mirror of
https://github.com/crskycode/GARbro.git
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349 lines
14 KiB
C#
349 lines
14 KiB
C#
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//! \file ArcEncrypted.cs
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//! \date Thu Jan 14 03:27:52 2016
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//! \brief Encrypted AZ system resource archives.
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//
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// Copyright (C) 2016 by morkt
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to
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// deal in the Software without restriction, including without limitation the
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// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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// sell copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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// IN THE SOFTWARE.
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//
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using GameRes.Compression;
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using GameRes.Utility;
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using System;
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using System.Collections.Generic;
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using System.ComponentModel.Composition;
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using System.IO;
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using System.Linq;
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namespace GameRes.Formats.AZSys
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{
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[Serializable]
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public class EncryptionScheme
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{
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public readonly uint IndexKey;
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public readonly uint? ContentKey;
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public static readonly uint[] DefaultSeed = { 0x2F4D7DFE, 0x47345292, 0x1BA5FE82, 0x7BC04525 };
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public EncryptionScheme (uint ikey, uint ckey)
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{
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IndexKey = ikey;
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ContentKey = ckey;
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}
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public EncryptionScheme (uint[] iseed)
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{
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IndexKey = GenerateKey (iseed);
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ContentKey = null;
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}
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public EncryptionScheme (uint[] iseed, byte[] cseed)
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{
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IndexKey = GenerateKey (iseed);
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ContentKey = GenerateContentKey (cseed);
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}
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public static uint GenerateKey (uint[] seed)
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{
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if (null == seed)
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throw new ArgumentNullException ("seed");
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if (seed.Length < 4)
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throw new ArgumentException();
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byte[] seed_bytes = new byte[0x10];
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Buffer.BlockCopy (seed, 0, seed_bytes, 0, 0x10);
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uint key = Crc32.UpdateCrc (~seed[0], seed_bytes, 0, seed_bytes.Length)
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^ Crc32.UpdateCrc (~(seed[1] & 0xFFFF), seed_bytes, 0, seed_bytes.Length)
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^ Crc32.UpdateCrc (~(seed[1] >> 16), seed_bytes, 0, seed_bytes.Length)
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^ Crc32.UpdateCrc (~seed[2], seed_bytes, 0, seed_bytes.Length)
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^ Crc32.UpdateCrc (~seed[3], seed_bytes, 0, seed_bytes.Length);
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return seed[0] ^ ~key;
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}
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public static uint GenerateContentKey (byte[] env_bytes)
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{
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if (null == env_bytes)
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throw new ArgumentNullException ("env_bytes");
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if (env_bytes.Length < 0x10)
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throw new ArgumentException();
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uint crc = Crc32.Compute (env_bytes, 0, 0x10);
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var sfmt = new FastMersenneTwister (crc);
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var seed = new uint[4];
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seed[0] = sfmt.GetRand32();
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seed[1] = sfmt.GetRand32() & 0xFFFF;
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seed[1] |= sfmt.GetRand32() << 16;
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seed[2] = sfmt.GetRand32();
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seed[3] = sfmt.GetRand32();
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return GenerateKey (seed);
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}
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}
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[Serializable]
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public class AzScheme : ResourceScheme
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{
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public Dictionary<string, EncryptionScheme> KnownSchemes;
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}
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internal class AzArchive : ArcFile
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{
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public readonly uint SysenvKey;
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public readonly uint RegularKey;
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public AzArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, uint syskey, uint regkey)
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: base (arc, impl, dir)
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{
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SysenvKey = syskey;
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RegularKey = regkey;
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}
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}
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[Export(typeof(ArchiveFormat))]
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public class ArcEncryptedOpener : ArchiveFormat
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{
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public override string Tag { get { return "ARC/AZ/encrypted"; } }
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public override string Description { get { return "AZ system encrypted resource archive"; } }
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public override uint Signature { get { return 0; } }
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public override bool IsHierarchic { get { return false; } }
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public override bool CanCreate { get { return false; } }
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public static Dictionary<string, EncryptionScheme> KnownSchemes = new Dictionary<string, EncryptionScheme>
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{
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{ "Default", new EncryptionScheme (EncryptionScheme.DefaultSeed) },
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};
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public override ResourceScheme Scheme
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{
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get { return new AzScheme { KnownSchemes = KnownSchemes }; }
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set { KnownSchemes = ((AzScheme)value).KnownSchemes; }
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}
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public ArcEncryptedOpener ()
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{
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Extensions = new string[] { "arc" };
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Signatures = new uint[] { 0x53EA06EB, 0x74F98F2F };
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}
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EncryptionScheme CurrentScheme;
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public override ArcFile TryOpen (ArcView file)
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{
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byte[] header_encrypted = file.View.ReadBytes (0, 0x30);
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if (header_encrypted.Length < 0x30)
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return null;
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byte[] header = new byte[header_encrypted.Length];
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if (CurrentScheme != null)
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{
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try
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{
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Buffer.BlockCopy (header_encrypted, 0, header, 0, header.Length);
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Decrypt (header, 0, CurrentScheme.IndexKey);
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if (Binary.AsciiEqual (header, 0, "ARC\0"))
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{
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var arc = ReadIndex (file, header, CurrentScheme);
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if (null != arc)
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return arc;
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}
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}
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catch { /* ignore parse errors */ }
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}
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foreach (var scheme in KnownSchemes.Values)
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{
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Buffer.BlockCopy (header_encrypted, 0, header, 0, header.Length);
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Decrypt (header, 0, scheme.IndexKey);
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if (Binary.AsciiEqual (header, 0, "ARC\0"))
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{
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var arc = ReadIndex (file, header, scheme);
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if (null != arc)
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CurrentScheme = new EncryptionScheme (arc.SysenvKey, arc.RegularKey);
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return arc;
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}
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}
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return null;
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}
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public override Stream OpenEntry (ArcFile arc, Entry entry)
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{
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var azarc = arc as AzArchive;
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if (null == azarc)
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return base.OpenEntry (arc, entry);
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var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
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if (entry.Name.Equals ("sysenv.tbl", StringComparison.InvariantCultureIgnoreCase))
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{
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Decrypt (data, entry.Offset, azarc.SysenvKey);
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return UnpackData (data);
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}
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Decrypt (data, entry.Offset, azarc.RegularKey);
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if (data.Length > 0x14 && Binary.AsciiEqual (data, 0, "ASB\0"))
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{
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return OpenAsb (data);
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}
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return new MemoryStream (data);
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}
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Stream OpenAsb (byte[] data)
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{
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int packed_size = LittleEndian.ToInt32 (data, 4);
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if (packed_size <= 4 || packed_size > data.Length-0x10)
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return new MemoryStream (data);
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uint unpacked_size = LittleEndian.ToUInt32 (data, 8);
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uint key = unpacked_size ^ 0x9E370001;
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unsafe
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{
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fixed (byte* raw = &data[0x10])
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{
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uint* data32 = (uint*)raw;
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for (int i = packed_size/4; i > 0; --i)
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*data32++ -= key;
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}
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}
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var asb = UnpackData (data, 0x10);
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var header = new byte[0x10];
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Buffer.BlockCopy (data, 0, header, 0, 0x10);
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return new PrefixStream (header, asb);
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}
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byte[] ReadSysenvSeed (ArcView file, Entry entry, uint key)
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{
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var data = file.View.ReadBytes (entry.Offset, entry.Size);
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if (data.Length <= 4)
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throw new InvalidFormatException ("Invalid sysenv.tbl size");
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Decrypt (data, entry.Offset, key);
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uint adler32 = LittleEndian.ToUInt32 (data, 0);
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if (adler32 != Adler32.Compute (data, 4, data.Length-4))
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throw new InvalidEncryptionScheme();
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using (var input = new MemoryStream (data, 4, data.Length-4))
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using (var sysenv_stream = new ZLibStream (input, CompressionMode.Decompress))
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{
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var seed = new byte[0x10];
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if (0x10 != sysenv_stream.Read (seed, 0, 0x10))
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throw new InvalidFormatException ("Invalid sysenv.tbl size");
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return seed;
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}
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}
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Stream UnpackData (byte[] data, int index = 0)
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{
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int length = data.Length - index;
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if (length <= 4)
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return new MemoryStream (data, index, length);
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uint adler32 = LittleEndian.ToUInt32 (data, index);
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if (adler32 != Adler32.Compute (data, index+4, length-4))
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return new MemoryStream (data, index, length);
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var input = new MemoryStream (data, index+4, length-4);
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return new ZLibStream (input, CompressionMode.Decompress);
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}
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AzArchive ReadIndex (ArcView file, byte[] header, EncryptionScheme scheme)
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{
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int ext_count = LittleEndian.ToInt32 (header, 4);
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int count = LittleEndian.ToInt32 (header, 8);
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uint index_length = LittleEndian.ToUInt32 (header, 12);
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if (ext_count < 1 || ext_count > 8 || !IsSaneCount (count) || index_length >= file.MaxOffset)
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return null;
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var packed_index = file.View.ReadBytes (header.Length, index_length);
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if (packed_index.Length != index_length)
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return null;
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Decrypt (packed_index, header.Length, scheme.IndexKey);
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uint checksum = LittleEndian.ToUInt32 (packed_index, 0);
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if (checksum != Adler32.Compute (packed_index, 4, packed_index.Length-4))
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{
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if (checksum != Crc32.Compute (packed_index, 4, packed_index.Length-4))
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throw new InvalidFormatException ("Index checksum mismatch");
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}
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uint base_offset = (uint)header.Length + index_length;
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using (var input = new MemoryStream (packed_index, 4, packed_index.Length-4))
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using (var zstream = new ZLibStream (input, CompressionMode.Decompress))
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using (var index = new BinaryReader (zstream))
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{
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var dir = new List<Entry> (count);
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var name_buffer = new byte[0x20];
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for (int i = 0; i < count; ++i)
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{
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uint offset = index.ReadUInt32();
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uint size = index.ReadUInt32();
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uint crc = index.ReadUInt32();
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index.ReadInt32();
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if (name_buffer.Length != index.Read (name_buffer, 0, name_buffer.Length))
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return null;
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var name = Binary.GetCString (name_buffer, 0, 0x20);
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if (0 == name.Length)
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return null;
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var entry = FormatCatalog.Instance.Create<Entry> (name);
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entry.Offset = base_offset + offset;
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entry.Size = size;
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if (!entry.CheckPlacement (file.MaxOffset))
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return null;
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dir.Add (entry);
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}
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uint content_key = GetContentKey (file, dir, scheme);
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return new AzArchive (file, this, dir, scheme.IndexKey, content_key);
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}
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}
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static void Decrypt (byte[] data, long offset, uint key)
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{
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ulong hash = key * 0x9E370001ul;
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if (0 != (offset & 0x3F))
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{
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hash = Binary.RotL (hash, (int)offset);
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}
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for (uint i = 0; i < data.Length; ++i)
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{
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data[i] ^= (byte)hash;
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hash = Binary.RotL (hash, 1);
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}
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}
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uint GetContentKey (ArcView file, List<Entry> dir, EncryptionScheme scheme)
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{
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if (null != scheme.ContentKey)
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return scheme.ContentKey.Value;
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if ("system.arc".Equals (Path.GetFileName (file.Name), StringComparison.InvariantCultureIgnoreCase))
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{
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var sysenv = dir.FirstOrDefault (e => e.Name.Equals ("sysenv.tbl", StringComparison.InvariantCultureIgnoreCase));
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if (null != sysenv)
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{
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var seed = ReadSysenvSeed (file, sysenv, scheme.IndexKey);
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return EncryptionScheme.GenerateContentKey (seed);
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}
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}
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else
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{
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var system_arc = VFS.CombinePath (Path.GetDirectoryName (file.Name), "system.arc");
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using (var arc = VFS.OpenView (system_arc))
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{
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var header = arc.View.ReadBytes (0, 0x30);
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Decrypt (header, 0, scheme.IndexKey);
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using (var arc_file = ReadIndex (arc, header, scheme))
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{
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var sysenv = arc_file.Dir.FirstOrDefault (e => e.Name.Equals ("sysenv.tbl", StringComparison.InvariantCultureIgnoreCase));
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if (null != sysenv)
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{
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var seed = ReadSysenvSeed (arc, sysenv, scheme.IndexKey);
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return EncryptionScheme.GenerateContentKey (seed);
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}
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}
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}
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}
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return scheme.IndexKey;
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}
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}
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}
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