GARbro-mirror/ArcFormats/Ikura/ImageGGP.cs

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2015-06-14 14:21:19 +08:00
//! \file ImageGGP.cs
//! \date Sun Jun 14 09:06:26 2015
//! \brief
//
// Copyright (C) 2014-2015 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.ComponentModel.Composition;
using System.IO;
using GameRes.Utility;
namespace GameRes.Formats.Ikura
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{
internal class GgpMetaData : ImageMetaData
{
public byte[] Key = new byte[8];
public uint Offset;
public uint Length;
}
[Export(typeof(ImageFormat))]
public class GgpFormat : PngFormat
{
public override string Tag { get { return "GGP"; } }
public override string Description { get { return "Digital Romance System encrypted image format"; } }
public override uint Signature { get { return 0x46504747u; } } // 'GGPF'
public override bool CanWrite { get { return false; } }
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public override ImageMetaData ReadMetaData (Stream stream)
{
var header = new byte[0x24];
if (header.Length != stream.Read (header, 0, header.Length))
return null;
if (!Binary.AsciiEqual (header, 0, "GGPFAIKE"))
return null;
var info = new GgpMetaData
{
Offset = LittleEndian.ToUInt32 (header, 0x14),
Length = LittleEndian.ToUInt32 (header, 0x18),
};
for (int i = 0; i < 8; ++i)
info.Key[i] = (byte)(header[i] ^ header[i+0xC]);
stream.Position = info.Offset;
using (var png = new EncryptedStream (stream, info.Key, true))
{
var png_info = base.ReadMetaData (png);
info.Width = png_info.Width;
info.Height = png_info.Height;
info.BPP = png_info.BPP;
info.OffsetX = png_info.OffsetX;
info.OffsetY = png_info.OffsetY;
return info;
}
}
public override ImageData Read (Stream file, ImageMetaData info)
{
var meta = info as GgpMetaData;
if (null == meta)
throw new ArgumentException ("GgpFormat.Read should be supplied with GgpMetaData", "info");
using (var input = new StreamRegion (file, meta.Offset, meta.Length, true))
using (var png = new EncryptedStream (input, meta.Key, true))
return base.Read (png, info);
}
public override void Write (Stream file, ImageData image)
{
throw new NotImplementedException ("GgpFormat.Write not implemented");
}
}
internal class EncryptedStream : InputProxyStream
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{
private byte[] m_key;
private long m_position;
public EncryptedStream (Stream main, byte[] key, bool leave_open = false)
: base (main, leave_open)
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{
if (null == key)
throw new ArgumentNullException ("key");
if (key.Length < 8)
throw new ArgumentException ("key");
m_key = key;
m_position = 0;
}
public override bool CanSeek { get { return false; } }
public override long Length { get { throw new NotSupportedException(); } }
public override long Position
{
get { throw new NotSupportedException(); }
set { throw new NotSupportedException(); }
}
public override long Seek (long offset, SeekOrigin origin)
{
throw new NotSupportedException();
}
public override int Read (byte[] buffer, int offset, int count)
{
int read = BaseStream.Read (buffer, offset, count);
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if (read > 0)
{
for (int i = 0; i < read; ++i)
{
buffer[offset+i] ^= m_key[m_position++ & 7];
}
}
return read;
}
public override int ReadByte ()
{
int b = BaseStream.ReadByte();
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if (-1 != b)
{
b ^= m_key[m_position++ & 7];
}
return b;
}
}
}