GARbro-mirror/ArcFormats/Emic/ArcPACK.cs

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//! \file ArcPACK.cs
//! \date Sun Aug 30 01:11:18 2015
//! \brief Emic engine archive implementation.
//
// Copyright (C) 2015 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 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; } }
public override bool IsHierarchic { get { return true; } }
public override bool CanCreate { get { return false; } }
public override ArcFile TryOpen (ArcView file)
{
int count = file.View.ReadInt32 (0x28);
if (!IsSaneCount (count))
return null;
var reader = new PacReader (file, count);
var dir = reader.ReadIndex();
if (null == dir)
return null;
if (reader.Encrypted)
return new EmicArchive (file, this, dir, reader.Key);
else
return new ArcFile (file, this, dir);
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var emic = arc as EmicArchive;
if (null == emic)
return arc.File.CreateStream (entry.Offset, entry.Size);
var reader = new PacReader (emic.File, emic.Key);
var data = new byte[entry.Size];
reader.Read (entry.Offset, data, 0, data.Length);
return new MemoryStream (data);
}
}
internal class PacReader
{
ArcView m_file;
int m_count;
public bool Encrypted { get; private set; }
public byte[] Key { get; private set; }
public PacReader (ArcView file, int count)
{
m_file = file;
m_count = count;
Key = new byte[0x20];
Encrypted = 1 == m_file.View.ReadInt32 (4);
file.View.Read (8, Key, 0, (uint)Key.Length);
for (int i = 0; i < Key.Length; ++i)
Key[i] ^= 0xAA;
}
public PacReader (ArcView file, byte[] key)
{
m_file = file;
Encrypted = true;
Key = key;
}
public List<Entry> ReadIndex ()
{
var index_buf = new byte[0x110];
var dir = new List<Entry> (m_count);
uint index_offset = 0x2C;
for (int i = 0; i < m_count; ++i)
{
Read (index_offset, index_buf, 0, 4);
int name_len = LittleEndian.ToInt32 (index_buf, 0);
if (name_len > index_buf.Length-8) // file name is too long
return null;
index_offset += 4;
Read (index_offset, index_buf, 0, name_len+8);
string name = Binary.GetCString (index_buf, 0, name_len);
var entry = FormatCatalog.Instance.Create<Entry> (name);
entry.Offset = LittleEndian.ToUInt32 (index_buf, name_len+4);
entry.Size = LittleEndian.ToUInt32 (index_buf, name_len);
if (!entry.CheckPlacement (m_file.MaxOffset))
return null;
dir.Add (entry);
index_offset += (uint)name_len + 8;
}
return dir;
}
public int Read (long offset, byte[] buf, int index, int count)
{
int read = m_file.View.Read (offset, buf, index, (uint)count);
if (Encrypted)
{
int key_offset = (int)offset;
for (int i = 0; i < read; ++i)
{
buf[i] ^= Key[key_offset++ & 0x1F];
}
}
return read;
}
}
}