static MemoryStream Decrypt(uint[] h, Blowfish fish) {
uint[] decrypted = fish.Decrypt(h);
var ms = new MemoryStream();
var writer = new BinaryWriter(ms);
foreach (uint t in decrypted)
writer.Write(t);
writer.Flush();
ms.Position = 0;
return ms;
}
public bool IsValid() {
Position = 0;
uint signature = ReadUInt32();
if ((signature & ~(uint)(MixFileFlags.Encrypted | MixFileFlags.Checksum)) != 0)
return false;
if ((signature & (uint)MixFileFlags.Encrypted) != 0) {
byte[] keyblock = Read(80);
byte[] blowfishKey = new BlowfishKeyProvider().DecryptKey(keyblock);
uint[] h = ReadUints(this, 2);
var fish = new Blowfish(blowfishKey);
MemoryStream ms = Decrypt(h, fish);
var reader2 = new BinaryReader(ms);
ushort numFiles = reader2.ReadUInt16();
uint dataSize = reader2.ReadUInt32(); /*datasize*/
return numFiles > 0 && 84 + (6 + numFiles * 12 + 7 & ~7) + dataSize + ((signature & (uint)MixFileFlags.Checksum) != 0 ? 20 : 0) == Length;
}
else {
ushort numFiles = ReadUInt16();
uint dataSize = ReadUInt32();
return numFiles > 0 && 4 + 6 + numFiles * 12 + dataSize + ((signature & (uint)MixFileFlags.Checksum) != 0 ? 20 : 0) == Length;
}
}
List<MixEntry> ParseRaHeader(VirtualFile reader, out long dataStart) {
//BinaryReader reader = new BinaryReader(s);
byte[] keyblock = reader.Read(80);
byte[] blowfishKey = new BlowfishKeyProvider().DecryptKey(keyblock);
uint[] h = ReadUints(reader, 2);
var fish = new Blowfish(blowfishKey);
MemoryStream ms = Decrypt(h, fish);
var reader2 = new BinaryReader(ms);
ushort numFiles = reader2.ReadUInt16();
reader2.ReadUInt32(); /*datasize*/
reader.Position = headerStart;
int byteCount = 6 + numFiles * MixEntry.Size;
h = ReadUints(reader, (byteCount + 3) / 4);
ms = Decrypt(h, fish);
dataStart = headerStart + byteCount + ((~byteCount + 1) & 7);
long ds;
return ParseTdHeader(new VirtualFile(ms), out ds);
}
