GARbro-mirror/ArcFormats/ArcIKS.cs

125 lines
5.0 KiB
C#

//! \file ArcIKS.cs
//! \date Wed Jul 08 07:07:09 2015
//! \brief [IKS] archives implementation.
//
// Copyright (C) 2015 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.Security.Cryptography;
using GameRes.Utility;
namespace GameRes.Formats.X
{
[Export(typeof(ArchiveFormat))]
public class IksOpener : ArchiveFormat
{
public override string Tag { get { return "IKS"; } }
public override string Description { get { return "X[iks] resource archive"; } }
public override uint Signature { get { return 0x5253504E; } } // 'NPSR'
public override bool IsHierarchic { get { return false; } }
public override bool CanCreate { get { return false; } }
public static Dictionary<string, byte> KnownKeys = new Dictionary<string, byte>() {
{ "Shikkan ~Hazukashimerareta Karada, Oreta Kokoro~", 0x66 },
};
public override ArcFile TryOpen (ArcView file)
{
int count = file.View.ReadInt32 (4);
if (count <= 0 || count > 0xfffff)
return null;
uint index_offset = 0x10;
uint index_size = (uint)(0x28 * count);
if (index_size > file.View.Reserve (index_offset, index_size))
return null;
long data_offset = index_offset + index_size;
var dir = new List<Entry> (count);
var name_buffer = new byte[0x18];
for (int i = 0; i < count; ++i)
{
byte name_length = Math.Min ((byte)0x17, file.View.ReadByte (index_offset));
if (name_length > name_buffer.Length)
return null;
file.View.Read (index_offset+1, name_buffer, 0, name_length);
string name = Encodings.cp932.GetString (name_buffer, 0, name_length);
var entry = FormatCatalog.Instance.CreateEntry (name);
entry.Offset = file.View.ReadUInt32 (index_offset+0x20);
entry.Size = file.View.ReadUInt32 (index_offset+0x1C);
if (entry.Offset < data_offset || !entry.CheckPlacement (file.MaxOffset))
return null;
dir.Add (entry);
index_offset += 0x28;
}
return new ArcFile (file, this, dir);
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
byte key = KnownKeys.First().Value;
var input = arc.File.CreateStream (entry.Offset, entry.Size);
return new CryptoStream (input, new XorTransform (key), CryptoStreamMode.Read);
}
}
public sealed class XorTransform : ICryptoTransform
{
private const int BlockSize = 256;
private byte m_key;
public bool CanReuseTransform { get { return true; } }
public bool CanTransformMultipleBlocks { get { return true; } }
public int InputBlockSize { get { return BlockSize; } }
public int OutputBlockSize { get { return BlockSize; } }
public XorTransform (byte key)
{
m_key = key;
}
public int TransformBlock (byte[] inputBuffer, int inputOffset, int inputCount,
byte[] outputBuffer, int outputOffset)
{
for (int i = 0; i < inputCount; ++i)
{
outputBuffer[outputOffset++] = (byte)(m_key ^ inputBuffer[inputOffset+i]);
}
return inputCount;
}
public byte[] TransformFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
{
byte[] outputBuffer = new byte[inputCount];
TransformBlock (inputBuffer, inputOffset, inputCount, outputBuffer, 0);
return outputBuffer;
}
public void Dispose ()
{
System.GC.SuppressFinalize (this);
}
}
}