Method __call__

pager_lib/pyasn1/codec/ber/decoder.py:2015–2133

Turns BER/CER/DER octet stream into an ASN.1 object. Takes BER/CER/DER octet-stream in form of :py:class:`bytes` 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.

(cls, substrate, asn1Spec=None, **options)

    @classmethod
    def __call__(cls, substrate, asn1Spec=None, **options):
        """Turns BER/CER/DER octet stream into an ASN.1 object.

        Takes BER/CER/DER octet-stream in form of :py:class:`bytes`
        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`
            BER/CER/DER octet-stream to parse

        Keyword Args
        ------------
        asn1Spec: :py:class:`~pyasn1.type.base.PyAsn1Item`
            A pyasn1 type object (:py:class:`~pyasn1.type.base.PyAsn1Item`
            derivative) 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.

        substrateFun: :py:class:`Union[
                Callable[[pyasn1.type.base.PyAsn1Item, bytes, int],
                         Tuple[pyasn1.type.base.PyAsn1Item, bytes]],
                Callable[[pyasn1.type.base.PyAsn1Item, io.BytesIO, int, dict],
                         Generator[Union[pyasn1.type.base.PyAsn1Item,
                                         pyasn1.error.SubstrateUnderrunError],
                                   None, None]]
            ]`
            User callback meant to generalize special use cases like non-recursive or
            partial decoding. A 3-arg non-streaming variant is supported for backwards
            compatiblilty in addition to the newer 4-arg streaming variant.
            The callback will receive the uninitialized object recovered from substrate
            as 1st argument, the uninterpreted payload as 2nd argument, and the length
            of the uninterpreted payload as 3rd argument. The streaming variant will
            additionally receive the decode(..., **options) kwargs as 4th argument.
            The non-streaming variant shall return an object that will be propagated
            as decode() return value as 1st item, and the remainig payload for further
            decode passes as 2nd item.
            The streaming variant shall yield an object that will be propagated as
            decode() return value, and leave the remaining payload in the stream.

        Returns
        -------
        : :py:class:`tuple`
            A tuple of :py:class:`~pyasn1.type.base.PyAsn1Item` object
            recovered from BER/CER/DER substrate and the unprocessed trailing
            portion of the `substrate` (may be empty)

        Raises
        ------
        : :py:class:`~pyasn1.error.PyAsn1Error`
            :py:class:`~pyasn1.error.SubstrateUnderrunError` on insufficient
            input or :py:class:`~pyasn1.error.PyAsn1Error` on decoding error.

        Examples
        --------