Class small_vector

include/pybind11/detail/argument_vector.h:128–218

template <typename T, std::size_t InlineSize>
struct small_vector {
public:
    small_vector() = default;

    // Disable copy ctor and assignment.
    small_vector(const small_vector &) = delete;
    small_vector &operator=(const small_vector &) = delete;
    small_vector(small_vector &&) noexcept = default;
    small_vector &operator=(small_vector &&) noexcept = default;

    std::size_t size() const {
        if (is_inline()) {
            return m_repr.iarray.size;
        }
        return m_repr.hvector.vec.size();
    }

    T const *data() const {
        if (is_inline()) {
            return m_repr.iarray.arr.data();
        }
        return m_repr.hvector.vec.data();
    }

    T &operator[](std::size_t idx) {
        assert(idx < size());
        if (is_inline()) {
            return m_repr.iarray.arr[idx];
        }
        return m_repr.hvector.vec[idx];
    }

    T const &operator[](std::size_t idx) const {
        assert(idx < size());
        if (is_inline()) {
            return m_repr.iarray.arr[idx];
        }
        return m_repr.hvector.vec[idx];
    }

    void push_back(const T &x) { emplace_back(x); }

    void push_back(T &&x) { emplace_back(std::move(x)); }

    template <typename... Args>
    void emplace_back(Args &&...x) {
        if (is_inline()) {
            auto &ha = m_repr.iarray;
            if (ha.size == InlineSize) {
                move_to_heap_vector_with_reserved_size(InlineSize + 1);
                m_repr.hvector.vec.emplace_back(std::forward<Args>(x)...);
            } else {
                ha.arr[ha.size++] = T(std::forward<Args>(x)...);
            }
        } else {
            m_repr.hvector.vec.emplace_back(std::forward<Args>(x)...);
        }
    }