Enumerated type¶

class pyasn1.type.univ.Enumerated(value=NoValue(), tagSet=TagSet(), subtypeSpec=ConstraintsIntersection(), namedValues=NamedValues())¶

Create Enumerated schema or value object.

Enumerated class is based on SimpleAsn1Type, its objects are immutable and duck-type Python int objects.

Keyword Arguments

value (int, str or Enumerated object) – Python int or str literal or Enumerated object. If value is not given, schema object will be created.
tagSet (TagSet) – Object representing non-default ASN.1 tag(s)
subtypeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 subtype constraint(s). Constraints verification for Enumerated type occurs automatically on object instantiation.
namedValues (NamedValues) – Object representing non-default symbolic aliases for numbers

Raises

ValueConstraintError, PyAsn1Error – On constraint violation or bad initializer.

Examples

class RadioButton(Enumerated):
    '''
    ASN.1 specification:

    RadioButton ::= ENUMERATED { button1(0), button2(1),
                                 button3(2) }

    selected-by-default RadioButton ::= button1
    '''
    namedValues = NamedValues(
        ('button1', 0), ('button2', 1),
        ('button3', 2)
    )

selected_by_default = RadioButton('button1')

Note

The Enumerated type models bounded set of named integer values. Other than that, it is identical to the Integer class.

clone(value=NoValue(), tagSet=TagSet(), subtypeSpec=ConstraintsIntersection(), namedValues=NamedValues())¶

Create a modified version of Enumerated schema or value object.

The clone() method accepts the same set arguments as Enumerated class takes on instantiation except that all arguments of the clone() method are optional.

Whatever arguments are supplied, they are used to create a copy of self taking precedence over the ones used to instantiate self.

Note

Due to the immutable nature of the Enumerated object, if no arguments are supplied, no new Enumerated object will be created and self will be returned instead.

subtype(value=NoValue(), implicitTag=Tag(), explicitTag=Tag(), subtypeSpec=ConstraintsIntersection(), namedValues=NamedValues())¶

Create a specialization of Enumerated schema or value object.

The subtype relationship between ASN.1 types has no correlation with subtype relationship between Python types. ASN.1 type is mainly identified by its tag(s) (TagSet) and value range constraints (ConstraintsIntersection). These ASN.1 type properties are implemented as Enumerated attributes.

The subtype() method accepts the same set arguments as Enumerated class takes on instantiation except that all parameters of the subtype() method are optional.

With the exception of the arguments described below, the rest of supplied arguments they are used to create a copy of self taking precedence over the ones used to instantiate self.

The following arguments to subtype() create a ASN.1 subtype out of Enumerated type:

Other Parameters

implicitTag (Tag) – Implicitly apply given ASN.1 tag object to self’s TagSet, then use the result as new object’s ASN.1 tag(s).
explicitTag (Tag) – Explicitly apply given ASN.1 tag object to self’s TagSet, then use the result as new object’s ASN.1 tag(s).
subtypeSpec (ConstraintsIntersection) – Add ASN.1 constraints object to one of the self’s, then use the result as new object’s ASN.1 constraints.

Returns

new instance of Enumerated schema or value object

Note

Due to the immutable nature of the Enumerated object, if no arguments are supplied, no new Enumerated object will be created and self will be returned instead.

tagSet = <TagSet object, tags 0:0:10>¶: Set (on class, not on instance) or return a TagSet object representing ASN.1 tag(s) associated with Enumerated type.

subtypeSpec = <ConstraintsIntersection object>¶: Set (on class, not on instance) or return a ConstraintsIntersection object imposing constraints on Enumerated type initialization values.

namedValues = <NamedValues object, enums >¶: Default NamedValues object representing symbolic aliases for numbers

property isValue¶

Indicate that Enumerated object represents ASN.1 value.

If isValue is False then this object represents just ASN.1 schema.

If isValue is True then, in addition to its ASN.1 schema features, this object can also be used like a Python built-in object (e.g. int, str, dict etc.).

Returns: bool – False if object represents just ASN.1 schema. True if object represents ASN.1 schema and can be used as a normal value.

Note

There is an important distinction between PyASN1 schema and value objects. The PyASN1 schema objects can only participate in ASN.1 schema-related operations (e.g. defining or testing the structure of the data). Most obvious uses of ASN.1 schema is to guide serialisation codecs whilst encoding/decoding serialised ASN.1 contents.

The PyASN1 value objects can additionally participate in many operations involving regular Python objects (e.g. arithmetic, comprehension etc).

isSameTypeWith(other, matchTags=True, matchConstraints=True)¶

Examine Enumerated type for equality with other ASN.1 type.

ASN.1 tags (tag) and constraints (constraint) are examined when carrying out ASN.1 types comparison.

Python class inheritance relationship is NOT considered.

Parameters: other (a pyasn1 type object) – Class instance representing ASN.1 type.
Returns: bool – True if other is Enumerated type, False otherwise.

isSuperTypeOf(other, matchTags=True, matchConstraints=True)¶

Examine Enumerated type for subtype relationship with other ASN.1 type.

ASN.1 tags (tag) and constraints (constraint) are examined when carrying out ASN.1 types comparison.

Python class inheritance relationship is NOT considered.

Parameters: other (a pyasn1 type object) – Class instance representing ASN.1 type.
Returns: bool – True if other is a subtype of Enumerated type, False otherwise.

property effectiveTagSet¶: For Enumerated type is equivalent to tagSet

property tagMap¶: Return a TagMap object mapping ASN.1 tags to ASN.1 objects within callee object.

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Related Topics

Enumerated type¶