implemented variation of Silky's archives.

ArcFormats/ArcFormats.csproj

@@ -247,6 +247,7 @@
     <Compile Include="ScrPlayer\ArcPAK.cs" />
     <Compile Include="ScrPlayer\ImageI.cs" />
     <Compile Include="ShiinaRio\WarcEncryption.cs" />
+    <Compile Include="Silky\ArcAzurite.cs" />
     <Compile Include="Silky\ImageZIT.cs" />
     <Compile Include="SimpleEncryption.cs" />
     <Compile Include="Slg\ArcSZS.cs" />

ArcFormats/Silky/ArcAzurite.cs

@@ -0,0 +1,85 @@
+//! \file       ArcAzurite.cs
+//! \date       Fri Dec 30 04:09:23 2016
+//! \brief      Silky's resource archive.
+//
+// Copyright (C) 2016 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 GameRes.Utility;
+
+namespace GameRes.Formats.Silky
+{
+    [Export(typeof(ArchiveFormat))]
+    public class SilkyArcOpener : Ai6Opener
+    {
+        public override string         Tag { get { return "ARC/AZURITE"; } }
+        public override string Description { get { return "Silky's 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)
+        {
+            if (!file.Name.EndsWith (".arc", StringComparison.InvariantCultureIgnoreCase))
+                return null;
+            uint index_size = file.View.ReadUInt32 (0);
+            if (index_size < 10 || index_size >= file.MaxOffset-4)
+                return null;
+            if (0 == file.View.ReadByte (4))
+                return null;
+
+            var dir = new List<Entry>();
+            using (var index = file.CreateStream (4, index_size))
+            {
+                var name_buffer = new byte[0x100];
+                while (index.PeekByte() != -1)
+                {
+                    int name_length = index.ReadByte();
+                    if (0 == name_length)
+                        return null;
+                    if (name_length != index.Read (name_buffer, 0, name_length))
+                        return null;
+                    DecryptName (name_buffer, name_length);
+                    var name = Encodings.cp932.GetString (name_buffer, 0, name_length);
+                    var entry = FormatCatalog.Instance.Create<PackedEntry> (name);
+                    entry.Size          = Binary.BigEndian (index.ReadUInt32());
+                    entry.UnpackedSize  = Binary.BigEndian (index.ReadUInt32());
+                    entry.Offset        = Binary.BigEndian (index.ReadUInt32());
+                    if (entry.Offset < index_size+4 || !entry.CheckPlacement (file.MaxOffset))
+                        return null;
+                    entry.IsPacked = entry.Size != entry.UnpackedSize;
+                    dir.Add (entry);
+                }
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        static void DecryptName (byte[] buffer, int length)
+        {
+            byte key = (byte)length;
+            for (int i = 0; i < length; ++i)
+                buffer[i] += key--;
+        }
+    }
+}