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//! \file ArcMRG.cs
//! \date Mon Jul 13 03:20:13 2015
//! \brief F&C Co. MGR archive format.
//
// Copyright (C) 2015-2016 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;
using GameRes.Utility;
namespace GameRes.Formats.FC01
{
internal class MrgEntry : PackedEntry
{
public int Method;
}
[Export(typeof(ArchiveFormat))]
public class MrgOpener : ArchiveFormat
{
public override string Tag { get { return "MRG"; } }
public override string Description { get { return "F&C Co. engine resource archive"; } }
public override uint Signature { get { return 0x0047524D; } } // 'MRG'
public override bool IsHierarchic { get { return false; } }
public override bool CanCreate { get { return false; } }
public static readonly Tuple<byte[], byte[]> KnownKey = Tuple.Create (
// Konata yori Kanata made
new byte[] { 0, 0x68, 0x5F }, new byte[] { 0, 0x37 }
);
public override ArcFile TryOpen (ArcView file)
{
int count = file.View.ReadInt32 (12);
if (!IsSaneCount (count))
return null;
int key1index = file.View.ReadUInt16 (4);
int key2index = file.View.ReadUInt16 (6);
if (key2index != 0 && key1index == 0)
return null;
uint index_size = file.View.ReadUInt32 (8) - 0x10;
if (index_size < 0x40 || index_size >= file.MaxOffset)
return null;
var index = file.View.ReadBytes (0x10, index_size);
if (index.Length != index_size)
return null;
/*
var key_src = KnownKey;
if (key1index >= key_src.Item1.Length || key2index >= key_src.Item2.Length)
return null;
byte? key = (byte)(key_src.Item1[key1index] + key_src.Item2[key2index]);
*/
if (key2index >= 2)
return null;
var key = GuessKey (file, index);
if (null == key)
throw new UnknownEncryptionScheme();
Decrypt (index, 0, index.Length, key.Value);
int current_offset = 0;
uint next_offset = LittleEndian.ToUInt32 (index, current_offset+0x1C);
var dir = new List<Entry> (count);
for (int i = 0; i < count; ++i)
{
string name = Binary.GetCString (index, current_offset, 0x0E);
var entry = FormatCatalog.Instance.Create<MrgEntry> (name);
entry.Offset = next_offset;
entry.Method = index[current_offset+0x12];
next_offset = LittleEndian.ToUInt32 (index, current_offset+0x3C);
entry.Size = next_offset - (uint)entry.Offset;
if (entry.Offset < index_size || !entry.CheckPlacement (file.MaxOffset))
return null;
entry.IsPacked = entry.Method != 0;
entry.UnpackedSize = LittleEndian.ToUInt32 (index, current_offset+0x0E);
dir.Add (entry);
current_offset += 0x20;
}
return new ArcFile (file, this, dir);
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var packed_entry = entry as MrgEntry;
if (null == packed_entry || !packed_entry.IsPacked || packed_entry.Method > 3)
return arc.File.CreateStream (entry.Offset, entry.Size);
Stream input;
if (packed_entry.Method >= 2)
{
if (entry.Size < 0x108)
return arc.File.CreateStream (entry.Offset, entry.Size);
var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
var reader = new MrgDecoder (data);
reader.Unpack();
input = new MemoryStream (reader.Data);
}
else
input = arc.File.CreateStream (entry.Offset, entry.Size);
if (packed_entry.Method < 3)
{
using (input)
using (var reader = new MrgLzssReader (input, (int)input.Length, (int)packed_entry.UnpackedSize))
{
reader.Unpack();
return new MemoryStream (reader.Data);
}
}
return input;
}
static public void Decrypt (byte[] data, int index, int length, int key)
{
while (length > 0)
{
var v = data[index];
data[index++] = (byte)(Binary.RotByteL (v, 1) ^ key);
key += length--;
}
}
private byte? GuessKey (ArcView file, byte[] index)
{
uint actual_offset = (uint)file.MaxOffset;
byte v = index[index.Length-1]; // last_offset
v = (byte)(v << 1 | v >> 7);
byte key = (byte)(v ^ (actual_offset >> 24));
int remaining = 1;
uint last_offset = (byte)(v ^ key);
for (int i = index.Length-2; i >= index.Length-4; --i)
{
key -= (byte)++remaining;
v = index[i];
v = (byte)(v << 1 | v >> 7);
last_offset = (last_offset << 8) | (uint)(v ^ key);
}
if (last_offset != actual_offset)
return null;
2015-07-19 15:30:45 +04:00
while (remaining++ < index.Length)
key -= (byte)remaining;
return key;
}
}
internal class Mrg2Entry : MrgEntry
{
public uint ArcKey;
public uint Key;
}
[Export(typeof(ArchiveFormat))]
public class Mrg2Opener : ArchiveFormat
{
public override string Tag { get { return "MRG/2"; } }
public override string Description { get { return "Overture engine resource archive"; } }
public override uint Signature { get { return 0x0047524D; } } // 'MRG'
public override bool IsHierarchic { get { return false; } }
public override bool CanCreate { get { return false; } }
public Mrg2Opener ()
{
Extensions = new string[] { "mrg" };
}
public override ArcFile TryOpen (ArcView file)
{
int count = file.View.ReadInt32 (12);
if (!IsSaneCount (count))
return null;
int version = file.View.ReadUInt16 (6);
if (version < 2)
return null;
uint index_size = file.View.ReadUInt32 (8) - 0x10;
if (index_size < 0x40 || index_size >= file.MaxOffset)
return null;
var index = file.View.ReadBytes (0x10, index_size);
if (index.Length != index_size)
return null;
uint arc_checksum = GetNameChecksum (Path.GetFileName (file.Name));
Decrypt (index, 0, index.Length, arc_checksum, 0x285EE76F);
int current_offset = 0;
uint next_offset = LittleEndian.ToUInt32 (index, current_offset+0x4F);
var dir = new List<Entry> (count);
for (int i = 0; i < count; ++i)
{
string name = Binary.GetCString (index, current_offset, 0x40);
var entry = FormatCatalog.Instance.Create<Mrg2Entry> (name);
entry.Offset = next_offset;
next_offset = LittleEndian.ToUInt32 (index, current_offset+0xA6);
entry.Size = next_offset - (uint)entry.Offset;
if (!entry.CheckPlacement (file.MaxOffset))
return null;
entry.Method = LittleEndian.ToUInt16 (index, current_offset+0x45);
if (0 == entry.Method)
{
entry.ArcKey = arc_checksum;
entry.Key = GetNameChecksum (entry.Name);
}
entry.IsPacked = entry.Method != 0;
entry.UnpackedSize = LittleEndian.ToUInt32 (index, current_offset+0x41);
dir.Add (entry);
current_offset += 0x57;
}
return new ArcFile (file, this, dir);
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var mrg_entry = entry as Mrg2Entry;
if (null == mrg_entry || mrg_entry.Method > 3)
return arc.File.CreateStream (entry.Offset, entry.Size);
Stream input;
if (0 == mrg_entry.Method)
{
var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
Decrypt (data, 0, data.Length, mrg_entry.Key, mrg_entry.ArcKey);
input = new MemoryStream (data);
}
else if (mrg_entry.Method >= 2)
{
var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
var reader = new MrgDecoder (data);
reader.Unpack();
input = new MemoryStream (reader.Data);
}
else
input = arc.File.CreateStream (entry.Offset, entry.Size);
if (1 == mrg_entry.Method || 3 == mrg_entry.Method)
{
using (input)
using (var reader = new MrgLzssReader (input, (int)input.Length, (int)mrg_entry.UnpackedSize))
{
reader.Unpack();
return new MemoryStream (reader.Data);
}
}
return input;
}
void Decrypt (byte[] data, int index, int length, uint checksum, uint key)
{
var table = new byte[0x100];
for (int i = 0; i < 0x100; ++i)
{
uint n = key + Binary.RotL (checksum, 16);
key = checksum;
checksum += n;
table[i] = (byte)checksum;
}
for (int i = 0; i < length; ++i)
{
data[index+i] ^= table[i & 0xFF];
}
}
uint GetNameChecksum (string name)
{
if (string.IsNullOrEmpty (name))
return 0;
uint checksum = char.ToUpper (name[0]);
for (int i = 0; i < name.Length; ++i)
{
if (name[i] != '.')
checksum += char.ToUpper (name[i]) + (checksum << 6);
}
return checksum;
}
}
/// <summary>
/// LZSS decompression with slightly modified offset/count values encoding.
/// </summary>
internal sealed class MrgLzssReader : IDisposable
{
BinaryReader m_input;
byte[] m_output;
int m_size;
public byte[] Data { get { return m_output; } }
public MrgLzssReader (Stream input, int input_length, int output_length)
{
m_input = new ArcView.Reader (input);
m_output = new byte[output_length];
m_size = input_length;
}
public void Unpack ()
{
int dst = 0;
var frame = new byte[0x1000];
int frame_pos = 0xfee;
int frame_mask = 0xfff;
int remaining = m_size;
while (remaining > 0)
{
int ctl = m_input.ReadByte();
--remaining;
for (int bit = 1; remaining > 0 && bit != 0x100; bit <<= 1)
{
if (dst >= m_output.Length)
return;
if (0 != (ctl & bit))
{
byte b = m_input.ReadByte();
--remaining;
frame[frame_pos++] = b;
frame_pos &= frame_mask;
m_output[dst++] = b;
}
else
{
if (remaining < 2)
return;
int offset = m_input.ReadUInt16();
remaining -= 2;
int count = (offset >> 12) + 3;
for ( ; count != 0; --count)
{
if (dst >= m_output.Length)
break;
offset &= frame_mask;
byte v = frame[offset++];
frame[frame_pos++] = v;
frame_pos &= frame_mask;
m_output[dst++] = v;
}
}
}
}
}
#region IDisposable Members
bool disposed = false;
public void Dispose ()
{
if (!disposed)
{
m_input.Dispose();
disposed = true;
}
GC.SuppressFinalize (this);
}
#endregion
}
internal class MrgDecoder
{
byte[] m_input;
byte[] m_output;
int m_start_index;
int m_src;
public byte[] Data { get { return m_output; } }
public byte Key { get; set; }
public MrgDecoder (byte[] data, int index = 0)
{
m_input = data;
m_src = index;
uint unpacked_size = LittleEndian.ToUInt32 (data, m_src);
unpacked_size ^= LittleEndian.ToUInt32 (data, m_src+0x104);
m_src += 4;
m_start_index = m_src;
m_output = new byte[unpacked_size];
}
public MrgDecoder (byte[] data, int index, uint unpacked_size)
{
m_input = data;
m_start_index = index;
m_src = index;
m_output = new byte[unpacked_size];
}
public void ResetKey (byte key)
{
m_src = m_start_index;
Key = key;
}
ushort[] word_10036650 = new ushort[0x200];
byte[] byte_table = new byte[0xff00];
public int Unpack () // sub_10026EB0
{
uint quant = InitTable();
if (0 == quant || quant > 0x10000)
throw new InvalidFormatException();
uint mask = GetMask (quant);
uint scale = 0x10000 / quant;
uint b = 0;
uint c = 0xffffffff;
int dst = 0;
uint a = BigEndian.ToUInt32 (m_input, m_src);
m_src += 4;
while (dst < m_output.Length)
{
c = ((c >> 8) * scale) >> 8;
uint v = (a - b) / c;
if (v > quant)
throw new InvalidFormatException();
v = byte_table[v];
m_output[dst++] = (byte)v;
b += word_10036650[v*2] * c;
c *= word_10036650[v*2+1];
while (0 == (((c + b) ^ b) & 0xFF000000))
{
if (m_src >= m_input.Length)
return dst;
a <<= 8;
b <<= 8;
c <<= 8;
a |= m_input[m_src++];
}
while (c <= mask)
{
if (m_src >= m_input.Length)
return dst;
c = (~b & mask) << 8;
a <<= 8;
b <<= 8;
a |= m_input[m_src++];
}
}
return dst;
}
ushort InitTable () // sub_10026E30
{
ushort d = 0;
int t = 0;
byte key = Key;
for (int i = 0; i < 0x100; i++)
{
byte c = m_input[m_src++];
if (0 != Key)
{
c = (byte)(Binary.RotByteL (c, 1) ^ key);
key -= (byte)i;
}
word_10036650[i*2] = d;
word_10036650[i*2+1] = c;
d += c;
for (int j = 0; j < c; ++j)
byte_table[t++] = (byte)i;
}
return d;
}
uint GetMask (uint d) // sub_10026DC0
{
d--;
d >>= 8;
uint result = 0xff;
while (d > 0)
{
d >>= 1;
result = (result << 1) | 1;
}
return result;
}
}
}