ring_buffer.hpp

// SPDX-License-Identifier: MIT
#ifndef LIBSBX_CONTAINERS_RING_BUFFER_HPP_
#define LIBSBX_CONTAINERS_RING_BUFFER_HPP_
 
#include <memory>
#include <utility>
 
namespace sbx::containers {
 
template<typename Type, std::size_t Capacity>
class ring_buffer {
 
public:
 
  using value_type = Type;
 
  ring_buffer() noexcept
  : _head{0},
    _tail{0} { }
 
  ~ring_buffer() noexcept {
    for (auto i = _head; i != _tail; i = (i + 1) % Capacity) {
      auto* ptr = _ptr_at(i);
      std::destroy_at(ptr);
      ptr = nullptr;
    }
  }
 
  auto push(Type&& value) noexcept -> void {
    auto* ptr = _ptr_at(_head);
 
    if (ptr != nullptr) {
      std::destroy_at(ptr);
      ptr = nullptr;
    }
 
    std::construct_at(_ptr_at(_head), std::move(value));
 
    _head = (_head + 1) % Capacity;
  }
 
  auto capacity() const noexcept -> std::size_t {
    return Capacity;
  }
 
private:
 
  auto _ptr_at(std::size_t i) -> Type* {
    return reinterpret_cast<Type*>(_buffer + i);
  }
 
  alignas(alignof(Type)) std::byte _buffer[sizeof(Type) * Capacity];
  std::size_t _head;
  std::size_t _tail;
 
}; // class ring_buffer
 
} // namespace sbx::containers
 
#endif // LIBSBX_CONTAINERS_RING_BUFFER_HPP_