CircularBuffer.cpp

// This code is distributed under the Unlicense license.
// For more details, please visit https://unlicense.org/

template <class T>
class CircularBuffer
{
  private:
    std::unique_ptr<T[]> buffer;
    size_t frontIndex;
    size_t backIndex;
    size_t maxSize;
    size_t count;

  public:
    CircularBuffer(size_t maxSize)
        : buffer(std::make_unique<T[]>(maxSize))
        , frontIndex(0), backIndex(0)
        , maxSize(maxSize), count(0) { }

    template <typename... Args>
    void emplace(Args&&... args)
    {
        if (full()) throw std::overflow_error("Queue is full.");
        buffer[backIndex] = T(std::forward<Args>(args)...);
        backIndex = (backIndex + 1) % maxSize;
        count++;
    }

    void push(T&& item)
    {
        if (full()) throw std::overflow_error("Queue is full.");
        buffer[backIndex] = std::move(item);
        backIndex = (backIndex + 1) % maxSize;
        count++;
    }

    void pop()
    {
        if (empty()) throw std::underflow_error("Queue is empty.");
        frontIndex = (frontIndex + 1) % maxSize;
        count--;
    }

    T& front() const
    {
        if (empty()) throw std::underflow_error("Queue is empty.");
        return buffer[frontIndex];
    }

    T& back() const
    {
        if (empty()) throw std::underflow_error("Queue is empty.");
        return buffer[(backIndex - 1 + maxSize) % maxSize];
    }

    bool empty() const noexcept { return count == 0; }
    bool full() const noexcept { return count == maxSize; }

    size_t size() const noexcept { return count; }
    size_t capacity() const noexcept { return maxSize; }
};