ArcFile Open(byte[] basename, ArcView file, EncryptionScheme scheme, Key key)
{
uint key1 = scheme.BaseKey.Key1;
uint key2 = scheme.BaseKey.Key2;
for (int b = 0, e = basename.Length - 1; e >= 0; ++b, --e)
{
key1 ^= basename[e];
key2 ^= basename[b];
key1 = Binary.RotR(key1, 7);
key2 = Binary.RotL(key2, 7);
}
if (null != key)
{
key1 ^= key.Key1;
key2 ^= key.Key2;
}
uint code = file.View.ReadUInt32(4) ^ key2;
int index_size = (int)(code & 0xffffff);
byte flags = (byte)(code >> 24);
if (0 != (flags & 1))
{
index_size = (index_size << 11) - 8;
}
if (index_size < 5 || index_size >= file.MaxOffset)
{
return(null);
}
var index = new byte[index_size];
if (index_size != file.View.Read(8, index, 0, (uint)index_size))
{
return(null);
}
scheme.DecryptIndex(index, index_size, key2);
var lpk_info = new LpkInfo
{
AlignedOffset = 0 != (flags & 1),
Flag1 = 0 != (flags & 2),
IsEncrypted = 0 != (flags & 4),
PackedEntries = 0 != (flags & 8),
WholeCrypt = 0 != (flags & 0x10),
Key = key1
};
var reader = new IndexReader(lpk_info);
var dir = reader.Read(index);
if (null == dir)
{
return(null);
}
// this condition is fishy, probably patch files have additional bitflag set
if (lpk_info.WholeCrypt && Binary.AsciiEqual(basename, "PATCH"))
{
lpk_info.WholeCrypt = false;
}
return(new LuciArchive(file, this, dir, scheme, reader.Info));
}
