GARbro-mirror/ArcFormats/RPGMaker/ImageRPGMV.cs

100 lines
3.8 KiB
C#

//! \file ImageRPGMV.cs
//! \date 2018 Oct 14
//! \brief RPG Maker encrypted PNG image.
//
// Copyright (C) 2018 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.ComponentModel.Composition;
using System.IO;
using System.Windows.Media;
namespace GameRes.Formats.RPGMaker
{
internal class RpgmvpMetaData : ImageMetaData
{
public byte[] Key;
}
[Export(typeof(ImageFormat))]
public class RpgmvpFormat : ImageFormat
{
public override string Tag { get { return "RPGMVP"; } }
public override string Description { get { return "RPG Maker engine image format"; } }
public override uint Signature { get { return 0x4D475052; } } // 'RPGMV'
internal static readonly byte[] DefaultKey = {
0x77, 0x4E, 0x46, 0x45, 0xFC, 0x43, 0x2F, 0x71, 0x47, 0x95, 0xA2, 0x43, 0xE5, 0x10, 0x13, 0xD8
};
public override ImageMetaData ReadMetaData (IBinaryStream file)
{
var header = file.ReadHeader (0x14);
if (header[4] != 'V')
return null;
var key = DefaultKey;
for (int i = 0; i < 4; ++i)
header[0x10+i] ^= key[i];
if (!header.AsciiEqual (0x10, "\x89PNG"))
return null;
using (var png = RpgmvDecryptor.DecryptStream (file, key, true))
{
var info = Png.ReadMetaData (png);
if (null == info)
return null;
return new RpgmvpMetaData {
Width = info.Width,
Height = info.Height,
OffsetX = info.OffsetX,
OffsetY = info.OffsetY,
BPP = info.BPP,
Key = key,
};
}
}
public override ImageData Read (IBinaryStream file, ImageMetaData info)
{
var meta = (RpgmvpMetaData)info;
using (var png = RpgmvDecryptor.DecryptStream (file, meta.Key, true))
return Png.Read (png, info);
}
public override void Write (Stream file, ImageData image)
{
throw new System.NotImplementedException ("RpgmvpFormat.Write not implemented");
}
}
internal class RpgmvDecryptor
{
public static IBinaryStream DecryptStream (IBinaryStream input, byte[] key, bool leave_open = false)
{
input.Position = 0x10;
var header = input.ReadBytes (key.Length);
for (int i = 0; i < key.Length; ++i)
header[i] ^= key[i];
var result = new PrefixStream (header, new StreamRegion (input.AsStream, 0x20, leave_open));
return new BinaryStream (result, input.Name);
}
}
}