(Ai5Win): guess obfuscation scheme.

This commit is contained in:
morkt 2018-09-14 00:09:12 +04:00
parent 652037f878
commit 72e54eb50d

View File

@ -2,7 +2,7 @@
//! \date Mon Jun 29 04:41:29 2015 //! \date Mon Jun 29 04:41:29 2015
//! \brief Ai5Win engine resource archive. //! \brief Ai5Win engine resource archive.
// //
// Copyright (C) 2015 by morkt // Copyright (C) 2015-2018 by morkt
// //
// Permission is hereby granted, free of charge, to any person obtaining a copy // Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to // of this software and associated documentation files (the "Software"), to
@ -57,17 +57,13 @@ namespace GameRes.Formats.Elf
public override bool IsHierarchic { get { return false; } } public override bool IsHierarchic { get { return false; } }
public override bool CanWrite { get { return false; } } public override bool CanWrite { get { return false; } }
public static Dictionary<string, ArcIndexScheme> KnownSchemes = new Dictionary<string, ArcIndexScheme>(); static Ai5Scheme DefaultScheme = new Ai5Scheme { KnownSchemes = new Dictionary<string, ArcIndexScheme>() };
public Dictionary<string, ArcIndexScheme> KnownSchemes { get { return DefaultScheme.KnownSchemes; } }
public ArcAI5Opener ()
{
Extensions = new string[] { "arc" };
}
public override ResourceScheme Scheme public override ResourceScheme Scheme
{ {
get { return new Ai5Scheme { KnownSchemes = KnownSchemes }; } get { return DefaultScheme; }
set { KnownSchemes = ((Ai5Scheme)value).KnownSchemes; } set { DefaultScheme = (Ai5Scheme)value; }
} }
public override ArcFile TryOpen (ArcView file) public override ArcFile TryOpen (ArcView file)
@ -79,9 +75,11 @@ namespace GameRes.Formats.Elf
return null; return null;
var reader = new Ai5ArcIndexReader (file, count); var reader = new Ai5ArcIndexReader (file, count);
var dir = reader.TrySchemes (KnownSchemes.Values); var dir = reader.TrySchemes (KnownSchemes.Values);
if (dir != null) if (null == dir)
return new ArcFile (file, this, dir); dir = reader.TrySchemes (reader.GuessSchemes());
return null; if (null == dir)
return null;
return new ArcFile (file, this, dir);
} }
public override Stream OpenEntry (ArcFile arc, Entry entry) public override Stream OpenEntry (ArcFile arc, Entry entry)
@ -167,5 +165,33 @@ namespace GameRes.Formats.Elf
else else
return null; return null;
} }
internal IEnumerable<ArcIndexScheme> GuessSchemes ()
{
if (m_count < 2)
yield break;
foreach (int name_length in NameLengths)
{
uint data_offset = (uint)((name_length + 8) * m_count + 4);
byte name_key = m_file.View.ReadByte (3 + name_length);
uint first_size = m_file.View.ReadUInt32 (4 + name_length);
uint first_offset = m_file.View.ReadUInt32 (8 + name_length);
uint offset_key = data_offset ^ first_offset;
uint second_offset = m_file.View.ReadUInt32 ((name_length+8) * 2) ^ offset_key;
if (second_offset < data_offset || second_offset >= m_file.MaxOffset)
continue;
uint size_key = (second_offset - data_offset) ^ first_size;
if (0 == offset_key || 0 == size_key)
continue;
yield return new ArcIndexScheme {
NameLength = name_length,
NameKey = name_key,
SizeKey = size_key,
OffsetKey = offset_key,
};
}
}
static readonly int[] NameLengths = { 0x14, 0x1E, 0x20, 0x100 };
} }
} }