Change fixed point types to have digit count

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

2 files changed, 73 insertions, 51 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;
 };