| 6569 | size_t m_activeIterators; |
| 6570 | |
| 6571 | iterator(Columns const& columns, EndTag) |
| 6572 | : m_columns(columns.m_columns), |
| 6573 | m_activeIterators(0) { |
| 6574 | m_iterators.reserve(m_columns.size()); |
| 6575 | |
| 6576 | for (auto const& col : m_columns) |
| 6577 | m_iterators.push_back(col.end()); |
| 6578 | } |
| 6579 | |
| 6580 | public: |
| 6581 | using difference_type = std::ptrdiff_t; |