GARbro-mirror/ArcFormats/Littlewitch/ArcDAT.cs

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//! \file ArcDAT.cs
//! \date 2017 Oct 27
//! \brief RepiPack resource archive.
//
// Copyright (C) 2017 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 System.Linq;
using System.Text;
using GameRes.Compression;
using GameRes.Cryptography;
using GameRes.Utility;
namespace GameRes.Formats.Littlewitch
{
[Serializable]
public class RepiScheme : ResourceScheme
{
public IDictionary<string, uint[]> KnownSchemes;
}
internal class RepiEntry : PackedEntry
{
public bool HasEncryptionKey;
public byte[] CreateKey ()
{
var name_bytes = DatOpener.ToLowerAscii (Name);
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int name_length = name_bytes.Length;
var md5 = new MD5();
Array.Reverse (name_bytes);
var key = new byte[1024];
int key_pos = 0;
for (int i = 0; i < 64; ++i)
{
int name_pos = i % name_length;
md5.Update (name_bytes, name_pos, name_length - name_pos);
md5.Final();
Buffer.BlockCopy (md5.State, 0, key, key_pos, 16);
key_pos += 16;
}
return key;
}
}
[Export(typeof(ArchiveFormat))]
public class DatOpener : ArchiveFormat
{
public override string Tag { get { return "DAT/RepiPack"; } }
public override string Description { get { return "Littlewitch engine resource archive"; } }
public override uint Signature { get { return 0x69706552; } } // 'Repi'
public override bool IsHierarchic { get { return false; } }
public override bool CanWrite { get { return false; } }
static readonly string ListFileName = "littlewitch.lst";
public override ArcFile TryOpen (ArcView file)
{
if (!file.View.AsciiEqual (4, "Pack"))
return null;
int version = file.View.ReadInt32 (8);
if (version != 5)
return null;
uint name_length = file.View.ReadUInt32 (0xC);
if (name_length < 4)
return null;
uint name_key = file.View.ReadUInt32 (0x10);
var key = FindKey (file.Name, name_key);
if (null == key)
return null;
int count = file.View.ReadInt32 (0x10 + name_length);
if (!IsSaneCount (count))
return null;
var index = file.View.ReadBytes (0x14 + name_length, (uint)count * 0x20);
int pos = 0;
var dir = new List<Entry> (count);
var name_builder = new StringBuilder();
for (int i = 0; i < count; ++i)
{
DecryptData (index, pos, 0x20, key[2], key[1]);
var entry = EntryFromMd5 (index, pos, name_builder);
entry.Offset = index.ToUInt32 (pos+0x10);
entry.Size = index.ToUInt32 (pos+0x14);
entry.UnpackedSize = index.ToUInt32 (pos+0x18);
if (!entry.CheckPlacement (file.MaxOffset))
return null;
entry.IsPacked = entry.Size != entry.UnpackedSize;
dir.Add (entry);
pos += 0x20;
}
return new ArcFile (file, this, dir);
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var rent = entry as RepiEntry;
if (null == rent || !rent.HasEncryptionKey)
return arc.File.CreateStream (entry.Offset, entry.Size);
var key = rent.CreateKey();
uint enc_length = Math.Min ((uint)key.Length, entry.Size);
byte[] encrypted = arc.File.View.ReadBytes (entry.Offset, enc_length);
DecryptEntry (encrypted, key);
Stream input;
if (enc_length == entry.Size)
{
input = new BinMemoryStream (encrypted, entry.Name);
}
else
{
input = arc.File.CreateStream (entry.Offset + enc_length, entry.Size - enc_length);
input = new PrefixStream (encrypted, input);
}
if (rent.IsPacked)
{
input = new LzssStream (input);
}
return input;
}
static void DecryptEntry (byte[] data, byte[] key)
{
for (int i = 0; i < data.Length; ++i)
{
data[i] ^= key[i];
}
}
static unsafe void DecryptData (byte[] data, int pos, int length, uint key, uint seed)
{
if (pos < 0 || pos + length > data.Length)
throw new ArgumentOutOfRangeException ("pos", "Invalid byte array index.");
fixed (byte* data8 = &data[pos])
{
uint* data32 = (uint*)data8;
for (int count = length / 4; count > 0; --count)
{
*data32 ^= key;
key += Binary.RotL (*data32, 16) ^ seed;
data32++;
}
}
}
RepiEntry EntryFromMd5 (byte[] data, int pos, StringBuilder builder)
{
var key = new CowArray<byte> (data, pos, 16).ToArray();
string name;
if (KnownNames.TryGetValue (key, out name))
{
var entry = FormatCatalog.Instance.Create<RepiEntry> (name);
entry.HasEncryptionKey = true;
return entry;
}
builder.Clear();
for (int i = 0; i < 16; ++i)
{
builder.AppendFormat ("{0:x2}", key[i]);
}
return new RepiEntry { Name = builder.ToString() };
}
static uint[] FindKey (string arc_name, uint arc_key)
{
arc_name = Path.GetFileName (arc_name);
var name_bytes = Encodings.cp932.GetBytes (arc_name);
arc_key ^= name_bytes.ToUInt32 (0);
return DatScheme.KnownSchemes.Values.FirstOrDefault (k => k[0] == arc_key);
}
static RepiScheme DatScheme = new RepiScheme { KnownSchemes = new Dictionary<string, uint[]>() };
public override ResourceScheme Scheme
{
get { return DatScheme; }
set { DatScheme = (RepiScheme)value; }
}
internal Dictionary<byte[], string> KnownNames { get { return s_known_file_names.Value; } }
static Lazy<Dictionary<byte[], string>> s_known_file_names = new Lazy<Dictionary<byte[], string>> (ReadFileList);
static Dictionary<byte[], string> ReadFileList ()
{
var dict = new Dictionary<byte[], string> (new Md5Comparer());
try
{
var md5 = new MD5();
FormatCatalog.Instance.ReadFileList (ListFileName, name => {
var name_bytes = ToLowerAscii (name);
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var hash = md5.ComputeHash (name_bytes);
dict[hash] = name;
});
}
catch (Exception X)
{
System.Diagnostics.Trace.WriteLine (X.Message, "[RepiPack]");
}
return dict;
}
internal static byte[] ToLowerAscii (string text)
{
var text_bytes = Encodings.cp932.GetBytes (text);
for (int i = 0; i < text_bytes.Length; ++i)
{
byte c = text_bytes[i];
if (c >= 'A' && c <= 'Z')
text_bytes[i] += 0x20;
else if (c > 0x7F && c < 0xA1 || c > 0xDF)
++i;
}
return text_bytes;
}
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}
internal class Md5Comparer : IEqualityComparer<byte[]>
{
public bool Equals (byte[] left, byte[] right)
{
if (left == null || right == null)
return left == right;
if (left.Length != right.Length)
return false;
for (int i = 0; i < left.Length; ++i)
{
if (left[i] != right[i])
return false;
}
return true;
}
public int GetHashCode (byte[] key)
{
if (null == key)
throw new ArgumentNullException ("key");
if (key.Length < 16)
throw new ArgumentException ("Invalid key length.", "key");
var hash = key.ToInt32 (0);
hash ^= key.ToInt32 (4);
hash ^= key.ToInt32 (8);
hash ^= key.ToInt32 (12);
return hash;
}
}
}