Method parse_date

src/toml.hpp:14405–14455

		TOML_NODISCARD
		TOML_NEVER_INLINE
		date parse_date(bool part_of_datetime = false)
		{
			return_if_error({});
			assert_not_eof();
			TOML_ASSERT_ASSUME(is_decimal_digit(*cp));
			push_parse_scope("date"sv);

			// "YYYY"
			uint32_t digits[4];
			if (!consume_digit_sequence(digits, 4u))
				set_error_and_return_default("expected 4-digit year, saw '"sv, to_sv(cp), "'"sv);
			const auto year			= digits[3] + digits[2] * 10u + digits[1] * 100u + digits[0] * 1000u;
			const auto is_leap_year = (year % 4u == 0u) && ((year % 100u != 0u) || (year % 400u == 0u));
			set_error_and_return_if_eof({});

			// '-'
			if (*cp != U'-')
				set_error_and_return_default("expected '-', saw '"sv, to_sv(*cp), "'"sv);
			advance_and_return_if_error_or_eof({});

			// "MM"
			if (!consume_digit_sequence(digits, 2u))
				set_error_and_return_default("expected 2-digit month, saw '"sv, to_sv(cp), "'"sv);
			const auto month = digits[1] + digits[0] * 10u;
			if (month == 0u || month > 12u)
				set_error_and_return_default("expected month between 1 and 12 (inclusive), saw "sv, month);
			const auto max_days_in_month = month == 2u
											 ? (is_leap_year ? 29u : 28u)
											 : (month == 4u || month == 6u || month == 9u || month == 11u ? 30u : 31u);
			set_error_and_return_if_eof({});

			// '-'
			if (*cp != U'-')
				set_error_and_return_default("expected '-', saw '"sv, to_sv(*cp), "'"sv);
			advance_and_return_if_error_or_eof({});

			// "DD"
			if (!consume_digit_sequence(digits, 2u))
				set_error_and_return_default("expected 2-digit day, saw '"sv, to_sv(cp), "'"sv);
			const auto day = digits[1] + digits[0] * 10u;
			if (day == 0u || day > max_days_in_month)
				set_error_and_return_default("expected day between 1 and "sv,
											 max_days_in_month,
											 " (inclusive), saw "sv,
											 day);

			if (!part_of_datetime && !is_eof() && !is_value_terminator(*cp))
				set_error_and_return_default("expected value-terminator, saw '"sv, to_sv(*cp), "'"sv);

			return { year, month, day };
		}

		TOML_NODISCARD
		TOML_NEVER_INLINE