SequenceOf type¶
-
class
pyasn1.type.univ.
SequenceOf
(componentType=None, tagSet=TagSet(), subtypeSpec=ConstraintsIntersection(), sizeSpec=ConstraintsIntersection())¶ Create SequenceOf type.
SequenceOf objects are mutable and duck-type Python
list
objects.Keyword Arguments: - componentType (
PyAsn1Item
derivative) – A pyasn1 object representing ASN.1 type allowed within SequenceOf type - tagSet (
TagSet
) – Object representing non-default ASN.1 tag(s) - subtypeSpec (
ConstraintsIntersection
) – Object representing non-default ASN.1 subtype constraint(s) - sizeSpec (
ConstraintsIntersection
) – Object representing collection size constraint
Examples
class LotteryDraw(SequenceOf): # SetOf is similar ''' ASN.1 specification: LotteryDraw ::= SEQUENCE OF INTEGER ''' componentType = Integer() lotteryDraw = LotteryDraw() lotteryDraw.extend([123, 456, 789])
Note
The SequenceOf type models a collection of elements of a single ASN.1 type. Ordering of the components is preserved upon de/serialisation.
-
clone
(componentType=None, tagSet=TagSet(), subtypeSpec=ConstraintsIntersection())¶ Create a modified version of SequenceOf schema object.
The clone() method accepts the same set arguments as SequenceOf 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.
Possible values of self are never copied over thus clone() can only create a new schema object.
Returns: new instance of SequenceOf type/value Note
Due to the mutable nature of the SequenceOf object, even if no arguments are supplied, new SequenceOf object will always be created as a shallow copy of self.
-
subtype
(componentType=None, implicitTag=Tag(), explicitTag=Tag(), subtypeSpec=ConstraintsIntersection())¶ Create a specialization of SequenceOf schema object.
The subtype() method accepts the same set arguments as SequenceOf 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 SequenceOf 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 SequenceOf type/value
Note
Due to the immutable nature of the SequenceOf object, if no arguments are supplied, no new SequenceOf object will be created and self will be returned instead.
- implicitTag (
-
tagSet
= <TagSet object at 0x7fcd8f439f90 tags 0:32:16>¶ Set (on class, not on instance) or return a
TagSet
object representing ASN.1 tag(s) associated with SequenceOf type.
-
componentType
= None¶ Default
PyAsn1Item
derivative object representing ASN.1 type allowed within SequenceOf type
-
subtypeSpec
= <ConstraintsIntersection object>¶ Set (on class, not on instance) or return a
ConstraintsIntersection
object imposing constraints on SequenceOf type initialization values.
-
sizeSpec
= <ConstraintsIntersection object>¶ Default
ConstraintsIntersection
object imposing size constraint on SequenceOf objects
-
effectiveTagSet
¶ For SequenceOf type is equivalent to tagSet
-
getComponentByPosition
(idx, default=<NoValue object at 140520848870480>, instantiate=True)¶ Return SequenceOf type component value by position.
Equivalent to Python sequence subscription operation (e.g. []).
Parameters: idx (
int
) – Component index (zero-based). Must either refer to an existing component or to N+1 component (if componentType is set). In the latter case a new component type gets instantiated and appended to the SequenceOf sequence.Keyword Arguments: - default (
object
) – If set and requested component is a schema object, return the default object instead of the requested component. - instantiate (
bool
) – If True (default), inner component will be automatically instantiated. If ‘False’ either existing component or the noValue object will be returned.
Returns: PyAsn1Item
– Instantiate SequenceOf component type or return existing component valueExamples
# can also be SetOf class MySequenceOf(SequenceOf): componentType = OctetString() s = MySequenceOf() # returns component #0 with `.isValue` property False s.getComponentByPosition(0) # returns None s.getComponentByPosition(0, default=None) s.clear() # returns noValue s.getComponentByPosition(0, instantiate=False) # sets component #0 to OctetString() ASN.1 schema # object and returns it s.getComponentByPosition(0, instantiate=True) # sets component #0 to ASN.1 value object s.setComponentByPosition(0, 'ABCD') # returns OctetString('ABCD') value object s.getComponentByPosition(0, instantiate=False) s.clear() # returns noValue s.getComponentByPosition(0, instantiate=False)
- default (
-
isSameTypeWith
(other, matchTags=True, matchConstraints=True)¶ Examine SequenceOf 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 SequenceOf type,False
otherwise.
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isSuperTypeOf
(other, matchTags=True, matchConstraints=True)¶ Examine SequenceOf 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 SequenceOf type,False
otherwise.
-
isValue
¶ Indicate that SequenceOf 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).
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setComponentByPosition
(idx, value=<NoValue object at 140520848870480>, verifyConstraints=True, matchTags=True, matchConstraints=True)¶ Assign SequenceOf type component by position.
Equivalent to Python sequence item assignment operation (e.g. []) or list.append() (when idx == len(self)).
Parameters: idx (
int
) – Component index (zero-based). Must either refer to existing component or to N+1 component. In the latter case a new component type gets instantiated (if componentType is set, or given ASN.1 object is taken otherwise) and appended to the SequenceOf sequence.Keyword Arguments: - value (
object
orPyAsn1Item
derivative) – A Python value to initialize SequenceOf component with (if componentType is set) or ASN.1 value object to assign to SequenceOf component. - verifyConstraints (
bool
) – If False, skip constraints validation - matchTags (
bool
) – If False, skip component tags matching - matchConstraints (
bool
) – If False, skip component constraints matching
Returns: self
Raises: IndexError: – When idx > len(self)
- value (
- componentType (