@@ -532,6 +535,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="DxLib\WidgetSCR.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="FC01\WidgetMCG.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>

ArcFormats/DxLib/ArcMED.cs

@@ -27,9 +27,69 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.IO;
+using GameRes.Formats.Properties;
+using GameRes.Formats.Strings;
+using GameRes.Utility;
 
 namespace GameRes.Formats.DxLib
 {
+    public interface IScriptEncryption
+    {
+        int StartOffset { get; }
+
+        bool IsEncrypted (byte[] data);
+        void Decrypt (byte[] data, int offset, int length);
+    }
+
+    [Serializable]
+    public class FudegakiEncryption : IScriptEncryption
+    {
+        readonly byte[] Key;
+
+        public FudegakiEncryption (string keyword)
+        {
+            Key = Encodings.cp932.GetBytes (keyword);
+        }
+
+        public int StartOffset { get { return 0x10; } }
+
+        public bool IsEncrypted (byte[] data)
+        {
+            return LittleEndian.ToInt32 (data, 0) + 0x10 == data.Length && Key.Length > 0;
+        }
+
+        public void Decrypt (byte[] data, int offset, int length)
+        {
+            for (int i = 0; i < length; ++i)
+            {
+                data[offset+i] += Key[(offset+i) % Key.Length];
+            }
+        }
+    }
+
+    [Serializable]
+    public class MedOptions : ResourceOptions
+    {
+        public IScriptEncryption Encryption;
+    }
+
+    [Serializable]
+    public class ScrMedScheme : ResourceScheme
+    {
+        public Dictionary<string, IScriptEncryption> KnownSchemes;
+    }
+
+    internal class ScrMedArchive : ArcFile
+    {
+        public readonly IScriptEncryption Encryption;
+
+        public ScrMedArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, IScriptEncryption enc)
+            : base (arc, impl, dir)
+        {
+            Encryption = enc;
+        }
+    }
+
     [Export(typeof(ArchiveFormat))]
     public class MedOpener : ArchiveFormat
     {
@@ -41,6 +101,14 @@ namespace GameRes.Formats.DxLib
 
         static readonly Lazy<ImageFormat> PrsFormat = new Lazy<ImageFormat> (() => ImageFormat.FindByTag ("PRS"));
 
+        public static Dictionary<string, IScriptEncryption> KnownSchemes = new Dictionary<string, IScriptEncryption>();
+
+        public override ResourceScheme Scheme
+        {
+            get { return new ScrMedScheme { KnownSchemes = KnownSchemes }; }
+            set { KnownSchemes = ((ScrMedScheme)value).KnownSchemes; }
+        }
+
         public override ArcFile TryOpen (ArcView file)
         {
             if (!file.View.AsciiEqual (0, "MD"))
@@ -72,7 +140,49 @@ namespace GameRes.Formats.DxLib
                 dir.Add (entry);
                 index_offset += 8;
             }
+            var base_name = Path.GetFileNameWithoutExtension (file.Name);
+            if (base_name.EndsWith ("_scr", StringComparison.InvariantCultureIgnoreCase)
+                && KnownSchemes.Count > 0)
+            {
+                var options = Query<MedOptions> (arcStrings.ArcEncryptedNotice);
+                if (options.Encryption != null)
+                    return new ScrMedArchive (file, this, dir, options.Encryption);
+            }
             return new ArcFile (file, this, dir);
         }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var scr_arc = arc as ScrMedArchive;
+            if (null == scr_arc || entry.Size <= scr_arc.Encryption.StartOffset)
+                return base.OpenEntry (arc, entry);
+            var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
+            if (scr_arc.Encryption.IsEncrypted (data))
+            {
+                var offset = scr_arc.Encryption.StartOffset;
+                scr_arc.Encryption.Decrypt (data, offset, data.Length-offset);
+            }
+            return new MemoryStream (data);
+        }
+
+        public override ResourceOptions GetDefaultOptions ()
+        {
+            return new MedOptions {
+                Encryption = GetEncryption (Settings.Default.MEDScriptScheme),
+            };
+        }
+
+        public override object GetAccessWidget ()
+        {
+            return new GUI.WidgetSCR();
+        }
+
+        public static IScriptEncryption GetEncryption (string scheme)
+        {
+            IScriptEncryption enc;
+            if (string.IsNullOrEmpty (scheme) || !KnownSchemes.TryGetValue (scheme, out enc))
+                return null;
+            return enc;
+        }
     }
 }

ArcFormats/DxLib/WidgetSCR.xaml

@@ -0,0 +1,9 @@
+<StackPanel x:Class="GameRes.Formats.GUI.WidgetSCR"
+            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+            xmlns:s="clr-namespace:GameRes.Formats.Strings"
+            xmlns:p="clr-namespace:GameRes.Formats.Properties"
+            xmlns:d="clr-namespace:GameRes.Formats.DxLib">
+    <ComboBox Name="ScriptScheme" ItemsSource="{Binding}" Width="250"
+              SelectedValue="{Binding Source={x:Static p:Settings.Default}, Path=MEDScriptScheme, Mode=TwoWay}"/>
+</StackPanel>

ArcFormats/DxLib/WidgetSCR.xaml.cs

@@ -0,0 +1,22 @@
+using System.Windows.Controls;
+using System.Linq;
+using GameRes.Formats.DxLib;
+using GameRes.Formats.Strings;
+
+namespace GameRes.Formats.GUI
+{
+    /// <summary>
+    /// Interaction logic for WidgetSCR.xaml
+    /// </summary>
+    public partial class WidgetSCR : StackPanel
+    {
+        public WidgetSCR()
+        {
+            InitializeComponent();
+            var keys = new string[] { arcStrings.ArcIgnoreEncryption };
+            ScriptScheme.ItemsSource = keys.Concat (MedOpener.KnownSchemes.Keys.OrderBy (x => x));
+            if (-1 == ScriptScheme.SelectedIndex)
+                ScriptScheme.SelectedIndex = 0;
+        }
+    }
+}

ArcFormats/Properties/Settings.Designer.cs

@@ -537,5 +537,17 @@ namespace GameRes.Formats.Properties {
                 this["NCARCScheme"] = value;
             }
         }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("")]
+        public string MEDScriptScheme {
+            get {
+                return ((string)(this["MEDScriptScheme"]));
+            }
+            set {
+                this["MEDScriptScheme"] = value;
+            }
+        }
     }
 }

ArcFormats/Properties/Settings.settings

@@ -131,5 +131,8 @@
     <Setting Name="NCARCScheme" Type="System.String" Scope="User">
       <Value Profile="(Default)" />
     </Setting>
+    <Setting Name="MEDScriptScheme" Type="System.String" Scope="User">
+      <Value Profile="(Default)" />
+    </Setting>
   </Settings>
 </SettingsFile>

ArcFormats/app.config

@@ -133,6 +133,9 @@
             <setting name="NCARCScheme" serializeAs="String">
                 <value />
             </setting>
+            <setting name="MEDScriptScheme" serializeAs="String">
+                <value />
+            </setting>
         </GameRes.Formats.Properties.Settings>
     </userSettings>
 <startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup></configuration>