GARbro-mirror/Legacy/Ags32i/ImageGSS.cs

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2018-03-29 01:17:11 +08:00
//! \file ImageGSS.cs
//! \date 2018 Mar 28
//! \brief AGS32i engine encrypted bitmap.
//
// 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;
using System.ComponentModel.Composition;
using System.IO;
using System.Security.Cryptography;
using System.Windows.Media;
using GameRes.Compression;
using GameRes.Utility;
// [041001][Innocence] China Chaime+
namespace GameRes.Formats.Ags32i
{
internal class GssMetaData : ImageMetaData
{
public uint Key;
public int DataOffset;
public int UnpackedSize;
}
[Export(typeof(ImageFormat))]
public class GssFormat : ImageFormat
{
public override string Tag { get { return "GSS"; } }
public override string Description { get { return "AGS32i engine encrypted bitmap"; } }
public override uint Signature { get { return 0x20575A52; } }
public GssFormat ()
{
Signatures = new uint[] { 0x20575A52, 0 };
}
//static readonly uint DefaultKey = 0x20040915;
public override ImageMetaData ReadMetaData (IBinaryStream file)
{
uint key = file.Signature ^ 0x535347u;
using (var ags = OpenStream (file, key))
{
var header = new byte[0x28];
ags.Read (header, 0, 8);
if (!header.AsciiEqual ("GSS\0"))
return null;
int unpacked_size = header.ToInt32 (4);
if (unpacked_size <= 0)
return null;
using (var bmp = new ZLibStream (ags, CompressionMode.Decompress))
{
if (0x28 != bmp.Read (header, 0, 0x28))
return null;
int header_length = header.ToInt32 (0);
if (header_length <= 0 || header_length >= unpacked_size)
return null;
return new GssMetaData {
Width = header.ToUInt32 (4),
Height = header.ToUInt32 (8),
BPP = header.ToInt16 (0xE),
Key = key,
DataOffset = header.ToInt32 (0),
UnpackedSize = unpacked_size,
};
}
}
}
public override ImageData Read (IBinaryStream file, ImageMetaData info)
{
var meta = (GssMetaData)info;
using (var ags = OpenStream (file, meta.Key))
{
var header = new byte[meta.DataOffset];
ags.Read (header, 0, 8);
using (var bmp = new ZLibStream (ags, CompressionMode.Decompress))
{
bmp.Read (header, 0, header.Length);
var pixels = new byte[meta.UnpackedSize - meta.DataOffset];
if (pixels.Length != bmp.Read (pixels, 0, pixels.Length))
throw new InvalidFormatException();
PixelFormat format;
if (32 == meta.BPP)
format = PixelFormats.Bgra32;
else if (24 == meta.BPP)
format = PixelFormats.Bgr24;
else
throw new InvalidFormatException();
int stride = (int)meta.Width * meta.BPP / 8;
return ImageData.CreateFlipped (info, format, null, pixels, stride);
}
}
}
public override void Write (Stream file, ImageData image)
{
throw new System.NotImplementedException ("GssFormat.Write not implemented");
}
Stream OpenStream (IBinaryStream input, uint key)
{
var proxy = new ProxyStream (input.AsStream, true);
return new InputCryptoStream (proxy, new Ags32Transform (key));
}
}
public sealed class Ags32Transform : ICryptoTransform
{
readonly uint m_key;
int m_position;
const int BlockSize = 4;
public bool CanReuseTransform { get { return false; } }
public bool CanTransformMultipleBlocks { get { return true; } }
public int InputBlockSize { get { return BlockSize; } }
public int OutputBlockSize { get { return BlockSize; } }
public Ags32Transform (uint key)
{
m_key = key;
m_position = 0;
}
public int TransformBlock (byte[] inputBuffer, int inputOffset, int inputCount,
byte[] outputBuffer, int outputOffset)
{
for (int i = 0; i < inputCount; i += 4)
{
int rem;
int div = Math.DivRem ((m_position+i) >> 2, 31, out rem);
uint t = Binary.RotL (m_key + (uint)div, rem);
for (int j = 0; j < 4; ++j)
outputBuffer[outputOffset++] = (byte)((t >> (j << 3)) ^ inputBuffer[inputOffset++]);
}
m_position += inputCount;
return inputCount;
}
public byte[] TransformFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
{
byte[] outputBuffer = new byte[inputCount];
int rem;
int div = Math.DivRem ((m_position) >> 2, 31, out rem);
uint t = Binary.RotL (m_key + (uint)div, rem);
for (int i = 0; i < inputCount; i++)
{
outputBuffer[i++] = (byte)((t >> (i << 3)) ^ inputBuffer[inputOffset+i]);
}
m_position += inputCount;
return outputBuffer;
}
public void Dispose ()
{
}
}
}