SparseArray

The SparseArray is a vector of optional Components.

For example, a SparseArray named 'Velocity' will be able to store the velocity of each Entity. If an Entity, for example a wall, doens't need a Velocity component, than the value for this Entity in the Velocity SparceArray will be empty, hence the "optional Component".

The class SparseArray looks like this:

class sparse_array
{
public:
    using value_type = std::optional<Component>;
    using reference_type = value_type &;
    using const_reference_type = value_type const &;
    using container_t = std::vector<value_type>;
    using size_type = typename container_t::size_type;
    using iterator = typename container_t::iterator;
    using const_iterator = typename container_t ::const_iterator;

    sparse_array() {};
    sparse_array(const sparse_array &other);
    sparse_array(sparse_array &&other) noexcept;
    ~sparse_array();

    sparse_array &operator=(const sparse_array &other);
    sparse_array &operator=(sparse_array &&other) noexcept;
    reference_type operator[](size_t idx);
    const_reference_type operator[](size_t idx) const;

    iterator begin();
    const_iterator begin() const;
    const_iterator cbegin() const;
    iterator end();
    const_iterator end() const;
    const_iterator cend() const;
    size_type size() const;

    reference_type insert_at(size_type pos, Component const &value);
    reference_type insert_at(size_type pos, Component &&value);
    template <class... Params>
    reference_type emplace_at(size_type pos, Params &&...data);
    reference_type push_back(std::optional<Component> &&value);
    void erase(size_type pos);
    size_type get_index(value_type const &value) const;

private:
    container_t _data;
};

Constructors/Destructor

sparse_array()

sparse_array() {};

The default constructor of the SparseArray class.

sparse_array(const sparse_array)

sparse_array(const sparse_array &other);

The copy constructor of the SparseArray class.

sparse_arrray(sparse_array &&)

sparse_array(sparse_array &&other) noexcept;

The move constructor of the SparseArray class.

~sparse_array()

~sparse_array();

The default destructor of the SparseArray class.

Operators

&operator=

sparse_array &operator=(const sparse_array &other);

The copy assignment operator of the SparseArray class.

&operator=

sparse_array &operator=(sparse_array &&other) noexcept;

The move assignment operator of the SparseArray class.

&operator[]

reference_type operator[](size_t idx);

Takes the index of a Entity and returns a reference to the value contained in the array for this entity.

&operator[]

const_reference_type operator[](size_t idx) const;

Same but returns a const reference instead of a reference.

Functions

insert_at()

reference_type insert_at(size_type pos, Component const &value);

Inserts the value at the specified position, and returns the reference to the value.

insert_at()

reference_type insert_at(size_type pos, Component &&value);

Same but moves the value instead of copying it.

emplace_at()

template <class... Params>
reference_type emplace_at(size_type pos, Params &&...data);

Same as insert_at but moves the value instead of copying it.

push_back()

reference_type push_back(std::optional<Component> &&value);

Insert the value at the back of the array, and returns a reference to the value.

erase()

void erase(size_type pos);

Erases the value at the specified position.

get_index()

size_type get_index(value_type const &value) const;

Take a reference to an optional Component, and return its index. Allows us to retreive the index of an Entity its value.

Value

_data

container_t _data

Vector of optional Components