rimossi cloudscraper, simplejson e torrentool, aggiornato sambatools

lib/pyasn1/type/__init__.py

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+# This file is necessary to make this directory a package.

lib/pyasn1/type/base.py

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+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+import sys
+
+from pyasn1 import error
+from pyasn1.type import constraint
+from pyasn1.type import tag
+from pyasn1.type import tagmap
+
+__all__ = ['Asn1Item', 'Asn1Type', 'SimpleAsn1Type',
+           'ConstructedAsn1Type']
+
+
+class Asn1Item(object):
+    @classmethod
+    def getTypeId(cls, increment=1):
+        try:
+            Asn1Item._typeCounter += increment
+        except AttributeError:
+            Asn1Item._typeCounter = increment
+        return Asn1Item._typeCounter
+
+
+class Asn1Type(Asn1Item):
+    """Base class for all classes representing ASN.1 types.
+
+    In the user code, |ASN.1| class is normally used only for telling
+    ASN.1 objects from others.
+
+    Note
+    ----
+    For as long as ASN.1 is concerned, a way to compare ASN.1 types
+    is to use :meth:`isSameTypeWith` and :meth:`isSuperTypeOf` methods.
+    """
+    #: Set or return a :py:class:`~pyasn1.type.tag.TagSet` object representing
+    #: ASN.1 tag(s) associated with |ASN.1| type.
+    tagSet = tag.TagSet()
+
+    #: Default :py:class:`~pyasn1.type.constraint.ConstraintsIntersection`
+    #: object imposing constraints on initialization values.
+    subtypeSpec = constraint.ConstraintsIntersection()
+
+    # Disambiguation ASN.1 types identification
+    typeId = None
+
+    def __init__(self, **kwargs):
+        readOnly = {
+            'tagSet': self.tagSet,
+            'subtypeSpec': self.subtypeSpec
+        }
+
+        readOnly.update(kwargs)
+
+        self.__dict__.update(readOnly)
+
+        self._readOnly = readOnly
+
+    def __setattr__(self, name, value):
+        if name[0] != '_' and name in self._readOnly:
+            raise error.PyAsn1Error('read-only instance attribute "%s"' % name)
+
+        self.__dict__[name] = value
+
+    def __str__(self):
+        return self.prettyPrint()
+
+    @property
+    def readOnly(self):
+        return self._readOnly
+
+    @property
+    def effectiveTagSet(self):
+        """For |ASN.1| type is equivalent to *tagSet*
+        """
+        return self.tagSet  # used by untagged types
+
+    @property
+    def tagMap(self):
+        """Return a :class:`~pyasn1.type.tagmap.TagMap` object mapping ASN.1 tags to ASN.1 objects within callee object.
+        """
+        return tagmap.TagMap({self.tagSet: self})
+
+    def isSameTypeWith(self, other, matchTags=True, matchConstraints=True):
+        """Examine |ASN.1| type for equality with other ASN.1 type.
+
+        ASN.1 tags (:py:mod:`~pyasn1.type.tag`) and constraints
+        (:py:mod:`~pyasn1.type.constraint`) are examined when carrying
+        out ASN.1 types comparison.
+
+        Python class inheritance relationship is NOT considered.
+
+        Parameters
+        ----------
+        other: a pyasn1 type object
+            Class instance representing ASN.1 type.
+
+        Returns
+        -------
+        : :class:`bool`
+            :obj:`True` if *other* is |ASN.1| type,
+            :obj:`False` otherwise.
+        """
+        return (self is other or
+                (not matchTags or self.tagSet == other.tagSet) and
+                (not matchConstraints or self.subtypeSpec == other.subtypeSpec))
+
+    def isSuperTypeOf(self, other, matchTags=True, matchConstraints=True):
+        """Examine |ASN.1| type for subtype relationship with other ASN.1 type.
+
+        ASN.1 tags (:py:mod:`~pyasn1.type.tag`) and constraints
+        (:py:mod:`~pyasn1.type.constraint`) are examined when carrying
+        out ASN.1 types comparison.
+
+        Python class inheritance relationship is NOT considered.
+
+        Parameters
+        ----------
+            other: a pyasn1 type object
+                Class instance representing ASN.1 type.
+
+        Returns
+        -------
+            : :class:`bool`
+                :obj:`True` if *other* is a subtype of |ASN.1| type,
+                :obj:`False` otherwise.
+        """
+        return (not matchTags or
+                (self.tagSet.isSuperTagSetOf(other.tagSet)) and
+                 (not matchConstraints or self.subtypeSpec.isSuperTypeOf(other.subtypeSpec)))
+
+    @staticmethod
+    def isNoValue(*values):
+        for value in values:
+            if value is not noValue:
+                return False
+        return True
+
+    def prettyPrint(self, scope=0):
+        raise NotImplementedError()
+
+    # backward compatibility
+
+    def getTagSet(self):
+        return self.tagSet
+
+    def getEffectiveTagSet(self):
+        return self.effectiveTagSet
+
+    def getTagMap(self):
+        return self.tagMap
+
+    def getSubtypeSpec(self):
+        return self.subtypeSpec
+
+    # backward compatibility
+    def hasValue(self):
+        return self.isValue
+
+# Backward compatibility
+Asn1ItemBase = Asn1Type
+
+
+class NoValue(object):
+    """Create a singleton instance of NoValue class.
+
+    The *NoValue* sentinel object represents an instance of ASN.1 schema
+    object as opposed to ASN.1 value object.
+
+    Only ASN.1 schema-related operations can be performed on ASN.1
+    schema objects.
+
+    Warning
+    -------
+    Any operation attempted on the *noValue* object will raise the
+    *PyAsn1Error* exception.
+    """
+    skipMethods = {
+        '__slots__',
+        # attributes
+        '__getattribute__',
+        '__getattr__',
+        '__setattr__',
+        '__delattr__',
+        # class instance
+        '__class__',
+        '__init__',
+        '__del__',
+        '__new__',
+        '__repr__',
+        '__qualname__',
+        '__objclass__',
+        'im_class',
+        '__sizeof__',
+        # pickle protocol
+        '__reduce__',
+        '__reduce_ex__',
+        '__getnewargs__',
+        '__getinitargs__',
+        '__getstate__',
+        '__setstate__',
+    }
+
+    _instance = None
+
+    def __new__(cls):
+        if cls._instance is None:
+            def getPlug(name):
+                def plug(self, *args, **kw):
+                    raise error.PyAsn1Error('Attempted "%s" operation on ASN.1 schema object' % name)
+                return plug
+
+            op_names = [name
+                        for typ in (str, int, list, dict)
+                        for name in dir(typ)
+                        if (name not in cls.skipMethods and
+                            name.startswith('__') and
+                            name.endswith('__') and
+                            callable(getattr(typ, name)))]
+
+            for name in set(op_names):
+                setattr(cls, name, getPlug(name))
+
+            cls._instance = object.__new__(cls)
+
+        return cls._instance
+
+    def __getattr__(self, attr):
+        if attr in self.skipMethods:
+            raise AttributeError('Attribute %s not present' % attr)
+
+        raise error.PyAsn1Error('Attempted "%s" operation on ASN.1 schema object' % attr)
+
+    def __repr__(self):
+        return '<%s object>' % self.__class__.__name__
+
+
+noValue = NoValue()
+
+
+class SimpleAsn1Type(Asn1Type):
+    """Base class for all simple classes representing ASN.1 types.
+
+    ASN.1 distinguishes types by their ability to hold other objects.
+    Scalar types are known as *simple* in ASN.1.
+
+    In the user code, |ASN.1| class is normally used only for telling
+    ASN.1 objects from others.
+
+    Note
+    ----
+    For as long as ASN.1 is concerned, a way to compare ASN.1 types
+    is to use :meth:`isSameTypeWith` and :meth:`isSuperTypeOf` methods.
+    """
+    #: Default payload value
+    defaultValue = noValue
+
+    def __init__(self, value=noValue, **kwargs):
+        Asn1Type.__init__(self, **kwargs)
+        if value is noValue:
+            value = self.defaultValue
+        else:
+            value = self.prettyIn(value)
+            try:
+                self.subtypeSpec(value)
+
+            except error.PyAsn1Error:
+                exType, exValue, exTb = sys.exc_info()
+                raise exType('%s at %s' % (exValue, self.__class__.__name__))
+
+        self._value = value
+
+    def __repr__(self):
+        representation = '%s %s object' % (
+            self.__class__.__name__, self.isValue and 'value' or 'schema')
+
+        for attr, value in self.readOnly.items():
+            if value:
+                representation += ', %s %s' % (attr, value)
+
+        if self.isValue:
+            value = self.prettyPrint()
+            if len(value) > 32:
+                value = value[:16] + '...' + value[-16:]
+            representation += ', payload [%s]' % value
+
+        return '<%s>' % representation
+
+    def __eq__(self, other):
+        return self is other and True or self._value == other
+
+    def __ne__(self, other):
+        return self._value != other
+
+    def __lt__(self, other):
+        return self._value < other
+
+    def __le__(self, other):
+        return self._value <= other
+
+    def __gt__(self, other):
+        return self._value > other
+
+    def __ge__(self, other):
+        return self._value >= other
+
+    if sys.version_info[0] <= 2:
+        def __nonzero__(self):
+            return self._value and True or False
+    else:
+        def __bool__(self):
+            return self._value and True or False
+
+    def __hash__(self):
+        return hash(self._value)
+
+    @property
+    def isValue(self):
+        """Indicate that |ASN.1| object represents ASN.1 value.
+
+        If *isValue* is :obj:`False` then this object represents just
+        ASN.1 schema.
+
+        If *isValue* is :obj:`True` then, in addition to its ASN.1 schema
+        features, this object can also be used like a Python built-in object
+        (e.g. :class:`int`, :class:`str`, :class:`dict` etc.).
+
+        Returns
+        -------
+        : :class:`bool`
+            :obj:`False` if object represents just ASN.1 schema.
+            :obj:`True` if object represents ASN.1 schema and can be used as a normal value.
+
+        Note
+        ----
+        There is an important distinction between PyASN1 schema and value objects.
+        The PyASN1 schema objects can only participate in ASN.1 schema-related
+        operations (e.g. defining or testing the structure of the data). Most
+        obvious uses of ASN.1 schema is to guide serialisation codecs whilst
+        encoding/decoding serialised ASN.1 contents.
+
+        The PyASN1 value objects can **additionally** participate in many operations
+        involving regular Python objects (e.g. arithmetic, comprehension etc).
+        """
+        return self._value is not noValue
+
+    def clone(self, value=noValue, **kwargs):
+        """Create a modified version of |ASN.1| schema or value object.
+
+        The `clone()` method accepts the same set arguments as |ASN.1|
+        class takes on instantiation except that all arguments
+        of the `clone()` method are optional.
+
+        Whatever arguments are supplied, they are used to create a copy
+        of `self` taking precedence over the ones used to instantiate `self`.
+
+        Note
+        ----
+        Due to the immutable nature of the |ASN.1| object, if no arguments
+        are supplied, no new |ASN.1| object will be created and `self` will
+        be returned instead.
+        """
+        if value is noValue:
+            if not kwargs:
+                return self
+
+            value = self._value
+
+        initializers = self.readOnly.copy()
+        initializers.update(kwargs)
+
+        return self.__class__(value, **initializers)
+
+    def subtype(self, value=noValue, **kwargs):
+        """Create a specialization of |ASN.1| schema or value object.
+
+        The subtype relationship between ASN.1 types has no correlation with
+        subtype relationship between Python types. ASN.1 type is mainly identified
+        by its tag(s) (:py:class:`~pyasn1.type.tag.TagSet`) and value range
+        constraints (:py:class:`~pyasn1.type.constraint.ConstraintsIntersection`).
+        These ASN.1 type properties are implemented as |ASN.1| attributes.  
+
+        The `subtype()` method accepts the same set arguments as |ASN.1|
+        class takes on instantiation except that all parameters
+        of the `subtype()` method are optional.
+
+        With the exception of the arguments described below, the rest of
+        supplied arguments they are used to create a copy of `self` taking
+        precedence over the ones used to instantiate `self`.
+
+        The following arguments to `subtype()` create a ASN.1 subtype out of
+        |ASN.1| type:
+
+        Other Parameters
+        ----------------
+        implicitTag: :py:class:`~pyasn1.type.tag.Tag`
+            Implicitly apply given ASN.1 tag object to `self`'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 `self`'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 `self`'s, then
+            use the result as new object's ASN.1 constraints.
+
+        Returns
+        -------
+        :
+            new instance of |ASN.1| schema or value object
+
+        Note
+        ----
+        Due to the immutable nature of the |ASN.1| object, if no arguments
+        are supplied, no new |ASN.1| object will be created and `self` will
+        be returned instead.
+        """
+        if value is noValue:
+            if not kwargs:
+                return self
+
+            value = self._value
+
+        initializers = self.readOnly.copy()
+
+        implicitTag = kwargs.pop('implicitTag', None)
+        if implicitTag is not None:
+            initializers['tagSet'] = self.tagSet.tagImplicitly(implicitTag)
+
+        explicitTag = kwargs.pop('explicitTag', None)
+        if explicitTag is not None:
+            initializers['tagSet'] = self.tagSet.tagExplicitly(explicitTag)
+
+        for arg, option in kwargs.items():
+            initializers[arg] += option
+
+        return self.__class__(value, **initializers)
+
+    def prettyIn(self, value):
+        return value
+
+    def prettyOut(self, value):
+        return str(value)
+
+    def prettyPrint(self, scope=0):
+        return self.prettyOut(self._value)
+
+    def prettyPrintType(self, scope=0):
+        return '%s -> %s' % (self.tagSet, self.__class__.__name__)
+
+# Backward compatibility
+AbstractSimpleAsn1Item = SimpleAsn1Type
+
+#
+# Constructed types:
+# * There are five of them: Sequence, SequenceOf/SetOf, Set and Choice
+# * ASN1 types and values are represened by Python class instances
+# * Value initialization is made for defaulted components only
+# * Primary method of component addressing is by-position. Data model for base
+#   type is Python sequence. Additional type-specific addressing methods
+#   may be implemented for particular types.
+# * SequenceOf and SetOf types do not implement any additional methods
+# * Sequence, Set and Choice types also implement by-identifier addressing
+# * Sequence, Set and Choice types also implement by-asn1-type (tag) addressing
+# * Sequence and Set types may include optional and defaulted
+#   components
+# * Constructed types hold a reference to component types used for value
+#   verification and ordering.
+# * Component type is a scalar type for SequenceOf/SetOf types and a list
+#   of types for Sequence/Set/Choice.
+#
+
+
+class ConstructedAsn1Type(Asn1Type):
+    """Base class for all constructed classes representing ASN.1 types.
+
+    ASN.1 distinguishes types by their ability to hold other objects.
+    Those "nesting" types are known as *constructed* in ASN.1.
+
+    In the user code, |ASN.1| class is normally used only for telling
+    ASN.1 objects from others.
+
+    Note
+    ----
+    For as long as ASN.1 is concerned, a way to compare ASN.1 types
+    is to use :meth:`isSameTypeWith` and :meth:`isSuperTypeOf` methods.
+    """
+
+    #: If :obj:`True`, requires exact component type matching,
+    #: otherwise subtype relation is only enforced
+    strictConstraints = False
+
+    componentType = None
+
+    # backward compatibility, unused
+    sizeSpec = constraint.ConstraintsIntersection()
+
+    def __init__(self, **kwargs):
+        readOnly = {
+            'componentType': self.componentType,
+            # backward compatibility, unused
+            'sizeSpec': self.sizeSpec
+        }
+
+        # backward compatibility: preserve legacy sizeSpec support
+        kwargs = self._moveSizeSpec(**kwargs)
+
+        readOnly.update(kwargs)
+
+        Asn1Type.__init__(self, **readOnly)
+
+    def _moveSizeSpec(self, **kwargs):
+        # backward compatibility, unused
+        sizeSpec = kwargs.pop('sizeSpec', self.sizeSpec)
+        if sizeSpec:
+            subtypeSpec = kwargs.pop('subtypeSpec', self.subtypeSpec)
+            if subtypeSpec:
+                subtypeSpec = sizeSpec
+
+            else:
+                subtypeSpec += sizeSpec
+
+            kwargs['subtypeSpec'] = subtypeSpec
+
+        return kwargs
+
+    def __repr__(self):
+        representation = '%s %s object' % (
+            self.__class__.__name__, self.isValue and 'value' or 'schema'
+        )
+
+        for attr, value in self.readOnly.items():
+            if value is not noValue:
+                representation += ', %s=%r' % (attr, value)
+
+        if self.isValue and self.components:
+            representation += ', payload [%s]' % ', '.join(
+                [repr(x) for x in self.components])
+
+        return '<%s>' % representation
+
+    def __eq__(self, other):
+        return self is other or self.components == other
+
+    def __ne__(self, other):
+        return self.components != other
+
+    def __lt__(self, other):
+        return self.components < other
+
+    def __le__(self, other):
+        return self.components <= other
+
+    def __gt__(self, other):
+        return self.components > other
+
+    def __ge__(self, other):
+        return self.components >= other
+
+    if sys.version_info[0] <= 2:
+        def __nonzero__(self):
+            return bool(self.components)
+    else:
+        def __bool__(self):
+            return bool(self.components)
+
+    @property
+    def components(self):
+        raise error.PyAsn1Error('Method not implemented')
+
+    def _cloneComponentValues(self, myClone, cloneValueFlag):
+        pass
+
+    def clone(self, **kwargs):
+        """Create a modified version of |ASN.1| schema object.
+
+        The `clone()` method accepts the same set arguments as |ASN.1|
+        class takes on instantiation except that all arguments
+        of the `clone()` method are optional.
+
+        Whatever arguments are supplied, they are used to create a copy
+        of `self` taking precedence over the ones used to instantiate `self`.
+
+        Possible values of `self` are never copied over thus `clone()` can
+        only create a new schema object.
+
+        Returns
+        -------
+        :
+            new instance of |ASN.1| type/value
+
+        Note
+        ----
+        Due to the mutable nature of the |ASN.1| object, even if no arguments
+        are supplied, a new |ASN.1| object will be created and returned.
+        """
+        cloneValueFlag = kwargs.pop('cloneValueFlag', False)
+
+        initializers = self.readOnly.copy()
+        initializers.update(kwargs)
+
+        clone = self.__class__(**initializers)
+
+        if cloneValueFlag:
+            self._cloneComponentValues(clone, cloneValueFlag)
+
+        return clone
+
+    def subtype(self, **kwargs):
+        """Create a specialization of |ASN.1| schema object.
+
+        The `subtype()` method accepts the same set arguments as |ASN.1|
+        class takes on instantiation except that all parameters
+        of the `subtype()` method are optional.
+
+        With the exception of the arguments described below, the rest of
+        supplied arguments they are used to create a copy of `self` taking
+        precedence over the ones used to instantiate `self`.
+
+        The following arguments to `subtype()` create a ASN.1 subtype out of
+        |ASN.1| type.
+
+        Other Parameters
+        ----------------
+        implicitTag: :py:class:`~pyasn1.type.tag.Tag`
+            Implicitly apply given ASN.1 tag object to `self`'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 `self`'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 `self`'s, then
+            use the result as new object's ASN.1 constraints.
+
+
+        Returns
+        -------
+        :
+            new instance of |ASN.1| type/value
+
+        Note
+        ----
+        Due to the mutable nature of the |ASN.1| object, even if no arguments
+        are supplied, a new |ASN.1| object will be created and returned.
+        """
+
+        initializers = self.readOnly.copy()
+
+        cloneValueFlag = kwargs.pop('cloneValueFlag', False)
+
+        implicitTag = kwargs.pop('implicitTag', None)
+        if implicitTag is not None:
+            initializers['tagSet'] = self.tagSet.tagImplicitly(implicitTag)
+
+        explicitTag = kwargs.pop('explicitTag', None)
+        if explicitTag is not None:
+            initializers['tagSet'] = self.tagSet.tagExplicitly(explicitTag)
+
+        for arg, option in kwargs.items():
+            initializers[arg] += option
+
+        clone = self.__class__(**initializers)
+
+        if cloneValueFlag:
+            self._cloneComponentValues(clone, cloneValueFlag)
+
+        return clone
+
+    def getComponentByPosition(self, idx):
+        raise error.PyAsn1Error('Method not implemented')
+
+    def setComponentByPosition(self, idx, value, verifyConstraints=True):
+        raise error.PyAsn1Error('Method not implemented')
+
+    def setComponents(self, *args, **kwargs):
+        for idx, value in enumerate(args):
+            self[idx] = value
+        for k in kwargs:
+            self[k] = kwargs[k]
+        return self
+
+    # backward compatibility
+
+    def setDefaultComponents(self):
+        pass
+
+    def getComponentType(self):
+        return self.componentType
+
+    # backward compatibility, unused
+    def verifySizeSpec(self):
+        self.subtypeSpec(self)
+
+
+        # Backward compatibility
+AbstractConstructedAsn1Item = ConstructedAsn1Type

lib/pyasn1/type/char.py

@@ -0,0 +1,335 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+import sys
+
+from pyasn1 import error
+from pyasn1.type import tag
+from pyasn1.type import univ
+
+__all__ = ['NumericString', 'PrintableString', 'TeletexString', 'T61String', 'VideotexString',
+           'IA5String', 'GraphicString', 'VisibleString', 'ISO646String',
+           'GeneralString', 'UniversalString', 'BMPString', 'UTF8String']
+
+NoValue = univ.NoValue
+noValue = univ.noValue
+
+
+class AbstractCharacterString(univ.OctetString):
+    """Creates |ASN.1| schema or value object.
+
+    |ASN.1| class is based on :class:`~pyasn1.type.base.SimpleAsn1Type`,
+    its objects are immutable and duck-type Python 2 :class:`str` or Python 3
+    :class:`bytes`. When used in octet-stream context, |ASN.1| type assumes
+    "|encoding|" encoding.
+
+    Keyword Args
+    ------------
+    value: :class:`unicode`, :class:`str`, :class:`bytes` or |ASN.1| object
+        :class:`unicode` object (Python 2) or :class:`str` (Python 3),
+        alternatively :class:`str` (Python 2) or :class:`bytes` (Python 3)
+        representing octet-stream of serialised unicode string
+        (note `encoding` parameter) or |ASN.1| class instance.
+        If `value` is not given, schema object will be created.
+
+    tagSet: :py:class:`~pyasn1.type.tag.TagSet`
+        Object representing non-default ASN.1 tag(s)
+
+    subtypeSpec: :py:class:`~pyasn1.type.constraint.ConstraintsIntersection`
+        Object representing non-default ASN.1 subtype constraint(s). Constraints
+        verification for |ASN.1| type occurs automatically on object
+        instantiation.
+
+    encoding: :py:class:`str`
+        Unicode codec ID to encode/decode :class:`unicode` (Python 2) or
+        :class:`str` (Python 3) the payload when |ASN.1| object is used
+        in octet-stream context.
+
+    Raises
+    ------
+    ~pyasn1.error.ValueConstraintError, ~pyasn1.error.PyAsn1Error
+        On constraint violation or bad initializer.
+    """
+
+    if sys.version_info[0] <= 2:
+        def __str__(self):
+            try:
+                # `str` is Py2 text representation
+                return self._value.encode(self.encoding)
+
+            except UnicodeEncodeError:
+                exc = sys.exc_info()[1]
+                raise error.PyAsn1UnicodeEncodeError(
+                    "Can't encode string '%s' with codec "
+                    "%s" % (self._value, self.encoding), exc
+                )
+
+        def __unicode__(self):
+            return unicode(self._value)
+
+        def prettyIn(self, value):
+            try:
+                if isinstance(value, unicode):
+                    return value
+                elif isinstance(value, str):
+                    return value.decode(self.encoding)
+                elif isinstance(value, (tuple, list)):
+                    return self.prettyIn(''.join([chr(x) for x in value]))
+                elif isinstance(value, univ.OctetString):
+                    return value.asOctets().decode(self.encoding)
+                else:
+                    return unicode(value)
+
+            except (UnicodeDecodeError, LookupError):
+                exc = sys.exc_info()[1]
+                raise error.PyAsn1UnicodeDecodeError(
+                    "Can't decode string '%s' with codec "
+                    "%s" % (value, self.encoding), exc
+                )
+
+        def asOctets(self, padding=True):
+            return str(self)
+
+        def asNumbers(self, padding=True):
+            return tuple([ord(x) for x in str(self)])
+
+    else:
+        def __str__(self):
+            # `unicode` is Py3 text representation
+            return str(self._value)
+
+        def __bytes__(self):
+            try:
+                return self._value.encode(self.encoding)
+            except UnicodeEncodeError:
+                exc = sys.exc_info()[1]
+                raise error.PyAsn1UnicodeEncodeError(
+                    "Can't encode string '%s' with codec "
+                    "%s" % (self._value, self.encoding), exc
+                )
+
+        def prettyIn(self, value):
+            try:
+                if isinstance(value, str):
+                    return value
+                elif isinstance(value, bytes):
+                    return value.decode(self.encoding)
+                elif isinstance(value, (tuple, list)):
+                    return self.prettyIn(bytes(value))
+                elif isinstance(value, univ.OctetString):
+                    return value.asOctets().decode(self.encoding)
+                else:
+                    return str(value)
+
+            except (UnicodeDecodeError, LookupError):
+                exc = sys.exc_info()[1]
+                raise error.PyAsn1UnicodeDecodeError(
+                    "Can't decode string '%s' with codec "
+                    "%s" % (value, self.encoding), exc
+                )
+
+        def asOctets(self, padding=True):
+            return bytes(self)
+
+        def asNumbers(self, padding=True):
+            return tuple(bytes(self))
+
+    #
+    # See OctetString.prettyPrint() for the explanation
+    #
+
+    def prettyOut(self, value):
+        return value
+
+    def prettyPrint(self, scope=0):
+        # first see if subclass has its own .prettyOut()
+        value = self.prettyOut(self._value)
+
+        if value is not self._value:
+            return value
+
+        return AbstractCharacterString.__str__(self)
+
+    def __reversed__(self):
+        return reversed(self._value)
+
+
+class NumericString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 18)
+    )
+    encoding = 'us-ascii'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class PrintableString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 19)
+    )
+    encoding = 'us-ascii'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class TeletexString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 20)
+    )
+    encoding = 'iso-8859-1'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class T61String(TeletexString):
+    __doc__ = TeletexString.__doc__
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class VideotexString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 21)
+    )
+    encoding = 'iso-8859-1'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class IA5String(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 22)
+    )
+    encoding = 'us-ascii'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class GraphicString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 25)
+    )
+    encoding = 'iso-8859-1'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class VisibleString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 26)
+    )
+    encoding = 'us-ascii'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class ISO646String(VisibleString):
+    __doc__ = VisibleString.__doc__
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+class GeneralString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 27)
+    )
+    encoding = 'iso-8859-1'
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class UniversalString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 28)
+    )
+    encoding = "utf-32-be"
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class BMPString(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 30)
+    )
+    encoding = "utf-16-be"
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()
+
+
+class UTF8String(AbstractCharacterString):
+    __doc__ = AbstractCharacterString.__doc__
+
+    #: Set (on class, not on instance) or return a
+    #: :py:class:`~pyasn1.type.tag.TagSet` object representing ASN.1 tag(s)
+    #: associated with |ASN.1| type.
+    tagSet = AbstractCharacterString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 12)
+    )
+    encoding = "utf-8"
+
+    # Optimization for faster codec lookup
+    typeId = AbstractCharacterString.getTypeId()

lib/pyasn1/type/constraint.py

@@ -0,0 +1,756 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+# Original concept and code by Mike C. Fletcher.
+#
+import sys
+
+from pyasn1.type import error
+
+__all__ = ['SingleValueConstraint', 'ContainedSubtypeConstraint',
+           'ValueRangeConstraint', 'ValueSizeConstraint',
+           'PermittedAlphabetConstraint', 'InnerTypeConstraint',
+           'ConstraintsExclusion', 'ConstraintsIntersection',
+           'ConstraintsUnion']
+
+
+class AbstractConstraint(object):
+
+    def __init__(self, *values):
+        self._valueMap = set()
+        self._setValues(values)
+        self.__hash = hash((self.__class__.__name__, self._values))
+
+    def __call__(self, value, idx=None):
+        if not self._values:
+            return
+
+        try:
+            self._testValue(value, idx)
+
+        except error.ValueConstraintError:
+            raise error.ValueConstraintError(
+                '%s failed at: %r' % (self, sys.exc_info()[1])
+            )
+
+    def __repr__(self):
+        representation = '%s object' % (self.__class__.__name__)
+
+        if self._values:
+            representation += ', consts %s' % ', '.join(
+                [repr(x) for x in self._values])
+
+        return '<%s>' % representation
+
+    def __eq__(self, other):
+        return self is other and True or self._values == other
+
+    def __ne__(self, other):
+        return self._values != other
+
+    def __lt__(self, other):
+        return self._values < other
+
+    def __le__(self, other):
+        return self._values <= other
+
+    def __gt__(self, other):
+        return self._values > other
+
+    def __ge__(self, other):
+        return self._values >= other
+
+    if sys.version_info[0] <= 2:
+        def __nonzero__(self):
+            return self._values and True or False
+    else:
+        def __bool__(self):
+            return self._values and True or False
+
+    def __hash__(self):
+        return self.__hash
+
+    def _setValues(self, values):
+        self._values = values
+
+    def _testValue(self, value, idx):
+        raise error.ValueConstraintError(value)
+
+    # Constraints derivation logic
+    def getValueMap(self):
+        return self._valueMap
+
+    def isSuperTypeOf(self, otherConstraint):
+        # TODO: fix possible comparison of set vs scalars here
+        return (otherConstraint is self or
+                not self._values or
+                otherConstraint == self or
+                self in otherConstraint.getValueMap())
+
+    def isSubTypeOf(self, otherConstraint):
+        return (otherConstraint is self or
+                not self or
+                otherConstraint == self or
+                otherConstraint in self._valueMap)
+
+
+class SingleValueConstraint(AbstractConstraint):
+    """Create a SingleValueConstraint object.
+
+    The SingleValueConstraint satisfies any value that
+    is present in the set of permitted values.
+
+    Objects of this type are iterable (emitting constraint values) and
+    can act as operands for some arithmetic operations e.g. addition
+    and subtraction. The latter can be used for combining multiple
+    SingleValueConstraint objects into one.
+
+    The SingleValueConstraint object can be applied to
+    any ASN.1 type.
+
+    Parameters
+    ----------
+    *values: :class:`int`
+        Full set of values permitted by this constraint object.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class DivisorOfSix(Integer):
+            '''
+            ASN.1 specification:
+
+            Divisor-Of-6 ::= INTEGER (1 | 2 | 3 | 6)
+            '''
+            subtypeSpec = SingleValueConstraint(1, 2, 3, 6)
+
+        # this will succeed
+        divisor_of_six = DivisorOfSix(1)
+
+        # this will raise ValueConstraintError
+        divisor_of_six = DivisorOfSix(7)
+    """
+    def _setValues(self, values):
+        self._values = values
+        self._set = set(values)
+
+    def _testValue(self, value, idx):
+        if value not in self._set:
+            raise error.ValueConstraintError(value)
+
+    # Constrains can be merged or reduced
+
+    def __contains__(self, item):
+        return item in self._set
+
+    def __iter__(self):
+        return iter(self._set)
+
+    def __sub__(self, constraint):
+        return self.__class__(*(self._set.difference(constraint)))
+
+    def __add__(self, constraint):
+        return self.__class__(*(self._set.union(constraint)))
+
+    def __sub__(self, constraint):
+        return self.__class__(*(self._set.difference(constraint)))
+
+
+class ContainedSubtypeConstraint(AbstractConstraint):
+    """Create a ContainedSubtypeConstraint object.
+
+    The ContainedSubtypeConstraint satisfies any value that
+    is present in the set of permitted values and also
+    satisfies included constraints.
+
+    The ContainedSubtypeConstraint object can be applied to
+    any ASN.1 type.
+
+    Parameters
+    ----------
+    *values:
+        Full set of values and constraint objects permitted
+        by this constraint object.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class DivisorOfEighteen(Integer):
+            '''
+            ASN.1 specification:
+
+            Divisors-of-18 ::= INTEGER (INCLUDES Divisors-of-6 | 9 | 18)
+            '''
+            subtypeSpec = ContainedSubtypeConstraint(
+                SingleValueConstraint(1, 2, 3, 6), 9, 18
+            )
+
+        # this will succeed
+        divisor_of_eighteen = DivisorOfEighteen(9)
+
+        # this will raise ValueConstraintError
+        divisor_of_eighteen = DivisorOfEighteen(10)
+    """
+    def _testValue(self, value, idx):
+        for constraint in self._values:
+            if isinstance(constraint, AbstractConstraint):
+                constraint(value, idx)
+            elif value not in self._set:
+                raise error.ValueConstraintError(value)
+
+
+class ValueRangeConstraint(AbstractConstraint):
+    """Create a ValueRangeConstraint object.
+
+    The ValueRangeConstraint satisfies any value that
+    falls in the range of permitted values.
+
+    The ValueRangeConstraint object can only be applied
+    to :class:`~pyasn1.type.univ.Integer` and
+    :class:`~pyasn1.type.univ.Real` types.
+
+    Parameters
+    ----------
+    start: :class:`int`
+        Minimum permitted value in the range (inclusive)
+
+    end: :class:`int`
+        Maximum permitted value in the range (inclusive)
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class TeenAgeYears(Integer):
+            '''
+            ASN.1 specification:
+
+            TeenAgeYears ::= INTEGER (13 .. 19)
+            '''
+            subtypeSpec = ValueRangeConstraint(13, 19)
+
+        # this will succeed
+        teen_year = TeenAgeYears(18)
+
+        # this will raise ValueConstraintError
+        teen_year = TeenAgeYears(20)
+    """
+    def _testValue(self, value, idx):
+        if value < self.start or value > self.stop:
+            raise error.ValueConstraintError(value)
+
+    def _setValues(self, values):
+        if len(values) != 2:
+            raise error.PyAsn1Error(
+                '%s: bad constraint values' % (self.__class__.__name__,)
+            )
+        self.start, self.stop = values
+        if self.start > self.stop:
+            raise error.PyAsn1Error(
+                '%s: screwed constraint values (start > stop): %s > %s' % (
+                    self.__class__.__name__,
+                    self.start, self.stop
+                )
+            )
+        AbstractConstraint._setValues(self, values)
+
+
+class ValueSizeConstraint(ValueRangeConstraint):
+    """Create a ValueSizeConstraint object.
+
+    The ValueSizeConstraint satisfies any value for
+    as long as its size falls within the range of
+    permitted sizes.
+
+    The ValueSizeConstraint object can be applied
+    to :class:`~pyasn1.type.univ.BitString`,
+    :class:`~pyasn1.type.univ.OctetString` (including
+    all :ref:`character ASN.1 types <type.char>`),
+    :class:`~pyasn1.type.univ.SequenceOf`
+    and :class:`~pyasn1.type.univ.SetOf` types.
+
+    Parameters
+    ----------
+    minimum: :class:`int`
+        Minimum permitted size of the value (inclusive)
+
+    maximum: :class:`int`
+        Maximum permitted size of the value (inclusive)
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class BaseballTeamRoster(SetOf):
+            '''
+            ASN.1 specification:
+
+            BaseballTeamRoster ::= SET SIZE (1..25) OF PlayerNames
+            '''
+            componentType = PlayerNames()
+            subtypeSpec = ValueSizeConstraint(1, 25)
+
+        # this will succeed
+        team = BaseballTeamRoster()
+        team.extend(['Jan', 'Matej'])
+        encode(team)
+
+        # this will raise ValueConstraintError
+        team = BaseballTeamRoster()
+        team.extend(['Jan'] * 26)
+        encode(team)
+
+    Note
+    ----
+    Whenever ValueSizeConstraint is applied to mutable types
+    (e.g. :class:`~pyasn1.type.univ.SequenceOf`,
+    :class:`~pyasn1.type.univ.SetOf`), constraint
+    validation only happens at the serialisation phase rather
+    than schema instantiation phase (as it is with immutable
+    types).
+    """
+    def _testValue(self, value, idx):
+        valueSize = len(value)
+        if valueSize < self.start or valueSize > self.stop:
+            raise error.ValueConstraintError(value)
+
+
+class PermittedAlphabetConstraint(SingleValueConstraint):
+    """Create a PermittedAlphabetConstraint object.
+
+    The PermittedAlphabetConstraint satisfies any character
+    string for as long as all its characters are present in
+    the set of permitted characters.
+
+    Objects of this type are iterable (emitting constraint values) and
+    can act as operands for some arithmetic operations e.g. addition
+    and subtraction.
+
+    The PermittedAlphabetConstraint object can only be applied
+    to the :ref:`character ASN.1 types <type.char>` such as
+    :class:`~pyasn1.type.char.IA5String`.
+
+    Parameters
+    ----------
+    *alphabet: :class:`str`
+        Full set of characters permitted by this constraint object.
+
+    Example
+    -------
+    .. code-block:: python
+
+        class BooleanValue(IA5String):
+            '''
+            ASN.1 specification:
+
+            BooleanValue ::= IA5String (FROM ('T' | 'F'))
+            '''
+            subtypeSpec = PermittedAlphabetConstraint('T', 'F')
+
+        # this will succeed
+        truth = BooleanValue('T')
+        truth = BooleanValue('TF')
+
+        # this will raise ValueConstraintError
+        garbage = BooleanValue('TAF')
+
+    ASN.1 `FROM ... EXCEPT ...` clause can be modelled by combining multiple
+    PermittedAlphabetConstraint objects into one:
+
+    Example
+    -------
+    .. code-block:: python
+
+        class Lipogramme(IA5String):
+            '''
+            ASN.1 specification:
+
+            Lipogramme ::=
+                IA5String (FROM (ALL EXCEPT ("e"|"E")))
+            '''
+            subtypeSpec = (
+                PermittedAlphabetConstraint(*string.printable) -
+                PermittedAlphabetConstraint('e', 'E')
+            )
+
+        # this will succeed
+        lipogramme = Lipogramme('A work of fiction?')
+
+        # this will raise ValueConstraintError
+        lipogramme = Lipogramme('Eel')
+
+    Note
+    ----
+    Although `ConstraintsExclusion` object could seemingly be used for this
+    purpose, practically, for it to work, it needs to represent its operand
+    constraints as sets and intersect one with the other. That would require
+    the insight into the constraint values (and their types) that are otherwise
+    hidden inside the constraint object.
+
+    Therefore it's more practical to model `EXCEPT` clause at
+    `PermittedAlphabetConstraint` level instead.
+    """
+    def _setValues(self, values):
+        self._values = values
+        self._set = set(values)
+
+    def _testValue(self, value, idx):
+        if not self._set.issuperset(value):
+            raise error.ValueConstraintError(value)
+
+
+class ComponentPresentConstraint(AbstractConstraint):
+    """Create a ComponentPresentConstraint object.
+
+    The ComponentPresentConstraint is only satisfied when the value
+    is not `None`.
+
+    The ComponentPresentConstraint object is typically used with
+    `WithComponentsConstraint`.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        present = ComponentPresentConstraint()
+
+        # this will succeed
+        present('whatever')
+
+        # this will raise ValueConstraintError
+        present(None)
+    """
+    def _setValues(self, values):
+        self._values = ('<must be present>',)
+
+        if values:
+            raise error.PyAsn1Error('No arguments expected')
+
+    def _testValue(self, value, idx):
+        if value is None:
+            raise error.ValueConstraintError(
+                'Component is not present:')
+
+
+class ComponentAbsentConstraint(AbstractConstraint):
+    """Create a ComponentAbsentConstraint object.
+
+    The ComponentAbsentConstraint is only satisfied when the value
+    is `None`.
+
+    The ComponentAbsentConstraint object is typically used with
+    `WithComponentsConstraint`.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        absent = ComponentAbsentConstraint()
+
+        # this will succeed
+        absent(None)
+
+        # this will raise ValueConstraintError
+        absent('whatever')
+    """
+    def _setValues(self, values):
+        self._values = ('<must be absent>',)
+
+        if values:
+            raise error.PyAsn1Error('No arguments expected')
+
+    def _testValue(self, value, idx):
+        if value is not None:
+            raise error.ValueConstraintError(
+                'Component is not absent: %r' % value)
+
+
+class WithComponentsConstraint(AbstractConstraint):
+    """Create a WithComponentsConstraint object.
+
+    The `WithComponentsConstraint` satisfies any mapping object that has
+    constrained fields present or absent, what is indicated by
+    `ComponentPresentConstraint` and `ComponentAbsentConstraint`
+    objects respectively.
+
+    The `WithComponentsConstraint` object is typically applied
+    to  :class:`~pyasn1.type.univ.Set` or
+    :class:`~pyasn1.type.univ.Sequence` types.
+
+    Parameters
+    ----------
+    *fields: :class:`tuple`
+        Zero or more tuples of (`field`, `constraint`) indicating constrained
+        fields.
+
+    Notes
+    -----
+    On top of the primary use of `WithComponentsConstraint` (ensuring presence
+    or absence of particular components of a :class:`~pyasn1.type.univ.Set` or
+    :class:`~pyasn1.type.univ.Sequence`), it is also possible to pass any other
+    constraint objects or their combinations. In case of scalar fields, these
+    constraints will be verified in addition to the constraints belonging to
+    scalar components themselves. However, formally, these additional
+    constraints do not change the type of these ASN.1 objects.
+
+    Examples
+    --------
+
+    .. code-block:: python
+
+        class Item(Sequence):  #  Set is similar
+            '''
+            ASN.1 specification:
+
+            Item ::= SEQUENCE {
+                id    INTEGER OPTIONAL,
+                name  OCTET STRING OPTIONAL
+            } WITH COMPONENTS id PRESENT, name ABSENT | id ABSENT, name PRESENT
+            '''
+            componentType = NamedTypes(
+                OptionalNamedType('id', Integer()),
+                OptionalNamedType('name', OctetString())
+            )
+            withComponents = ConstraintsUnion(
+                WithComponentsConstraint(
+                    ('id', ComponentPresentConstraint()),
+                    ('name', ComponentAbsentConstraint())
+                ),
+                WithComponentsConstraint(
+                    ('id', ComponentAbsentConstraint()),
+                    ('name', ComponentPresentConstraint())
+                )
+            )
+
+        item = Item()
+
+        # This will succeed
+        item['id'] = 1
+
+        # This will succeed
+        item.reset()
+        item['name'] = 'John'
+
+        # This will fail (on encoding)
+        item.reset()
+        descr['id'] = 1
+        descr['name'] = 'John'
+    """
+    def _testValue(self, value, idx):
+        for field, constraint in self._values:
+            constraint(value.get(field))
+
+    def _setValues(self, values):
+        AbstractConstraint._setValues(self, values)
+
+
+# This is a bit kludgy, meaning two op modes within a single constraint
+class InnerTypeConstraint(AbstractConstraint):
+    """Value must satisfy the type and presence constraints"""
+
+    def _testValue(self, value, idx):
+        if self.__singleTypeConstraint:
+            self.__singleTypeConstraint(value)
+        elif self.__multipleTypeConstraint:
+            if idx not in self.__multipleTypeConstraint:
+                raise error.ValueConstraintError(value)
+            constraint, status = self.__multipleTypeConstraint[idx]
+            if status == 'ABSENT':  # XXX presence is not checked!
+                raise error.ValueConstraintError(value)
+            constraint(value)
+
+    def _setValues(self, values):
+        self.__multipleTypeConstraint = {}
+        self.__singleTypeConstraint = None
+        for v in values:
+            if isinstance(v, tuple):
+                self.__multipleTypeConstraint[v[0]] = v[1], v[2]
+            else:
+                self.__singleTypeConstraint = v
+        AbstractConstraint._setValues(self, values)
+
+
+# Logic operations on constraints
+
+class ConstraintsExclusion(AbstractConstraint):
+    """Create a ConstraintsExclusion logic operator object.
+
+    The ConstraintsExclusion logic operator succeeds when the
+    value does *not* satisfy the operand constraint.
+
+    The ConstraintsExclusion object can be applied to
+    any constraint and logic operator object.
+
+    Parameters
+    ----------
+    *constraints:
+        Constraint or logic operator objects.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class LuckyNumber(Integer):
+            subtypeSpec = ConstraintsExclusion(
+                SingleValueConstraint(13)
+            )
+
+        # this will succeed
+        luckyNumber = LuckyNumber(12)
+
+        # this will raise ValueConstraintError
+        luckyNumber = LuckyNumber(13)
+
+    Note
+    ----
+    The `FROM ... EXCEPT ...` ASN.1 clause should be modeled by combining
+    constraint objects into one. See `PermittedAlphabetConstraint` for more
+    information.
+    """
+    def _testValue(self, value, idx):
+        for constraint in self._values:
+            try:
+                constraint(value, idx)
+
+            except error.ValueConstraintError:
+                continue
+
+            raise error.ValueConstraintError(value)
+
+    def _setValues(self, values):
+        AbstractConstraint._setValues(self, values)
+
+
+class AbstractConstraintSet(AbstractConstraint):
+
+    def __getitem__(self, idx):
+        return self._values[idx]
+
+    def __iter__(self):
+        return iter(self._values)
+
+    def __add__(self, value):
+        return self.__class__(*(self._values + (value,)))
+
+    def __radd__(self, value):
+        return self.__class__(*((value,) + self._values))
+
+    def __len__(self):
+        return len(self._values)
+
+    # Constraints inclusion in sets
+
+    def _setValues(self, values):
+        self._values = values
+        for constraint in values:
+            if constraint:
+                self._valueMap.add(constraint)
+                self._valueMap.update(constraint.getValueMap())
+
+
+class ConstraintsIntersection(AbstractConstraintSet):
+    """Create a ConstraintsIntersection logic operator object.
+
+    The ConstraintsIntersection logic operator only succeeds
+    if *all* its operands succeed.
+
+    The ConstraintsIntersection object can be applied to
+    any constraint and logic operator objects.
+
+    The ConstraintsIntersection object duck-types the immutable
+    container object like Python :py:class:`tuple`.
+
+    Parameters
+    ----------
+    *constraints:
+        Constraint or logic operator objects.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class CapitalAndSmall(IA5String):
+            '''
+            ASN.1 specification:
+
+            CapitalAndSmall ::=
+                IA5String (FROM ("A".."Z"|"a".."z"))
+            '''
+            subtypeSpec = ConstraintsIntersection(
+                PermittedAlphabetConstraint('A', 'Z'),
+                PermittedAlphabetConstraint('a', 'z')
+            )
+
+        # this will succeed
+        capital_and_small = CapitalAndSmall('Hello')
+
+        # this will raise ValueConstraintError
+        capital_and_small = CapitalAndSmall('hello')
+    """
+    def _testValue(self, value, idx):
+        for constraint in self._values:
+            constraint(value, idx)
+
+
+class ConstraintsUnion(AbstractConstraintSet):
+    """Create a ConstraintsUnion logic operator object.
+
+    The ConstraintsUnion logic operator succeeds if
+    *at least* a single operand succeeds.
+
+    The ConstraintsUnion object can be applied to
+    any constraint and logic operator objects.
+
+    The ConstraintsUnion object duck-types the immutable
+    container object like Python :py:class:`tuple`.
+
+    Parameters
+    ----------
+    *constraints:
+        Constraint or logic operator objects.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class CapitalOrSmall(IA5String):
+            '''
+            ASN.1 specification:
+
+            CapitalOrSmall ::=
+                IA5String (FROM ("A".."Z") | FROM ("a".."z"))
+            '''
+            subtypeSpec = ConstraintsUnion(
+                PermittedAlphabetConstraint('A', 'Z'),
+                PermittedAlphabetConstraint('a', 'z')
+            )
+
+        # this will succeed
+        capital_or_small = CapitalAndSmall('Hello')
+
+        # this will raise ValueConstraintError
+        capital_or_small = CapitalOrSmall('hello!')
+    """
+    def _testValue(self, value, idx):
+        for constraint in self._values:
+            try:
+                constraint(value, idx)
+            except error.ValueConstraintError:
+                pass
+            else:
+                return
+
+        raise error.ValueConstraintError(
+            'all of %s failed for "%s"' % (self._values, value)
+        )
+
+# TODO:
+# refactor InnerTypeConstraint
+# add tests for type check
+# implement other constraint types
+# make constraint validation easy to skip

lib/pyasn1/type/error.py

@@ -0,0 +1,11 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+from pyasn1.error import PyAsn1Error
+
+
+class ValueConstraintError(PyAsn1Error):
+    pass

lib/pyasn1/type/namedtype.py

@@ -0,0 +1,561 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+import sys
+
+from pyasn1 import error
+from pyasn1.type import tag
+from pyasn1.type import tagmap
+
+__all__ = ['NamedType', 'OptionalNamedType', 'DefaultedNamedType',
+           'NamedTypes']
+
+try:
+    any
+
+except NameError:
+    any = lambda x: bool(filter(bool, x))
+
+
+class NamedType(object):
+    """Create named field object for a constructed ASN.1 type.
+
+    The |NamedType| object represents a single name and ASN.1 type of a constructed ASN.1 type.
+
+    |NamedType| objects are immutable and duck-type Python :class:`tuple` objects
+    holding *name* and *asn1Object* components.
+
+    Parameters
+    ----------
+    name: :py:class:`str`
+        Field name
+
+    asn1Object:
+        ASN.1 type object
+    """
+    isOptional = False
+    isDefaulted = False
+
+    def __init__(self, name, asn1Object, openType=None):
+        self.__name = name
+        self.__type = asn1Object
+        self.__nameAndType = name, asn1Object
+        self.__openType = openType
+
+    def __repr__(self):
+        representation = '%s=%r' % (self.name, self.asn1Object)
+
+        if self.openType:
+            representation += ', open type %r' % self.openType
+
+        return '<%s object, type %s>' % (
+            self.__class__.__name__, representation)
+
+    def __eq__(self, other):
+        return self.__nameAndType == other
+
+    def __ne__(self, other):
+        return self.__nameAndType != other
+
+    def __lt__(self, other):
+        return self.__nameAndType < other
+
+    def __le__(self, other):
+        return self.__nameAndType <= other
+
+    def __gt__(self, other):
+        return self.__nameAndType > other
+
+    def __ge__(self, other):
+        return self.__nameAndType >= other
+
+    def __hash__(self):
+        return hash(self.__nameAndType)
+
+    def __getitem__(self, idx):
+        return self.__nameAndType[idx]
+
+    def __iter__(self):
+        return iter(self.__nameAndType)
+
+    @property
+    def name(self):
+        return self.__name
+
+    @property
+    def asn1Object(self):
+        return self.__type
+
+    @property
+    def openType(self):
+        return self.__openType
+
+    # Backward compatibility
+
+    def getName(self):
+        return self.name
+
+    def getType(self):
+        return self.asn1Object
+
+
+class OptionalNamedType(NamedType):
+    __doc__ = NamedType.__doc__
+
+    isOptional = True
+
+
+class DefaultedNamedType(NamedType):
+    __doc__ = NamedType.__doc__
+
+    isDefaulted = True
+
+
+class NamedTypes(object):
+    """Create a collection of named fields for a constructed ASN.1 type.
+
+    The NamedTypes object represents a collection of named fields of a constructed ASN.1 type.
+
+    *NamedTypes* objects are immutable and duck-type Python :class:`dict` objects
+    holding *name* as keys and ASN.1 type object as values.
+
+    Parameters
+    ----------
+    *namedTypes: :class:`~pyasn1.type.namedtype.NamedType`
+
+    Examples
+    --------
+
+    .. code-block:: python
+
+        class Description(Sequence):
+            '''
+            ASN.1 specification:
+
+            Description ::= SEQUENCE {
+                surname    IA5String,
+                first-name IA5String OPTIONAL,
+                age        INTEGER DEFAULT 40
+            }
+            '''
+            componentType = NamedTypes(
+                NamedType('surname', IA5String()),
+                OptionalNamedType('first-name', IA5String()),
+                DefaultedNamedType('age', Integer(40))
+            )
+
+        descr = Description()
+        descr['surname'] = 'Smith'
+        descr['first-name'] = 'John'
+    """
+    def __init__(self, *namedTypes, **kwargs):
+        self.__namedTypes = namedTypes
+        self.__namedTypesLen = len(self.__namedTypes)
+        self.__minTagSet = self.__computeMinTagSet()
+        self.__nameToPosMap = self.__computeNameToPosMap()
+        self.__tagToPosMap = self.__computeTagToPosMap()
+        self.__ambiguousTypes = 'terminal' not in kwargs and self.__computeAmbiguousTypes() or {}
+        self.__uniqueTagMap = self.__computeTagMaps(unique=True)
+        self.__nonUniqueTagMap = self.__computeTagMaps(unique=False)
+        self.__hasOptionalOrDefault = any([True for namedType in self.__namedTypes
+                                           if namedType.isDefaulted or namedType.isOptional])
+        self.__hasOpenTypes = any([True for namedType in self.__namedTypes
+                                   if namedType.openType])
+
+        self.__requiredComponents = frozenset(
+                [idx for idx, nt in enumerate(self.__namedTypes) if not nt.isOptional and not nt.isDefaulted]
+            )
+        self.__keys = frozenset([namedType.name for namedType in self.__namedTypes])
+        self.__values = tuple([namedType.asn1Object for namedType in self.__namedTypes])
+        self.__items = tuple([(namedType.name, namedType.asn1Object) for namedType in self.__namedTypes])
+
+    def __repr__(self):
+        representation = ', '.join(['%r' % x for x in self.__namedTypes])
+        return '<%s object, types %s>' % (
+            self.__class__.__name__, representation)
+
+    def __eq__(self, other):
+        return self.__namedTypes == other
+
+    def __ne__(self, other):
+        return self.__namedTypes != other
+
+    def __lt__(self, other):
+        return self.__namedTypes < other
+
+    def __le__(self, other):
+        return self.__namedTypes <= other
+
+    def __gt__(self, other):
+        return self.__namedTypes > other
+
+    def __ge__(self, other):
+        return self.__namedTypes >= other
+
+    def __hash__(self):
+        return hash(self.__namedTypes)
+
+    def __getitem__(self, idx):
+        try:
+            return self.__namedTypes[idx]
+
+        except TypeError:
+            return self.__namedTypes[self.__nameToPosMap[idx]]
+
+    def __contains__(self, key):
+        return key in self.__nameToPosMap
+
+    def __iter__(self):
+        return (x[0] for x in self.__namedTypes)
+
+    if sys.version_info[0] <= 2:
+        def __nonzero__(self):
+            return self.__namedTypesLen > 0
+    else:
+        def __bool__(self):
+            return self.__namedTypesLen > 0
+
+    def __len__(self):
+        return self.__namedTypesLen
+
+    # Python dict protocol
+
+    def values(self):
+        return self.__values
+
+    def keys(self):
+        return self.__keys
+
+    def items(self):
+        return self.__items
+
+    def clone(self):
+        return self.__class__(*self.__namedTypes)
+
+    class PostponedError(object):
+        def __init__(self, errorMsg):
+            self.__errorMsg = errorMsg
+
+        def __getitem__(self, item):
+            raise  error.PyAsn1Error(self.__errorMsg)
+
+    def __computeTagToPosMap(self):
+        tagToPosMap = {}
+        for idx, namedType in enumerate(self.__namedTypes):
+            tagMap = namedType.asn1Object.tagMap
+            if isinstance(tagMap, NamedTypes.PostponedError):
+                return tagMap
+            if not tagMap:
+                continue
+            for _tagSet in tagMap.presentTypes:
+                if _tagSet in tagToPosMap:
+                    return NamedTypes.PostponedError('Duplicate component tag %s at %s' % (_tagSet, namedType))
+                tagToPosMap[_tagSet] = idx
+
+        return tagToPosMap
+
+    def __computeNameToPosMap(self):
+        nameToPosMap = {}
+        for idx, namedType in enumerate(self.__namedTypes):
+            if namedType.name in nameToPosMap:
+                return NamedTypes.PostponedError('Duplicate component name %s at %s' % (namedType.name, namedType))
+            nameToPosMap[namedType.name] = idx
+
+        return nameToPosMap
+
+    def __computeAmbiguousTypes(self):
+        ambiguousTypes = {}
+        partialAmbiguousTypes = ()
+        for idx, namedType in reversed(tuple(enumerate(self.__namedTypes))):
+            if namedType.isOptional or namedType.isDefaulted:
+                partialAmbiguousTypes = (namedType,) + partialAmbiguousTypes
+            else:
+                partialAmbiguousTypes = (namedType,)
+            if len(partialAmbiguousTypes) == len(self.__namedTypes):
+                ambiguousTypes[idx] = self
+            else:
+                ambiguousTypes[idx] = NamedTypes(*partialAmbiguousTypes, **dict(terminal=True))
+        return ambiguousTypes
+
+    def getTypeByPosition(self, idx):
+        """Return ASN.1 type object by its position in fields set.
+
+        Parameters
+        ----------
+        idx: :py:class:`int`
+            Field index
+
+        Returns
+        -------
+        :
+            ASN.1 type
+
+        Raises
+        ------
+        ~pyasn1.error.PyAsn1Error
+            If given position is out of fields range
+        """
+        try:
+            return self.__namedTypes[idx].asn1Object
+
+        except IndexError:
+            raise error.PyAsn1Error('Type position out of range')
+
+    def getPositionByType(self, tagSet):
+        """Return field position by its ASN.1 type.
+
+        Parameters
+        ----------
+        tagSet: :class:`~pysnmp.type.tag.TagSet`
+            ASN.1 tag set distinguishing one ASN.1 type from others.
+
+        Returns
+        -------
+        : :py:class:`int`
+            ASN.1 type position in fields set
+
+        Raises
+        ------
+        ~pyasn1.error.PyAsn1Error
+            If *tagSet* is not present or ASN.1 types are not unique within callee *NamedTypes*
+        """
+        try:
+            return self.__tagToPosMap[tagSet]
+
+        except KeyError:
+            raise error.PyAsn1Error('Type %s not found' % (tagSet,))
+
+    def getNameByPosition(self, idx):
+        """Return field name by its position in fields set.
+
+        Parameters
+        ----------
+        idx: :py:class:`idx`
+            Field index
+
+        Returns
+        -------
+        : :py:class:`str`
+            Field name
+
+        Raises
+        ------
+        ~pyasn1.error.PyAsn1Error
+            If given field name is not present in callee *NamedTypes*
+        """
+        try:
+            return self.__namedTypes[idx].name
+
+        except IndexError:
+            raise error.PyAsn1Error('Type position out of range')
+
+    def getPositionByName(self, name):
+        """Return field position by filed name.
+
+        Parameters
+        ----------
+        name: :py:class:`str`
+            Field name
+
+        Returns
+        -------
+        : :py:class:`int`
+            Field position in fields set
+
+        Raises
+        ------
+        ~pyasn1.error.PyAsn1Error
+            If *name* is not present or not unique within callee *NamedTypes*
+        """
+        try:
+            return self.__nameToPosMap[name]
+
+        except KeyError:
+            raise error.PyAsn1Error('Name %s not found' % (name,))
+
+    def getTagMapNearPosition(self, idx):
+        """Return ASN.1 types that are allowed at or past given field position.
+
+        Some ASN.1 serialisation allow for skipping optional and defaulted fields.
+        Some constructed ASN.1 types allow reordering of the fields. When recovering
+        such objects it may be important to know which types can possibly be
+        present at any given position in the field sets.
+
+        Parameters
+        ----------
+        idx: :py:class:`int`
+            Field index
+
+        Returns
+        -------
+        : :class:`~pyasn1.type.tagmap.TagMap`
+            Map if ASN.1 types allowed at given field position
+
+        Raises
+        ------
+        ~pyasn1.error.PyAsn1Error
+            If given position is out of fields range
+        """
+        try:
+            return self.__ambiguousTypes[idx].tagMap
+
+        except KeyError:
+            raise error.PyAsn1Error('Type position out of range')
+
+    def getPositionNearType(self, tagSet, idx):
+        """Return the closest field position where given ASN.1 type is allowed.
+
+        Some ASN.1 serialisation allow for skipping optional and defaulted fields.
+        Some constructed ASN.1 types allow reordering of the fields. When recovering
+        such objects it may be important to know at which field position, in field set,
+        given *tagSet* is allowed at or past *idx* position.
+
+        Parameters
+        ----------
+        tagSet: :class:`~pyasn1.type.tag.TagSet`
+           ASN.1 type which field position to look up
+
+        idx: :py:class:`int`
+            Field position at or past which to perform ASN.1 type look up
+
+        Returns
+        -------
+        : :py:class:`int`
+            Field position in fields set
+
+        Raises
+        ------
+        ~pyasn1.error.PyAsn1Error
+            If *tagSet* is not present or not unique within callee *NamedTypes*
+            or *idx* is out of fields range
+        """
+        try:
+            return idx + self.__ambiguousTypes[idx].getPositionByType(tagSet)
+
+        except KeyError:
+            raise error.PyAsn1Error('Type position out of range')
+
+    def __computeMinTagSet(self):
+        minTagSet = None
+        for namedType in self.__namedTypes:
+            asn1Object = namedType.asn1Object
+
+            try:
+                tagSet = asn1Object.minTagSet
+
+            except AttributeError:
+                tagSet = asn1Object.tagSet
+
+            if minTagSet is None or tagSet < minTagSet:
+                minTagSet = tagSet
+
+        return minTagSet or tag.TagSet()
+
+    @property
+    def minTagSet(self):
+        """Return the minimal TagSet among ASN.1 type in callee *NamedTypes*.
+
+        Some ASN.1 types/serialisation protocols require ASN.1 types to be
+        arranged based on their numerical tag value. The *minTagSet* property
+        returns that.
+
+        Returns
+        -------
+        : :class:`~pyasn1.type.tagset.TagSet`
+            Minimal TagSet among ASN.1 types in callee *NamedTypes*
+        """
+        return self.__minTagSet
+
+    def __computeTagMaps(self, unique):
+        presentTypes = {}
+        skipTypes = {}
+        defaultType = None
+        for namedType in self.__namedTypes:
+            tagMap = namedType.asn1Object.tagMap
+            if isinstance(tagMap, NamedTypes.PostponedError):
+                return tagMap
+            for tagSet in tagMap:
+                if unique and tagSet in presentTypes:
+                    return NamedTypes.PostponedError('Non-unique tagSet %s of %s at %s' % (tagSet, namedType, self))
+                presentTypes[tagSet] = namedType.asn1Object
+            skipTypes.update(tagMap.skipTypes)
+
+            if defaultType is None:
+                defaultType = tagMap.defaultType
+            elif tagMap.defaultType is not None:
+                return NamedTypes.PostponedError('Duplicate default ASN.1 type at %s' % (self,))
+
+        return tagmap.TagMap(presentTypes, skipTypes, defaultType)
+
+    @property
+    def tagMap(self):
+        """Return a *TagMap* object from tags and types recursively.
+
+        Return a :class:`~pyasn1.type.tagmap.TagMap` object by
+        combining tags from *TagMap* objects of children types and
+        associating them with their immediate child type.
+
+        Example
+        -------
+        .. code-block:: python
+
+           OuterType ::= CHOICE {
+               innerType INTEGER
+           }
+
+        Calling *.tagMap* on *OuterType* will yield a map like this:
+
+        .. code-block:: python
+
+           Integer.tagSet -> Choice
+        """
+        return self.__nonUniqueTagMap
+
+    @property
+    def tagMapUnique(self):
+        """Return a *TagMap* object from unique tags and types recursively.
+
+        Return a :class:`~pyasn1.type.tagmap.TagMap` object by
+        combining tags from *TagMap* objects of children types and
+        associating them with their immediate child type.
+
+        Example
+        -------
+        .. code-block:: python
+
+           OuterType ::= CHOICE {
+               innerType INTEGER
+           }
+
+        Calling *.tagMapUnique* on *OuterType* will yield a map like this:
+
+        .. code-block:: python
+
+           Integer.tagSet -> Choice
+
+        Note
+        ----
+
+        Duplicate *TagSet* objects found in the tree of children
+        types would cause error.
+        """
+        return self.__uniqueTagMap
+
+    @property
+    def hasOptionalOrDefault(self):
+        return self.__hasOptionalOrDefault
+
+    @property
+    def hasOpenTypes(self):
+        return self.__hasOpenTypes
+
+    @property
+    def namedTypes(self):
+        return tuple(self.__namedTypes)
+
+    @property
+    def requiredComponents(self):
+        return self.__requiredComponents

lib/pyasn1/type/namedval.py

@@ -0,0 +1,192 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+# ASN.1 named integers
+#
+from pyasn1 import error
+
+__all__ = ['NamedValues']
+
+
+class NamedValues(object):
+    """Create named values object.
+
+    The |NamedValues| object represents a collection of string names
+    associated with numeric IDs. These objects are used for giving
+    names to otherwise numerical values.
+
+    |NamedValues| objects are immutable and duck-type Python
+    :class:`dict` object mapping ID to name and vice-versa.
+
+    Parameters
+    ----------
+    *args: variable number of two-element :py:class:`tuple`
+
+        name: :py:class:`str`
+            Value label
+
+        value: :py:class:`int`
+            Numeric value
+
+    Keyword Args
+    ------------
+    name: :py:class:`str`
+        Value label
+
+    value: :py:class:`int`
+        Numeric value
+
+    Examples
+    --------
+
+    .. code-block:: pycon
+
+        >>> nv = NamedValues('a', 'b', ('c', 0), d=1)
+        >>> nv
+        >>> {'c': 0, 'd': 1, 'a': 2, 'b': 3}
+        >>> nv[0]
+        'c'
+        >>> nv['a']
+        2
+    """
+    def __init__(self, *args, **kwargs):
+        self.__names = {}
+        self.__numbers = {}
+
+        anonymousNames = []
+
+        for namedValue in args:
+            if isinstance(namedValue, (tuple, list)):
+                try:
+                    name, number = namedValue
+
+                except ValueError:
+                    raise error.PyAsn1Error('Not a proper attribute-value pair %r' % (namedValue,))
+
+            else:
+                anonymousNames.append(namedValue)
+                continue
+
+            if name in self.__names:
+                raise error.PyAsn1Error('Duplicate name %s' % (name,))
+
+            if number in self.__numbers:
+                raise error.PyAsn1Error('Duplicate number  %s=%s' % (name, number))
+
+            self.__names[name] = number
+            self.__numbers[number] = name
+
+        for name, number in kwargs.items():
+            if name in self.__names:
+                raise error.PyAsn1Error('Duplicate name %s' % (name,))
+
+            if number in self.__numbers:
+                raise error.PyAsn1Error('Duplicate number  %s=%s' % (name, number))
+
+            self.__names[name] = number
+            self.__numbers[number] = name
+
+        if anonymousNames:
+
+            number = self.__numbers and max(self.__numbers) + 1 or 0
+
+            for name in anonymousNames:
+
+                if name in self.__names:
+                    raise error.PyAsn1Error('Duplicate name %s' % (name,))
+
+                self.__names[name] = number
+                self.__numbers[number] = name
+
+                number += 1
+
+    def __repr__(self):
+        representation = ', '.join(['%s=%d' % x for x in self.items()])
+
+        if len(representation) > 64:
+            representation = representation[:32] + '...' + representation[-32:]
+
+        return '<%s object, enums %s>' % (
+            self.__class__.__name__, representation)
+
+    def __eq__(self, other):
+        return dict(self) == other
+
+    def __ne__(self, other):
+        return dict(self) != other
+
+    def __lt__(self, other):
+        return dict(self) < other
+
+    def __le__(self, other):
+        return dict(self) <= other
+
+    def __gt__(self, other):
+        return dict(self) > other
+
+    def __ge__(self, other):
+        return dict(self) >= other
+
+    def __hash__(self):
+        return hash(self.items())
+
+    # Python dict protocol (read-only)
+
+    def __getitem__(self, key):
+        try:
+            return self.__numbers[key]
+
+        except KeyError:
+            return self.__names[key]
+
+    def __len__(self):
+        return len(self.__names)
+
+    def __contains__(self, key):
+        return key in self.__names or key in self.__numbers
+
+    def __iter__(self):
+        return iter(self.__names)
+
+    def values(self):
+        return iter(self.__numbers)
+
+    def keys(self):
+        return iter(self.__names)
+
+    def items(self):
+        for name in self.__names:
+            yield name, self.__names[name]
+
+    # support merging
+
+    def __add__(self, namedValues):
+        return self.__class__(*tuple(self.items()) + tuple(namedValues.items()))
+
+    # XXX clone/subtype?
+
+    def clone(self, *args, **kwargs):
+        new = self.__class__(*args, **kwargs)
+        return self + new
+
+    # legacy protocol
+
+    def getName(self, value):
+        if value in self.__numbers:
+            return self.__numbers[value]
+
+    def getValue(self, name):
+        if name in self.__names:
+            return self.__names[name]
+
+    def getValues(self, *names):
+        try:
+            return [self.__names[name] for name in names]
+
+        except KeyError:
+            raise error.PyAsn1Error(
+                'Unknown bit identifier(s): %s' % (set(names).difference(self.__names),)
+            )

lib/pyasn1/type/opentype.py

@@ -0,0 +1,104 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+
+__all__ = ['OpenType']
+
+
+class OpenType(object):
+    """Create ASN.1 type map indexed by a value
+
+    The *OpenType* object models an untyped field of a constructed ASN.1
+    type. In ASN.1 syntax it is usually represented by the
+    `ANY DEFINED BY` for scalars or `SET OF ANY DEFINED BY`,
+    `SEQUENCE OF ANY DEFINED BY` for container types clauses. Typically
+    used together with :class:`~pyasn1.type.univ.Any` object.
+
+    OpenType objects duck-type a read-only Python :class:`dict` objects,
+    however the passed `typeMap` is not copied, but stored by reference.
+    That means the user can manipulate `typeMap` at run time having this
+    reflected on *OpenType* object behavior.
+
+    The |OpenType| class models an untyped field of a constructed ASN.1
+    type. In ASN.1 syntax it is usually represented by the
+    `ANY DEFINED BY` for scalars or `SET OF ANY DEFINED BY`,
+    `SEQUENCE OF ANY DEFINED BY` for container types clauses. Typically
+    used with :class:`~pyasn1.type.univ.Any` type.
+
+    Parameters
+    ----------
+    name: :py:class:`str`
+        Field name
+
+    typeMap: :py:class:`dict`
+        A map of value->ASN.1 type. It's stored by reference and can be
+        mutated later to register new mappings.
+
+    Examples
+    --------
+
+    For untyped scalars:
+
+    .. code-block:: python
+
+        openType = OpenType(
+            'id', {1: Integer(),
+                   2: OctetString()}
+        )
+        Sequence(
+            componentType=NamedTypes(
+                NamedType('id', Integer()),
+                NamedType('blob', Any(), openType=openType)
+            )
+        )
+
+    For untyped `SET OF` or `SEQUENCE OF` vectors:
+
+    .. code-block:: python
+
+        openType = OpenType(
+            'id', {1: Integer(),
+                   2: OctetString()}
+        )
+        Sequence(
+            componentType=NamedTypes(
+                NamedType('id', Integer()),
+                NamedType('blob', SetOf(componentType=Any()),
+                          openType=openType)
+            )
+        )
+    """
+
+    def __init__(self, name, typeMap=None):
+        self.__name = name
+        if typeMap is None:
+            self.__typeMap = {}
+        else:
+            self.__typeMap = typeMap
+
+    @property
+    def name(self):
+        return self.__name
+
+    # Python dict protocol
+
+    def values(self):
+        return self.__typeMap.values()
+
+    def keys(self):
+        return self.__typeMap.keys()
+
+    def items(self):
+        return self.__typeMap.items()
+
+    def __contains__(self, key):
+        return key in self.__typeMap
+
+    def __getitem__(self, key):
+        return self.__typeMap[key]
+
+    def __iter__(self):
+        return iter(self.__typeMap)

lib/pyasn1/type/tag.py

@@ -0,0 +1,335 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+from pyasn1 import error
+
+__all__ = ['tagClassUniversal', 'tagClassApplication', 'tagClassContext',
+           'tagClassPrivate', 'tagFormatSimple', 'tagFormatConstructed',
+           'tagCategoryImplicit', 'tagCategoryExplicit',
+           'tagCategoryUntagged', 'Tag', 'TagSet']
+
+#: Identifier for ASN.1 class UNIVERSAL
+tagClassUniversal = 0x00
+
+#: Identifier for ASN.1 class APPLICATION
+tagClassApplication = 0x40
+
+#: Identifier for ASN.1 class context-specific
+tagClassContext = 0x80
+
+#: Identifier for ASN.1 class private
+tagClassPrivate = 0xC0
+
+#: Identifier for "simple" ASN.1 structure (e.g. scalar)
+tagFormatSimple = 0x00
+
+#: Identifier for "constructed" ASN.1 structure (e.g. may have inner components)
+tagFormatConstructed = 0x20
+
+tagCategoryImplicit = 0x01
+tagCategoryExplicit = 0x02
+tagCategoryUntagged = 0x04
+
+
+class Tag(object):
+    """Create ASN.1 tag
+
+    Represents ASN.1 tag that can be attached to a ASN.1 type to make
+    types distinguishable from each other.
+
+    *Tag* objects are immutable and duck-type Python :class:`tuple` objects
+    holding three integer components of a tag.
+
+    Parameters
+    ----------
+    tagClass: :py:class:`int`
+        Tag *class* value
+
+    tagFormat: :py:class:`int`
+        Tag *format* value
+
+    tagId: :py:class:`int`
+        Tag ID value
+    """
+    def __init__(self, tagClass, tagFormat, tagId):
+        if tagId < 0:
+            raise error.PyAsn1Error('Negative tag ID (%s) not allowed' % tagId)
+        self.__tagClass = tagClass
+        self.__tagFormat = tagFormat
+        self.__tagId = tagId
+        self.__tagClassId = tagClass, tagId
+        self.__hash = hash(self.__tagClassId)
+
+    def __repr__(self):
+        representation = '[%s:%s:%s]' % (
+            self.__tagClass, self.__tagFormat, self.__tagId)
+        return '<%s object, tag %s>' % (
+            self.__class__.__name__, representation)
+
+    def __eq__(self, other):
+        return self.__tagClassId == other
+
+    def __ne__(self, other):
+        return self.__tagClassId != other
+
+    def __lt__(self, other):
+        return self.__tagClassId < other
+
+    def __le__(self, other):
+        return self.__tagClassId <= other
+
+    def __gt__(self, other):
+        return self.__tagClassId > other
+
+    def __ge__(self, other):
+        return self.__tagClassId >= other
+
+    def __hash__(self):
+        return self.__hash
+
+    def __getitem__(self, idx):
+        if idx == 0:
+            return self.__tagClass
+        elif idx == 1:
+            return self.__tagFormat
+        elif idx == 2:
+            return self.__tagId
+        else:
+            raise IndexError()
+
+    def __iter__(self):
+        yield self.__tagClass
+        yield self.__tagFormat
+        yield self.__tagId
+
+    def __and__(self, otherTag):
+        return self.__class__(self.__tagClass & otherTag.tagClass,
+                              self.__tagFormat & otherTag.tagFormat,
+                              self.__tagId & otherTag.tagId)
+
+    def __or__(self, otherTag):
+        return self.__class__(self.__tagClass | otherTag.tagClass,
+                              self.__tagFormat | otherTag.tagFormat,
+                              self.__tagId | otherTag.tagId)
+
+    @property
+    def tagClass(self):
+        """ASN.1 tag class
+
+        Returns
+        -------
+        : :py:class:`int`
+            Tag class
+        """
+        return self.__tagClass
+
+    @property
+    def tagFormat(self):
+        """ASN.1 tag format
+
+        Returns
+        -------
+        : :py:class:`int`
+            Tag format
+        """
+        return self.__tagFormat
+
+    @property
+    def tagId(self):
+        """ASN.1 tag ID
+
+        Returns
+        -------
+        : :py:class:`int`
+            Tag ID
+        """
+        return self.__tagId
+
+
+class TagSet(object):
+    """Create a collection of ASN.1 tags
+
+    Represents a combination of :class:`~pyasn1.type.tag.Tag` objects
+    that can be attached to a ASN.1 type to make types distinguishable
+    from each other.
+
+    *TagSet* objects are immutable and duck-type Python :class:`tuple` objects
+    holding arbitrary number of :class:`~pyasn1.type.tag.Tag` objects.
+
+    Parameters
+    ----------
+    baseTag: :class:`~pyasn1.type.tag.Tag`
+        Base *Tag* object. This tag survives IMPLICIT tagging.
+
+    *superTags: :class:`~pyasn1.type.tag.Tag`
+        Additional *Tag* objects taking part in subtyping.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        class OrderNumber(NumericString):
+            '''
+            ASN.1 specification
+
+            Order-number ::=
+                [APPLICATION 5] IMPLICIT NumericString
+            '''
+            tagSet = NumericString.tagSet.tagImplicitly(
+                Tag(tagClassApplication, tagFormatSimple, 5)
+            )
+
+        orderNumber = OrderNumber('1234')
+    """
+    def __init__(self, baseTag=(), *superTags):
+        self.__baseTag = baseTag
+        self.__superTags = superTags
+        self.__superTagsClassId = tuple(
+            [(superTag.tagClass, superTag.tagId) for superTag in superTags]
+        )
+        self.__lenOfSuperTags = len(superTags)
+        self.__hash = hash(self.__superTagsClassId)
+
+    def __repr__(self):
+        representation = '-'.join(['%s:%s:%s' % (x.tagClass, x.tagFormat, x.tagId)
+                                   for x in self.__superTags])
+        if representation:
+            representation = 'tags ' + representation
+        else:
+            representation = 'untagged'
+
+        return '<%s object, %s>' % (self.__class__.__name__, representation)
+
+    def __add__(self, superTag):
+        return self.__class__(self.__baseTag, *self.__superTags + (superTag,))
+
+    def __radd__(self, superTag):
+        return self.__class__(self.__baseTag, *(superTag,) + self.__superTags)
+
+    def __getitem__(self, i):
+        if i.__class__ is slice:
+            return self.__class__(self.__baseTag, *self.__superTags[i])
+        else:
+            return self.__superTags[i]
+
+    def __eq__(self, other):
+        return self.__superTagsClassId == other
+
+    def __ne__(self, other):
+        return self.__superTagsClassId != other
+
+    def __lt__(self, other):
+        return self.__superTagsClassId < other
+
+    def __le__(self, other):
+        return self.__superTagsClassId <= other
+
+    def __gt__(self, other):
+        return self.__superTagsClassId > other
+
+    def __ge__(self, other):
+        return self.__superTagsClassId >= other
+
+    def __hash__(self):
+        return self.__hash
+
+    def __len__(self):
+        return self.__lenOfSuperTags
+
+    @property
+    def baseTag(self):
+        """Return base ASN.1 tag
+
+        Returns
+        -------
+        : :class:`~pyasn1.type.tag.Tag`
+            Base tag of this *TagSet*
+        """
+        return self.__baseTag
+
+    @property
+    def superTags(self):
+        """Return ASN.1 tags
+
+        Returns
+        -------
+        : :py:class:`tuple`
+            Tuple of :class:`~pyasn1.type.tag.Tag` objects that this *TagSet* contains
+        """
+        return self.__superTags
+
+    def tagExplicitly(self, superTag):
+        """Return explicitly tagged *TagSet*
+
+        Create a new *TagSet* representing callee *TagSet* explicitly tagged
+        with passed tag(s). With explicit tagging mode, new tags are appended
+        to existing tag(s).
+
+        Parameters
+        ----------
+        superTag: :class:`~pyasn1.type.tag.Tag`
+            *Tag* object to tag this *TagSet*
+
+        Returns
+        -------
+        : :class:`~pyasn1.type.tag.TagSet`
+            New *TagSet* object
+        """
+        if superTag.tagClass == tagClassUniversal:
+            raise error.PyAsn1Error("Can't tag with UNIVERSAL class tag")
+        if superTag.tagFormat != tagFormatConstructed:
+            superTag = Tag(superTag.tagClass, tagFormatConstructed, superTag.tagId)
+        return self + superTag
+
+    def tagImplicitly(self, superTag):
+        """Return implicitly tagged *TagSet*
+
+        Create a new *TagSet* representing callee *TagSet* implicitly tagged
+        with passed tag(s). With implicit tagging mode, new tag(s) replace the
+        last existing tag.
+
+        Parameters
+        ----------
+        superTag: :class:`~pyasn1.type.tag.Tag`
+            *Tag* object to tag this *TagSet*
+
+        Returns
+        -------
+        : :class:`~pyasn1.type.tag.TagSet`
+            New *TagSet* object
+        """
+        if self.__superTags:
+            superTag = Tag(superTag.tagClass, self.__superTags[-1].tagFormat, superTag.tagId)
+        return self[:-1] + superTag
+
+    def isSuperTagSetOf(self, tagSet):
+        """Test type relationship against given *TagSet*
+
+        The callee is considered to be a supertype of given *TagSet*
+        tag-wise if all tags in *TagSet* are present in the callee and
+        they are in the same order.
+
+        Parameters
+        ----------
+        tagSet: :class:`~pyasn1.type.tag.TagSet`
+            *TagSet* object to evaluate against the callee
+
+        Returns
+        -------
+        : :py:class:`bool`
+            :obj:`True` if callee is a supertype of *tagSet*
+        """
+        if len(tagSet) < self.__lenOfSuperTags:
+            return False
+        return self.__superTags == tagSet[:self.__lenOfSuperTags]
+
+    # Backward compatibility
+
+    def getBaseTag(self):
+        return self.__baseTag
+
+def initTagSet(tag):
+    return TagSet(tag, tag)

lib/pyasn1/type/tagmap.py

@@ -0,0 +1,96 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+from pyasn1 import error
+
+__all__ = ['TagMap']
+
+
+class TagMap(object):
+    """Map *TagSet* objects to ASN.1 types
+
+    Create an object mapping *TagSet* object to ASN.1 type.
+
+    *TagMap* objects are immutable and duck-type read-only Python
+    :class:`dict` objects holding *TagSet* objects as keys and ASN.1
+    type objects as values.
+
+    Parameters
+    ----------
+    presentTypes: :py:class:`dict`
+        Map of :class:`~pyasn1.type.tag.TagSet` to ASN.1 objects considered
+        as being unconditionally present in the *TagMap*.
+
+    skipTypes: :py:class:`dict`
+        A collection of :class:`~pyasn1.type.tag.TagSet` objects considered
+        as absent in the *TagMap* even when *defaultType* is present.
+
+    defaultType: ASN.1 type object
+        An ASN.1 type object callee *TagMap* returns for any *TagSet* key not present
+        in *presentTypes* (unless given key is present in *skipTypes*).
+    """
+    def __init__(self, presentTypes=None, skipTypes=None, defaultType=None):
+        self.__presentTypes = presentTypes or {}
+        self.__skipTypes = skipTypes or {}
+        self.__defaultType = defaultType
+
+    def __contains__(self, tagSet):
+        return (tagSet in self.__presentTypes or
+                self.__defaultType is not None and tagSet not in self.__skipTypes)
+
+    def __getitem__(self, tagSet):
+        try:
+            return self.__presentTypes[tagSet]
+        except KeyError:
+            if self.__defaultType is None:
+                raise KeyError()
+            elif tagSet in self.__skipTypes:
+                raise error.PyAsn1Error('Key in negative map')
+            else:
+                return self.__defaultType
+
+    def __iter__(self):
+        return iter(self.__presentTypes)
+
+    def __repr__(self):
+        representation = '%s object' % self.__class__.__name__
+
+        if self.__presentTypes:
+            representation += ', present %s' % repr(self.__presentTypes)
+
+        if self.__skipTypes:
+            representation += ', skip %s' % repr(self.__skipTypes)
+
+        if self.__defaultType is not None:
+            representation += ', default %s' % repr(self.__defaultType)
+
+        return '<%s>' % representation
+
+    @property
+    def presentTypes(self):
+        """Return *TagSet* to ASN.1 type map present in callee *TagMap*"""
+        return self.__presentTypes
+
+    @property
+    def skipTypes(self):
+        """Return *TagSet* collection unconditionally absent in callee *TagMap*"""
+        return self.__skipTypes
+
+    @property
+    def defaultType(self):
+        """Return default ASN.1 type being returned for any missing *TagSet*"""
+        return self.__defaultType
+
+    # Backward compatibility
+
+    def getPosMap(self):
+        return self.presentTypes
+
+    def getNegMap(self):
+        return self.skipTypes
+
+    def getDef(self):
+        return self.defaultType

lib/pyasn1/type/useful.py

@@ -0,0 +1,189 @@
+#
+# This file is part of pyasn1 software.
+#
+# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
+# License: http://snmplabs.com/pyasn1/license.html
+#
+import datetime
+
+from pyasn1 import error
+from pyasn1.type import char
+from pyasn1.type import tag
+from pyasn1.type import univ
+
+__all__ = ['ObjectDescriptor', 'GeneralizedTime', 'UTCTime']
+
+NoValue = univ.NoValue
+noValue = univ.noValue
+
+
+class ObjectDescriptor(char.GraphicString):
+    __doc__ = char.GraphicString.__doc__
+
+    #: Default :py:class:`~pyasn1.type.tag.TagSet` object for |ASN.1| objects
+    tagSet = char.GraphicString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 7)
+    )
+
+    # Optimization for faster codec lookup
+    typeId = char.GraphicString.getTypeId()
+
+
+class TimeMixIn(object):
+
+    _yearsDigits = 4
+    _hasSubsecond = False
+    _optionalMinutes = False
+    _shortTZ = False
+
+    class FixedOffset(datetime.tzinfo):
+        """Fixed offset in minutes east from UTC."""
+
+        # defaulted arguments required
+        # https: // docs.python.org / 2.3 / lib / datetime - tzinfo.html
+        def __init__(self, offset=0, name='UTC'):
+            self.__offset = datetime.timedelta(minutes=offset)
+            self.__name = name
+
+        def utcoffset(self, dt):
+            return self.__offset
+
+        def tzname(self, dt):
+            return self.__name
+
+        def dst(self, dt):
+            return datetime.timedelta(0)
+
+    UTC = FixedOffset()
+
+    @property
+    def asDateTime(self):
+        """Create :py:class:`datetime.datetime` object from a |ASN.1| object.
+
+        Returns
+        -------
+        :
+            new instance of :py:class:`datetime.datetime` object
+        """
+        text = str(self)
+        if text.endswith('Z'):
+            tzinfo = TimeMixIn.UTC
+            text = text[:-1]
+
+        elif '-' in text or '+' in text:
+            if '+' in text:
+                text, plusminus, tz = text.partition('+')
+            else:
+                text, plusminus, tz = text.partition('-')
+
+            if self._shortTZ and len(tz) == 2:
+                tz += '00'
+
+            if len(tz) != 4:
+                raise error.PyAsn1Error('malformed time zone offset %s' % tz)
+
+            try:
+                minutes = int(tz[:2]) * 60 + int(tz[2:])
+                if plusminus == '-':
+                    minutes *= -1
+
+            except ValueError:
+                raise error.PyAsn1Error('unknown time specification %s' % self)
+
+            tzinfo = TimeMixIn.FixedOffset(minutes, '?')
+
+        else:
+            tzinfo = None
+
+        if '.' in text or ',' in text:
+            if '.' in text:
+                text, _, ms = text.partition('.')
+            else:
+                text, _, ms = text.partition(',')
+
+            try:
+                ms = int(ms) * 1000
+
+            except ValueError:
+                raise error.PyAsn1Error('bad sub-second time specification %s' % self)
+
+        else:
+            ms = 0
+
+        if self._optionalMinutes and len(text) - self._yearsDigits == 6:
+            text += '0000'
+        elif len(text) - self._yearsDigits == 8:
+            text += '00'
+
+        try:
+            dt = datetime.datetime.strptime(text, self._yearsDigits == 4 and '%Y%m%d%H%M%S' or '%y%m%d%H%M%S')
+
+        except ValueError:
+            raise error.PyAsn1Error('malformed datetime format %s' % self)
+
+        return dt.replace(microsecond=ms, tzinfo=tzinfo)
+
+    @classmethod
+    def fromDateTime(cls, dt):
+        """Create |ASN.1| object from a :py:class:`datetime.datetime` object.
+
+        Parameters
+        ----------
+        dt: :py:class:`datetime.datetime` object
+            The `datetime.datetime` object to initialize the |ASN.1| object
+            from
+
+        Returns
+        -------
+        :
+            new instance of |ASN.1| value
+        """
+        text = dt.strftime(cls._yearsDigits == 4 and '%Y%m%d%H%M%S' or '%y%m%d%H%M%S')
+        if cls._hasSubsecond:
+            text += '.%d' % (dt.microsecond // 1000)
+
+        if dt.utcoffset():
+            seconds = dt.utcoffset().seconds
+            if seconds < 0:
+                text += '-'
+            else:
+                text += '+'
+            text += '%.2d%.2d' % (seconds // 3600, seconds % 3600)
+        else:
+            text += 'Z'
+
+        return cls(text)
+
+
+class GeneralizedTime(char.VisibleString, TimeMixIn):
+    __doc__ = char.VisibleString.__doc__
+
+    #: Default :py:class:`~pyasn1.type.tag.TagSet` object for |ASN.1| objects
+    tagSet = char.VisibleString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 24)
+    )
+
+    # Optimization for faster codec lookup
+    typeId = char.VideotexString.getTypeId()
+
+    _yearsDigits = 4
+    _hasSubsecond = True
+    _optionalMinutes = True
+    _shortTZ = True
+
+
+class UTCTime(char.VisibleString, TimeMixIn):
+    __doc__ = char.VisibleString.__doc__
+
+    #: Default :py:class:`~pyasn1.type.tag.TagSet` object for |ASN.1| objects
+    tagSet = char.VisibleString.tagSet.tagImplicitly(
+        tag.Tag(tag.tagClassUniversal, tag.tagFormatSimple, 23)
+    )
+
+    # Optimization for faster codec lookup
+    typeId = char.VideotexString.getTypeId()
+
+    _yearsDigits = 2
+    _hasSubsecond = False
+    _optionalMinutes = False
+    _shortTZ = False