Class SelectionView

src/include/common/data_chunk/sel_vector.h:18–94

A lightweight, immutable view over a SelectionVector, or a subsequence of a selection vector SelectionVectors are also SelectionViews so that you can pass a SelectionVector to functions which take a SelectionView&

// SelectionVectors are also SelectionViews so that you can pass a SelectionVector to functions
// which take a SelectionView&
class SelectionView {
protected:
    // In DYNAMIC mode, selectedPositions points to a mutable buffer that can be modified through
    // getMutableBuffer In STATIC mode, selectedPositions points to somewhere in
    // INCREMENTAL_SELECTED_POS
    // Note that the vector is considered unfiltered only if it is both STATIC and the first
    // selected position is 0
    enum class State {
        DYNAMIC,
        STATIC,
    };

public:
    // STATIC selectionView over 0..selectedSize
    explicit SelectionView(sel_t selectedSize);

    template<class Func>
    void forEach(Func&& func) const {
        if (state == State::DYNAMIC) {
            for (size_t i = 0; i < selectedSize; i++) {
                func(selectedPositions[i]);
            }
        } else {
            const auto start = selectedPositions[0];
            for (size_t i = start; i < start + selectedSize; i++) {
                func(i);
            }
        }
    }

    template<class Func>
    void forEachBreakWhenFalse(Func&& func) const {
        if (state == State::DYNAMIC) {
            for (size_t i = 0; i < selectedSize; i++) {
                if (!func(selectedPositions[i])) {
                    break;
                }
            }
        } else {
            const auto start = selectedPositions[0];
            for (size_t i = start; i < start + selectedSize; i++) {
                if (!func(i)) {
                    break;
                }
            }
        }
    }

    sel_t getSelSize() const { return selectedSize; }

    sel_t operator[](sel_t index) const {
        DASSERT(index < selectedSize);
        return selectedPositions[index];
    }

    bool isUnfiltered() const { return state == State::STATIC && selectedPositions[0] == 0; }
    bool isStatic() const { return state == State::STATIC; }