private FolderInfo GetNextFolderItem(DataReader mReader)
{
FolderInfo folder = new FolderInfo();
int numInStreams = 0;
int numOutStreams = 0;
int numCoders = mReader.ReadPackedUInt31();
folder.Coders = new CoderInfo[numCoders];
for(int i = 0; i < numCoders; i++)
{
CoderInfo coder = new CoderInfo();
folder.Coders[i] = coder;
byte mainByte = mReader.ReadByte();
int idSize = mainByte & 15;
if(idSize > 8) // standard 7z also is limited to 8 byte coder ids
throw new InvalidDataException();
ulong id = 0;
for(int j = idSize - 1; j >= 0; j--)
id += (ulong)mReader.ReadByte() << (j * 8);
coder.MethodId = id;
if((mainByte & 0x10) != 0)
{
coder.NumInStreams = mReader.ReadPackedUInt31();
coder.NumOutStreams = mReader.ReadPackedUInt31();
}
else
{
coder.NumInStreams = 1;
coder.NumOutStreams = 1;
}
if((mainByte & 0x20) != 0)
{
int propsSize = mReader.ReadPackedUInt31();
coder.Props = mReader.ReadBytes(propsSize);
}
// TODO: Warn if 0x40 is set, since it is not defined in the supported versions of the format.
if((mainByte & 0x80) != 0)
throw new InvalidDataException();
numInStreams += coder.NumInStreams;
numOutStreams += coder.NumOutStreams;
}
int numBindPairs = mReader.ReadPackedUInt31();
folder.BindPairs = new BindPair[numBindPairs];
for(int i = 0; i < numBindPairs; i++)
{
int inIndex = mReader.ReadPackedUInt31();
int outIndex = mReader.ReadPackedUInt31();
folder.BindPairs[i] = new BindPair(inIndex, outIndex);
}
if(numInStreams < numBindPairs)
throw new InvalidDataException();
int numPackStreams = numInStreams - numBindPairs;
folder.PackStreams = new int[numPackStreams];
if(numPackStreams == 1)
{
bool found = false;
for(int i = 0; i < numInStreams; i++)
{
if(folder.FindBindPairForInStream(i) < 0)
{
folder.PackStreams[0] = i;
found = true;
break;
}
}
if(!found)
throw new InvalidDataException();
}
else
{
for(int i = 0; i < numPackStreams; i++)
folder.PackStreams[i] = mReader.ReadPackedUInt31();
}
return folder;
}
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);
}
}