RingBufferRange

Simple implementation of a ring buffer that makes its content accessible to STL algorithms including modern range based algorithms first introduced in C++20

• exposes an Iterator class for accessing entries
• only forward iteration is supported

RingBufferRange class template

template<typename ContentType, size_t length>
requires std::is_default_constructible_v<ContentType> && std::is_nothrow_copy_assignable_v<ContentType>
&& (std::has_single_bit(length))
struct RingBufferRange

• ContentType: type that will be enqueued
• type constaints ensure that queue elements can be default constructed when the queue object is constructed, (nothrow) copy assigned when an element is enqueued and (nothrow) copy constructed when it's dequeued
• length: max number of elements the queue can contain, determines the size of the ring buffer
• constrained to powers of two to prevent costly modulus operations when computing indices in ring buffer

relevant members and interfaces

Iterator

• forward iterator type exposed to access content of ring buffer

Iterator::Iterator(ContentType* const, ContentType* const)

• constructor for iterator member type, takes a pointer to the base of the ring buffer and a pointer to the first element as arguments

Iterator::operator*

ContentType& Iterator::operator*() const noexcept

• dereference operator
• returns a reference to the buffere entry the iterator object currently points to

Iterator::operator++

const Iterator& Iterator::operator++() noexcept

• increments iterator to next position in buffer

Iterator::operator==

bool Iterator::operator==(const Iterator&) const noexcept

• comparison operator
• determines whether two iterators point to the same position within the buffer

begin

Iterator begin() const noexcept

• returns an Iterator object pointing to the position after the last dequeued entry within the buffer
• points to the first element if buffer is not empty

end

Iterator end() const noexcept

• returns an Iterator pointing to the position after the last enqueued entry within the buffer
• points to position behind last element if buffer is not empty

n_entries

std::uint64_t n_entries() const noexcept

• returns the number of entries currently currently contained in the ring buffer

pop

bool pop() noexcept

• removes first entry from buffer if buffer is not empty
• returns false if buffer was not empty and true otherwise

enqueue

bool enqueue(const ContentType&) noexcept

• adds a new entry to the buffer provided its not currently filled to capacity
• returns true if entry could be added and false otherwise

dequeue

std::optional<ContentType> dequeue() noexcept

• removes the first element from the buffer provided the buffer is not empty and returns it within a std::optional
• returns a std::optional without a values if buffer was empty

emplace

template<typename... Args>
requires std::is_nothrow_constructible_v<ContentType, Args...> && std::is_move_assignable_v<ContentType>
bool emplace(Args... args) noexcept

• contructs an entry in-place using args as arguments for the constructor of ContentType