// ring_buffer.cpp
// A simple fixed‑size circular (ring) buffer for uint8_t values.

#include <algorithm>   // std::fill_n
#include <cstddef>     // std::size_t
#include <iostream>    // demo output (optional)

namespace had {
    // Alias matching the original code – unsigned 8‑bit type.
    using uint8_t = unsigned char;

    // Buffer capacity (must be a compile‑time constant).
    constexpr std::size_t bufferSize = 16;

    class RingBuffer {
        uint8_t data[bufferSize];   // storage array
        std::size_t newest_index;   // position to write next byte
        std::size_t oldest_index;   // position to read next byte
        std::size_t count;          // number of bytes currently stored

    public:
        // Status codes returned by read/write operations.
        enum BufferStatus { OK, EMPTY, FULL };

        // Constructor – clears the buffer and sets indices to 0.
        RingBuffer() noexcept
            : newest_index(0), oldest_index(0), count(0) {
            std::fill_n(data, bufferSize, 0);
        }

        // Write a byte into the buffer.
        BufferStatus bufferWrite(uint8_t byte) noexcept {
            if (count == bufferSize) return FULL;          // no space left
            data[newest_index] = byte;
            newest_index = (newest_index + 1) % bufferSize;
            ++count;
            return OK;
        }

        // Read a byte from the buffer.
        BufferStatus bufferRead(uint8_t& byte) noexcept {
            if (count == 0) return EMPTY;                 // nothing to read
            byte = data[oldest_index];
            oldest_index = (oldest_index + 1) % bufferSize;
            --count;
            return OK;
        }
    };
} // namespace had

int main() {
    had::RingBuffer r_buffer;
    had::uint8_t tempCharStorage;

    // -------------------------------------------------
    // Fill the buffer with consecutive letters starting at 'A'.
    // The loop stops when the buffer reports FULL.
    // -------------------------------------------------
    for (int i = 0;
         r_buffer.bufferWrite(static_cast<had::uint8_t>('A' + i)) == had::RingBuffer::OK;
         ++i) {
        // nothing else needed here
    }

    // -------------------------------------------------
    // Read and display the contents until the buffer is EMPTY.
    // -------------------------------------------------
    while (r_buffer.bufferRead(tempCharStorage) == had::RingBuffer::OK) {
        std::cout << static_cast<char>(tempCharStorage) << ' ';
    }
    std::cout << '\n';

    return 0;
}