Function hash

extern/json/json.hpp:5955–6040

*/
template<typename BasicJsonType>
std::size_t hash(const BasicJsonType& j)
{
    using string_t = typename BasicJsonType::string_t;
    using number_integer_t = typename BasicJsonType::number_integer_t;
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
    using number_float_t = typename BasicJsonType::number_float_t;

    const auto type = static_cast<std::size_t>(j.type());
    switch (j.type())
    {
        case BasicJsonType::value_t::null:
        case BasicJsonType::value_t::discarded:
        {
            return combine(type, 0);
        }

        case BasicJsonType::value_t::object:
        {
            auto seed = combine(type, j.size());
            for (const auto& element : j.items())
            {
                const auto h = std::hash<string_t> {}(element.key());
                seed = combine(seed, h);
                seed = combine(seed, hash(element.value()));
            }
            return seed;
        }

        case BasicJsonType::value_t::array:
        {
            auto seed = combine(type, j.size());
            for (const auto& element : j)
            {
                seed = combine(seed, hash(element));
            }
            return seed;
        }

        case BasicJsonType::value_t::string:
        {
            const auto h = std::hash<string_t> {}(j.template get_ref<const string_t&>());
            return combine(type, h);
        }

        case BasicJsonType::value_t::boolean:
        {
            const auto h = std::hash<bool> {}(j.template get<bool>());
            return combine(type, h);
        }

        case BasicJsonType::value_t::number_integer:
        {
            const auto h = std::hash<number_integer_t> {}(j.template get<number_integer_t>());
            return combine(type, h);
        }

        case BasicJsonType::value_t::number_unsigned:
        {