#
# This file is part of pyasn1 software.
#
# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com>
# License: https://pyasn1.readthedocs.io/en/latest/license.html
#
import sys
from pyasn1 import error
from pyasn1.type import tag
from pyasn1.type import tagmap
__all__ = ['NamedType', 'OptionalNamedType', 'DefaultedNamedType',
'NamedTypes']
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)
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
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