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mirror of https://github.com/crskycode/GARbro.git synced 2024-12-23 03:14:13 +08:00
2023-08-24 01:33:50 +04:00

134 lines
4.7 KiB
C#

//! \file ImageJMG.cs
//! \date 2022 Jun 11
//! \brief JAMES engine encrypted image.
//
// Copyright (C) 2022 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 GameRes.Utility;
using System.ComponentModel.Composition;
using System.IO;
// [981105][Berserker] Situation
// [991109][Berserker] Situation 2
namespace GameRes.Formats.James
{
public enum Obfuscation
{
None,
RotateWords,
ReverseBits
}
public class JmgMetaData : ImageMetaData
{
public Obfuscation Method;
public ImageMetaData BmpInfo;
}
[Export(typeof(ImageFormat))]
public class JmgFormat : ImageFormat
{
public override string Tag { get { return "JMG"; } }
public override string Description { get { return "JAMES engine obfuscated bitmap"; } }
public override uint Signature { get { return 0; } }
public override ImageMetaData ReadMetaData (IBinaryStream file)
{
var header = file.ReadHeader (2);
Obfuscation method;
if (header[0] == 0xD4 && header[1] == 0x24)
method = Obfuscation.RotateWords;
else if (header[0] == 0xB2 && header[1] == 0x42)
method = Obfuscation.ReverseBits;
else
return null;
using (var input = OpenAsBitmap (file, 0x40, method))
{
var info = Bmp.ReadMetaData (input);
if (null == info)
return null;
return new JmgMetaData
{
Width = info.Width,
Height = info.Height,
BPP = info.BPP,
Method = method,
BmpInfo = info,
};
}
}
IBinaryStream OpenAsBitmap (IBinaryStream input, int length, Obfuscation method)
{
input.Position = 0;
var data = input.ReadBytes (length);
Deobfuscate (data, 0, length, method);
return new BinMemoryStream (data, input.Name);
}
public override ImageData Read (IBinaryStream file, ImageMetaData info)
{
var meta = (JmgMetaData)info;
using (var bmp = OpenAsBitmap (file, (int)file.Length, meta.Method))
return Bmp.Read (bmp, meta.BmpInfo);
}
void Deobfuscate (byte[] data, int pos, int length, Obfuscation method)
{
switch (method)
{
case Obfuscation.RotateWords: RotateWords (data, pos, length); break;
case Obfuscation.ReverseBits: ReverseBits (data, pos, length); break;
}
}
void RotateWords (byte[] data, int pos, int length)
{
for (int i = 0; i < length; i += 2)
{
ushort w = LittleEndian.ToUInt16 (data, pos+i);
w = (ushort)(w >> 12 | w << 4);
LittleEndian.Pack (w, data, pos+i);
}
}
void ReverseBits (byte[] data, int pos, int length)
{
for (int i = 0; i < length; i += 2)
{
int v = LittleEndian.ToUInt16 (data, pos+i);
v = (v & 0xAAAA) >> 1 | (v & 0x5555) << 1;
v = (v & 0xCCCC) >> 2 | (v & 0x3333) << 2;
v = (v & 0xF0F0) >> 4 | (v & 0x0F0F) << 4;
v = (v & 0xFF00) >> 8 | (v & 0x00FF) << 8;
LittleEndian.Pack ((ushort)v, data, pos+i);
}
}
public override void Write (Stream file, ImageData image)
{
throw new System.NotImplementedException ("JmgFormat.Write not implemented");
}
}
}