Convenient decod() helper method

[pyderasn.git] / pyderasn.py

diff --git a/pyderasn.py b/pyderasn.py
index 172c1f6474705de88d59918be509c1658a79e0aa..5f0c0343ccd0d4153d29e6328fde4a73882229ec 100755 (executable)
--- a/pyderasn.py
+++ b/pyderasn.py
@@ -1,12 +1,11 @@
 #!/usr/bin/env python
 # coding: utf-8
 # PyDERASN -- Python ASN.1 DER/BER codec with abstract structures
 #!/usr/bin/env python
 # coding: utf-8
 # PyDERASN -- Python ASN.1 DER/BER codec with abstract structures

-# Copyright (C) 2017-2019 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2017-2020 Sergey Matveev <stargrave@stargrave.org>

 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Lesser General Public License as
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Lesser General Public License as

-# published by the Free Software Foundation, either version 3 of the
-# License, or (at your option) any later version.
+# published by the Free Software Foundation, version 3 of the License.

 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of


@@ -14,8 +13,7 @@
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public

-# License along with this program.  If not, see
-# <http://www.gnu.org/licenses/>.
+# License along with this program.  If not, see <http://www.gnu.org/licenses/>.

 """Python ASN.1 DER/BER codec with abstract structures
 
 This library allows you to marshal various structures in ASN.1 DER
 """Python ASN.1 DER/BER codec with abstract structures
 
 This library allows you to marshal various structures in ASN.1 DER


@@ -239,6 +237,105 @@ all object ``repr``. But it is easy to write custom formatters.
     >>> print(pprint(obj))
         0   [1,1,   2] INTEGER -12345
 
     >>> print(pprint(obj))
         0   [1,1,   2] INTEGER -12345
 

+.. _pprint_example:
+
+Example certificate::
+
+    >>> print(pprint(crt))
+        0   [1,3,1604] Certificate SEQUENCE
+        4   [1,3,1453]  . tbsCertificate: TBSCertificate SEQUENCE
+       10-2 [1,1,   1]  . . version: [0] EXPLICIT Version INTEGER v3 OPTIONAL
+       13   [1,1,   3]  . . serialNumber: CertificateSerialNumber INTEGER 61595
+       18   [1,1,  13]  . . signature: AlgorithmIdentifier SEQUENCE
+       20   [1,1,   9]  . . . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
+       31   [0,0,   2]  . . . parameters: [UNIV 5] ANY OPTIONAL
+                        . . . . 05:00
+       33   [0,0, 278]  . . issuer: Name CHOICE rdnSequence
+       33   [1,3, 274]  . . . rdnSequence: RDNSequence SEQUENCE OF
+       37   [1,1,  11]  . . . . 0: RelativeDistinguishedName SET OF
+       39   [1,1,   9]  . . . . . 0: AttributeTypeAndValue SEQUENCE
+       41   [1,1,   3]  . . . . . . type: AttributeType OBJECT IDENTIFIER 2.5.4.6
+       46   [0,0,   4]  . . . . . . value: [UNIV 19] AttributeValue ANY
+                        . . . . . . . 13:02:45:53
+    [...]
+     1461   [1,1,  13]  . signatureAlgorithm: AlgorithmIdentifier SEQUENCE
+     1463   [1,1,   9]  . . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
+     1474   [0,0,   2]  . . parameters: [UNIV 5] ANY OPTIONAL
+                        . . . 05:00
+     1476   [1,2, 129]  . signatureValue: BIT STRING 1024 bits
+                        . . 68:EE:79:97:97:DD:3B:EF:16:6A:06:F2:14:9A:6E:CD
+                        . . 9E:12:F7:AA:83:10:BD:D1:7C:98:FA:C7:AE:D4:0E:2C
+     [...]
+
+    Trailing data: 0a
+
+Let's parse that output, human::
+
+       10-2 [1,1,   1]    . . version: [0] EXPLICIT Version INTEGER v3 OPTIONAL
+       ^  ^  ^ ^    ^     ^   ^        ^            ^       ^       ^  ^
+       0  1  2 3    4     5   6        7            8       9       10 11
+
+::
+
+       20   [1,1,   9]    . . . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
+       ^     ^ ^    ^     ^     ^          ^                 ^
+       0     2 3    4     5     6          9                 10
+
+::
+
+       33   [0,0, 278]    . . issuer: Name CHOICE rdnSequence
+       ^     ^ ^    ^     ^   ^       ^    ^      ^
+       0     2 3    4     5   6       8    9      10
+
+::
+
+       52-2∞ B [1,1,1054]∞  . . . . eContent: [0] EXPLICIT BER OCTET STRING 1046 bytes
+             ^           ^                                 ^   ^            ^
+            12          13                                14   9            10
+
+:0:
+ Offset of the object, where its DER/BER encoding begins.
+ Pay attention that it does **not** include explicit tag.
+:1:
+ If explicit tag exists, then this is its length (tag + encoded length).
+:2:
+ Length of object's tag. For example CHOICE does not have its own tag,
+ so it is zero.
+:3:
+ Length of encoded length.
+:4:
+ Length of encoded value.
+:5:
+ Visual indentation to show the depth of object in the hierarchy.
+:6:
+ Object's name inside SEQUENCE/CHOICE.
+:7:
+ If either IMPLICIT or EXPLICIT tag is set, then it will be shown
+ here. "IMPLICIT" is omitted.
+:8:
+ Object's class name, if set. Omitted if it is just an ordinary simple
+ value (like with ``algorithm`` in example above).
+:9:
+ Object's ASN.1 type.
+:10:
+ Object's value, if set. Can consist of multiple words (like OCTET/BIT
+ STRINGs above). We see ``v3`` value in Version, because it is named.
+ ``rdnSequence`` is the choice of CHOICE type.
+:11:
+ Possible other flags like OPTIONAL and DEFAULT, if value equals to the
+ default one, specified in the schema.
+:12:
+ Shows does object contains any kind of BER encoded data (possibly
+ Sequence holding BER-encoded underlying value).
+:13:
+ Only applicable to BER encoded data. Indefinite length encoding mark.
+:14:
+ Only applicable to BER encoded data. If object has BER-specific
+ encoding, then ``BER`` will be shown. It does not depend on indefinite
+ length encoding. ``EOC``, ``BOOLEAN``, ``BIT STRING``, ``OCTET STRING``
+ (and its derivatives), ``SET``, ``SET OF`` could be BERed.
+
+

 .. _definedby:
 
 DEFINED BY
 .. _definedby:
 
 DEFINED BY


@@ -249,6 +346,8 @@ DEFINED BY some previously met ObjectIdentifier. This library provides
 ability to specify mapping between some OID and field that must be
 decoded with specific specification.
 
 ability to specify mapping between some OID and field that must be
 decoded with specific specification.
 

+.. _defines:
+

 defines kwarg
 _____________
 
 defines kwarg
 _____________
 


@@ -322,15 +421,15 @@ value must be sequence of following tuples::
 
 where ``decode_path`` is a tuple holding so-called decode path to the
 exact :py:class:`pyderasn.ObjectIdentifier` field you want to apply
 
 where ``decode_path`` is a tuple holding so-called decode path to the
 exact :py:class:`pyderasn.ObjectIdentifier` field you want to apply

-``defines``, holding exactly the same value as accepted in its keyword
-argument.
+``defines``, holding exactly the same value as accepted in its
+:ref:`keyword argument <defines>`.

 
 For example, again for CMS, you want to automatically decode
 ``SignedData`` and CMC's (:rfc:`5272`) ``PKIData`` and ``PKIResponse``
 structures it may hold. Also, automatically decode ``controlSequence``
 of ``PKIResponse``::
 
 
 For example, again for CMS, you want to automatically decode
 ``SignedData`` and CMC's (:rfc:`5272`) ``PKIData`` and ``PKIResponse``
 structures it may hold. Also, automatically decode ``controlSequence``
 of ``PKIResponse``::
 

-    content_info, tail = ContentInfo().decode(data, defines_by_path=(
+    content_info, tail = ContentInfo().decode(data, ctx={"defines_by_path": (

         (
             ("contentType",),
             ((("content",), {id_signedData: SignedData()}),),
         (
             ("contentType",),
             ((("content",), {id_signedData: SignedData()}),),


@@ -365,7 +464,7 @@ of ``PKIResponse``::
                 id_cmc_transactionId: TransactionId(),
             })),
         ),
                 id_cmc_transactionId: TransactionId(),
             })),
         ),

-    ))
+    )})

 
 Pay attention for :py:class:`pyderasn.DecodePathDefBy` and ``any``.
 First function is useful for path construction when some automatic
 
 Pay attention for :py:class:`pyderasn.DecodePathDefBy` and ``any``.
 First function is useful for path construction when some automatic


@@ -418,6 +517,11 @@ lengths will be invalid in that case.
    This option should be used only for skipping some decode errors, just
    to see the decoded structure somehow.
 
    This option should be used only for skipping some decode errors, just
    to see the decoded structure somehow.
 

+Base Obj
+--------
+.. autoclass:: pyderasn.Obj
+   :members:
+

 Primitive types
 ---------------
 
 Primitive types
 ---------------
 


@@ -527,10 +631,10 @@ Various
 .. autofunction:: pyderasn.tag_decode
 .. autofunction:: pyderasn.tag_ctxp
 .. autofunction:: pyderasn.tag_ctxc
 .. autofunction:: pyderasn.tag_decode
 .. autofunction:: pyderasn.tag_ctxp
 .. autofunction:: pyderasn.tag_ctxc

-.. autoclass:: pyderasn.Obj

 .. autoclass:: pyderasn.DecodeError
    :members: __init__
 .. autoclass:: pyderasn.NotEnoughData
 .. autoclass:: pyderasn.DecodeError
    :members: __init__
 .. autoclass:: pyderasn.NotEnoughData

+.. autoclass:: pyderasn.ExceedingData

 .. autoclass:: pyderasn.LenIndefForm
 .. autoclass:: pyderasn.TagMismatch
 .. autoclass:: pyderasn.InvalidLength
 .. autoclass:: pyderasn.LenIndefForm
 .. autoclass:: pyderasn.TagMismatch
 .. autoclass:: pyderasn.InvalidLength


@@ -571,9 +675,10 @@ from six.moves import xrange as six_xrange
 try:
     from termcolor import colored
 except ImportError:  # pragma: no cover
 try:
     from termcolor import colored
 except ImportError:  # pragma: no cover

-    def colored(what, *args):
+    def colored(what, *args, **kwargs):

         return what
 
         return what
 

+__version__ = "5.6"

 
 __all__ = (
     "Any",
 
 __all__ = (
     "Any",


@@ -585,6 +690,7 @@ __all__ = (
     "DecodeError",
     "DecodePathDefBy",
     "Enumerated",
     "DecodeError",
     "DecodePathDefBy",
     "Enumerated",

+    "ExceedingData",

     "GeneralizedTime",
     "GeneralString",
     "GraphicString",
     "GeneralizedTime",
     "GeneralString",
     "GraphicString",


@@ -695,6 +801,18 @@ class NotEnoughData(DecodeError):
     pass
 
 
     pass
 
 

+class ExceedingData(ASN1Error):
+    def __init__(self, nbytes):
+        super(ExceedingData, self).__init__()
+        self.nbytes = nbytes
+
+    def __str__(self):
+        return "%d trailing bytes" % self.nbytes
+
+    def __repr__(self):
+        return "%s(%s)" % (self.__class__.__name__, self)
+
+

 class LenIndefForm(DecodeError):
     pass
 
 class LenIndefForm(DecodeError):
     pass
 


@@ -920,9 +1038,9 @@ def len_decode(data):
 ########################################################################
 
 class AutoAddSlots(type):
 ########################################################################
 
 class AutoAddSlots(type):

-    def __new__(mcs, name, bases, _dict):
+    def __new__(cls, name, bases, _dict):

         _dict["__slots__"] = _dict.get("__slots__", ())
         _dict["__slots__"] = _dict.get("__slots__", ())

-        return type.__new__(mcs, name, bases, _dict)
+        return type.__new__(cls, name, bases, _dict)

 
 
 @add_metaclass(AutoAddSlots)
 
 
 @add_metaclass(AutoAddSlots)


@@ -996,10 +1114,14 @@ class Obj(object):
 
     @property
     def tlen(self):
 
     @property
     def tlen(self):

+        """See :ref:`decoding`
+        """

         return len(self.tag)
 
     @property
     def tlvlen(self):
         return len(self.tag)
 
     @property
     def tlvlen(self):

+        """See :ref:`decoding`
+        """

         return self.tlen + self.llen + self.vlen
 
     def __str__(self):  # pragma: no cover
         return self.tlen + self.llen + self.vlen
 
     def __str__(self):  # pragma: no cover


@@ -1024,6 +1146,10 @@ class Obj(object):
         raise NotImplementedError()
 
     def encode(self):
         raise NotImplementedError()
 
     def encode(self):

+        """Encode the structure
+
+        :returns: DER representation
+        """

         raw = self._encode()
         if self._expl is None:
             return raw
         raw = self._encode()
         if self._expl is None:
             return raw


@@ -1051,6 +1177,8 @@ class Obj(object):
                          determine if tag satisfies the scheme)
         :param _ctx_immutable: do we need to copy ``ctx`` before using it
         :returns: (Obj, remaining data)
                          determine if tag satisfies the scheme)
         :param _ctx_immutable: do we need to copy ``ctx`` before using it
         :returns: (Obj, remaining data)

+
+        .. seealso:: :ref:`decoding`

         """
         if ctx is None:
             ctx = {}
         """
         if ctx is None:
             ctx = {}


@@ -1066,7 +1194,7 @@ class Obj(object):
                 tag_only=tag_only,
             )
             if tag_only:
                 tag_only=tag_only,
             )
             if tag_only:

-                return
+                return None

             obj, tail = result
         else:
             try:
             obj, tail = result
         else:
             try:


@@ -1104,7 +1232,7 @@ class Obj(object):
                     tag_only=tag_only,
                 )
                 if tag_only:  # pragma: no cover
                     tag_only=tag_only,
                 )
                 if tag_only:  # pragma: no cover

-                    return
+                    return None

                 obj, tail = result
                 eoc_expected, tail = tail[:EOC_LEN], tail[EOC_LEN:]
                 if eoc_expected.tobytes() != EOC:
                 obj, tail = result
                 eoc_expected, tail = tail[:EOC_LEN], tail[EOC_LEN:]
                 if eoc_expected.tobytes() != EOC:


@@ -1139,7 +1267,7 @@ class Obj(object):
                     tag_only=tag_only,
                 )
                 if tag_only:  # pragma: no cover
                     tag_only=tag_only,
                 )
                 if tag_only:  # pragma: no cover

-                    return
+                    return None

                 obj, tail = result
                 if obj.tlvlen < l and not ctx.get("allow_expl_oob", False):
                     raise DecodeError(
                 obj, tail = result
                 if obj.tlvlen < l and not ctx.get("allow_expl_oob", False):
                     raise DecodeError(


@@ -1150,42 +1278,80 @@ class Obj(object):
                     )
         return obj, (tail if leavemm else tail.tobytes())
 
                     )
         return obj, (tail if leavemm else tail.tobytes())
 

+    def decod(self, data, offset=0, decode_path=(), ctx=None):
+        """Decode the data, check that tail is empty
+
+        :raises ExceedingData: if tail is not empty
+
+        This is just a wrapper over :py:meth:`pyderasn.Obj.decode`
+        (decode without tail) that also checks that there is no
+        trailing data left.
+        """
+        obj, tail = self.decode(
+            data,
+            offset=offset,
+            decode_path=decode_path,
+            ctx=ctx,
+            leavemm=True,
+        )
+        if len(tail) > 0:
+            raise ExceedingData(len(tail))
+        return obj
+

     @property
     def expled(self):
     @property
     def expled(self):

+        """See :ref:`decoding`
+        """

         return self._expl is not None
 
     @property
     def expl_tag(self):
         return self._expl is not None
 
     @property
     def expl_tag(self):

+        """See :ref:`decoding`
+        """

         return self._expl
 
     @property
     def expl_tlen(self):
         return self._expl
 
     @property
     def expl_tlen(self):

+        """See :ref:`decoding`
+        """

         return len(self._expl)
 
     @property
     def expl_llen(self):
         return len(self._expl)
 
     @property
     def expl_llen(self):

+        """See :ref:`decoding`
+        """

         if self.expl_lenindef:
             return 1
         return len(len_encode(self.tlvlen))
 
     @property
     def expl_offset(self):
         if self.expl_lenindef:
             return 1
         return len(len_encode(self.tlvlen))
 
     @property
     def expl_offset(self):

+        """See :ref:`decoding`
+        """

         return self.offset - self.expl_tlen - self.expl_llen
 
     @property
     def expl_vlen(self):
         return self.offset - self.expl_tlen - self.expl_llen
 
     @property
     def expl_vlen(self):

+        """See :ref:`decoding`
+        """

         return self.tlvlen
 
     @property
     def expl_tlvlen(self):
         return self.tlvlen
 
     @property
     def expl_tlvlen(self):

+        """See :ref:`decoding`
+        """

         return self.expl_tlen + self.expl_llen + self.expl_vlen
 
     @property
     def fulloffset(self):
         return self.expl_tlen + self.expl_llen + self.expl_vlen
 
     @property
     def fulloffset(self):

+        """See :ref:`decoding`
+        """

         return self.expl_offset if self.expled else self.offset
 
     @property
     def fulllen(self):
         return self.expl_offset if self.expled else self.offset
 
     @property
     def fulllen(self):

+        """See :ref:`decoding`
+        """

         return self.expl_tlvlen if self.expled else self.tlvlen
 
     def pps_lenindef(self, decode_path):
         return self.expl_tlvlen if self.expled else self.tlvlen
 
     def pps_lenindef(self, decode_path):


@@ -1336,7 +1502,7 @@ def colonize_hex(hexed):
 
 def pp_console_row(
         pp,
 
 def pp_console_row(
         pp,

-        oids=None,
+        oid_maps=(),

         with_offsets=False,
         with_blob=True,
         with_colours=False,
         with_offsets=False,
         with_blob=True,
         with_colours=False,


@@ -1371,14 +1537,18 @@ def pp_console_row(
         if isinstance(ent, DecodePathDefBy):
             cols.append(_colourize("DEFINED BY", "red", with_colours, ("reverse",)))
             value = str(ent.defined_by)
         if isinstance(ent, DecodePathDefBy):
             cols.append(_colourize("DEFINED BY", "red", with_colours, ("reverse",)))
             value = str(ent.defined_by)

+            oid_name = None

             if (
             if (

-                    oids is not None and
+                    len(oid_maps) > 0 and

                     ent.defined_by.asn1_type_name ==
                     ent.defined_by.asn1_type_name ==

-                    ObjectIdentifier.asn1_type_name and
-                    value in oids
+                    ObjectIdentifier.asn1_type_name

             ):
             ):

-                cols.append(_colourize("%s:" % oids[value], "green", with_colours))
-            else:
+                for oid_map in oid_maps:
+                    oid_name = oid_map.get(value)
+                    if oid_name is not None:
+                        cols.append(_colourize("%s:" % oid_name, "green", with_colours))
+                        break
+            if oid_name is None:

                 cols.append(_colourize("%s:" % value, "white", with_colours, ("reverse",)))
         else:
             cols.append(_colourize("%s:" % ent, "yellow", with_colours, ("reverse",)))
                 cols.append(_colourize("%s:" % value, "white", with_colours, ("reverse",)))
         else:
             cols.append(_colourize("%s:" % ent, "yellow", with_colours, ("reverse",)))


@@ -1399,11 +1569,14 @@ def pp_console_row(
         value = pp.value
         cols.append(_colourize(value, "white", with_colours, ("reverse",)))
         if (
         value = pp.value
         cols.append(_colourize(value, "white", with_colours, ("reverse",)))
         if (

-                oids is not None and
-                pp.asn1_type_name == ObjectIdentifier.asn1_type_name and
-                value in oids
+                len(oid_maps) > 0 and
+                pp.asn1_type_name == ObjectIdentifier.asn1_type_name

         ):
         ):

-            cols.append(_colourize("(%s)" % oids[value], "green", with_colours))
+            for oid_map in oid_maps:
+                oid_name = oid_map.get(value)
+                if oid_name is not None:
+                    cols.append(_colourize("(%s)" % oid_name, "green", with_colours))
+                    break

         if pp.asn1_type_name == Integer.asn1_type_name:
             hex_repr = hex(int(pp.obj._value))[2:].upper()
             if len(hex_repr) % 2 != 0:
         if pp.asn1_type_name == Integer.asn1_type_name:
             hex_repr = hex(int(pp.obj._value))[2:].upper()
             if len(hex_repr) % 2 != 0:


@@ -1447,7 +1620,7 @@ def pp_console_blob(pp, decode_path_len_decrease=0):
 
 def pprint(
         obj,
 
 def pprint(
         obj,

-        oids=None,
+        oid_maps=(),

         big_blobs=False,
         with_colours=False,
         with_decode_path=False,
         big_blobs=False,
         with_colours=False,
         with_decode_path=False,


@@ -1456,8 +1629,9 @@ def pprint(
     """Pretty print object
 
     :param Obj obj: object you want to pretty print
     """Pretty print object
 
     :param Obj obj: object you want to pretty print

-    :param oids: ``OID <-> humand readable string`` dictionary. When OID
-                 from it is met, then its humand readable form is printed
+    :param oid_maps: list of ``OID <-> humand readable string`` dictionary.
+                     When OID from it is met, then its humand readable form
+                     is printed

     :param big_blobs: if large binary objects are met (like OctetString
                       values), do we need to print them too, on separate
                       lines
     :param big_blobs: if large binary objects are met (like OctetString
                       values), do we need to print them too, on separate
                       lines


@@ -1479,7 +1653,7 @@ def pprint(
                 if big_blobs:
                     yield pp_console_row(
                         pp,
                 if big_blobs:
                     yield pp_console_row(
                         pp,

-                        oids=oids,
+                        oid_maps=oid_maps,

                         with_offsets=True,
                         with_blob=False,
                         with_colours=with_colours,
                         with_offsets=True,
                         with_blob=False,
                         with_colours=with_colours,


@@ -1494,7 +1668,7 @@ def pprint(
                 else:
                     yield pp_console_row(
                         pp,
                 else:
                     yield pp_console_row(
                         pp,

-                        oids=oids,
+                        oid_maps=oid_maps,

                         with_offsets=True,
                         with_blob=True,
                         with_colours=with_colours,
                         with_offsets=True,
                         with_blob=True,
                         with_colours=with_colours,


@@ -1640,7 +1814,7 @@ class Boolean(Obj):
                 offset=offset,
             )
         if tag_only:
                 offset=offset,
             )
         if tag_only:

-            return
+            return None

         try:
             l, _, v = len_decode(lv)
         except DecodeError as err:
         try:
             l, _, v = len_decode(lv)
         except DecodeError as err:


@@ -1870,6 +2044,7 @@ class Integer(Obj):
         for name, value in iteritems(self.specs):
             if value == self._value:
                 return name
         for name, value in iteritems(self.specs):
             if value == self._value:
                 return name

+        return None

 
     def __call__(
             self,
 
     def __call__(
             self,


@@ -1949,7 +2124,7 @@ class Integer(Obj):
                 offset=offset,
             )
         if tag_only:
                 offset=offset,
             )
         if tag_only:

-            return
+            return None

         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:
         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:


@@ -2169,7 +2344,7 @@ class BitString(Obj):
                     if not frozenset(value) <= SET01:
                         raise ValueError("B's coding contains unacceptable chars")
                     return self._bits2octets(value)
                     if not frozenset(value) <= SET01:
                         raise ValueError("B's coding contains unacceptable chars")
                     return self._bits2octets(value)

-                elif value.endswith("'H"):
+                if value.endswith("'H"):

                     value = value[1:-2]
                     return (
                         len(value) * 4,
                     value = value[1:-2]
                     return (
                         len(value) * 4,


@@ -2177,8 +2352,7 @@ class BitString(Obj):
                     )
             if isinstance(value, binary_type):
                 return (len(value) * 8, value)
                     )
             if isinstance(value, binary_type):
                 return (len(value) * 8, value)

-            else:
-                raise InvalidValueType((self.__class__, string_types, binary_type))
+            raise InvalidValueType((self.__class__, string_types, binary_type))

         if isinstance(value, tuple):
             if (
                     len(value) == 2 and
         if isinstance(value, tuple):
             if (
                     len(value) == 2 and


@@ -2297,7 +2471,7 @@ class BitString(Obj):
             octets,
         ))
 
             octets,
         ))
 

-    def _decode_chunk(self, lv, offset, decode_path, ctx):
+    def _decode_chunk(self, lv, offset, decode_path):

         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:
         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:


@@ -2367,8 +2541,8 @@ class BitString(Obj):
             )
         if t == self.tag:
             if tag_only:  # pragma: no cover
             )
         if t == self.tag:
             if tag_only:  # pragma: no cover

-                return
-            return self._decode_chunk(lv, offset, decode_path, ctx)
+                return None
+            return self._decode_chunk(lv, offset, decode_path)

         if t == self.tag_constructed:
             if not ctx.get("bered", False):
                 raise DecodeError(
         if t == self.tag_constructed:
             if not ctx.get("bered", False):
                 raise DecodeError(


@@ -2378,7 +2552,7 @@ class BitString(Obj):
                     offset=offset,
                 )
             if tag_only:  # pragma: no cover
                     offset=offset,
                 )
             if tag_only:  # pragma: no cover

-                return
+                return None

             lenindef = False
             try:
                 l, llen, v = len_decode(lv)
             lenindef = False
             try:
                 l, llen, v = len_decode(lv)


@@ -2687,7 +2861,7 @@ class OctetString(Obj):
             self._value,
         ))
 
             self._value,
         ))
 

-    def _decode_chunk(self, lv, offset, decode_path, ctx):
+    def _decode_chunk(self, lv, offset, decode_path):

         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:
         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:


@@ -2743,8 +2917,8 @@ class OctetString(Obj):
             )
         if t == self.tag:
             if tag_only:
             )
         if t == self.tag:
             if tag_only:

-                return
-            return self._decode_chunk(lv, offset, decode_path, ctx)
+                return None
+            return self._decode_chunk(lv, offset, decode_path)

         if t == self.tag_constructed:
             if not ctx.get("bered", False):
                 raise DecodeError(
         if t == self.tag_constructed:
             if not ctx.get("bered", False):
                 raise DecodeError(


@@ -2754,7 +2928,7 @@ class OctetString(Obj):
                     offset=offset,
                 )
             if tag_only:
                     offset=offset,
                 )
             if tag_only:

-                return
+                return None

             lenindef = False
             try:
                 l, llen, v = len_decode(lv)
             lenindef = False
             try:
                 l, llen, v = len_decode(lv)


@@ -2970,7 +3144,7 @@ class Null(Obj):
                 offset=offset,
             )
         if tag_only:  # pragma: no cover
                 offset=offset,
             )
         if tag_only:  # pragma: no cover

-            return
+            return None

         try:
             l, _, v = len_decode(lv)
         except DecodeError as err:
         try:
             l, _, v = len_decode(lv)
         except DecodeError as err:


@@ -3225,7 +3399,7 @@ class ObjectIdentifier(Obj):
                 offset=offset,
             )
         if tag_only:  # pragma: no cover
                 offset=offset,
             )
         if tag_only:  # pragma: no cover

-            return
+            return None

         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:
         try:
             l, llen, v = len_decode(lv)
         except DecodeError as err:


@@ -3733,7 +3907,7 @@ class UTCTime(CommonString):
             try:
                 value_decoded = value.decode("ascii")
             except (UnicodeEncodeError, UnicodeDecodeError) as err:
             try:
                 value_decoded = value.decode("ascii")
             except (UnicodeEncodeError, UnicodeDecodeError) as err:

-                raise DecodeError("invalid UTCTime encoding")
+                raise DecodeError("invalid UTCTime encoding: %r" % err)

             try:
                 self._strptime(value_decoded)
             except (TypeError, ValueError) as err:
             try:
                 self._strptime(value_decoded)
             except (TypeError, ValueError) as err:


@@ -3878,7 +4052,7 @@ class GeneralizedTime(UTCTime):
             try:
                 value_decoded = value.decode("ascii")
             except (UnicodeEncodeError, UnicodeDecodeError) as err:
             try:
                 value_decoded = value.decode("ascii")
             except (UnicodeEncodeError, UnicodeDecodeError) as err:

-                raise DecodeError("invalid GeneralizedTime encoding")
+                raise DecodeError("invalid GeneralizedTime encoding: %r" % err)

             try:
                 self._strptime(value_decoded)
             except (TypeError, ValueError) as err:
             try:
                 self._strptime(value_decoded)
             except (TypeError, ValueError) as err:


@@ -4143,7 +4317,7 @@ class Choice(Obj):
                 offset=offset,
             )
         if tag_only:  # pragma: no cover
                 offset=offset,
             )
         if tag_only:  # pragma: no cover

-            return
+            return None

         value, tail = spec.decode(
             tlv,
             offset=offset,
         value, tail = spec.decode(
             tlv,
             offset=offset,


@@ -4612,9 +4786,8 @@ class Sequence(Obj):
                 if spec.optional:
                     continue
                 return False
                 if spec.optional:
                     continue
                 return False

-            else:
-                if not value.ready:
-                    return False
+            if not value.ready:
+                return False

         return True
 
     @property
         return True
 
     @property


@@ -4726,7 +4899,7 @@ class Sequence(Obj):
                 offset=offset,
             )
         if tag_only:  # pragma: no cover
                 offset=offset,
             )
         if tag_only:  # pragma: no cover

-            return
+            return None

         lenindef = False
         ctx_bered = ctx.get("bered", False)
         try:
         lenindef = False
         ctx_bered = ctx.get("bered", False)
         try:


@@ -4778,8 +4951,8 @@ class Sequence(Obj):
                     ctx=ctx,
                     _ctx_immutable=False,
                 )
                     ctx=ctx,
                     _ctx_immutable=False,
                 )

-            except TagMismatch:
-                if spec.optional:
+            except TagMismatch as err:
+                if (len(err.decode_path) == len(decode_path) + 1) and spec.optional:

                     continue
                 raise
 
                     continue
                 raise
 


@@ -4976,7 +5149,7 @@ class Set(Sequence):
                 offset=offset,
             )
         if tag_only:
                 offset=offset,
             )
         if tag_only:

-            return
+            return None

         lenindef = False
         ctx_bered = ctx.get("bered", False)
         try:
         lenindef = False
         ctx_bered = ctx.get("bered", False)
         try:


@@ -5309,7 +5482,7 @@ class SequenceOf(Obj):
                 offset=offset,
             )
         if tag_only:
                 offset=offset,
             )
         if tag_only:

-            return
+            return None

         lenindef = False
         ctx_bered = ctx.get("bered", False)
         try:
         lenindef = False
         ctx_bered = ctx.get("bered", False)
         try:


@@ -5505,7 +5678,7 @@ def generic_decoder():  # pragma: no cover
 
     def pprint_any(
             obj,
 
     def pprint_any(
             obj,

-            oids=None,
+            oid_maps=(),

             with_colours=False,
             with_decode_path=False,
             decode_path_only=(),
             with_colours=False,
             with_decode_path=False,
             decode_path_only=(),


@@ -5525,7 +5698,7 @@ def generic_decoder():  # pragma: no cover
                     pp = _pp(**pp_kwargs)
                     yield pp_console_row(
                         pp,
                     pp = _pp(**pp_kwargs)
                     yield pp_console_row(
                         pp,

-                        oids=oids,
+                        oid_maps=oid_maps,

                         with_offsets=True,
                         with_blob=False,
                         with_colours=with_colours,
                         with_offsets=True,
                         with_blob=False,
                         with_colours=with_colours,


@@ -5555,7 +5728,7 @@ def main():  # pragma: no cover
     )
     parser.add_argument(
         "--oids",
     )
     parser.add_argument(
         "--oids",

-        help="Python path to dictionary with OIDs",
+        help="Python paths to dictionary with OIDs, comma separated",

     )
     parser.add_argument(
         "--schema",
     )
     parser.add_argument(
         "--schema",


@@ -5593,7 +5766,10 @@ def main():  # pragma: no cover
     args.DERFile.seek(args.skip)
     der = memoryview(args.DERFile.read())
     args.DERFile.close()
     args.DERFile.seek(args.skip)
     der = memoryview(args.DERFile.read())
     args.DERFile.close()

-    oids = obj_by_path(args.oids) if args.oids else {}
+    oid_maps = (
+        [obj_by_path(_path) for _path in (args.oids or "").split(",")]
+        if args.oids else ()
+    )

     if args.schema:
         schema = obj_by_path(args.schema)
         from functools import partial
     if args.schema:
         schema = obj_by_path(args.schema)
         from functools import partial


@@ -5609,8 +5785,8 @@ def main():  # pragma: no cover
     obj, tail = schema().decode(der, ctx=ctx)
     print(pprinter(
         obj,
     obj, tail = schema().decode(der, ctx=ctx)
     print(pprinter(
         obj,

-        oids=oids,
-        with_colours=True if environ.get("NO_COLOR") is None else False,
+        oid_maps=oid_maps,
+        with_colours=environ.get("NO_COLOR") is None,

         with_decode_path=args.print_decode_path,
         decode_path_only=(
             () if args.decode_path_only is None else
         with_decode_path=args.print_decode_path,
         decode_path_only=(
             () if args.decode_path_only is None else