#include <array>
#include <iostream>
#include <iomanip>

namespace {
    template <typename T, std::size_t N>
    auto print_array(std::array<T, N> a) {
        std::cout << "array: |";
        for (auto const& e : a) {
            std::cout << std::setw(2) << e << "|";
        }
        std::cout << "\n";
    }

    template <typename T, std::size_t N>
    auto mask(std::array<T, N>, T val) {
        return val & (N - 1);
    }

    template <typename T, std::size_t N>
    auto push(std::array<T, N>& buffer, T val, uint32_t& write) {
        buffer[mask(buffer, write++)] = val;
    }

    template <typename T, std::size_t N>
    auto shift(std::array<T, N>& buffer, T val, uint32_t& read) {
        return buffer[mask(buffer, read++)];
    }

    auto empty(uint32_t read, uint32_t write) {
        return read == write;
    }

    auto size(uint32_t read, uint32_t write) {
        return write - read;
    }

    template <typename T, std::size_t N>
    auto full(std::array<T, N>, uint32_t read, uint32_t write) {
        return size(read, write) == N;
    }
}

int main() {
    std::array<uint32_t, 4> buffer = { 0, 0, 0, 0 };
    uint32_t read = 1;
    uint32_t write = 1;
    print_array(buffer);
    for (uint32_t i = 1; i < 11; ++i) {
        push(buffer, i, write);
        print_array(buffer);
        std::cout << "Buffer is " << (full(buffer, read, write) ? "full" : "not full") << "\n";
    }
}