solidity/libsolidity/ast/Types.h

1356 lines
55 KiB
C++

/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Solidity data types
*/
#pragma once
#include <liblangutil/Exceptions.h>
#include <libsolidity/ast/ASTForward.h>
#include <libsolidity/ast/ASTEnums.h>
#include <liblangutil/Token.h>
#include <libdevcore/Common.h>
#include <libdevcore/CommonIO.h>
#include <boost/noncopyable.hpp>
#include <boost/rational.hpp>
#include <boost/optional.hpp>
#include <memory>
#include <string>
#include <map>
#include <set>
namespace dev
{
namespace solidity
{
class Type; // forward
class FunctionType; // forward
using TypePointer = std::shared_ptr<Type const>;
using FunctionTypePointer = std::shared_ptr<FunctionType const>;
using TypePointers = std::vector<TypePointer>;
using rational = boost::rational<dev::bigint>;
inline rational makeRational(bigint const& _numerator, bigint const& _denominator)
{
solAssert(_denominator != 0, "division by zero");
// due to a bug in certain versions of boost the denominator has to be positive
if (_denominator < 0)
return rational(-_numerator, -_denominator);
else
return rational(_numerator, _denominator);
}
enum class DataLocation { Storage, CallData, Memory };
/**
* Helper class to compute storage offsets of members of structs and contracts.
*/
class StorageOffsets
{
public:
/// Resets the StorageOffsets objects and determines the position in storage for each
/// of the elements of @a _types.
void computeOffsets(TypePointers const& _types);
/// @returns the offset of the given member, might be null if the member is not part of storage.
std::pair<u256, unsigned> const* offset(size_t _index) const;
/// @returns the total number of slots occupied by all members.
u256 const& storageSize() const { return m_storageSize; }
private:
u256 m_storageSize;
std::map<size_t, std::pair<u256, unsigned>> m_offsets;
};
/**
* List of members of a type.
*/
class MemberList
{
public:
struct Member
{
Member(std::string const& _name, TypePointer const& _type, Declaration const* _declaration = nullptr):
name(_name),
type(_type),
declaration(_declaration)
{
}
std::string name;
TypePointer type;
Declaration const* declaration = nullptr;
};
using MemberMap = std::vector<Member>;
explicit MemberList(MemberMap const& _members): m_memberTypes(_members) {}
void combine(MemberList const& _other);
TypePointer memberType(std::string const& _name) const
{
TypePointer type;
for (auto const& it: m_memberTypes)
if (it.name == _name)
{
solAssert(!type, "Requested member type by non-unique name.");
type = it.type;
}
return type;
}
MemberMap membersByName(std::string const& _name) const
{
MemberMap members;
for (auto const& it: m_memberTypes)
if (it.name == _name)
members.push_back(it);
return members;
}
/// @returns the offset of the given member in storage slots and bytes inside a slot or
/// a nullptr if the member is not part of storage.
std::pair<u256, unsigned> const* memberStorageOffset(std::string const& _name) const;
/// @returns the number of storage slots occupied by the members.
u256 const& storageSize() const;
MemberMap::const_iterator begin() const { return m_memberTypes.begin(); }
MemberMap::const_iterator end() const { return m_memberTypes.end(); }
private:
MemberMap m_memberTypes;
mutable std::unique_ptr<StorageOffsets> m_storageOffsets;
};
static_assert(std::is_nothrow_move_constructible<MemberList>::value, "MemberList should be noexcept move constructible");
/**
* Abstract base class that forms the root of the type hierarchy.
*/
class Type: private boost::noncopyable, public std::enable_shared_from_this<Type>
{
public:
virtual ~Type() = default;
enum class Category
{
Address, Integer, RationalNumber, StringLiteral, Bool, FixedPoint, Array,
FixedBytes, Contract, Struct, Function, Enum, Tuple,
Mapping, TypeType, Modifier, Magic, Module,
InaccessibleDynamic
};
/// @{
/// @name Factory functions
/// Factory functions that convert an AST @ref TypeName to a Type.
static TypePointer fromElementaryTypeName(ElementaryTypeNameToken const& _type);
/// Converts a given elementary type name with optional data location
/// suffix " storage", " calldata" or " memory" to a type pointer. If suffix not given, defaults to " storage".
static TypePointer fromElementaryTypeName(std::string const& _name);
/// @}
/// Auto-detect the proper type for a literal. @returns an empty pointer if the literal does
/// not fit any type.
static TypePointer forLiteral(Literal const& _literal);
/// @returns a pointer to _a or _b if the other is implicitly convertible to it or nullptr otherwise
static TypePointer commonType(TypePointer const& _a, TypePointer const& _b);
virtual Category category() const = 0;
/// @returns a valid solidity identifier such that two types should compare equal if and
/// only if they have the same identifier.
/// The identifier should start with "t_".
/// Can contain characters which are invalid in identifiers.
virtual std::string richIdentifier() const = 0;
/// @returns a valid solidity identifier such that two types should compare equal if and
/// only if they have the same identifier.
/// The identifier should start with "t_".
/// Will not contain any character which would be invalid as an identifier.
std::string identifier() const;
/// More complex identifier strings use "parentheses", where $_ is interpreted as
/// "opening parenthesis", _$ as "closing parenthesis", _$_ as "comma" and any $ that
/// appears as part of a user-supplied identifier is escaped as _$$$_.
/// @returns an escaped identifier (will not contain any parenthesis or commas)
static std::string escapeIdentifier(std::string const& _identifier);
virtual bool isImplicitlyConvertibleTo(Type const& _other) const { return *this == _other; }
virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const
{
return isImplicitlyConvertibleTo(_convertTo);
}
/// @returns the resulting type of applying the given unary operator or an empty pointer if
/// this is not possible.
/// The default implementation does not allow any unary operator.
virtual TypePointer unaryOperatorResult(Token) const { return TypePointer(); }
/// @returns the resulting type of applying the given binary operator or an empty pointer if
/// this is not possible.
/// The default implementation allows comparison operators if a common type exists
virtual TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const
{
return TokenTraits::isCompareOp(_operator) ? commonType(shared_from_this(), _other) : TypePointer();
}
virtual bool operator==(Type const& _other) const { return category() == _other.category(); }
virtual bool operator!=(Type const& _other) const { return !this->operator ==(_other); }
/// @returns number of bytes used by this type when encoded for CALL. If it is a dynamic type,
/// returns the size of the pointer (usually 32). Returns 0 if the type cannot be encoded
/// in calldata.
/// @note: This should actually not be called on types, where isDynamicallyEncoded returns true.
/// If @a _padded then it is assumed that each element is padded to a multiple of 32 bytes.
virtual unsigned calldataEncodedSize(bool _padded) const { (void)_padded; return 0; }
/// @returns the size of this data type in bytes when stored in memory. For memory-reference
/// types, this is the size of the memory pointer.
virtual unsigned memoryHeadSize() const { return calldataEncodedSize(); }
/// Convenience version of @see calldataEncodedSize(bool)
unsigned calldataEncodedSize() const { return calldataEncodedSize(true); }
/// @returns true if the type is a dynamic array
virtual bool isDynamicallySized() const { return false; }
/// @returns true if the type is dynamically encoded in the ABI
virtual bool isDynamicallyEncoded() const { return false; }
/// @returns the number of storage slots required to hold this value in storage.
/// For dynamically "allocated" types, it returns the size of the statically allocated head,
virtual u256 storageSize() const { return 1; }
/// Multiple small types can be packed into a single storage slot. If such a packing is possible
/// this function @returns the size in bytes smaller than 32. Data is moved to the next slot if
/// it does not fit.
/// In order to avoid computation at runtime of whether such moving is necessary, structs and
/// array data (not each element) always start a new slot.
virtual unsigned storageBytes() const { return 32; }
/// Returns true if the type can be stored in storage.
virtual bool canBeStored() const { return true; }
/// Returns false if the type cannot live outside the storage, i.e. if it includes some mapping.
virtual bool canLiveOutsideStorage() const { return true; }
/// Returns true if the type can be stored as a value (as opposed to a reference) on the stack,
/// i.e. it behaves differently in lvalue context and in value context.
virtual bool isValueType() const { return false; }
virtual unsigned sizeOnStack() const { return 1; }
/// If it is possible to initialize such a value in memory by just writing zeros
/// of the size memoryHeadSize().
virtual bool hasSimpleZeroValueInMemory() const { return true; }
/// @returns the mobile (in contrast to static) type corresponding to the given type.
/// This returns the corresponding IntegerType or FixedPointType for RationalNumberType
/// and the pointer type for storage reference types.
/// Might return a null pointer if there is no fitting type.
virtual TypePointer mobileType() const { return shared_from_this(); }
/// @returns true if this is a non-value type and the data of this type is stored at the
/// given location.
virtual bool dataStoredIn(DataLocation) const { return false; }
/// @returns the type of a temporary during assignment to a variable of the given type.
/// Specifically, returns the requested itself if it can be dynamically allocated (or is a value type)
/// and the mobile type otherwise.
virtual TypePointer closestTemporaryType(TypePointer const& _targetType) const
{
return _targetType->dataStoredIn(DataLocation::Storage) ? mobileType() : _targetType;
}
/// Returns the list of all members of this type. Default implementation: no members apart from bound.
/// @param _currentScope scope in which the members are accessed.
MemberList const& members(ContractDefinition const* _currentScope) const;
/// Convenience method, returns the type of the given named member or an empty pointer if no such member exists.
TypePointer memberType(std::string const& _name, ContractDefinition const* _currentScope = nullptr) const
{
return members(_currentScope).memberType(_name);
}
virtual std::string toString(bool _short) const = 0;
std::string toString() const { return toString(false); }
/// @returns the canonical name of this type for use in library function signatures.
virtual std::string canonicalName() const { return toString(true); }
/// @returns the signature of this type in external functions, i.e. `uint256` for integers
/// or `(uint256,bytes8)[2]` for an array of structs. If @a _structsByName,
/// structs are given by canonical name like `ContractName.StructName[2]`.
virtual std::string signatureInExternalFunction(bool /*_structsByName*/) const
{
return canonicalName();
}
virtual u256 literalValue(Literal const*) const
{
solAssert(false, "Literal value requested for type without literals: " + toString(false));
}
/// @returns a (simpler) type that is encoded in the same way for external function calls.
/// This for example returns address for contract types.
/// If there is no such type, returns an empty shared pointer.
virtual TypePointer encodingType() const { return TypePointer(); }
/// @returns the encoding type used under the given circumstances for the type of an expression
/// when used for e.g. abi.encode(...) or the empty pointer if the object
/// cannot be encoded.
/// This is different from encodingType since it takes implicit conversions into account.
TypePointer fullEncodingType(bool _inLibraryCall, bool _encoderV2, bool _packed) const;
/// @returns a (simpler) type that is used when decoding this type in calldata.
virtual TypePointer decodingType() const { return encodingType(); }
/// @returns a type that will be used outside of Solidity for e.g. function signatures.
/// This for example returns address for contract types.
/// If there is no such type, returns an empty shared pointer.
/// @param _inLibrary if set, returns types as used in a library, e.g. struct and contract types
/// are returned without modification.
virtual TypePointer interfaceType(bool /*_inLibrary*/) const { return TypePointer(); }
/// @returns true iff this type can be passed on via calls (to libraries if _inLibrary is true),
/// should be have identical to !!interfaceType(_inLibrary) but might do optimizations.
virtual bool canBeUsedExternally(bool _inLibrary) const { return !!interfaceType(_inLibrary); }
private:
/// @returns a member list containing all members added to this type by `using for` directives.
static MemberList::MemberMap boundFunctions(Type const& _type, ContractDefinition const& _scope);
protected:
/// @returns the members native to this type depending on the given context. This function
/// is used (in conjunction with boundFunctions to fill m_members below.
virtual MemberList::MemberMap nativeMembers(ContractDefinition const* /*_currentScope*/) const
{
return MemberList::MemberMap();
}
/// List of member types (parameterised by scape), will be lazy-initialized.
mutable std::map<ContractDefinition const*, std::unique_ptr<MemberList>> m_members;
};
/**
* Type for addresses.
*/
class AddressType: public Type
{
public:
static AddressType& address() { static std::shared_ptr<AddressType> addr(std::make_shared<AddressType>(StateMutability::NonPayable)); return *addr; }
static AddressType& addressPayable() { static std::shared_ptr<AddressType> addr(std::make_shared<AddressType>(StateMutability::Payable)); return *addr; }
Category category() const override { return Category::Address; }
explicit AddressType(StateMutability _stateMutability);
std::string richIdentifier() const override;
bool isImplicitlyConvertibleTo(Type const& _other) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const override;
bool operator==(Type const& _other) const override;
unsigned calldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : 160 / 8; }
unsigned storageBytes() const override { return 160 / 8; }
bool isValueType() const override { return true; }
MemberList::MemberMap nativeMembers(ContractDefinition const*) const override;
std::string toString(bool _short) const override;
std::string canonicalName() const override;
u256 literalValue(Literal const* _literal) const override;
TypePointer encodingType() const override { return shared_from_this(); }
TypePointer interfaceType(bool) const override { return shared_from_this(); }
StateMutability stateMutability(void) const { return m_stateMutability; }
private:
StateMutability m_stateMutability;
};
/**
* Any kind of integer type (signed, unsigned).
*/
class IntegerType: public Type
{
public:
enum class Modifier
{
Unsigned, Signed
};
Category category() const override { return Category::Integer; }
explicit IntegerType(unsigned _bits, Modifier _modifier = Modifier::Unsigned);
std::string richIdentifier() const override;
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const override;
bool operator==(Type const& _other) const override;
unsigned calldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : m_bits / 8; }
unsigned storageBytes() const override { return m_bits / 8; }
bool isValueType() const override { return true; }
std::string toString(bool _short) const override;
TypePointer encodingType() const override { return shared_from_this(); }
TypePointer interfaceType(bool) const override { return shared_from_this(); }
unsigned numBits() const { return m_bits; }
bool isSigned() const { return m_modifier == Modifier::Signed; }
bigint minValue() const;
bigint maxValue() const;
private:
unsigned m_bits;
Modifier m_modifier;
};
/**
* A fixed point type number (signed, unsigned).
*/
class FixedPointType: public Type
{
public:
enum class Modifier
{
Unsigned, Signed
};
Category category() const override { return Category::FixedPoint; }
explicit FixedPointType(unsigned _totalBits, unsigned _fractionalDigits, Modifier _modifier = Modifier::Unsigned);
std::string richIdentifier() const override;
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const override;
bool operator==(Type const& _other) const override;
unsigned calldataEncodedSize(bool _padded = true) const override { return _padded ? 32 : m_totalBits / 8; }
unsigned storageBytes() const override { return m_totalBits / 8; }
bool isValueType() const override { return true; }
std::string toString(bool _short) const override;
TypePointer encodingType() const override { return shared_from_this(); }
TypePointer interfaceType(bool) const override { return shared_from_this(); }
/// Number of bits used for this type in total.
unsigned numBits() const { return m_totalBits; }
/// Number of decimal digits after the radix point.
unsigned fractionalDigits() const { return m_fractionalDigits; }
bool isSigned() const { return m_modifier == Modifier::Signed; }
/// @returns the largest integer value this type con hold. Note that this is not the
/// largest value in general.
bigint maxIntegerValue() const;
/// @returns the smallest integer value this type can hold. Note hat this is not the
/// smallest value in general.
bigint minIntegerValue() const;
/// @returns the smallest integer type that can hold this type with fractional parts shifted to integers.
std::shared_ptr<IntegerType> asIntegerType() const;
private:
unsigned m_totalBits;
unsigned m_fractionalDigits;
Modifier m_modifier;
};
/**
* Integer and fixed point constants either literals or computed.
* Example expressions: 2, 3.14, 2+10.2, ~10.
* There is one distinct type per value.
*/
class RationalNumberType: public Type
{
public:
Category category() const override { return Category::RationalNumber; }
static TypePointer forLiteral(Literal const& _literal);
explicit RationalNumberType(rational const& _value, TypePointer const& _compatibleBytesType = TypePointer()):
m_value(_value), m_compatibleBytesType(_compatibleBytesType)
{}
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const override;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
bool canBeStored() const override { return false; }
bool canLiveOutsideStorage() const override { return false; }
std::string toString(bool _short) const override;
u256 literalValue(Literal const* _literal) const override;
TypePointer mobileType() const override;
/// @returns the smallest integer type that can hold the value or an empty pointer if not possible.
std::shared_ptr<IntegerType const> integerType() const;
/// @returns the smallest fixed type that can hold the value or incurs the least precision loss,
/// unless the value was truncated, then a suitable type will be chosen to indicate such event.
/// If the integer part does not fit, returns an empty pointer.
std::shared_ptr<FixedPointType const> fixedPointType() const;
/// @returns true if the value is not an integer.
bool isFractional() const { return m_value.denominator() != 1; }
/// @returns true if the value is negative.
bool isNegative() const { return m_value < 0; }
/// @returns true if the value is zero.
bool isZero() const { return m_value == 0; }
private:
rational m_value;
/// Bytes type to which the rational can be explicitly converted.
/// Empty for all rationals that are not directly parsed from hex literals.
TypePointer m_compatibleBytesType;
/// @returns true if the literal is a valid integer.
static std::tuple<bool, rational> isValidLiteral(Literal const& _literal);
/// @returns true if the literal is a valid rational number.
static std::tuple<bool, rational> parseRational(std::string const& _value);
/// @returns a truncated readable representation of the bigint keeping only
/// up to 4 leading and 4 trailing digits.
static std::string bigintToReadableString(dev::bigint const& num);
};
/**
* Literal string, can be converted to bytes, bytesX or string.
*/
class StringLiteralType: public Type
{
public:
Category category() const override { return Category::StringLiteral; }
explicit StringLiteralType(Literal const& _literal);
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer binaryOperatorResult(Token, TypePointer const&) const override
{
return TypePointer();
}
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
bool canBeStored() const override { return false; }
bool canLiveOutsideStorage() const override { return false; }
unsigned sizeOnStack() const override { return 0; }
std::string toString(bool) const override;
TypePointer mobileType() const override;
bool isValidUTF8() const;
std::string const& value() const { return m_value; }
private:
std::string m_value;
};
/**
* Bytes type with fixed length of up to 32 bytes.
*/
class FixedBytesType: public Type
{
public:
Category category() const override { return Category::FixedBytes; }
explicit FixedBytesType(unsigned _bytes);
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const override;
unsigned calldataEncodedSize(bool _padded) const override { return _padded && m_bytes > 0 ? 32 : m_bytes; }
unsigned storageBytes() const override { return m_bytes; }
bool isValueType() const override { return true; }
std::string toString(bool) const override { return "bytes" + dev::toString(m_bytes); }
MemberList::MemberMap nativeMembers(ContractDefinition const*) const override;
TypePointer encodingType() const override { return shared_from_this(); }
TypePointer interfaceType(bool) const override { return shared_from_this(); }
unsigned numBytes() const { return m_bytes; }
private:
unsigned m_bytes;
};
/**
* The boolean type.
*/
class BoolType: public Type
{
public:
BoolType() {}
Category category() const override { return Category::Bool; }
std::string richIdentifier() const override { return "t_bool"; }
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token _operator, TypePointer const& _other) const override;
unsigned calldataEncodedSize(bool _padded) const override{ return _padded ? 32 : 1; }
unsigned storageBytes() const override { return 1; }
bool isValueType() const override { return true; }
std::string toString(bool) const override { return "bool"; }
u256 literalValue(Literal const* _literal) const override;
TypePointer encodingType() const override { return shared_from_this(); }
TypePointer interfaceType(bool) const override { return shared_from_this(); }
};
/**
* Base class used by types which are not value types and can be stored either in storage, memory
* or calldata. This is currently used by arrays and structs.
*/
class ReferenceType: public Type
{
public:
explicit ReferenceType(DataLocation _location): m_location(_location) {}
DataLocation location() const { return m_location; }
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token, TypePointer const&) const override
{
return TypePointer();
}
unsigned memoryHeadSize() const override { return 32; }
/// @returns a copy of this type with location (recursively) changed to @a _location,
/// whereas isPointer is only shallowly changed - the deep copy is always a bound reference.
virtual TypePointer copyForLocation(DataLocation _location, bool _isPointer) const = 0;
TypePointer mobileType() const override { return copyForLocation(m_location, true); }
bool dataStoredIn(DataLocation _location) const override { return m_location == _location; }
bool hasSimpleZeroValueInMemory() const override { return false; }
/// Storage references can be pointers or bound references. In general, local variables are of
/// pointer type, state variables are bound references. Assignments to pointers or deleting
/// them will not modify storage (that will only change the pointer). Assignment from
/// non-storage objects to a variable of storage pointer type is not possible.
bool isPointer() const { return m_isPointer; }
bool operator==(ReferenceType const& _other) const
{
return location() == _other.location() && isPointer() == _other.isPointer();
}
/// @returns a copy of @a _type having the same location as this (and is not a pointer type)
/// if _type is a reference type and an unmodified copy of _type otherwise.
/// This function is mostly useful to modify inner types appropriately.
static TypePointer copyForLocationIfReference(DataLocation _location, TypePointer const& _type);
protected:
TypePointer copyForLocationIfReference(TypePointer const& _type) const;
/// @returns a human-readable description of the reference part of the type.
std::string stringForReferencePart() const;
/// @returns the suffix computed from the reference part to be used by identifier();
std::string identifierLocationSuffix() const;
DataLocation m_location = DataLocation::Storage;
bool m_isPointer = true;
};
/**
* The type of an array. The flavours are byte array (bytes), statically- (<type>[<length>])
* and dynamically-sized array (<type>[]).
* In storage, all arrays are packed tightly (as long as more than one elementary type fits in
* one slot). Dynamically sized arrays (including byte arrays) start with their size as a uint and
* thus start on their own slot.
*/
class ArrayType: public ReferenceType
{
public:
static ArrayType& bytesMemory() { static std::shared_ptr<ArrayType> addr(std::make_shared<ArrayType>(DataLocation::Memory)); return *addr; }
static ArrayType& stringMemory() { static std::shared_ptr<ArrayType> addr(std::make_shared<ArrayType>(DataLocation::Memory, true)); return *addr; }
Category category() const override { return Category::Array; }
/// Constructor for a byte array ("bytes") and string.
explicit ArrayType(DataLocation _location, bool _isString = false):
ReferenceType(_location),
m_arrayKind(_isString ? ArrayKind::String : ArrayKind::Bytes),
m_baseType(std::make_shared<FixedBytesType>(1))
{
}
/// Constructor for a dynamically sized array type ("type[]")
ArrayType(DataLocation _location, TypePointer const& _baseType):
ReferenceType(_location),
m_baseType(copyForLocationIfReference(_baseType))
{
}
/// Constructor for a fixed-size array type ("type[20]")
ArrayType(DataLocation _location, TypePointer const& _baseType, u256 const& _length):
ReferenceType(_location),
m_baseType(copyForLocationIfReference(_baseType)),
m_hasDynamicLength(false),
m_length(_length)
{}
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
std::string richIdentifier() const override;
bool operator==(const Type& _other) const override;
unsigned calldataEncodedSize(bool _padded) const override;
bool isDynamicallySized() const override { return m_hasDynamicLength; }
bool isDynamicallyEncoded() const override;
u256 storageSize() const override;
bool canLiveOutsideStorage() const override { return m_baseType->canLiveOutsideStorage(); }
unsigned sizeOnStack() const override;
std::string toString(bool _short) const override;
std::string canonicalName() const override;
std::string signatureInExternalFunction(bool _structsByName) const override;
MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
TypePointer encodingType() const override;
TypePointer decodingType() const override;
TypePointer interfaceType(bool _inLibrary) const override;
bool canBeUsedExternally(bool _inLibrary) const override;
/// @returns true if this is valid to be stored in calldata
bool validForCalldata() const;
/// @returns true if this is a byte array or a string
bool isByteArray() const { return m_arrayKind != ArrayKind::Ordinary; }
/// @returns true if this is a string
bool isString() const { return m_arrayKind == ArrayKind::String; }
TypePointer const& baseType() const { solAssert(!!m_baseType, ""); return m_baseType;}
u256 const& length() const { return m_length; }
u256 memorySize() const;
TypePointer copyForLocation(DataLocation _location, bool _isPointer) const override;
private:
/// String is interpreted as a subtype of Bytes.
enum class ArrayKind { Ordinary, Bytes, String };
bigint unlimitedCalldataEncodedSize(bool _padded) const;
///< Byte arrays ("bytes") and strings have different semantics from ordinary arrays.
ArrayKind m_arrayKind = ArrayKind::Ordinary;
TypePointer m_baseType;
bool m_hasDynamicLength = true;
u256 m_length;
};
/**
* The type of a contract instance or library, there is one distinct type for each contract definition.
*/
class ContractType: public Type
{
public:
Category category() const override { return Category::Contract; }
explicit ContractType(ContractDefinition const& _contract, bool _super = false):
m_contract(_contract), m_super(_super) {}
/// Contracts can be implicitly converted only to base contracts.
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
/// Contracts can only be explicitly converted to address types and base contracts.
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
unsigned calldataEncodedSize(bool _padded ) const override
{
solAssert(!isSuper(), "");
return encodingType()->calldataEncodedSize(_padded);
}
unsigned storageBytes() const override { solAssert(!isSuper(), ""); return 20; }
bool canLiveOutsideStorage() const override { return !isSuper(); }
unsigned sizeOnStack() const override { return m_super ? 0 : 1; }
bool isValueType() const override { return !isSuper(); }
std::string toString(bool _short) const override;
std::string canonicalName() const override;
MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
TypePointer encodingType() const override
{
if (isSuper())
return TypePointer{};
return std::make_shared<AddressType>(isPayable() ? StateMutability::Payable : StateMutability::NonPayable);
}
TypePointer interfaceType(bool _inLibrary) const override
{
if (isSuper())
return TypePointer{};
return _inLibrary ? shared_from_this() : encodingType();
}
bool isSuper() const { return m_super; }
// @returns true if and only if the contract has a payable fallback function
bool isPayable() const;
ContractDefinition const& contractDefinition() const { return m_contract; }
/// Returns the function type of the constructor modified to return an object of the contract's type.
FunctionTypePointer const& newExpressionType() const;
/// @returns a list of all state variables (including inherited) of the contract and their
/// offsets in storage.
std::vector<std::tuple<VariableDeclaration const*, u256, unsigned>> stateVariables() const;
private:
ContractDefinition const& m_contract;
/// If true, it is the "super" type of the current contract, i.e. it contains only inherited
/// members.
bool m_super = false;
/// Type of the constructor, @see constructorType. Lazily initialized.
mutable FunctionTypePointer m_constructorType;
};
/**
* The type of a struct instance, there is one distinct type per struct definition.
*/
class StructType: public ReferenceType
{
public:
Category category() const override { return Category::Struct; }
explicit StructType(StructDefinition const& _struct, DataLocation _location = DataLocation::Storage):
ReferenceType(_location), m_struct(_struct) {}
bool isImplicitlyConvertibleTo(const Type& _convertTo) const override;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
unsigned calldataEncodedSize(bool _padded) const override;
bool isDynamicallyEncoded() const override;
u256 memorySize() const;
u256 storageSize() const override;
bool canLiveOutsideStorage() const override { return true; }
std::string toString(bool _short) const override;
MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
TypePointer encodingType() const override
{
return location() == DataLocation::Storage ? std::make_shared<IntegerType>(256) : shared_from_this();
}
TypePointer interfaceType(bool _inLibrary) const override;
bool canBeUsedExternally(bool _inLibrary) const override;
TypePointer copyForLocation(DataLocation _location, bool _isPointer) const override;
std::string canonicalName() const override;
std::string signatureInExternalFunction(bool _structsByName) const override;
/// @returns a function that performs the type conversion between a list of struct members
/// and a memory struct of this type.
FunctionTypePointer constructorType() const;
std::pair<u256, unsigned> const& storageOffsetsOfMember(std::string const& _name) const;
u256 memoryOffsetOfMember(std::string const& _name) const;
StructDefinition const& structDefinition() const { return m_struct; }
/// @returns the vector of types of members available in memory.
TypePointers memoryMemberTypes() const;
/// @returns the set of all members that are removed in the memory version (typically mappings).
std::set<std::string> membersMissingInMemory() const;
/// @returns true if the same struct is used recursively in one of its members. Only
/// analyses the "memory" representation, i.e. mappings are ignored in all structs.
bool recursive() const;
private:
StructDefinition const& m_struct;
/// Cache for the recursive() function.
mutable boost::optional<bool> m_recursive;
};
/**
* The type of an enum instance, there is one distinct type per enum definition.
*/
class EnumType: public Type
{
public:
Category category() const override { return Category::Enum; }
explicit EnumType(EnumDefinition const& _enum): m_enum(_enum) {}
TypePointer unaryOperatorResult(Token _operator) const override;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
unsigned calldataEncodedSize(bool _padded) const override
{
return encodingType()->calldataEncodedSize(_padded);
}
unsigned storageBytes() const override;
bool canLiveOutsideStorage() const override { return true; }
std::string toString(bool _short) const override;
std::string canonicalName() const override;
bool isValueType() const override { return true; }
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer encodingType() const override
{
return std::make_shared<IntegerType>(8 * int(storageBytes()));
}
TypePointer interfaceType(bool _inLibrary) const override
{
return _inLibrary ? shared_from_this() : encodingType();
}
EnumDefinition const& enumDefinition() const { return m_enum; }
/// @returns the value that the string has in the Enum
unsigned int memberValue(ASTString const& _member) const;
size_t numberOfMembers() const;
private:
EnumDefinition const& m_enum;
};
/**
* Type that can hold a finite sequence of values of different types.
* In some cases, the components are empty pointers (when used as placeholders).
*/
class TupleType: public Type
{
public:
Category category() const override { return Category::Tuple; }
explicit TupleType(std::vector<TypePointer> const& _types = std::vector<TypePointer>()): m_components(_types) {}
bool isImplicitlyConvertibleTo(Type const& _other) const override;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
TypePointer binaryOperatorResult(Token, TypePointer const&) const override { return TypePointer(); }
std::string toString(bool) const override;
bool canBeStored() const override { return false; }
u256 storageSize() const override;
bool canLiveOutsideStorage() const override { return false; }
unsigned sizeOnStack() const override;
bool hasSimpleZeroValueInMemory() const override { return false; }
TypePointer mobileType() const override;
/// Converts components to their temporary types and performs some wildcard matching.
TypePointer closestTemporaryType(TypePointer const& _targetType) const override;
std::vector<TypePointer> const& components() const { return m_components; }
private:
std::vector<TypePointer> const m_components;
};
/**
* The type of a function, identified by its (return) parameter types.
* @todo the return parameters should also have names, i.e. return parameters should be a struct
* type.
*/
class FunctionType: public Type
{
public:
/// How this function is invoked on the EVM.
enum class Kind
{
Internal, ///< stack-call using plain JUMP
External, ///< external call using CALL
DelegateCall, ///< external call using DELEGATECALL, i.e. not exchanging the storage
BareCall, ///< CALL without function hash
BareCallCode, ///< CALLCODE without function hash
BareDelegateCall, ///< DELEGATECALL without function hash
BareStaticCall, ///< STATICCALL without function hash
Creation, ///< external call using CREATE
Send, ///< CALL, but without data and gas
Transfer, ///< CALL, but without data and throws on error
KECCAK256, ///< KECCAK256
Selfdestruct, ///< SELFDESTRUCT
Revert, ///< REVERT
ECRecover, ///< CALL to special contract for ecrecover
SHA256, ///< CALL to special contract for sha256
RIPEMD160, ///< CALL to special contract for ripemd160
Log0,
Log1,
Log2,
Log3,
Log4,
Event, ///< syntactic sugar for LOG*
SetGas, ///< modify the default gas value for the function call
SetValue, ///< modify the default value transfer for the function call
BlockHash, ///< BLOCKHASH
AddMod, ///< ADDMOD
MulMod, ///< MULMOD
ArrayPush, ///< .push() to a dynamically sized array in storage
ArrayPop, ///< .pop() from a dynamically sized array in storage
ByteArrayPush, ///< .push() to a dynamically sized byte array in storage
ObjectCreation, ///< array creation using new
Assert, ///< assert()
Require, ///< require()
ABIEncode,
ABIEncodePacked,
ABIEncodeWithSelector,
ABIEncodeWithSignature,
ABIDecode,
GasLeft, ///< gasleft()
};
Category category() const override { return Category::Function; }
/// Creates the type of a function.
explicit FunctionType(FunctionDefinition const& _function, bool _isInternal = true);
/// Creates the accessor function type of a state variable.
explicit FunctionType(VariableDeclaration const& _varDecl);
/// Creates the function type of an event.
explicit FunctionType(EventDefinition const& _event);
/// Creates the type of a function type name.
explicit FunctionType(FunctionTypeName const& _typeName);
/// Function type constructor to be used for a plain type (not derived from a declaration).
FunctionType(
strings const& _parameterTypes,
strings const& _returnParameterTypes,
Kind _kind = Kind::Internal,
bool _arbitraryParameters = false,
StateMutability _stateMutability = StateMutability::NonPayable
): FunctionType(
parseElementaryTypeVector(_parameterTypes),
parseElementaryTypeVector(_returnParameterTypes),
strings(),
strings(),
_kind,
_arbitraryParameters,
_stateMutability
)
{
}
/// @returns the type of the "new Contract" function, i.e. basically the constructor.
static FunctionTypePointer newExpressionType(ContractDefinition const& _contract);
/// Detailed constructor, use with care.
FunctionType(
TypePointers const& _parameterTypes,
TypePointers const& _returnParameterTypes,
strings _parameterNames = strings(),
strings _returnParameterNames = strings(),
Kind _kind = Kind::Internal,
bool _arbitraryParameters = false,
StateMutability _stateMutability = StateMutability::NonPayable,
Declaration const* _declaration = nullptr,
bool _gasSet = false,
bool _valueSet = false,
bool _bound = false
):
m_parameterTypes(_parameterTypes),
m_returnParameterTypes(_returnParameterTypes),
m_parameterNames(_parameterNames),
m_returnParameterNames(_returnParameterNames),
m_kind(_kind),
m_stateMutability(_stateMutability),
m_arbitraryParameters(_arbitraryParameters),
m_gasSet(_gasSet),
m_valueSet(_valueSet),
m_bound(_bound),
m_declaration(_declaration)
{
solAssert(
!m_bound || !m_parameterTypes.empty(),
"Attempted construction of bound function without self type"
);
}
TypePointers parameterTypes() const;
std::vector<std::string> parameterNames() const;
TypePointers const& returnParameterTypes() const { return m_returnParameterTypes; }
/// @returns the list of return parameter types. All dynamically-sized types (this excludes
/// storage pointers) are replaced by InaccessibleDynamicType instances.
TypePointers returnParameterTypesWithoutDynamicTypes() const;
std::vector<std::string> const& returnParameterNames() const { return m_returnParameterNames; }
/// @returns the "self" parameter type for a bound function
TypePointer const& selfType() const;
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
TypePointer unaryOperatorResult(Token _operator) const override;
TypePointer binaryOperatorResult(Token, TypePointer const&) const override;
std::string canonicalName() const override;
std::string toString(bool _short) const override;
unsigned calldataEncodedSize(bool _padded) const override;
bool canBeStored() const override { return m_kind == Kind::Internal || m_kind == Kind::External; }
u256 storageSize() const override;
unsigned storageBytes() const override;
bool isValueType() const override { return true; }
bool canLiveOutsideStorage() const override { return m_kind == Kind::Internal || m_kind == Kind::External; }
unsigned sizeOnStack() const override;
bool hasSimpleZeroValueInMemory() const override { return false; }
MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
TypePointer encodingType() const override;
TypePointer interfaceType(bool _inLibrary) const override;
/// @returns TypePointer of a new FunctionType object. All input/return parameters are an
/// appropriate external types (i.e. the interfaceType()s) of input/return parameters of
/// current function.
/// @returns an empty shared pointer if one of the input/return parameters does not have an
/// external type.
FunctionTypePointer interfaceFunctionType() const;
/// @returns true if this function can take the given argument types (possibly
/// after implicit conversion).
/// @param _selfType if the function is bound, this has to be supplied and is the type of the
/// expression the function is called on.
bool canTakeArguments(TypePointers const& _arguments, TypePointer const& _selfType = TypePointer()) const;
/// @returns true if the types of parameters are equal (does not check return parameter types)
bool hasEqualParameterTypes(FunctionType const& _other) const;
/// @returns true iff the return types are equal (does not check parameter types)
bool hasEqualReturnTypes(FunctionType const& _other) const;
/// @returns true iff the function type is equal to the given type, ignoring state mutability differences.
bool equalExcludingStateMutability(FunctionType const& _other) const;
/// @returns true if the ABI is NOT used for this call (only meaningful for external calls)
bool isBareCall() const;
Kind const& kind() const { return m_kind; }
StateMutability stateMutability() const { return m_stateMutability; }
/// @returns the external signature of this function type given the function name
std::string externalSignature() const;
/// @returns the external identifier of this function (the hash of the signature).
u256 externalIdentifier() const;
Declaration const& declaration() const
{
solAssert(m_declaration, "Requested declaration from a FunctionType that has none");
return *m_declaration;
}
bool hasDeclaration() const { return !!m_declaration; }
/// @returns true if the result of this function only depends on its arguments,
/// does not modify the state and is a compile-time constant.
/// Currently, this will only return true for internal functions like keccak and ecrecover.
bool isPure() const;
bool isPayable() const { return m_stateMutability == StateMutability::Payable; }
/// @return A shared pointer of an ASTString.
/// Can contain a nullptr in which case indicates absence of documentation
ASTPointer<ASTString> documentation() const;
/// true iff arguments are to be padded to multiples of 32 bytes for external calls
/// The only functions that do not pad are hash functions, the low-level call functions
/// and abi.encodePacked.
bool padArguments() const;
bool takesArbitraryParameters() const { return m_arbitraryParameters; }
/// true iff the function takes a single bytes parameter and it is passed on without padding.
bool takesSinglePackedBytesParameter() const
{
switch (m_kind)
{
case FunctionType::Kind::KECCAK256:
case FunctionType::Kind::SHA256:
case FunctionType::Kind::RIPEMD160:
case FunctionType::Kind::BareCall:
case FunctionType::Kind::BareCallCode:
case FunctionType::Kind::BareDelegateCall:
case FunctionType::Kind::BareStaticCall:
return true;
default:
return false;
}
}
bool gasSet() const { return m_gasSet; }
bool valueSet() const { return m_valueSet; }
bool bound() const { return m_bound; }
/// @returns a copy of this type, where gas or value are set manually. This will never set one
/// of the parameters to false.
TypePointer copyAndSetGasOrValue(bool _setGas, bool _setValue) const;
/// @returns a copy of this function type where all return parameters of dynamic size are
/// removed and the location of reference types is changed from CallData to Memory.
/// This is needed if external functions are called on other contracts, as they cannot return
/// dynamic values.
/// Returns empty shared pointer on a failure. Namely, if a bound function has no parameters.
/// @param _inLibrary if true, uses DelegateCall as location.
/// @param _bound if true, the arguments are placed as `arg1.functionName(arg2, ..., argn)`.
FunctionTypePointer asMemberFunction(bool _inLibrary, bool _bound = false) const;
private:
static TypePointers parseElementaryTypeVector(strings const& _types);
TypePointers m_parameterTypes;
TypePointers m_returnParameterTypes;
std::vector<std::string> m_parameterNames;
std::vector<std::string> m_returnParameterNames;
Kind const m_kind;
StateMutability m_stateMutability = StateMutability::NonPayable;
/// true if the function takes an arbitrary number of arguments of arbitrary types
bool const m_arbitraryParameters = false;
bool const m_gasSet = false; ///< true iff the gas value to be used is on the stack
bool const m_valueSet = false; ///< true iff the value to be sent is on the stack
bool const m_bound = false; ///< true iff the function is called as arg1.fun(arg2, ..., argn)
Declaration const* m_declaration = nullptr;
};
/**
* The type of a mapping, there is one distinct type per key/value type pair.
* Mappings always occupy their own storage slot, but do not actually use it.
*/
class MappingType: public Type
{
public:
Category category() const override { return Category::Mapping; }
MappingType(TypePointer const& _keyType, TypePointer const& _valueType):
m_keyType(_keyType), m_valueType(_valueType) {}
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
std::string toString(bool _short) const override;
std::string canonicalName() const override;
bool canLiveOutsideStorage() const override { return false; }
TypePointer binaryOperatorResult(Token, TypePointer const&) const override { return TypePointer(); }
TypePointer encodingType() const override
{
return std::make_shared<IntegerType>(256);
}
TypePointer interfaceType(bool _inLibrary) const override
{
return _inLibrary ? shared_from_this() : TypePointer();
}
bool dataStoredIn(DataLocation _location) const override { return _location == DataLocation::Storage; }
/// Cannot be stored in memory, but just in case.
bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
TypePointer const& keyType() const { return m_keyType; }
TypePointer const& valueType() const { return m_valueType; }
private:
TypePointer m_keyType;
TypePointer m_valueType;
};
/**
* The type of a type reference. The type of "uint32" when used in "a = uint32(2)" is an example
* of a TypeType.
* For super contracts or libraries, this has members directly.
*/
class TypeType: public Type
{
public:
Category category() const override { return Category::TypeType; }
explicit TypeType(TypePointer const& _actualType): m_actualType(_actualType) {}
TypePointer const& actualType() const { return m_actualType; }
TypePointer binaryOperatorResult(Token, TypePointer const&) const override { return TypePointer(); }
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
bool canBeStored() const override { return false; }
u256 storageSize() const override;
bool canLiveOutsideStorage() const override { return false; }
unsigned sizeOnStack() const override;
bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
std::string toString(bool _short) const override { return "type(" + m_actualType->toString(_short) + ")"; }
MemberList::MemberMap nativeMembers(ContractDefinition const* _currentScope) const override;
private:
TypePointer m_actualType;
};
/**
* The type of a function modifier. Not used for anything for now.
*/
class ModifierType: public Type
{
public:
Category category() const override { return Category::Modifier; }
explicit ModifierType(ModifierDefinition const& _modifier);
TypePointer binaryOperatorResult(Token, TypePointer const&) const override { return TypePointer(); }
bool canBeStored() const override { return false; }
u256 storageSize() const override;
bool canLiveOutsideStorage() const override { return false; }
unsigned sizeOnStack() const override { return 0; }
bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
std::string toString(bool _short) const override;
private:
TypePointers m_parameterTypes;
};
/**
* Special type for imported modules. These mainly give access to their scope via members.
*/
class ModuleType: public Type
{
public:
Category category() const override { return Category::Module; }
explicit ModuleType(SourceUnit const& _source): m_sourceUnit(_source) {}
TypePointer binaryOperatorResult(Token, TypePointer const&) const override { return TypePointer(); }
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
bool canBeStored() const override { return false; }
bool canLiveOutsideStorage() const override { return true; }
bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
unsigned sizeOnStack() const override { return 0; }
MemberList::MemberMap nativeMembers(ContractDefinition const*) const override;
std::string toString(bool _short) const override;
private:
SourceUnit const& m_sourceUnit;
};
/**
* Special type for magic variables (block, msg, tx), similar to a struct but without any reference
* (it always references a global singleton by name).
*/
class MagicType: public Type
{
public:
enum class Kind { Block, Message, Transaction, ABI };
Category category() const override { return Category::Magic; }
explicit MagicType(Kind _kind): m_kind(_kind) {}
TypePointer binaryOperatorResult(Token, TypePointer const&) const override
{
return TypePointer();
}
std::string richIdentifier() const override;
bool operator==(Type const& _other) const override;
bool canBeStored() const override { return false; }
bool canLiveOutsideStorage() const override { return true; }
bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
unsigned sizeOnStack() const override { return 0; }
MemberList::MemberMap nativeMembers(ContractDefinition const*) const override;
std::string toString(bool _short) const override;
Kind kind() const { return m_kind; }
private:
Kind m_kind;
};
/**
* Special type that is used for dynamic types in returns from external function calls
* (The EVM currently cannot access dynamically-sized return values).
*/
class InaccessibleDynamicType: public Type
{
public:
Category category() const override { return Category::InaccessibleDynamic; }
std::string richIdentifier() const override { return "t_inaccessible"; }
bool isImplicitlyConvertibleTo(Type const&) const override { return false; }
bool isExplicitlyConvertibleTo(Type const&) const override { return false; }
TypePointer binaryOperatorResult(Token, TypePointer const&) const override { return TypePointer(); }
unsigned calldataEncodedSize(bool _padded) const override { (void)_padded; return 32; }
bool canBeStored() const override { return false; }
bool canLiveOutsideStorage() const override { return false; }
bool isValueType() const override { return true; }
unsigned sizeOnStack() const override { return 1; }
bool hasSimpleZeroValueInMemory() const override { solAssert(false, ""); }
std::string toString(bool) const override { return "inaccessible dynamic type"; }
TypePointer decodingType() const override { return std::make_shared<IntegerType>(256); }
};
}
}