net.cpp

#include <cstdint>
#include <utility>

namespace sysd {
    constexpr bool is_big_endian() {
        return __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__;
    }

    template<class T, std::size_t... N>
    constexpr T byte_swap_impl(T t, std::index_sequence<N...>) {
        return ((((t >> (N * 8)) & (T)(unsigned char)(-1)) << ((sizeof(T) - 1 - N) * 8)) | ...);
    }

    template<class T, class U = typename std::make_unsigned_t<T>>
    constexpr U byte_swap(T t) {
        return byte_swap_impl<U>(t, std::make_index_sequence<sizeof(T)>{});
    }

    constexpr auto to_network(const auto &t) {
        if constexpr (is_big_endian()) {
            return t;
        }
        return byte_swap(t);
    }
}