HUF_BITS_IN_CONTAINER
assert((bitC->bitPos[idx] & 0xFF) <= HUF_BITS_IN_CONTAINER);
assert(!kFast || (bitC->bitPos[idx] & 0xFF) <= HUF_BITS_IN_CONTAINER);
assert((bitC->bitPos[1] & 0xFF) < HUF_BITS_IN_CONTAINER);
assert((bitC->bitPos[0] & 0xFF) <= HUF_BITS_IN_CONTAINER);
size_t const bitContainer = bitC->bitContainer[0] >> (HUF_BITS_IN_CONTAINER - nbBits);