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Current Path : /proc/thread-self/root/lib/python3.6/site-packages/pyasn1/codec/cer/ |
Current File : //proc/thread-self/root/lib/python3.6/site-packages/pyasn1/codec/cer/decoder.py |
# # This file is part of pyasn1 software. # # Copyright (c) 2005-2017, Ilya Etingof <etingof@gmail.com> # License: http://pyasn1.sf.net/license.html # from pyasn1.type import univ from pyasn1.codec.ber import decoder from pyasn1.compat.octets import oct2int from pyasn1 import error __all__ = ['decode'] class BooleanDecoder(decoder.AbstractSimpleDecoder): protoComponent = univ.Boolean(0) def valueDecoder(self, substrate, asn1Spec, tagSet=None, length=None, state=None, decodeFun=None, substrateFun=None, **options): head, tail = substrate[:length], substrate[length:] if not head or length != 1: raise error.PyAsn1Error('Not single-octet Boolean payload') byte = oct2int(head[0]) # CER/DER specifies encoding of TRUE as 0xFF and FALSE as 0x0, while # BER allows any non-zero value as TRUE; cf. sections 8.2.2. and 11.1 # in http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf if byte == 0xff: value = 1 elif byte == 0x00: value = 0 else: raise error.PyAsn1Error('Unexpected Boolean payload: %s' % byte) return self._createComponent(asn1Spec, tagSet, value), tail # TODO: prohibit non-canonical encoding BitStringDecoder = decoder.BitStringDecoder OctetStringDecoder = decoder.OctetStringDecoder RealDecoder = decoder.RealDecoder tagMap = decoder.tagMap.copy() tagMap.update( {univ.Boolean.tagSet: BooleanDecoder(), univ.BitString.tagSet: BitStringDecoder(), univ.OctetString.tagSet: OctetStringDecoder(), univ.Real.tagSet: RealDecoder()} ) typeMap = decoder.typeMap.copy() # Put in non-ambiguous types for faster codec lookup for typeDecoder in tagMap.values(): if typeDecoder.protoComponent is not None: typeId = typeDecoder.protoComponent.__class__.typeId if typeId is not None and typeId not in typeMap: typeMap[typeId] = typeDecoder class Decoder(decoder.Decoder): pass #: Turns CER octet stream into an ASN.1 object. #: #: Takes CER octetstream and decode it into an ASN.1 object #: (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative) which #: may be a scalar or an arbitrary nested structure. #: #: Parameters #: ---------- #: substrate: :py:class:`bytes` (Python 3) or :py:class:`str` (Python 2) #: CER octetstream #: #: asn1Spec: any pyasn1 type object e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative #: A pyasn1 type object to act as a template guiding the decoder. Depending on the ASN.1 structure #: being decoded, *asn1Spec* may or may not be required. Most common reason for #: it to require is that ASN.1 structure is encoded in *IMPLICIT* tagging mode. #: #: Returns #: ------- #: : :py:class:`tuple` #: A tuple of pyasn1 object recovered from CER substrate (:py:class:`~pyasn1.type.base.PyAsn1Item` derivative) #: and the unprocessed trailing portion of the *substrate* (may be empty) #: #: Raises #: ------ #: : :py:class:`pyasn1.error.PyAsn1Error` #: On decoding errors decode = Decoder(tagMap, decoder.typeMap)