GetLenToPosState
UInt32 lenToPosState = GetLenToPosState(len);
UInt32 lenToPosState = GetLenToPosState(lenTest);
RcTree_Encode(&p->rc, p->posSlotEncoder[GetLenToPosState(len)], kNumPosSlotBits, (1 << kNumPosSlotBits) - 1);
RcTree_Encode(&p->rc, p->posSlotEncoder[GetLenToPosState(len)], kNumPosSlotBits, posSlot);