=head1 NAME

XS::Framework::Manual::SVAPI::Array - XS::Framework Array C++ class reference

=head1 Array

=head2 Overview

The C<Array> class is the wrapper around Perls C<AV*> type, which is a variant
of C<SV*>. As with C<Sv>, it might hold an underlying Perl array C<AV*> or might

=head2 Construction

    static Array noinc  (SV* val)
    static Array noinc  (AV* val)

    Array (std::nullptr_t = nullptr)
    Array (SV* sv, bool policy = INCREMENT)
    Array (AV* sv, bool policy = INCREMENT)

The new C<Array> is created, and it either takes ownership on the underlying
C<SV*>/C<AV*> with corresponding refcounting policy, or just empty wrapper
is created, which holds no value. On invalid C<SV*>, e.g. pointer to Hash,
an exception will be thrown. The valid C<SV*> should be either C<AV*> or
reference to C<AV*> or C<undef>.

Please, note, that empty C<Array> means that it holds no value (aka NULL),
it is not the same, when it holds underlying empty AV* with zero items.

    static Array create()
    static Array create (size_t cap)

It is possible to create new C<Array> with empty underlying C<AV*>, optionally
reserving space for C<cap> items (SV*).

If there is a list of items, it it possible to create new C<Array> filled with
them. However, the C<SV*> values can be either copied/cloned into new values,
or may be just I<aliased>; in the later case refcounter just increased. The
inteface is the following:

    enum create_type_t { ALIAS, COPY };

    static Array create (size_t size, SV** content, create_type_t type = ALIAS);
    static Array create (std::initializer_list<Scalar> l, create_type_t type = ALIAS)
    static Array create (const Array& from, create_type_t type = ALIAS)
    Array (std::initializer_list<Scalar> l, create_type_t type = ALIAS);

For example,

    Array source = ...;
    Array dest = Array::create(source, Array::COPY);

The copy and move constructors are also available:

    Array (const Array& oth)
    Array (Array&& oth)
    Array (const Sv& oth)
    Array (Sv&& oth)
=head2 assignment operators

    Array& operator= (SV* val)
    Array& operator= (AV* val)
    Array& operator= (const Array& oth)
    Array& operator= (Array&& oth)
    Array& operator= (const Sv& oth)
    Array& operator= (Sv&& oth)

The assignment operators are complementaty to the constructors above. They
inherit behaviour from C<Sv>, including NULL-safety. The previously held
C<SV*> will be C<dec>-remented.

The last operator performs proxy call in B<scalar> context, the same as in
appropriate constructor above.

    void set (SV* val)

The C<set> method directly assigns the value to the underlying C<SV*>,
I<bypassing all checks>. Use the method with caution.

=head2 getters

There are zero-cost NULL-safe getters:

    operator AV* () const
    AV* operator-> () const
    template <typename T = SV> one_of_t<T,SV,AV>* get () const

For example,

    Array arr = ...;
    AV* av = *arr;

=head2 element access

    Scalar front () const
    Scalar back  () const

To access first or last element of an array the C<front> and C<back> methods
can be used (simiar to C<std::vector>). The result type is always C<Scalar>.
The both methods are NULL-safe.

    Scalar fetch (size_t key) const
    Scalar at (size_t key) const
    Scalar operator[] (size_t key) const
    KeyProxy operator[] (size_t key)

The first three methods return C<Scalar> type. C<fetch> provides bounary-safe
access to the elements, if the index is out of bounds, then empty C<Scalar>
is returned and underlying C<AV*> is kept untouched. The C<at> method also
checks array bounds, and if the index is out of bounds, then exception will
be thrown (similar to C<std::vector::at()>). The C<operator[]> does not
boundary check, so this is the fastest method, however memory corruption
is possible on usafe usage. The non-const acccessor is needed to allow
in-place fast modification of underlying element, i.e.

    Array arr = ...;
    arr[10] = Simple(10);

C<fetch> is NULL-safe method, while C<at> and C<operator[]> are NULL-unsafe.

    void store (size_t key, const Scalar& val);
    void store (size_t key, std::nullptr_t)
    void store (size_t key, SV* v)
    void store (size_t key, const Sv& v)

The C<store> method is used store item in the array. If underlyging Perl
array AV* is NULL, then C<store> will throw exception.

To check element existance, the NULL-safe C<exist> method can be used:

    bool exists (size_t key) const

To delete arbitrary element by index the NULL-safe and boundary-safe
C<del> method can be used (the previous value is returned).

    Scalar del (size_t key)

To access the first element with discarding it, as well as to access
the last element with discarding it the C<shift>/C<pop> NULL-safe methods
can be used.

    Scalar shift()
    Scalar pop()

The opposite operations, i.e. C<push> and C<unshift>

    void push (const std::initializer_list<Scalar>& l)
    void push (const List& l)
    void push (const Scalar& v)
    void push (SV* v)
    void push (const Sv& v)

    void unshift (const std::initializer_list<Scalar>& l);
    void unshift (const List& l);
    void unshift (const Scalar& v);
    void unshift (SV* v)
    void unshift (const Sv& v)

Please note, that C<push> and C<unshift> are NULL-unsafe methods.

=head2 clear()

    void clear ()

Frees all items in the underlying C<AV*> array. This is NULL-safe method.

=head2 undef()

    void undef()

Frees all items in the underlying C<AV*> array; the array container C<AV*>
itself remains alive. This is NULL-safe method.

=head2 push_on_stack()

    U32 push_on_stack (SV** sp, U32 max = 0) const

This method copies all array items into perl stack C<SV**>, possibly extending
it upto C<max> size. If C<max> is less then the actual number of elemetns, then
C<max> value is ignored.

It returns the count of copied items. The method takes care of all needed
mechanis, e.g. C<sv_2mortal> and increasing refcounter of the items.

This is NULL-unsafe method.

=head2 size()

    size_t  size      () const

Returns size of underlying array. If it is NULL, then C<0> is returned. In
other words, this method is NULL-safe.

=head2 capacity()

    size_t  capacity  () const

Returns capacity of underlying array. If it is NULL, then C<0> is returned. In
other words, this method is NULL-safe.

=head2 top_index ()

    SSize_t top_index () const

Returns index of top element of underlying array. If it is NULL, then C<-1>
is returned. In  other words, this method is NULL-safe.

=head2 resize()

    void resize  (size_t newsz)

Resizes the container to contain count elements. If the current size is greater
than count, the container is reduced to its first count elements.

This is NULL-unsafe method.

=head2 reserve()

    void reserve (size_t newsz)

Increases the capacity of the container. This is NULL-unsafe method.

=head2 itearators

C<Array> provides iterator and const-iterator random-access accessors for it's content:

    const_iterator cbegin () const
    const_iterator cend   () const
    const_iterator begin  () const
    const_iterator end    () const
    iterator       begin  ()
    iterator       end    ()

This methods are NULL-safe. As usually, when underlying array is modified, the
used iterators become invalid, and should not used any longer.

=head1 SEE ALSO