omni::detail::PointerIterator

Defined in omni/detail/PointerIterator.h

template<typename TPointer, typename TContainer>
class PointerIterator

This iterator adapter wraps a pointer type into a class. It does not change the semantics of any operations from the fundamental logic of pointers. There are no bounds checks, there is no additional safety.

// This is meant to be used on contiguous containers where returning a pointer from @c begin and @c end would be
// inappropriate.
template <typename T>
class MyContainer
{
public:
    using iterator       = detail::PointerIterator<T*,       MyContainer>;
    using const_iterator = detail::PointerIterator<T const*, MyContainer>;

    // ...

    iterator begin() { return iterator{data()}; }
};

Template Parameters

• TPointer – The pointer to base this wrapper on. The underlying value type of the pointer can be const-qualified.

• TContainer – The container type this iterator iterates over. This is useful to make types distinct, even in cases where TPointer would be identical; for example, a string vs a vector<char>. This is allowed to be void for cases where there is no underlying container.

Public Types

using value_type = typename underlying_traits_type::value_type

The underlying value that dereferencing this iterator returns. Note that this is not const-qualified; the const_iterator for a container will still return T.

using reference = typename underlying_traits_type::reference

The reference type dereferencing this iterator returns. This is const-qualified, so iterator for a container will return T& and const_iterator will return const T&.

using pointer = typename underlying_traits_type::pointer

The underlying pointer type operator->() returns. This is const-qualified, so iterator for a container will return T* and const_iterator will return const T*.

using difference_type = typename underlying_traits_type::difference_type

The type used to represent the distance between two iterators. This will always be std::ptrdiff_t.

using iterator_category = typename underlying_traits_type::iterator_category

The category of this iterator. This will always be std::random_access_iterator_tag.

Public Functions

inline constexpr PointerIterator() noexcept

Default construction of a pointer-iterator results in an iterator pointing to nullptr.

inline explicit constexpr PointerIterator(pointer src) noexcept

Create an iterator from src pointer.

PointerIterator(const PointerIterator&) = default

Instances are trivially copy-constructible.

PointerIterator(PointerIterator&&) = default

Instances are trivially move-constructible.

PointerIterator &operator=(const PointerIterator&) = default

Instances are trivially copyable.

PointerIterator &operator=(PointerIterator&&) = default

Instances are trivially movable.

~PointerIterator() = default

Instances are trivially destructible.

template<typename UPointer, typename = std::enable_if_t<!std::is_same<TPointer, UPointer>::value && std::is_convertible<std::remove_reference_t<typename PointerIterator<UPointer, TContainer>::reference> (*)[], std::remove_reference_t<reference> (*)[]>::value>>
inline constexpr PointerIterator(const PointerIterator<UPointer, TContainer> &src) noexcept

Converting constructor to allow conversion from a non-const iterator type to a const iterator type. Generally, this allows a TContainer::iterator to become a TContainer::const_iterator.

This constructor is only enabled if:

1. The TContainer for the two types is the same.

2. The TPointer is different from UPointer (there is a conversion which needs to occur).

3. A pointer to an array of the src const-qualified value_type (aka remove_reference_t<reference>) is convertible to an array of this const-qualified value_type. This restricts conversion of iterators from a derived to a base class pointer type.

inline constexpr reference operator*() const noexcept

Dereference this iterator to get its value.

inline constexpr reference operator[](difference_type idx) const noexcept

Get the value at offset idx from this iterator. Negative values are supported to reference behind this instance.

inline constexpr pointer operator->() const noexcept

Get a pointer to the value.

inline constexpr PointerIterator &operator++() noexcept

Move the iterator forward by one.

inline constexpr PointerIterator operator++(int) noexcept

Move the iterator forward by one, but return the previous position.

inline constexpr PointerIterator &operator--() noexcept

Move the iterator backwards by one.

inline constexpr PointerIterator operator--(int) noexcept

Move the iterator backwards by one, but return the previous position.

inline constexpr PointerIterator &operator+=(difference_type dist) noexcept

Move the iterator forward by dist.

inline constexpr PointerIterator operator+(difference_type dist) const noexcept

Get a new iterator pointing dist elements forward from this one.

inline constexpr PointerIterator &operator-=(difference_type dist) noexcept

Move the iterator backwards by dist.

inline constexpr PointerIterator operator-(difference_type dist) const noexcept

Get a new iterator pointing dist elements backwards from this one.