Function CloneVehicleName

src/vehicle_cmd.cpp:775–820

* Clone the custom name of a vehicle, adding or incrementing a number. * @param src Source vehicle, with a custom name. * @param dst Destination vehicle. */

 * @param dst Destination vehicle.
 */
static void CloneVehicleName(const Vehicle *src, Vehicle *dst)
{
	std::string buf;

	/* Find the position of the first digit in the last group of digits. */
	size_t number_position;
	for (number_position = src->name.length(); number_position > 0; number_position--) {
		/* The design of UTF-8 lets this work simply without having to check
		 * for UTF-8 sequences. */
		if (src->name[number_position - 1] < '0' || src->name[number_position - 1] > '9') break;
	}

	/* Format buffer and determine starting number. */
	long num;
	uint8_t padding = 0;
	if (number_position == src->name.length()) {
		/* No digit at the end, so start at number 2. */
		buf = src->name;
		buf += " ";
		number_position = buf.length();
		num = 2;
	} else {
		/* Found digits, parse them and start at the next number. */
		buf = src->name.substr(0, number_position);

		auto num_str = std::string_view(src->name).substr(number_position);
		padding = (uint8_t)num_str.length();

		[[maybe_unused]] auto err = std::from_chars(num_str.data(), num_str.data() + num_str.size(), num, 10).ec;
		assert(err == std::errc());
		num++;
	}

	/* Check if this name is already taken. */
	for (int max_iterations = 1000; max_iterations > 0; max_iterations--, num++) {
		std::string new_name = fmt::format("{}{:0{}}", buf, num, padding);

		/* Check the name is unique. */
		if (IsUniqueVehicleName(new_name)) {
			dst->name = std::move(new_name);
			break;
		}
	}

	/* All done. If we didn't find a name, it'll just use its default. */
}

/**
 * Clone a vehicle. If it is a train, it will clone all the cars too