UniversalString type¶
- class pyasn1.type.char.UniversalString(value=NoValue(), tagSet=TagSet(), subtypeSpec=ConstraintsIntersection(), encoding='us-ascii')¶
Creates UniversalString schema or value object.
UniversalString class is based on
SimpleAsn1Type
, its objects are immutable and duck-type Python 2str
or Python 3bytes
. When used in octet-stream context, UniversalString type assumes “utf-32-be” encoding.- Keyword Arguments
value (
unicode
,str
,bytes
or UniversalString object) –unicode
object (Python 2) orstr
(Python 3), alternativelystr
(Python 2) orbytes
(Python 3) representing octet-stream of serialised unicode string (note encoding parameter) or UniversalString class instance. 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 UniversalString type occurs automatically on object instantiation.encoding (
str
) – Unicode codec ID to encode/decodeunicode
(Python 2) orstr
(Python 3) the payload when UniversalString object is used in octet-stream context.
- Raises
ValueConstraintError, PyAsn1Error – On constraint violation or bad initializer.
Note
The UniversalString type models a Unicode (ISO10646-1) character string implicitly serialised into UTF-32 big endian.
- clone(value=NoValue(), tagSet=TagSet(), subtypeSpec=ConstraintsIntersection(), encoding='us-ascii')¶
Create a modified version of UniversalString schema or value object.
The clone() method accepts the same set arguments as UniversalString 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 UniversalString object, if no arguments are supplied, no new UniversalString object will be created and self will be returned instead.
- subtype(value=NoValue(), implicitTag=Tag(), explicitTag=Tag(), subtypeSpec=ConstraintsIntersection(), encoding='us-ascii')¶
Create a specialization of UniversalString 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 UniversalString attributes.The subtype() method accepts the same set arguments as UniversalString 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 UniversalString type:
- Other Parameters
implicitTag (
Tag
) – Implicitly apply given ASN.1 tag object to self’sTagSet
, then use the result as new object’s ASN.1 tag(s).explicitTag (
Tag
) – Explicitly apply given ASN.1 tag object to self’sTagSet
, 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 UniversalString schema or value object
Note
Due to the immutable nature of the UniversalString object, if no arguments are supplied, no new UniversalString object will be created and self will be returned instead.
- tagSet = <TagSet object, tags 0:0:28>¶
Set (on class, not on instance) or return a
TagSet
object representing ASN.1 tag(s) associated with UniversalString type.
- property isValue¶
Indicate that UniversalString 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 UniversalString 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.
- isSuperTypeOf(other, matchTags=True, matchConstraints=True)¶
Examine UniversalString 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.
- property effectiveTagSet¶
For UniversalString type is equivalent to tagSet