private void SkipAttribute(DataReader mReader)
{
ulong size = mReader.ReadPackedUInt64();
if(size > (ulong)mReader.Remaining)
throw new InvalidDataException();
mReader.Skip((long)size);
}
private void ReadHeader(DataReader mReader)
{
byte[] signature = mReader.ReadBytes(kSignature.Length);
if(signature.Length != kSignature.Length)
throw new InvalidDataException();
for(int i = 0; i < signature.Length; i++)
if(signature[i] != kSignature[i])
throw new InvalidDataException();
mMajorVersion = mReader.ReadByte();
mMinorVersion = mReader.ReadByte();
if(mMajorVersion != 0)
throw new NotSupportedException();
// TODO: Weak check of supported minor versions
uint startHeaderCRC = mReader.ReadUInt32();
long nextHeaderOffset = mReader.ReadInt64();
long nextHeaderLength = mReader.ReadInt64();
uint nextHeaderCRC = mReader.ReadUInt32();
Utils.Assert(mReader.Position == kPrimaryHeaderSize);
if(mCheckCRC)
{
uint crc = CRC.kInitCRC;
crc = CRC.Update(crc, nextHeaderOffset);
crc = CRC.Update(crc, nextHeaderLength);
crc = CRC.Update(crc, nextHeaderCRC);
crc = CRC.Finish(crc);
if(crc != startHeaderCRC)
throw new InvalidDataException();
}
if(nextHeaderLength < 0 || nextHeaderOffset < 0
|| nextHeaderOffset > mReader.Remaining - nextHeaderLength)
throw new InvalidDataException();
if(nextHeaderLength > 0) // zero is ok, empty archive
{
mReader.Skip(nextHeaderOffset);
if(mCheckCRC)
{
if(mReader.CalculateCRC(nextHeaderLength) != nextHeaderCRC)
throw new InvalidDataException();
mReader.Seek(kPrimaryHeaderSize + nextHeaderOffset);
}
using(mReader.Constrain(nextHeaderLength))
ReadHeader2(mReader);
}
}
