From e24c01ad0f930783ef2a45a48d174044a57fb72a Mon Sep 17 00:00:00 2001
From: morkt <morkt@users.noreply.github.com>
Date: Sun, 27 Jan 2019 02:27:21 +0400
Subject: [PATCH] implemented 'arc2' archives.

---
 ArcFormats/ArcFormats.csproj |   1 +
 ArcFormats/CsWare/ArcARC2.cs | 111 +++++++++++++++++++++++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 ArcFormats/CsWare/ArcARC2.cs

diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index d376c95b..8d5345f7 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -148,6 +148,7 @@
     <Compile Include="Cmvs\HuffmanDecoder.cs" />
     <Compile Include="Crc16.cs" />
     <Compile Include="Crowd\ImageCRZ.cs" />
+    <Compile Include="CsWare\ArcARC2.cs" />
     <Compile Include="CsWare\ArcDAT.cs" />
     <Compile Include="CsWare\ImageB5.cs" />
     <Compile Include="CsWare\ImageBPC.cs" />
diff --git a/ArcFormats/CsWare/ArcARC2.cs b/ArcFormats/CsWare/ArcARC2.cs
new file mode 100644
index 00000000..4c49a4d6
--- /dev/null
+++ b/ArcFormats/CsWare/ArcARC2.cs
@@ -0,0 +1,111 @@
+//! \file       ArcARC2.cs
+//! \date       2019 Jan 26
+//! \brief      C's ware resource archive.
+//
+// Copyright (C) 2019 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;
+
+// [960405][C's Ware] GLO-RI-A ~Kindan no Ketsuzoku~
+
+namespace GameRes.Formats.CsWare
+{
+    internal class Arc2Entry : Entry
+    {
+        public uint Key1;
+        public uint Key2;
+    }
+
+    [Export(typeof(ArchiveFormat))]
+    public class Arc2Opener : ArchiveFormat
+    {
+        public override string         Tag { get { return "DAT/ARC2"; } }
+        public override string Description { get { return "C's ware resource archive"; } }
+        public override uint     Signature { get { return 0x32637261; } } // 'arc2'
+        public override bool  IsHierarchic { get { return false; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            int count = file.View.ReadInt32 (4);
+            if (!IsSaneCount (count))
+                return null;
+            uint index_offset = file.View.ReadUInt32 (8);
+            if (index_offset >= file.MaxOffset)
+                return null;
+            var names = new HashSet<string>();
+            var dir = new List<Entry> (count);
+            for (int i = 0; i < count; ++i)
+            {
+                var name = file.View.ReadString (index_offset, 0x10);
+                if (names.Add (name))
+                {
+                    var entry = Create<Arc2Entry> (name);
+                    entry.Offset = file.View.ReadUInt32 (index_offset+0x10);
+                    entry.Size   = file.View.ReadUInt32 (index_offset+0x14);
+                    if (!entry.CheckPlacement (file.MaxOffset))
+                        return null;
+                    entry.Key1   = file.View.ReadUInt32 (index_offset+0x18);
+                    entry.Key2   = file.View.ReadUInt32 (index_offset+0x1C);
+                    dir.Add (entry);
+                }
+                index_offset += 0x20;
+            }
+            foreach (Arc2Entry entry in dir)
+            {
+                uint signature = file.View.ReadUInt32 (entry.Offset) - (entry.Key1 + entry.Key2);
+                entry.ChangeType (AutoEntry.DetectFileType (signature));
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var a2ent = entry as Arc2Entry;
+            if (null == a2ent || 0 == (a2ent.Key1 | a2ent.Key2))
+                return base.OpenEntry (arc, entry);
+            uint length = (entry.Size + 3) & ~3u;
+            var data = new byte[length];
+            arc.File.View.Read (entry.Offset, data, 0, entry.Size);
+            uint key1 = a2ent.Key1;
+            uint key2 = a2ent.Key2;
+            unsafe
+            {
+                fixed (byte* data8 = data)
+                {
+                    uint* data32 = (uint*)data8;
+                    for (uint i = 0; i < length; i += 4)
+                    {
+                        uint key_sum = key1 + key2;
+                        *data32++ -= key_sum;
+                        key1 = key2;
+                        key2 = key_sum;
+                    }
+                }
+            }
+            return new BinMemoryStream (data, 0, (int)entry.Size, entry.Name);
+        }
+    }
+}