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Diffstat (limited to '.venv/lib/python3.12/site-packages/pyasn1/codec/cer/decoder.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/pyasn1/codec/cer/decoder.py | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/pyasn1/codec/cer/decoder.py b/.venv/lib/python3.12/site-packages/pyasn1/codec/cer/decoder.py new file mode 100644 index 00000000..d6890f01 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/pyasn1/codec/cer/decoder.py @@ -0,0 +1,149 @@ +# +# This file is part of pyasn1 software. +# +# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com> +# License: https://pyasn1.readthedocs.io/en/latest/license.html +# +import warnings + +from pyasn1 import error +from pyasn1.codec.streaming import readFromStream +from pyasn1.codec.ber import decoder +from pyasn1.type import univ + +__all__ = ['decode', 'StreamingDecoder'] + +SubstrateUnderrunError = error.SubstrateUnderrunError + + +class BooleanPayloadDecoder(decoder.AbstractSimplePayloadDecoder): + protoComponent = univ.Boolean(0) + + def valueDecoder(self, substrate, asn1Spec, + tagSet=None, length=None, state=None, + decodeFun=None, substrateFun=None, + **options): + + if length != 1: + raise error.PyAsn1Error('Not single-octet Boolean payload') + + for chunk in readFromStream(substrate, length, options): + if isinstance(chunk, SubstrateUnderrunError): + yield chunk + + byte = chunk[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 https://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) + + yield self._createComponent(asn1Spec, tagSet, value, **options) + + +# TODO: prohibit non-canonical encoding +BitStringPayloadDecoder = decoder.BitStringPayloadDecoder +OctetStringPayloadDecoder = decoder.OctetStringPayloadDecoder +RealPayloadDecoder = decoder.RealPayloadDecoder + +TAG_MAP = decoder.TAG_MAP.copy() +TAG_MAP.update( + {univ.Boolean.tagSet: BooleanPayloadDecoder(), + univ.BitString.tagSet: BitStringPayloadDecoder(), + univ.OctetString.tagSet: OctetStringPayloadDecoder(), + univ.Real.tagSet: RealPayloadDecoder()} +) + +TYPE_MAP = decoder.TYPE_MAP.copy() + +# Put in non-ambiguous types for faster codec lookup +for typeDecoder in TAG_MAP.values(): + if typeDecoder.protoComponent is not None: + typeId = typeDecoder.protoComponent.__class__.typeId + if typeId is not None and typeId not in TYPE_MAP: + TYPE_MAP[typeId] = typeDecoder + + +class SingleItemDecoder(decoder.SingleItemDecoder): + __doc__ = decoder.SingleItemDecoder.__doc__ + + TAG_MAP = TAG_MAP + TYPE_MAP = TYPE_MAP + + +class StreamingDecoder(decoder.StreamingDecoder): + __doc__ = decoder.StreamingDecoder.__doc__ + + SINGLE_ITEM_DECODER = SingleItemDecoder + + +class Decoder(decoder.Decoder): + __doc__ = decoder.Decoder.__doc__ + + STREAMING_DECODER = StreamingDecoder + + +#: Turns CER octet stream into an ASN.1 object. +#: +#: Takes CER octet-stream 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` +#: CER octet-stream +#: +#: Keyword Args +#: ------------ +#: 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 +#: ------ +#: ~pyasn1.error.PyAsn1Error, ~pyasn1.error.SubstrateUnderrunError +#: On decoding errors +#: +#: Examples +#: -------- +#: Decode CER serialisation without ASN.1 schema +#: +#: .. code-block:: pycon +#: +#: >>> s, _ = decode(b'0\x80\x02\x01\x01\x02\x01\x02\x02\x01\x03\x00\x00') +#: >>> str(s) +#: SequenceOf: +#: 1 2 3 +#: +#: Decode CER serialisation with ASN.1 schema +#: +#: .. code-block:: pycon +#: +#: >>> seq = SequenceOf(componentType=Integer()) +#: >>> s, _ = decode(b'0\x80\x02\x01\x01\x02\x01\x02\x02\x01\x03\x00\x00', asn1Spec=seq) +#: >>> str(s) +#: SequenceOf: +#: 1 2 3 +#: +decode = Decoder() + +def __getattr__(attr: str): + if newAttr := {"tagMap": "TAG_MAP", "typeMap": "TYPE_MAP"}.get(attr): + warnings.warn(f"{attr} is deprecated. Please use {newAttr} instead.", DeprecationWarning) + return globals()[newAttr] + raise AttributeError(attr) |