(Unity): 'PMaster' resource archive.

ArcFormats/Unity/PMaster/ArcDAT.cs

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+//! \file       ArcDAT.cs
+//! \date       2019 Feb 26
+//! \brief      Unity PMaster engine 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;
+using GameRes.Utility;
+
+namespace GameRes.Formats.Unity.PMaster
+{
+    internal class PMasterEntry : Entry
+    {
+        public uint Key;
+    }
+
+    [Export(typeof(ArchiveFormat))]
+    public class DatOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "DAT/PMASTER"; } }
+        public override string Description { get { return "Unity PMaster engine resource archive"; } }
+        public override uint     Signature { get { return 0; } }
+        public override bool  IsHierarchic { get { return true; } }
+        public override bool      CanWrite { get { return false; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            int count = 0;
+            for (int i = 0; i < 0x400; i += 4)
+                count += file.View.ReadInt32 (i);
+            if (!IsSaneCount (count))
+                return null;
+            uint index_length = (uint)count * 0x10;
+            if (index_length >= file.MaxOffset)
+                return null;
+            var index = file.View.ReadBytes (0x400, index_length);
+            DecryptData (index, file.View.ReadUInt32 (0xD4));
+
+            uint first_offset = index.ToUInt32 (4);
+            if (first_offset >= file.MaxOffset || first_offset <= (0x400 + index_length))
+                return null;
+            uint names_length = first_offset - (0x400 + index_length);
+            var names = file.View.ReadBytes (0x400 + index_length, names_length);
+            DecryptData (names, file.View.ReadUInt32 (0x5C));
+
+            int index_pos = 0;
+            var dir = new List<Entry> (count);
+            for (int i = 0; i < count; ++i)
+            {
+                int name_pos = index.ToInt32 (index_pos);
+                var name = Binary.GetCString (names, name_pos);
+                var entry = Create<PMasterEntry> (name);
+                entry.Offset = index.ToUInt32 (index_pos+4);
+                entry.Size   = index.ToUInt32 (index_pos+8);
+                entry.Key    = index.ToUInt32 (index_pos+12);
+                if (!entry.CheckPlacement (file.MaxOffset))
+                    return null;
+                dir.Add (entry);
+                index_pos += 16;
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var pent = (PMasterEntry)entry;
+            var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
+            DecryptData (data, pent.Key);
+            return new BinMemoryStream (data, entry.Name);
+        }
+
+        void DecryptData (byte[] data, uint seed)
+        {
+            var key = GenerateKey (seed);
+            for (int i = 0; i < data.Length; i++)
+            {
+                byte b = data[i];
+                b ^= key[i & 0xFF];
+                b += 0x4D;
+                b += key[i % 0x2B];
+                b -= key[i & 0xFF];
+                b ^= 0x23;
+                data[i] = b;
+            }
+        }
+
+        byte[] GenerateKey (uint seed)
+        {
+            var key = new byte[256];
+            uint n = seed * 2281 + 59455;
+            uint n2 = (n << 17) ^ n;
+            for (int i = 0; i < 256; i++)
+            {
+                n >>= 5;
+                n ^= n2;
+                n *= 471;
+                n -= seed;
+                n += n2;
+                n2 = n + 87;
+                n ^= n2 & 91;
+                key[i] = (byte)n;
+                n >>= 1;
+            }
+            return key;
+        }
+    }
+}