Change fixed point types to have digit count

Signed-off-by: VoR0220 <rj@erisindustries.com>

5 files changed, 127 insertions, 113 deletions

diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 76bfb1a8..14e948cc 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -196,9 +196,9 @@ TypePointer Type::fromElementaryTypeName(ElementaryTypeNameToken const& _type)
 	case Token::UInt:
 		return make_shared<IntegerType>(256, IntegerType::Modifier::Unsigned);
 	case Token::Fixed:
-		return make_shared<FixedPointType>(128, 128, FixedPointType::Modifier::Signed);
+		return make_shared<FixedPointType>(128, 19, FixedPointType::Modifier::Signed);
 	case Token::UFixed:
-		return make_shared<FixedPointType>(128, 128, FixedPointType::Modifier::Unsigned);
+		return make_shared<FixedPointType>(128, 19, FixedPointType::Modifier::Unsigned);
 	case Token::Byte:
 		return make_shared<FixedBytesType>(1);
 	case Token::Address:
@@ -352,12 +352,13 @@ bool IntegerType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 	else if (_convertTo.category() == Category::FixedPoint)
 	{
 		FixedPointType const& convertTo = dynamic_cast<FixedPointType const&>(_convertTo);
-		if (convertTo.integerBits() < m_bits || isAddress())
+
+		if (((u256(1) << m_bits) <= convertTo.numBits() && convertTo.fractionalDigits() == 0) || isAddress())
 			return false;
 		else if (isSigned())
 			return convertTo.isSigned();
 		else
-			return !convertTo.isSigned() || convertTo.integerBits() > m_bits;
+			return !convertTo.isSigned() || convertTo.numBits() > m_bits;
 	}
 	else
 		return false;
@@ -487,22 +488,20 @@ MemberList::MemberMap IntegerType::nativeMembers(ContractDefinition const*) cons
 		return MemberList::MemberMap();
 }
 
-FixedPointType::FixedPointType(int _integerBits, int _fractionalBits, FixedPointType::Modifier _modifier):
-	m_integerBits(_integerBits), m_fractionalBits(_fractionalBits), m_modifier(_modifier)
+FixedPointType::FixedPointType(int _totalBits, int _fractionalDigits, FixedPointType::Modifier _modifier):
+	m_totalBits(_totalBits), m_fractionalDigits(_fractionalDigits), m_modifier(_modifier)
 {
 	solAssert(
-		m_integerBits + m_fractionalBits > 0 && 
-		m_integerBits + m_fractionalBits <= 256 && 
-		m_integerBits % 8 == 0 && 
-		m_fractionalBits % 8 == 0,
+		8 <= m_totalBits && m_totalBits <= 256 && m_totalBits % 8 == 0 &&
+		0 <= m_fractionalDigits && m_fractionalDigits <= 80, 
 		"Invalid bit number(s) for fixed type: " + 
-		dev::toString(_integerBits) + "x" + dev::toString(_fractionalBits)
-				);
+		dev::toString(_totalBits) + "x" + dev::toString(_fractionalDigits)
+	);
 }
 
 string FixedPointType::identifier() const
 {
-	return "t_" + string(isSigned() ? "" : "u") + "fixed" + std::to_string(integerBits()) + "x" + std::to_string(fractionalBits());
+	return "t_" + string(isSigned() ? "" : "u") + "fixed" + std::to_string(numBits()) + "x" + std::to_string(fractionalDigits());
 }
 
 bool FixedPointType::isImplicitlyConvertibleTo(Type const& _convertTo) const
@@ -510,12 +509,10 @@ bool FixedPointType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 	if (_convertTo.category() == category())
 	{
 		FixedPointType const& convertTo = dynamic_cast<FixedPointType const&>(_convertTo);
-		if (convertTo.m_integerBits < m_integerBits || convertTo.m_fractionalBits < m_fractionalBits)
+		if (convertTo.numBits() < m_totalBits || convertTo.fractionalDigits() < m_fractionalDigits)
 			return false;
-		else if (isSigned())
-			return convertTo.isSigned();
 		else
-			return !convertTo.isSigned() || (convertTo.m_integerBits > m_integerBits);
+			return convertTo.maximumPossibleInteger() >= maximumPossibleInteger();
 	}
 	return false;
 }
@@ -527,6 +524,31 @@ bool FixedPointType::isExplicitlyConvertibleTo(Type const& _convertTo) const
 		_convertTo.category() == Category::FixedBytes;
 }
 
+/*bool FixedPointType::canHoldInteger(unsigned const _bits, bool const _signed) const 
+{
+	// If fixed type has 200 bits and 2 fractional digits, integer has 8 bits, then conversion is possible. 
+	// Write helper function that returns max integer number, not necessarily the bits. 
+	// 2^m_bits <= integer
+
+	// REMINDER: The below was a work in progress until better solution thought up, see below:
+	// add min and max number functions to integer and fixed types, use them when converting types.
+	if (_signed && isSigned()) 
+	{
+		u256 maxInteger = (u256(1) << _bits) - 1;
+		u256 maxFixedInteger = u256(((u256(1) << numBits()) - 1) / (pow(bigint(10), decimalDigits())));
+	} 
+	else if (_signed && !isSigned())
+	{
+
+	}
+	else 
+	{
+		u256 maxInteger = (u256(1) << _bits) - 1;
+		u256 maxFixedInteger = u256(((u256(1) << numBits()) - 1) / (pow(bigint(10), decimalDigits())));
+		return maxInteger <= maxFixedInteger;
+	}
+}*/
+
 TypePointer FixedPointType::unaryOperatorResult(Token::Value _operator) const
 {
 	// "delete" is ok for all fixed types
@@ -549,13 +571,13 @@ bool FixedPointType::operator==(Type const& _other) const
 	if (_other.category() != category())
 		return false;
 	FixedPointType const& other = dynamic_cast<FixedPointType const&>(_other);
-	return other.m_integerBits == m_integerBits && other.m_fractionalBits == m_fractionalBits && other.m_modifier == m_modifier;
+	return other.m_totalBits == m_totalBits && other.m_fractionalDigits == m_fractionalDigits && other.m_modifier == m_modifier;
 }
 
 string FixedPointType::toString(bool) const
 {
 	string prefix = isSigned() ? "fixed" : "ufixed";
-	return prefix + dev::toString(m_integerBits) + "x" + dev::toString(m_fractionalBits);
+	return prefix + dev::toString(m_totalBits) + "x" + dev::toString(m_fractionalDigits);
 }
 
 TypePointer FixedPointType::binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
@@ -746,9 +768,12 @@ bool RationalNumberType::isImplicitlyConvertibleTo(Type const& _convertTo) const
 		{
 			// We disallow implicit conversion if we would have to truncate (fixedPointType()
 			// can return a type that requires truncation).
-			rational value = m_value * (bigint(1) << fixed->fractionalBits());
+			rational value = m_value * boost::multiprecision::pow(bigint(10), fixed->fractionalDigits());
+			cout << "value denominator: " << value.denominator() << endl;
+			cout << "value: " << value << endl;
 			return value.denominator() == 1 && fixed->isImplicitlyConvertibleTo(_convertTo);
 		}
+		cout << "could not convert to fixed type" << endl;
 		return false;
 	}
 	else if (_convertTo.category() == Category::FixedBytes)
@@ -954,9 +979,9 @@ u256 RationalNumberType::literalValue(Literal const*) const
 	{
 		auto fixed = fixedPointType();
 		solAssert(!!fixed, "");
-		rational shifted = m_value * (bigint(1) << fixed->fractionalBits());
 		// truncate
-		shiftedValue = shifted.numerator() / shifted.denominator();
+		shiftedValue = m_value.numerator() / m_value.denominator();
+		cout << "Shifted value: " << shiftedValue << endl;
 	}
 
 	// we ignore the literal and hope that the type was correctly determined
@@ -997,23 +1022,27 @@ shared_ptr<IntegerType const> RationalNumberType::integerType() const
 shared_ptr<FixedPointType const> RationalNumberType::fixedPointType() const
 {
 	bool negative = (m_value < 0);
-	unsigned fractionalBits = 0;
+	unsigned fractionalDigits = 0;
 	rational value = abs(m_value); // We care about the sign later.
 	rational maxValue = negative ? 
 		rational(bigint(1) << 255, 1):
 		rational((bigint(1) << 256) - 1, 1);
 
-	while (value * 0x100 <= maxValue && value.denominator() != 1 && fractionalBits < 256)
+	while (value * 10 <= maxValue && value.denominator() != 1 && fractionalDigits < 80)
 	{
-		value *= 0x100;
-		fractionalBits += 8;
+		value *= 10;
+		fractionalDigits++;
 	}
 	
 	if (value > maxValue)
+	{
+		cout << "value > maxValue" << endl;
 		return shared_ptr<FixedPointType const>();
+	}
 	// u256(v) is the actual value that will be put on the stack
 	// From here on, very similar to integerType()
 	bigint v = value.numerator() / value.denominator();
+	cout << "Big int: " << u256(v) << endl;
 	if (negative)
 		// modify value to satisfy bit requirements for negative numbers:
 		// add one bit for sign and decrement because negative numbers can be larger
@@ -1022,26 +1051,12 @@ shared_ptr<FixedPointType const> RationalNumberType::fixedPointType() const
 	if (v > u256(-1))
 		return shared_ptr<FixedPointType const>();
 
-	unsigned totalBits = bytesRequired(v) * 8;
+	unsigned totalBits = max(bytesRequired(v), 1u) * 8;
 	solAssert(totalBits <= 256, "");
-	unsigned integerBits = totalBits >= fractionalBits ? totalBits - fractionalBits : 0;
-	// Special case: Numbers between -1 and 0 have their sign bit in the fractional part.
-	if (negative && abs(m_value) < 1 && totalBits > fractionalBits)
-	{
-		fractionalBits += 8;
-		integerBits = 0;
-	}
-
-	if (integerBits > 256 || fractionalBits > 256 || fractionalBits + integerBits > 256)
-		return shared_ptr<FixedPointType const>();
-	if (integerBits == 0 && fractionalBits == 0)
-	{
-		integerBits = 0;
-		fractionalBits = 8;
-	}
 
+	cout << "rational turned into " << (negative ? "fixed" : "ufixed") << totalBits << "x" << fractionalDigits << endl;
 	return make_shared<FixedPointType>(
-		integerBits, fractionalBits,
+		totalBits, fractionalDigits,
 		negative ? FixedPointType::Modifier::Signed : FixedPointType::Modifier::Unsigned
 	);
 }
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index c24cc11a..d5ef343a 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -321,6 +321,10 @@ public:
 	int numBits() const { return m_bits; }
 	bool isAddress() const { return m_modifier == Modifier::Address; }
 	bool isSigned() const { return m_modifier == Modifier::Signed; }
+	u256 maximumPossibleInteger() const { return isSigned() ? 
+		u256((u256(1) << m_bits) - 1):
+		u256((u256(1) << m_bits));
+	}
 
 	bigint minValue() const;
 	bigint maxValue() const;
@@ -342,7 +346,7 @@ public:
 	};
 	virtual Category category() const override { return Category::FixedPoint; }
 
-	explicit FixedPointType(int _integerBits, int _fractionalBits, Modifier _modifier = Modifier::Unsigned);
+	explicit FixedPointType(int _totalBits, int _fractionalDigits, Modifier _modifier = Modifier::Unsigned);
 
 	virtual std::string identifier() const override;
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
@@ -352,8 +356,8 @@ public:
 
 	virtual bool operator==(Type const& _other) const override;
 
-	virtual unsigned calldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : (m_integerBits + m_fractionalBits) / 8; }
-	virtual unsigned storageBytes() const override { return (m_integerBits + m_fractionalBits) / 8; }
+	virtual unsigned calldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : m_totalBits / 8; }
+	virtual unsigned storageBytes() const override { return m_totalBits / 8; }
 	virtual bool isValueType() const override { return true; }
 
 	virtual std::string toString(bool _short) const override;
@@ -361,14 +365,17 @@ public:
 	virtual TypePointer encodingType() const override { return shared_from_this(); }
 	virtual TypePointer interfaceType(bool) const override { return shared_from_this(); }
 
-	int numBits() const { return m_integerBits + m_fractionalBits; }
-	int integerBits() const { return m_integerBits; }
-	int fractionalBits() const { return m_fractionalBits; }
+	int numBits() const { return m_totalBits; }
+	int fractionalDigits() const { return m_fractionalDigits; }
 	bool isSigned() const { return m_modifier == Modifier::Signed; }
+	u256 maximumPossibleInteger() const { return isSigned() ? 
+		u256(((u256(1) << m_totalBits) - 1) / (pow(bigint(10), m_fractionalDigits))):
+		u256(((u256(1) << m_totalBits)) / (pow(bigint(10), m_fractionalDigits)));
+	}
 
 private:
-	int m_integerBits;
-	int m_fractionalBits;
+	int m_totalBits;
+	int m_fractionalDigits;
 	Modifier m_modifier;
 };
 
diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index 7067ddd5..782aad9d 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -504,7 +504,7 @@ void CompilerUtils::convertType(
 			//shift all integer bits onto the left side of the fixed type
 			FixedPointType const& targetFixedPointType = dynamic_cast<FixedPointType const&>(_targetType);
 			if (auto typeOnStack = dynamic_cast<IntegerType const*>(&_typeOnStack))
-				if (targetFixedPointType.integerBits() > typeOnStack->numBits())
+				if (targetFixedPointType.numBits() > typeOnStack->numBits())
 					cleanHigherOrderBits(*typeOnStack);
 			solUnimplemented("Not yet implemented - FixedPointType.");
 		}
diff --git a/libsolidity/parsing/Token.cpp b/libsolidity/parsing/Token.cpp
index 66312f69..d290bedb 100644
--- a/libsolidity/parsing/Token.cpp
+++ b/libsolidity/parsing/Token.cpp
@@ -70,7 +70,7 @@ void ElementaryTypeNameToken::assertDetails(Token::Value _baseType, unsigned con
 	else if (_baseType == Token::UFixedMxN || _baseType == Token::FixedMxN)
 	{
 		solAssert(
-			_first + _second <= 256 && _first % 8 == 0 && _second % 8 == 0,
+			_first <= 256 && _first % 8 == 0 && _second >= 0 && _second <= 80,
 			"No elementary type " + string(Token::toString(_baseType)) + to_string(_first) + "x" + to_string(_second) + "."
 		);
 	}
@@ -157,12 +157,8 @@ tuple<Token::Value, unsigned int, unsigned int> Token::fromIdentifierOrKeyword(s
 			) {
 				int n = parseSize(positionX + 1, _literal.end());
 				if (
-					0 <= m && m <= 256 &&
-					8 <= n && n <= 256 &&
-					m + n > 0 &&
-					m + n <= 256 &&
-					m % 8 == 0 &&
-					n % 8 == 0
+					8 <= m && m <= 256 && m % 8 == 0 &&
+					0 <= n && n <= 80
 				) {
 					if (keyword == Token::UFixed)
 						return make_tuple(Token::UFixedMxN, m, n);
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index 2a5613c0..d511ca02 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -4145,20 +4145,8 @@ BOOST_AUTO_TEST_CASE(rational_unary_operation)
 	char const* text = R"(
 		contract test {
 			function f() {
-				ufixed8x16 a = 3.25;
-				fixed8x16 b = -3.25;
-				a;
-				b;
-			}
-		}
-	)";
-	CHECK_SUCCESS_NO_WARNINGS(text);
-	text = R"(
-		contract test {
-			function f() {
-				ufixed8x16 a = +3.25;
-				fixed8x16 b = -3.25;
-				a; b;
+				ufixed16x2 a = +3.25;
+				fixed16x2 b = -3.25;
 			}
 		}
 	)";
@@ -4179,11 +4167,10 @@ BOOST_AUTO_TEST_CASE(leading_zero_rationals_convert)
 	char const* text = R"(
 		contract A {
 			function f() {
-				ufixed0x8 a = 0.5;
-				ufixed0x56 b = 0.0000000000000006661338147750939242541790008544921875;
-				fixed0x8 c = -0.5;
-				fixed0x56 d = -0.0000000000000006661338147750939242541790008544921875;
-				a; b; c; d;
+				ufixed16x8 a = 0.5;
+				ufixed256x56 b = 0.0000000000000006661338147750939242541790008544921875;
+				fixed16x8 c = -0.5;
+				fixed256x56 d = -0.0000000000000006661338147750939242541790008544921875;
 			}
 		}
 	)";
@@ -4195,13 +4182,25 @@ BOOST_AUTO_TEST_CASE(size_capabilities_of_fixed_point_types)
 	char const* text = R"(
 		contract test {
 			function f() {
-				ufixed248x8 a = 123456781234567979695948382928485849359686494864095409282048094275023098123.5;
-				ufixed0x256 b = 0.920890746623327805482905058466021565416131529487595827354393978494366605267637829135688384325135165352082715782143655824815685807141335814463015972119819459298455224338812271036061391763384038070334798471324635050876128428143374549108557403087615966796875;
-				ufixed0x256 c = 0.0000000000015198847363997979984922685411315294875958273543939784943666052676464653042434787697605517039455161817147718251801220885263595179331845639229818863564267318422845592626219390573301877339317935702714669975697814319204326238832436501979827880859375;
-				fixed248x8 d = -123456781234567979695948382928485849359686494864095409282048094275023098123.5;
-				fixed0x256 e = -0.93322335481643744342575580035176794825198893968114429702091846411734101080123092162893656820177312738451291806995868682861328125;
-				fixed0x256 g = -0.00011788606643744342575580035176794825198893968114429702091846411734101080123092162893656820177312738451291806995868682861328125;
-				a; b; c; d; e; g;
+				ufixed256x1 a = 123456781234567979695948382928485849359686494864095409282048094275023098123.5;
+				ufixed256x77 b = 0.920890746623327805482905058466021565416131529487595827354393978494366605267637;
+				ufixed224x78 c = 0.000000000001519884736399797998492268541131529487595827354393978494366605267646;
+				fixed256x1 d = -123456781234567979695948382928485849359686494864095409282048094275023098123.5;
+				fixed256x76 e = -0.93322335481643744342575580035176794825198893968114429702091846411734101080123;
+				fixed256x79 g = -0.0001178860664374434257558003517679482519889396811442970209184641173410108012309;
+			}
+		}
+	)";
+	CHECK_SUCCESS(text);
+}
+
+BOOST_AUTO_TEST_CASE(zero_handling)
+{
+	char const* text = R"(
+		contract test {
+			function f() {
+				fixed16x8 a = 0;
+				ufixed8x8 b = 0;
 			}
 		}
 	)";
@@ -4226,7 +4225,7 @@ BOOST_AUTO_TEST_CASE(fixed_type_invalid_implicit_conversion_lost_data)
 	char const* text = R"(
 		contract test {
 			function f() {
-				ufixed0x256 a = 1/3;
+				ufixed256x1 a = 1/3;
 			}
 		}
 	)";
@@ -4238,10 +4237,9 @@ BOOST_AUTO_TEST_CASE(fixed_type_valid_explicit_conversions)
 	char const* text = R"(
 		contract test {
 			function f() {
-				ufixed0x256 a = ufixed0x256(1/3);
-				ufixed0x248 b = ufixed0x248(1/3);
-				ufixed0x8 c = ufixed0x8(1/3);
-				a; b; c;
+				ufixed256x80 a = ufixed256x80(1/3);
+				ufixed248x80 b = ufixed248x80(1/3);
+				ufixed8x1 c = ufixed8x1(1/3);
 			}
 		}
 	)";
@@ -4260,7 +4258,7 @@ BOOST_AUTO_TEST_CASE(invalid_array_declaration_with_rational)
 	BOOST_CHECK(!success(text));
 }
 
-BOOST_AUTO_TEST_CASE(invalid_array_declaration_with_fixed_type)
+BOOST_AUTO_TEST_CASE(invalid_array_declaration_with_signed_fixed_type)
 {
 	char const* text = R"(
 		contract test {
@@ -4272,6 +4270,18 @@ BOOST_AUTO_TEST_CASE(invalid_array_declaration_with_fixed_type)
 	BOOST_CHECK(!success(text));
 }
 
+BOOST_AUTO_TEST_CASE(invalid_array_declaration_with_unsigned_fixed_type)
+{
+	char const* text = R"(
+		contract test {
+			function f() {
+				uint[ufixed(3.5)] a;
+			}
+		}
+	)";
+	BOOST_CHECK(!success(text));
+}
+
 BOOST_AUTO_TEST_CASE(rational_to_bytes_implicit_conversion)
 {
 	char const* text = R"(
@@ -4301,7 +4311,7 @@ BOOST_AUTO_TEST_CASE(mapping_with_fixed_literal)
 {
 	char const* text = R"(
 		contract test {
-			mapping(ufixed8x248 => string) fixedString;
+			mapping(ufixed8x1 => string) fixedString;
 			function f() {
 				fixedString[0.5] = "Half";
 			}
@@ -4341,7 +4351,7 @@ BOOST_AUTO_TEST_CASE(inline_array_rationals)
 	char const* text = R"(
 		contract test {
 			function f() {
-				ufixed8x8[4] memory a = [3.5, 4.125, 2.5, 4.0];
+				ufixed16x3[4] memory a = [3.5, 4.125, 2.5, 4.0];
 			}
 		}
 	)";
@@ -4368,10 +4378,10 @@ BOOST_AUTO_TEST_CASE(rational_to_fixed_literal_expression)
 			function f() {
 				ufixed8x8 a = 3.5 * 3;
 				ufixed8x8 b = 4 - 2.5;
-				ufixed8x8 c = 11 / 4;
-				ufixed16x240 d = 599 + 0.21875;
-				ufixed8x248 e = ufixed8x248(35.245 % 12.9);
-				ufixed8x248 f = ufixed8x248(1.2 % 2);
+				ufixed16x8 c = 11 / 4;
+				ufixed240x5 d = 599 + 0.21875;
+				ufixed256x80 e = ufixed256x80(35.245 % 12.9);
+				ufixed256x80 f = ufixed256x80(1.2 % 2);
 				fixed g = 2 ** -2;
 				a; b; c; d; e; f; g;
 			}
@@ -4380,7 +4390,7 @@ BOOST_AUTO_TEST_CASE(rational_to_fixed_literal_expression)
 	CHECK_SUCCESS(text);
 }
 
-BOOST_AUTO_TEST_CASE(rational_as_exponent_value_neg_decimal)
+BOOST_AUTO_TEST_CASE(rational_as_exponent_value_signed)
 {
 	char const* text = R"(
 		contract test {
@@ -4392,7 +4402,7 @@ BOOST_AUTO_TEST_CASE(rational_as_exponent_value_neg_decimal)
 	BOOST_CHECK(!success(text));
 }
 
-BOOST_AUTO_TEST_CASE(rational_as_exponent_value_pos_decimal)
+BOOST_AUTO_TEST_CASE(rational_as_exponent_value_unsigned)
 {
 	char const* text = R"(
 		contract test {
@@ -4564,20 +4574,6 @@ BOOST_AUTO_TEST_CASE(rational_bitand_binary_operation)
 	BOOST_CHECK(!success(text));
 }
 
-BOOST_AUTO_TEST_CASE(zero_handling)
-{
-	char const* text = R"(
-		contract test {
-			function f() {
-				fixed8x8 a = 0;
-				ufixed8x8 b = 0;
-				a; b;
-			}
-		}
-	)";
-	CHECK_SUCCESS(text);
-}
-
 BOOST_AUTO_TEST_CASE(missing_bool_conversion)
 {
 	char const* text = R"(