coded_index

A xmr::coded_index<T> represents a row in a database table, where the table is not known until run time, but it is one of a fixed set of possibilities.

A coded_index is used when the value could be one of various things. For example, a coded_index<TypeDefOrRef> represents a row in the TypeDef table, a row in the TypeRef table, a row in the TypeSpec table, or nothing at all. (The type should be more accurately named TypeDefRefOrSpec, but it's too late to fix it now.)

In the ECMA-335 file format, a coded index is represented as a row number and a type code packed together. A selected number of low-order bits encode the type code, and the remaining bits encode the row. The row number is incremented before being combined with the type code, to ensure that a valid entry always has a nonzero value.

(The incrementing of the row number by 1 is not mentioned in the ECMA-335 file format specification, section II.24.2.6 "If e is a coded index...", but the incrementing appears to be done in practice.)

Internally, a coded_index<T> derives from typed_index<T>, which in turn derives from index_base<T>.

Members

operator bool

operator bool() const noexcept;

Returns true if the coded_index (really, the index_base) is not "nothing".

If the boolean conversion operator returns false, then the only other method you can call is get_database().

Performance: O(1). Very fast.

type

T type() const noexcept;

Returns the enumeration value that indicates which table the coded index refers to.

Performance: O(1). Fast.

type

T index() const noexcept;

Returns the (zero-based) row index in the destination table.

Performance: O(1). Fast.

get_row

template<typename Row>
Row get_row() const;

Returns a reference to the index()th row of the Row table. The type() of the coded_index must match Row.

Performance: O(1).

get_database

xmr::database const& get_database() const noexcept;

Returns a reference to the database that contains this row.

Performance: O(1). Very fast.

operators

bool operator==(index_base<T> const& other) const noexcept;
bool operator!=(index_base<T> const& other) const noexcept;

Determine whether the current index_base<T> object refers to the same row and table as the other index_base<T> object.

bool operator<(index_base<T> const& other) const noexcept;

Imposes a total order on the index_base<T> objects.

The order is numeric by the encoded values, because that matches the sort order used by various tables. This is generally not something you need to worry about.

The presence of an < operator has the pleasant side effect of allowing the index_base to be used as a key in a std::map, std::set, or other data structure that requires a total order.

Specializations

Specializations of coded_index<T> typically provide helper methods to follow the coded index into the appropriate table. The helper method has the same name as the table, and it returns a row from that table.

For example, if coded_index<TypeDefOrRef>.type() returns TypeDefOrRef::TypeDef, then you can call the coded_index<TypeDefOrRef>.TypeDef() method, and it produces the TypeDef row that the coded index represents.

T	If type() is...	Then call coded_index<T> method...	... returns a...
TypeDefOrRef	TypeDef	TypeDef()	TypeDef
TypeDefOrRef	TypeRef	TypeRef()	TypeRef
TypeDefOrRef	TypeSpec	TypeSpec()	TypeSpec
HasConstant	Field	Field()	Field
HasConstant	Param	Param()	Param
HasConstant	Property	Property()	Property
CustomAttributeType	MethodDef	MethodDef()	MethodDef
CustomAttributeType	MethodRef	MethodRef()	MethodRef
HasSemantics	Event	Event()	Event
HasSemantics	Property	Property()	Property
MethodDefOrRef	MethodDef	MethodDef()	MethodDef
MethodDefOrRef	MethodRef	MethodRef()	MethodRef
ResolutionScope	Module	Module()	Module
ResolutionScope	ModuleRef	ModuleRef()	ModuleRef
ResolutionScope	AssemblyRef	AssemblyRef()	AssemblyRef
ResolutionScope	TypeRef	TypeRef()	TypeRef
MemberRefParent	TypeDef	TypeDef()	TypeDef
MemberRefParent	TypeRef	TypeRef()	TypeRef
MemberRefParent	ModuleRef	ModuleRef()	ModuleRef
MemberRefParent	MethodDef	MethodDef()	MethodDef
MemberRefParent	TypeSpec	TypeSpec()	TypeSpec

Non-member operators

There are a number of overloads for the < operator to facilitate searching through sorted tables. They are not intended for general use.

Comparing...	With...	Compares the...
coded_index<HasCustomAttribute>	CustomAttribute	CustomAttribute::Parent()
coded_index<TypeOrMethodDef>	GenericParam	GenericParam::Owner()
coded_index<HasConstant>	Constant	Constant::Parent()
coded_index<HasSemantics>	MethodSemantics	MethodSemantics::Association()