256 lines
7.8 KiB
Python
256 lines
7.8 KiB
Python
#
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# This file is part of pyasn1 software.
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#
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# Copyright (c) 2005-2019, Ilya Etingof <etingof@gmail.com>
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# License: http://snmplabs.com/pyasn1/license.html
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#
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try:
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from collections import OrderedDict
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except ImportError:
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OrderedDict = dict
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from pyasn1 import debug
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from pyasn1 import error
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from pyasn1.type import base
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from pyasn1.type import char
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from pyasn1.type import tag
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from pyasn1.type import univ
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from pyasn1.type import useful
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__all__ = ['encode']
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LOG = debug.registerLoggee(__name__, flags=debug.DEBUG_ENCODER)
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class AbstractItemEncoder(object):
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def encode(self, value, encodeFun, **options):
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raise error.PyAsn1Error('Not implemented')
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class BooleanEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return bool(value)
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class IntegerEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return int(value)
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class BitStringEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return str(value)
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class OctetStringEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return value.asOctets()
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class TextStringEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return str(value)
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class NullEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return None
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class ObjectIdentifierEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return str(value)
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class RealEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return float(value)
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class SetEncoder(AbstractItemEncoder):
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protoDict = dict
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def encode(self, value, encodeFun, **options):
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inconsistency = value.isInconsistent
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if inconsistency:
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raise inconsistency
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namedTypes = value.componentType
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substrate = self.protoDict()
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for idx, (key, subValue) in enumerate(value.items()):
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if namedTypes and namedTypes[idx].isOptional and not value[idx].isValue:
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continue
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substrate[key] = encodeFun(subValue, **options)
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return substrate
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class SequenceEncoder(SetEncoder):
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protoDict = OrderedDict
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class SequenceOfEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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inconsistency = value.isInconsistent
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if inconsistency:
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raise inconsistency
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return [encodeFun(x, **options) for x in value]
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class ChoiceEncoder(SequenceEncoder):
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pass
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class AnyEncoder(AbstractItemEncoder):
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def encode(self, value, encodeFun, **options):
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return value.asOctets()
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tagMap = {
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univ.Boolean.tagSet: BooleanEncoder(),
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univ.Integer.tagSet: IntegerEncoder(),
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univ.BitString.tagSet: BitStringEncoder(),
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univ.OctetString.tagSet: OctetStringEncoder(),
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univ.Null.tagSet: NullEncoder(),
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univ.ObjectIdentifier.tagSet: ObjectIdentifierEncoder(),
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univ.Enumerated.tagSet: IntegerEncoder(),
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univ.Real.tagSet: RealEncoder(),
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# Sequence & Set have same tags as SequenceOf & SetOf
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univ.SequenceOf.tagSet: SequenceOfEncoder(),
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univ.SetOf.tagSet: SequenceOfEncoder(),
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univ.Choice.tagSet: ChoiceEncoder(),
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# character string types
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char.UTF8String.tagSet: TextStringEncoder(),
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char.NumericString.tagSet: TextStringEncoder(),
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char.PrintableString.tagSet: TextStringEncoder(),
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char.TeletexString.tagSet: TextStringEncoder(),
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char.VideotexString.tagSet: TextStringEncoder(),
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char.IA5String.tagSet: TextStringEncoder(),
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char.GraphicString.tagSet: TextStringEncoder(),
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char.VisibleString.tagSet: TextStringEncoder(),
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char.GeneralString.tagSet: TextStringEncoder(),
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char.UniversalString.tagSet: TextStringEncoder(),
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char.BMPString.tagSet: TextStringEncoder(),
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# useful types
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useful.ObjectDescriptor.tagSet: OctetStringEncoder(),
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useful.GeneralizedTime.tagSet: OctetStringEncoder(),
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useful.UTCTime.tagSet: OctetStringEncoder()
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}
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# Put in ambiguous & non-ambiguous types for faster codec lookup
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typeMap = {
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univ.Boolean.typeId: BooleanEncoder(),
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univ.Integer.typeId: IntegerEncoder(),
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univ.BitString.typeId: BitStringEncoder(),
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univ.OctetString.typeId: OctetStringEncoder(),
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univ.Null.typeId: NullEncoder(),
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univ.ObjectIdentifier.typeId: ObjectIdentifierEncoder(),
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univ.Enumerated.typeId: IntegerEncoder(),
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univ.Real.typeId: RealEncoder(),
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# Sequence & Set have same tags as SequenceOf & SetOf
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univ.Set.typeId: SetEncoder(),
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univ.SetOf.typeId: SequenceOfEncoder(),
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univ.Sequence.typeId: SequenceEncoder(),
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univ.SequenceOf.typeId: SequenceOfEncoder(),
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univ.Choice.typeId: ChoiceEncoder(),
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univ.Any.typeId: AnyEncoder(),
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# character string types
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char.UTF8String.typeId: OctetStringEncoder(),
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char.NumericString.typeId: OctetStringEncoder(),
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char.PrintableString.typeId: OctetStringEncoder(),
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char.TeletexString.typeId: OctetStringEncoder(),
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char.VideotexString.typeId: OctetStringEncoder(),
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char.IA5String.typeId: OctetStringEncoder(),
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char.GraphicString.typeId: OctetStringEncoder(),
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char.VisibleString.typeId: OctetStringEncoder(),
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char.GeneralString.typeId: OctetStringEncoder(),
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char.UniversalString.typeId: OctetStringEncoder(),
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char.BMPString.typeId: OctetStringEncoder(),
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# useful types
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useful.ObjectDescriptor.typeId: OctetStringEncoder(),
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useful.GeneralizedTime.typeId: OctetStringEncoder(),
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useful.UTCTime.typeId: OctetStringEncoder()
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}
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class Encoder(object):
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# noinspection PyDefaultArgument
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def __init__(self, tagMap, typeMap={}):
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self.__tagMap = tagMap
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self.__typeMap = typeMap
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def __call__(self, value, **options):
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if not isinstance(value, base.Asn1Item):
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raise error.PyAsn1Error('value is not valid (should be an instance of an ASN.1 Item)')
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if LOG:
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debug.scope.push(type(value).__name__)
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LOG('encoder called for type %s <%s>' % (type(value).__name__, value.prettyPrint()))
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tagSet = value.tagSet
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try:
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concreteEncoder = self.__typeMap[value.typeId]
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except KeyError:
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# use base type for codec lookup to recover untagged types
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baseTagSet = tag.TagSet(value.tagSet.baseTag, value.tagSet.baseTag)
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try:
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concreteEncoder = self.__tagMap[baseTagSet]
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except KeyError:
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raise error.PyAsn1Error('No encoder for %s' % (value,))
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if LOG:
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LOG('using value codec %s chosen by %s' % (concreteEncoder.__class__.__name__, tagSet))
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pyObject = concreteEncoder.encode(value, self, **options)
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if LOG:
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LOG('encoder %s produced: %s' % (type(concreteEncoder).__name__, repr(pyObject)))
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debug.scope.pop()
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return pyObject
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#: Turns ASN.1 object into a Python built-in type object(s).
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#:
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#: Takes any ASN.1 object (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative)
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#: walks all its components recursively and produces a Python built-in type or a tree
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#: of those.
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#:
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#: One exception is that instead of :py:class:`dict`, the :py:class:`OrderedDict`
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#: can be produced (whenever available) to preserve ordering of the components
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#: in ASN.1 SEQUENCE.
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#:
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#: Parameters
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#: ----------
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# asn1Value: any pyasn1 object (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative)
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#: pyasn1 object to encode (or a tree of them)
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#:
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#: Returns
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#: -------
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#: : :py:class:`object`
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#: Python built-in type instance (or a tree of them)
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#:
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#: Raises
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#: ------
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#: ~pyasn1.error.PyAsn1Error
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#: On encoding errors
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#:
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#: Examples
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#: --------
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#: Encode ASN.1 value object into native Python types
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#:
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#: .. code-block:: pycon
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#:
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#: >>> seq = SequenceOf(componentType=Integer())
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#: >>> seq.extend([1, 2, 3])
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#: >>> encode(seq)
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#: [1, 2, 3]
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#:
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encode = Encoder(tagMap, typeMap)
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