2016-09-29 11:30:54 +04:00

157 lines
5.8 KiB
C#

//! \file ArcPACK.cs
//! \date Sun Aug 30 01:11:18 2015
//! \brief Emic engine archive implementation.
//
// 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.Collections.Generic;
using System.ComponentModel.Composition;
using System.IO;
using GameRes.Utility;
namespace GameRes.Formats.Emic
{
internal class EmicArchive : ArcFile
{
public readonly byte[] Key;
public EmicArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, byte[] key)
: base (arc, impl, dir)
{
Key = key;
}
}
[Export(typeof(ArchiveFormat))]
public class PacOpener : ArchiveFormat
{
public override string Tag { get { return "PAC/EMIC"; } }
public override string Description { get { return "Emic engine resource archive"; } }
public override uint Signature { get { return 0x4B434150; } } // 'PACK'
public override bool IsHierarchic { get { return true; } }
public override bool CanCreate { get { return false; } }
public PacOpener ()
{
Extensions = new string[] { "pac" };
}
public override ArcFile TryOpen (ArcView file)
{
byte[] key;
int count = file.View.ReadInt32 (0x28);
uint is_encrypted = file.View.ReadUInt32 (4);
if (IsSaneCount (count) && is_encrypted <= 1)
{
key = file.View.ReadBytes (8, 0x20);
for (int i = 0; i < key.Length; ++i)
key[i] ^= 0xAA;
}
else
{
count = file.View.ReadInt32 (4);
is_encrypted = file.View.ReadUInt32 (8);
if (!IsSaneCount (count) || is_encrypted > 1)
return null;
key = file.View.ReadBytes (0xC, 0x20);
for (int i = 0; i < key.Length; ++i)
key[i] ^= 0xAB;
}
Stream input = file.CreateStream();
if (1 == is_encrypted)
input = new ByteStringEncryptedStream (input, 0, key);
using (var reader = new BinaryReader (input))
{
input.Position = 0x2C;
var index_buf = new byte[0x108];
var dir = new List<Entry> (count);
for (int i = 0; i < count; ++i)
{
int name_len = reader.ReadInt32();
if (name_len <= 0 || name_len > index_buf.Length) // file name is too long
return null;
if (name_len != reader.Read (index_buf, 0, name_len))
return null;
string name = Binary.GetCString (index_buf, 0, name_len);
var entry = FormatCatalog.Instance.Create<Entry> (name);
entry.Size = reader.ReadUInt32();
entry.Offset = reader.ReadUInt32();
if (!entry.CheckPlacement (file.MaxOffset))
return null;
dir.Add (entry);
}
if (1 == is_encrypted)
return new EmicArchive (file, this, dir, key);
else
return new ArcFile (file, this, dir);
}
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var emic = arc as EmicArchive;
Stream input = arc.File.CreateStream (entry.Offset, entry.Size);
if (null != emic)
input = new ByteStringEncryptedStream (input, entry.Offset, emic.Key);
return input;
}
}
internal class ByteStringEncryptedStream : InputProxyStream
{
byte[] m_key;
int m_base_pos;
public ByteStringEncryptedStream (Stream main, long start_pos, byte[] key, bool leave_open = false)
: base (main, leave_open)
{
m_key = key;
m_base_pos = (int)(start_pos % m_key.Length);
}
public override int Read (byte[] buffer, int offset, int count)
{
int start_pos = (int)((m_base_pos + BaseStream.Position) % m_key.Length);
int read = BaseStream.Read (buffer, offset, count);
if (read > 0)
{
for (int i = 0; i < read; ++i)
{
buffer[offset+i] ^= m_key[(start_pos + i) % m_key.Length];
}
}
return read;
}
public override int ReadByte ()
{
long pos = BaseStream.Position;
int b = BaseStream.ReadByte();
if (-1 != b)
{
b ^= m_key[(m_base_pos + pos) % m_key.Length];
}
return b;
}
}
}