Method Rank

libs/coding/bwt.cpp:60–72

Returns the rank of the i-th symbol among symbols with the same value.

  // Returns the rank of the i-th symbol among symbols with the same
  // value.
  size_t Rank(size_t i) const
  {
    ASSERT_LESS(i, Size(), ());
    if (i == 0)
      return 0;

    --i;
    auto it = std::upper_bound(m_starts.begin(), m_starts.end(), i);
    if (it == m_starts.begin())
      return i;
    --it;
    return i - *it;
  }

private:
  size_t const m_n;