GARbro-mirror/ArcFormats/Nonono/ArcNPF.cs

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2019-02-25 16:54:18 +08:00
//! \file ArcNPF.cs
//! \date 2019 Feb 02
//! \brief NGS engine resource archive.
//
// Copyright (C) 2019 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.Collections.Generic;
using System.ComponentModel.Composition;
using System.IO;
namespace GameRes.Formats.Nonono
{
internal class NpfEntry : Entry
{
public int Seed;
}
[Export(typeof(ArchiveFormat))]
public class NpfOpener : ArchiveFormat
{
public override string Tag { get { return "NPF"; } }
public override string Description { get { return "NGS engine resource archive"; } }
public override uint Signature { get { return 0x4B434150; } } // 'PACK'
public override bool IsHierarchic { get { return true; } }
public override bool CanWrite { get { return false; } }
const int DefaultSeed = 0x46415420; // 'FAT '
public override ArcFile TryOpen (ArcView file)
{
if (file.View.ReadInt32 (4) != 4 || file.View.ReadInt32 (8) != 1)
return null;
var header = file.View.ReadBytes (12, 20);
var rnd = new RandomGenerator (DefaultSeed);
Decrypt (header, 0, header.Length, rnd);
if (!header.AsciiEqual ("FAT "))
return null;
int count = header.ToInt32 (8);
if (!IsSaneCount (count))
return null;
rnd.SRand (count);
var index = file.View.ReadBytes (0x20, 20 * (uint)count);
Decrypt (index, 0, index.Length, rnd);
int pos = 0;
int name_pos = 0x20 + 20 * count;
var dir = new List<Entry> (count);
var name_buffer = new byte[0x100];
for (int i = 0; i < count; ++i)
{
int name_length = index.ToInt32 (pos+12);
if (name_length <= 0 || name_length > name_buffer.Length)
return null;
file.View.Read (name_pos, name_buffer, 0, (uint)name_length);
int seed = index.ToInt32 (pos+8);
rnd.SRand (seed);
Decrypt (name_buffer, 0, name_length, rnd);
var name = Encodings.cp932.GetString (name_buffer, 0, name_length);
var entry = Create<NpfEntry> (name);
entry.Offset = index.ToUInt32 (pos+4);
entry.Size = index.ToUInt32 (pos+16);
if (!entry.CheckPlacement (file.MaxOffset))
return null;
entry.Seed = seed;
dir.Add (entry);
pos += 20;
name_pos += name_length;
}
return new ArcFile (file, this, dir);
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var nent = entry as NpfEntry;
if (null == nent)
return base.OpenEntry (arc, entry);
var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
var rnd = new RandomGenerator (nent.Seed);
Decrypt (data, 0, data.Length, rnd);
return new BinMemoryStream (data, entry.Name);
}
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public override IImageDecoder OpenImage (ArcFile arc, Entry entry)
{
var input = arc.OpenBinaryEntry (entry);
if (input.Length <= 8 || input.Signature != 0x58474D49) // 'IMGX'
return ImageFormatDecoder.Create (input);
return new ImgXDecoder (input);
}
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internal void Decrypt (byte[] data, int pos, int count, RandomGenerator rnd)
{
for (int i = 0; i < count; ++i)
data[pos + i] ^= (byte)rnd.Rand();
}
}
internal class RandomGenerator
{
int m_seed;
const int DefaultSeed = 0x67895;
public RandomGenerator (int seed = DefaultSeed)
{
SRand (seed);
}
public void SRand (int seed)
{
m_seed = seed;
for (int i = 0; i < 32; ++i)
{
Rand();
}
}
public int Rand ()
{
m_seed ^= 0x65AC9365;
m_seed ^= (((m_seed >> 1) ^ m_seed) >> 3)
^ (((m_seed << 1) ^ m_seed) << 3);
return m_seed;
}
}
}