public static bool TryRead(BinaryReader reader, int version, out QarArchiveEntryHeader header)
{
header = new QarArchiveEntryHeader();
// hash 8 bytes
uint hashLow = reader.ReadUInt32() ^ xorMask1;
uint hashHigh = reader.ReadUInt32() ^ xorMask1;
header.Hash = (ulong)hashHigh << 32 | hashLow;
// size 8 bytes (4+4), compressed and not, the order depends on the version
header.Size1 = reader.ReadUInt32() ^ xorMask2;
header.Size2 = reader.ReadUInt32() ^ xorMask3;
// data hash 16 bytes
uint md51 = reader.ReadUInt32() ^ xorMask4;
uint md52 = reader.ReadUInt32() ^ xorMask1;
uint md53 = reader.ReadUInt32() ^ xorMask1;
uint md54 = reader.ReadUInt32() ^ xorMask2;
byte[] md5Hash = new byte[16];
Buffer.BlockCopy(BitConverter.GetBytes(md51), 0, md5Hash, 0, sizeof(uint));
Buffer.BlockCopy(BitConverter.GetBytes(md52), 0, md5Hash, 4, sizeof(uint));
Buffer.BlockCopy(BitConverter.GetBytes(md53), 0, md5Hash, 8, sizeof(uint));
Buffer.BlockCopy(BitConverter.GetBytes(md54), 0, md5Hash, 12, sizeof(uint));
header.DataHash = md5Hash;
// some file have a special signature if they are crypted
// here we attempt to read the file signature
QarArchiveEntryContentHeader.TryRead(reader, version, header.Hash, header.Seed, out header.Content);
return(true);
}
public static bool TryRead(BinaryReader reader, int version, ulong hash, ulong seed, out QarArchiveEntryContentHeader header)
{
header = new QarArchiveEntryContentHeader();
// attemtp to read the file signature
// read a chunk for processing
// a chunk is 8 bytes
byte[] buffer = new byte[8];
// not enough data
if (reader.Read(buffer, 0, buffer.Length) != buffer.Length)
{
return(false);
}
var decryptAlgorithm = new Decrypt1Transform(version, hash, seed);
// decrypt the buffer
decryptAlgorithm.TransformBlock(buffer, 0, buffer.Length, buffer, 0);
// get the encryption type and the key
header.Signature = BitConverter.ToUInt32(buffer, 0);
header.Key = BitConverter.ToUInt32(buffer, 4);
// file not encrypted
// unset the encryption and the key
if (header.Signature != Signature1 && header.Signature != Signature2)
{
header.Signature = 0;
header.Key = 0;
}
else if (header.Signature == Signature2)
{
// not enough data
if (reader.Read(buffer, 0, buffer.Length) != buffer.Length)
{
return(false);
}
decryptAlgorithm.TransformBlock(buffer, 0, buffer.Length, buffer, 0);
// additional 8 bytes
// the size of the file, excluding the header
header.Size1 = BitConverter.ToUInt32(buffer, 0);
header.Size2 = BitConverter.ToUInt32(buffer, 4);
if (header.Size1 != header.Size2)
{
return(false);
}
}
return(true);
}
