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(Emic): encrypted archive variation.

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This commit is contained in:
morkt 2016-09-29 11:30:54 +04:00
parent 37023024b7
commit e5128d3690
1 changed files with 74 additions and 70 deletions
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144
ArcFormats/Emic/ArcPACK.cs
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@ -2,7 +2,7 @@
//! \date Sun Aug 30 01:11:18 2015
//! \brief Emic engine archive implementation.
//
// Copyright (C) 2015 by morkt
// 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
@ -23,7 +23,6 @@
// IN THE SOFTWARE.
//
using System;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.IO;
@ -47,7 +46,7 @@ namespace GameRes.Formats.Emic
{
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 uint Signature { get { return 0x4B434150; } } // 'PACK'
public override bool IsHierarchic { get { return true; } }
public override bool CanCreate { get { return false; } }
@ -58,95 +57,100 @@ namespace GameRes.Formats.Emic
public override ArcFile TryOpen (ArcView file)
{
byte[] key;
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);
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
return new ArcFile (file, this, dir);
{
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;
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);
Stream input = arc.File.CreateStream (entry.Offset, entry.Size);
if (null != emic)
input = new ByteStringEncryptedStream (input, entry.Offset, emic.Key);
return input;
}
}
internal class PacReader
internal class ByteStringEncryptedStream : InputProxyStream
{
ArcView m_file;
int m_count;
byte[] m_key;
int m_base_pos;
public bool Encrypted { get; private set; }
public byte[] Key { get; private set; }
public PacReader (ArcView file, int count)
public ByteStringEncryptedStream (Stream main, long start_pos, byte[] key, bool leave_open = false)
: base (main, leave_open)
{
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;
m_key = key;
m_base_pos = (int)(start_pos % m_key.Length);
}
public PacReader (ArcView file, byte[] key)
public override int Read (byte[] buffer, int offset, int count)
{
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)
int start_pos = (int)((m_base_pos + BaseStream.Position) % m_key.Length);
int read = BaseStream.Read (buffer, offset, count);
if (read > 0)
{
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];
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;
}
}
}