Function hash

Source/external/json.hpp:5951–6036

*/
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:
		{