Method CalculateSize

include/Eigen/Eigen/src/ThreadPool/RunQueue.h:219–230

  }

  EIGEN_ALWAYS_INLINE
  unsigned CalculateSize(unsigned front, unsigned back) const {
    int size = (front & kMask2) - (back & kMask2);
    // Fix overflow.
    if (size < 0) size += 2 * kSize;
    // Order of modification in push/pop is crafted to make the queue look
    // larger than it is during concurrent modifications. E.g. push can
    // increment size before the corresponding pop has decremented it.
    // So the computed size can be up to kSize + 1, fix it.
    if (size > static_cast<int>(kSize)) size = kSize;
    return static_cast<unsigned>(size);
  }

  RunQueue(const RunQueue&) = delete;
  void operator=(const RunQueue&) = delete;