univ.py 文件源码

def subtype(self, value=noValue, implicitTag=None, explicitTag=None,
                subtypeSpec=None, namedValues=None):
        """Create a copy of a |ASN.1| type or object.

        Any parameters to the *subtype()* method will be added to the corresponding
        properties of the |ASN.1| object.

        Parameters
        ----------
        value: :class:`int`, :class:`str` or |ASN.1| object
            Initialization value to pass to new ASN.1 object instead of 
            inheriting one from the caller.

        implicitTag: :py:class:`~pyasn1.type.tag.Tag`
            Implicitly apply given ASN.1 tag object to caller's 
            :py:class:`~pyasn1.type.tag.TagSet`, then use the result as
            new object's ASN.1 tag(s).

        explicitTag: :py:class:`~pyasn1.type.tag.Tag`
            Explicitly apply given ASN.1 tag object to caller's 
            :py:class:`~pyasn1.type.tag.TagSet`, then use the result as
            new object's ASN.1 tag(s).

        subtypeSpec: :py:class:`~pyasn1.type.constraint.ConstraintsIntersection`
            Add ASN.1 constraints object to one of the caller, then
            use the result as new object's ASN.1 constraints.

        namedValues: :py:class:`~pyasn1.type.namedval.NamedValues`
            Add given object representing symbolic aliases for numbers
            to one of the caller, then use the result as new object's
            named numbers.

        Returns
        -------
        :
            new instance of |ASN.1| type/value
        """
        if self.isNoValue(value):
            value = self._value
        if implicitTag is not None:
            tagSet = self._tagSet.tagImplicitly(implicitTag)
        elif explicitTag is not None:
            tagSet = self._tagSet.tagExplicitly(explicitTag)
        else:
            tagSet = self._tagSet
        if subtypeSpec is None:
            subtypeSpec = self._subtypeSpec
        else:
            subtypeSpec = self._subtypeSpec + subtypeSpec
        if namedValues is None:
            namedValues = self.__namedValues
        else:
            namedValues = namedValues + self.__namedValues
        return self.__class__(value, tagSet, subtypeSpec, namedValues)