GARbro-mirror/ArcFormats/RPGMaker/ArcRGSS.cs

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2017-11-19 03:10:18 +08:00
//! \file ArcRGSS3.cs
//! \date 2017 Nov 18
//! \brief RPG Maker resource archive implementation.
//
// Copyright (C) 2017 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.Collections.Generic;
using System.ComponentModel.Composition;
using System.IO;
using System.Text;
namespace GameRes.Formats.RPGMaker
{
[Export(typeof(ArchiveFormat))]
public class RgssOpener : ArchiveFormat
{
public override string Tag { get { return "RGSSAD"; } }
public override string Description { get { return "RPG Maker engine resource archive"; } }
public override uint Signature { get { return 0x53534752; } } // 'RGSS'
public override bool IsHierarchic { get { return true; } }
public override bool CanWrite { get { return false; } }
public RgssOpener ()
{
Extensions = new string[] { "rgss3a", "rgss2a", "rgssad" };
}
public override ArcFile TryOpen (ArcView file)
{
if (!file.View.AsciiEqual (4, "AD\0"))
return null;
int version = file.View.ReadByte (7);
using (var index = file.CreateStream())
{
List<Entry> dir = null;
if (3 == version)
dir = ReadIndexV3 (index);
else if (1 == version)
dir = ReadIndexV1 (index);
if (null == dir || 0 == dir.Count)
return null;
return new ArcFile (file, this, dir);
}
}
List<Entry> ReadIndexV1 (IBinaryStream file)
{
var max_offset = file.Length;
file.Position = 8;
var key_gen = new KeyGenerator (0xDEADCAFE);
var dir = new List<Entry>();
while (file.PeekByte() != -1)
{
uint name_length = file.ReadUInt32() ^ key_gen.GetNext();
var name_bytes = file.ReadBytes ((int)name_length);
var name = DecryptName (name_bytes, key_gen);
var entry = FormatCatalog.Instance.Create<RgssEntry> (name);
entry.Size = file.ReadUInt32() ^ key_gen.GetNext();
entry.Offset = file.Position;
entry.Key = key_gen.Current;
if (!entry.CheckPlacement (max_offset))
return null;
dir.Add (entry);
file.Seek (entry.Size, SeekOrigin.Current);
}
return dir;
}
List<Entry> ReadIndexV3 (IBinaryStream file)
{
var max_offset = file.Length;
file.Position = 8;
uint key = file.ReadUInt32() * 9 + 3;
var dir = new List<Entry>();
while (file.PeekByte() != -1)
{
uint offset = file.ReadUInt32() ^ key;
if (0 == offset)
break;
uint size = file.ReadUInt32() ^ key;
uint entry_key = file.ReadUInt32() ^ key;
uint name_length = file.ReadUInt32() ^ key;
var name_bytes = file.ReadBytes ((int)name_length);
var name = DecryptName (name_bytes, key);
var entry = FormatCatalog.Instance.Create<RgssEntry> (name);
entry.Offset = offset;
entry.Size = size;
entry.Key = entry_key;
if (!entry.CheckPlacement (max_offset))
return null;
dir.Add (entry);
}
return dir;
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var rent = (RgssEntry)entry;
var data = arc.File.View.ReadBytes (rent.Offset, rent.Size);
var key_gen = new KeyGenerator (rent.Key);
uint key = key_gen.GetNext();
for (int i = 0; i < data.Length; )
{
data[i] ^= (byte)(key >> (i << 3));
++i;
if (0 == (i & 3))
{
key = key_gen.GetNext();
}
}
return new BinMemoryStream (data);
}
string DecryptName (byte[] name, KeyGenerator key_gen)
{
for (int i = 0; i < name.Length; ++i)
{
name[i] ^= (byte)key_gen.GetNext();
}
return Encoding.UTF8.GetString (name);
}
string DecryptName (byte[] name, uint key)
{
for (int i = 0; i < name.Length; ++i)
{
name[i] ^= (byte)(key >> (i << 3));
}
return Encoding.UTF8.GetString (name);
}
}
internal class RgssEntry : Entry
{
public uint Key;
}
internal class KeyGenerator
{
uint m_seed;
public KeyGenerator (uint seed)
{
m_seed = seed;
}
public uint Current { get { return m_seed; } }
public uint GetNext ()
{
uint key = m_seed;
m_seed = m_seed * 7 + 3;
return key;
}
}
}