forked from s434596/CatOrNot
297 lines
8.7 KiB
Python
297 lines
8.7 KiB
Python
#
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# This file is part of pyasn1 software.
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#
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# Copyright (c) 2005-2018, Ilya Etingof <etingof@gmail.com>
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# License: http://snmplabs.com/pyasn1/license.html
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#
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from pyasn1 import error
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from pyasn1.codec.ber import encoder
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from pyasn1.compat.octets import str2octs, null
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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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class BooleanEncoder(encoder.IntegerEncoder):
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def encodeValue(self, value, asn1Spec, encodeFun, **options):
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if value == 0:
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substrate = (0,)
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else:
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substrate = (255,)
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return substrate, False, False
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class RealEncoder(encoder.RealEncoder):
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def _chooseEncBase(self, value):
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m, b, e = value
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return self._dropFloatingPoint(m, b, e)
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# specialized GeneralStringEncoder here
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class TimeEncoderMixIn(object):
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zchar, = str2octs('Z')
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pluschar, = str2octs('+')
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minuschar, = str2octs('-')
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commachar, = str2octs(',')
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minLength = 12
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maxLength = 19
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def encodeValue(self, value, asn1Spec, encodeFun, **options):
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# Encoding constraints:
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# - minutes are mandatory, seconds are optional
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# - subseconds must NOT be zero
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# - no hanging fraction dot
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# - time in UTC (Z)
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# - only dot is allowed for fractions
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if asn1Spec is not None:
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value = asn1Spec.clone(value)
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octets = value.asOctets()
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if not self.minLength < len(octets) < self.maxLength:
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raise error.PyAsn1Error('Length constraint violated: %r' % value)
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if self.pluschar in octets or self.minuschar in octets:
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raise error.PyAsn1Error('Must be UTC time: %r' % octets)
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if octets[-1] != self.zchar:
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raise error.PyAsn1Error('Missing "Z" time zone specifier: %r' % octets)
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if self.commachar in octets:
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raise error.PyAsn1Error('Comma in fractions disallowed: %r' % value)
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options.update(maxChunkSize=1000)
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return encoder.OctetStringEncoder.encodeValue(
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self, value, asn1Spec, encodeFun, **options
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)
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class GeneralizedTimeEncoder(TimeEncoderMixIn, encoder.OctetStringEncoder):
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minLength = 12
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maxLength = 19
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class UTCTimeEncoder(TimeEncoderMixIn, encoder.OctetStringEncoder):
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minLength = 10
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maxLength = 14
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class SetEncoder(encoder.SequenceEncoder):
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@staticmethod
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def _componentSortKey(componentAndType):
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"""Sort SET components by tag
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Sort regardless of the Choice value (static sort)
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"""
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component, asn1Spec = componentAndType
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if asn1Spec is None:
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asn1Spec = component
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if asn1Spec.typeId == univ.Choice.typeId and not asn1Spec.tagSet:
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if asn1Spec.tagSet:
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return asn1Spec.tagSet
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else:
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return asn1Spec.componentType.minTagSet
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else:
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return asn1Spec.tagSet
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def encodeValue(self, value, asn1Spec, encodeFun, **options):
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substrate = null
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comps = []
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compsMap = {}
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if asn1Spec is None:
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# instance of ASN.1 schema
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value.verifySizeSpec()
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namedTypes = value.componentType
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for idx, component in enumerate(value.values()):
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if namedTypes:
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namedType = namedTypes[idx]
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if namedType.isOptional and not component.isValue:
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continue
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if namedType.isDefaulted and component == namedType.asn1Object:
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continue
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compsMap[id(component)] = namedType
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else:
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compsMap[id(component)] = None
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comps.append((component, asn1Spec))
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else:
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# bare Python value + ASN.1 schema
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for idx, namedType in enumerate(asn1Spec.componentType.namedTypes):
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try:
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component = value[namedType.name]
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except KeyError:
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raise error.PyAsn1Error('Component name "%s" not found in %r' % (namedType.name, value))
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if namedType.isOptional and namedType.name not in value:
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continue
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if namedType.isDefaulted and component == namedType.asn1Object:
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continue
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compsMap[id(component)] = namedType
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comps.append((component, asn1Spec[idx]))
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for comp, compType in sorted(comps, key=self._componentSortKey):
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namedType = compsMap[id(comp)]
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if namedType:
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options.update(ifNotEmpty=namedType.isOptional)
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chunk = encodeFun(comp, compType, **options)
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# wrap open type blob if needed
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if namedType and namedType.openType:
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wrapType = namedType.asn1Object
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if wrapType.tagSet and not wrapType.isSameTypeWith(comp):
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chunk = encodeFun(chunk, wrapType, **options)
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substrate += chunk
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return substrate, True, True
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class SetOfEncoder(encoder.SequenceOfEncoder):
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def encodeValue(self, value, asn1Spec, encodeFun, **options):
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if asn1Spec is None:
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value.verifySizeSpec()
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else:
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asn1Spec = asn1Spec.componentType
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components = [encodeFun(x, asn1Spec, **options)
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for x in value]
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# sort by serialised and padded components
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if len(components) > 1:
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zero = str2octs('\x00')
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maxLen = max(map(len, components))
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paddedComponents = [
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(x.ljust(maxLen, zero), x) for x in components
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]
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paddedComponents.sort(key=lambda x: x[0])
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components = [x[1] for x in paddedComponents]
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substrate = null.join(components)
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return substrate, True, True
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class SequenceEncoder(encoder.SequenceEncoder):
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omitEmptyOptionals = True
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class SequenceOfEncoder(encoder.SequenceOfEncoder):
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def encodeValue(self, value, asn1Spec, encodeFun, **options):
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if options.get('ifNotEmpty', False) and not len(value):
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return null, True, True
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if asn1Spec is None:
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value.verifySizeSpec()
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else:
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asn1Spec = asn1Spec.componentType
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substrate = null
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for idx, component in enumerate(value):
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substrate += encodeFun(value[idx], asn1Spec, **options)
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return substrate, True, True
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tagMap = encoder.tagMap.copy()
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tagMap.update({
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univ.Boolean.tagSet: BooleanEncoder(),
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univ.Real.tagSet: RealEncoder(),
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useful.GeneralizedTime.tagSet: GeneralizedTimeEncoder(),
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useful.UTCTime.tagSet: UTCTimeEncoder(),
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# Sequence & Set have same tags as SequenceOf & SetOf
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univ.SetOf.tagSet: SetOfEncoder(),
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univ.Sequence.typeId: SequenceEncoder()
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})
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typeMap = encoder.typeMap.copy()
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typeMap.update({
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univ.Boolean.typeId: BooleanEncoder(),
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univ.Real.typeId: RealEncoder(),
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useful.GeneralizedTime.typeId: GeneralizedTimeEncoder(),
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useful.UTCTime.typeId: UTCTimeEncoder(),
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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: SetOfEncoder(),
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univ.Sequence.typeId: SequenceEncoder(),
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univ.SequenceOf.typeId: SequenceOfEncoder()
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})
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class Encoder(encoder.Encoder):
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fixedDefLengthMode = False
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fixedChunkSize = 1000
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#: Turns ASN.1 object into CER octet stream.
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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 CER octet stream.
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#:
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#: Parameters
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#: ----------
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#: value: either a Python or pyasn1 object (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative)
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#: A Python or pyasn1 object to encode. If Python object is given, `asnSpec`
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#: parameter is required to guide the encoding process.
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#:
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#: Keyword Args
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#: ------------
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#: asn1Spec:
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#: Optional ASN.1 schema or value object e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative
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#:
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#: Returns
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#: -------
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#: : :py:class:`bytes` (Python 3) or :py:class:`str` (Python 2)
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#: Given ASN.1 object encoded into BER octet-stream
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#:
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#: Raises
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#: ------
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#: :py:class:`~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 Python value into CER with ASN.1 schema
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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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#: >>> encode([1, 2, 3], asn1Spec=seq)
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#: b'0\x80\x02\x01\x01\x02\x01\x02\x02\x01\x03\x00\x00'
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#:
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#: Encode ASN.1 value object into CER
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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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#: b'0\x80\x02\x01\x01\x02\x01\x02\x02\x01\x03\x00\x00'
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#:
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encode = Encoder(tagMap, typeMap)
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# EncoderFactory queries class instance and builds a map of tags -> encoders
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