public byte[] BuildXorKey(ReadOnlySpan <byte> mixData)
{
// Seed value was pulled from ds.exe
Span <byte> key = new byte[] { 0x43, 0x94, 0x3A, 0xFA, 0x62, 0xAB, 0x1C, 0xF4, 0x1C, 0x81, 0x76, 0xF3, 0x3E, 0x9E, 0xA8, 0xD2 };
for (int i = 0; i < mixData.Length; i++)
{
key[i] = mixData[i];
}
SMHasher.MurmurHash3_x64_128(key, 42, out ulong[] hash);
Bits.TryWriteBytes(key.Slice(0), hash[0]);
Bits.TryWriteBytes(key.Slice(8), hash[1]);
return(key.ToArray());
}
public IndexEntry FromData(BinaryReader reader)
{
uint pathLength = reader.ReadUInt32();
if (pathLength > 0)
{
// Strings are expected to be lowercase and prefixed with "cache:"
var fullPath = Encoding.UTF8.GetString(reader.ReadBytesStrict(pathLength));
FilePath = fullPath.Replace("cache:", "");
SMHasher.MurmurHash3_x64_128(Encoding.UTF8.GetBytes(FilePath + char.MinValue), 42, out ulong[] hash);
PathHash = hash[0];
}
GUID = new BaseGGUUID().FromData(reader);
var unknown = reader.ReadBytesStrict(16);
return(this);
}
private byte[] BuildXorKey()
{
// Murmurhash3 of the first 16 bytes of the BlockEntry header as stored in the file. No type casting = very ugly in C#.
Span <byte> seed = stackalloc byte[16];
Bits.TryWriteBytes(seed.Slice(0), DecompressedOffset);
Bits.TryWriteBytes(seed.Slice(8), DecompressedSize);
Bits.TryWriteBytes(seed.Slice(12), XorKey1);
SMHasher.MurmurHash3_x64_128(seed, 42, out ulong[] hash);
Bits.TryWriteBytes(seed.Slice(0), hash[0]);
Bits.TryWriteBytes(seed.Slice(8), hash[1]);
// XOR the seed with the data key
var key = new byte[] { 0x37, 0x4A, 0x08, 0x6C, 0x95, 0x9D, 0x15, 0x7E, 0xE8, 0xF7, 0x5A, 0x3D, 0x3F, 0x7D, 0xAA, 0x18 };
for (int i = 0; i < key.Length; i++)
{
key[i] ^= seed[i];
}
return(MD5Context.Value.ComputeHash(key));
}
private ulong GetHashForPath(string path)
{
SMHasher.MurmurHash3_x64_128(Encoding.UTF8.GetBytes(path + char.MinValue), 42, out ulong[] hash);
return(hash[0]);
}
public static ulong GetHashForPath(string path, bool stream = false)
{
path = EnsureExt(path, stream).Replace('\\', '/');
SMHasher.MurmurHash3_x64_128(Encoding.UTF8.GetBytes(path + char.MinValue), 42, out ulong[] hash);
return(hash[0]);
}
