Method push

src/librawspeed/io/BitStream.h:79–91

struct BitStreamCacheRightInLeftOut : BitStreamCacheBase
{
  inline void push(uint64_t bits, uint32_t count) noexcept {
    assert(count + fillLevel <= Size);
    assert(count != 0);
    // If the maximal size of the cache is BitStreamCacheBase::Size, and we
    // have fillLevel [high] bits set, how many empty [low] bits do we have?
    const uint32_t vacantBits = BitStreamCacheBase::Size - fillLevel;
    // If we just directly 'or' these low bits into the cache right now,
    // how many unfilled bits of a gap will there be in the middle of a cache?
    const uint32_t emptyBitsGap = vacantBits - count;
    // So just shift the new bits so that there is no gap in the middle.
    cache |= bits << emptyBitsGap;
    fillLevel += count;
  }

  inline uint32_t peek(uint32_t count) const noexcept {
    return extractHighBits(cache, count, /*effectiveBitwidth=*/BitStreamCacheBase::Size);