qmk_firmware/drivers/bluetooth/ringbuffer.hpp

#pragma once
// A simple ringbuffer holding Size elements of type T
template <typename T, uint8_t Size>
class RingBuffer {
   protected:
    T       buf_[Size];
    uint8_t head_{0}, tail_{0};

   public:
    inline uint8_t nextPosition(uint8_t position) {
        return (position + 1) % Size;
    }

    inline uint8_t prevPosition(uint8_t position) {
        if (position == 0) {
            return Size - 1;
        }
        return position - 1;
    }

    inline bool enqueue(const T &item) {
        static_assert(Size > 1, "RingBuffer size must be > 1");
        uint8_t next = nextPosition(head_);
        if (next == tail_) {
            // Full
            return false;
        }

        buf_[head_] = item;
        head_       = next;
        return true;
    }

    inline bool get(T &dest, bool commit = true) {
        auto tail = tail_;
        if (tail == head_) {
            // No more data
            return false;
        }

        dest = buf_[tail];
        tail = nextPosition(tail);

        if (commit) {
            tail_ = tail;
        }
        return true;
    }

    inline bool empty() const {
        return head_ == tail_;
    }

    inline uint8_t size() const {
        int diff = head_ - tail_;
        if (diff >= 0) {
            return diff;
        }
        return Size + diff;
    }

    inline T &front() {
        return buf_[tail_];
    }

    inline bool peek(T &item) {
        return get(item, false);
    }
};