Method isValidLiteral

libsolidity/ast/Types.cpp:909–1008

}

std::tuple<bool, rational> RationalNumberType::isValidLiteral(Literal const& _literal)
{
	rational value;
	try
	{
		ASTString valueString = _literal.valueWithoutUnderscores();

		auto expPoint = find(valueString.begin(), valueString.end(), 'e');
		if (expPoint == valueString.end())
			expPoint = find(valueString.begin(), valueString.end(), 'E');

		if (boost::starts_with(valueString, "0x"))
		{
			// process as hex
			value = bigint(valueString);
		}
		else if (expPoint != valueString.end())
		{
			// Parse mantissa and exponent. Checks numeric limit.
			std::tuple<bool, rational> mantissa = parseRational(std::string(valueString.begin(), expPoint));

			if (!std::get<0>(mantissa))
				return std::make_tuple(false, rational(0));
			value = std::get<1>(mantissa);

			// 0E... is always zero.
			if (value == 0)
				return std::make_tuple(true, rational(0));

			bigint exp = bigint(std::string(expPoint + 1, valueString.end()));

			if (exp > std::numeric_limits<int32_t>::max() || exp < std::numeric_limits<int32_t>::min())
				return std::make_tuple(false, rational(0));

			uint32_t expAbs = bigint(abs(exp)).convert_to<uint32_t>();

			if (exp < 0)
			{
				if (!fitsPrecisionBase10(abs(value.denominator()), expAbs))
					return std::make_tuple(false, rational(0));
				value /= boost::multiprecision::pow(
					bigint(10),
					expAbs
				);
			}
			else if (exp > 0)
			{
				if (!fitsPrecisionBase10(abs(value.numerator()), expAbs))
					return std::make_tuple(false, rational(0));
				value *= boost::multiprecision::pow(
					bigint(10),
					expAbs
				);
			}
		}
		else
		{
			// parse as rational number