Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/pyasn1/codec/der/decoder.py: 89%

1# 

2# This file is part of pyasn1 software. 

3# 

4# Copyright (c) 2005-2020, Ilya Etingof <etingof@gmail.com> 

5# License: https://pyasn1.readthedocs.io/en/latest/license.html 

6# 

7import warnings 

8 

9from pyasn1.codec.cer import decoder 

10from pyasn1.type import univ 

11 

12__all__ = ['decode', 'StreamingDecoder'] 

13 

14 

15class BitStringPayloadDecoder(decoder.BitStringPayloadDecoder): 

16 supportConstructedForm = False 

17 

18 

19class OctetStringPayloadDecoder(decoder.OctetStringPayloadDecoder): 

20 supportConstructedForm = False 

21 

22 

23# TODO: prohibit non-canonical encoding 

24RealPayloadDecoder = decoder.RealPayloadDecoder 

25 

26TAG_MAP = decoder.TAG_MAP.copy() 

27TAG_MAP.update( 

28 {univ.BitString.tagSet: BitStringPayloadDecoder(), 

29 univ.OctetString.tagSet: OctetStringPayloadDecoder(), 

30 univ.Real.tagSet: RealPayloadDecoder()} 

31) 

32 

33TYPE_MAP = decoder.TYPE_MAP.copy() 

34 

35# Put in non-ambiguous types for faster codec lookup 

36for typeDecoder in TAG_MAP.values(): 

37 if typeDecoder.protoComponent is not None: 

38 typeId = typeDecoder.protoComponent.__class__.typeId 

39 if typeId is not None and typeId not in TYPE_MAP: 

40 TYPE_MAP[typeId] = typeDecoder 

41 

42 

43class SingleItemDecoder(decoder.SingleItemDecoder): 

44 __doc__ = decoder.SingleItemDecoder.__doc__ 

45 

46 TAG_MAP = TAG_MAP 

47 TYPE_MAP = TYPE_MAP 

48 

49 supportIndefLength = False 

50 

51 

52class StreamingDecoder(decoder.StreamingDecoder): 

53 __doc__ = decoder.StreamingDecoder.__doc__ 

54 

55 SINGLE_ITEM_DECODER = SingleItemDecoder 

56 

57 

58class Decoder(decoder.Decoder): 

59 __doc__ = decoder.Decoder.__doc__ 

60 

61 STREAMING_DECODER = StreamingDecoder 

62 

63 

64#: Turns DER octet stream into an ASN.1 object. 

65#: 

66#: Takes DER octet-stream and decode it into an ASN.1 object 

67#: (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative) which 

68#: may be a scalar or an arbitrary nested structure. 

69#: 

70#: Parameters 

71#: ---------- 

72#: substrate: :py:class:`bytes` 

73#: DER octet-stream 

74#: 

75#: Keyword Args 

76#: ------------ 

77#: asn1Spec: any pyasn1 type object e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative 

78#: A pyasn1 type object to act as a template guiding the decoder. Depending on the ASN.1 structure 

79#: being decoded, *asn1Spec* may or may not be required. Most common reason for 

80#: it to require is that ASN.1 structure is encoded in *IMPLICIT* tagging mode. 

81#: 

82#: Returns 

83#: ------- 

84#: : :py:class:`tuple` 

85#: A tuple of pyasn1 object recovered from DER substrate (:py:class:`~pyasn1.type.base.PyAsn1Item` derivative) 

86#: and the unprocessed trailing portion of the *substrate* (may be empty) 

87#: 

88#: Raises 

89#: ------ 

90#: ~pyasn1.error.PyAsn1Error, ~pyasn1.error.SubstrateUnderrunError 

91#: On decoding errors 

92#: 

93#: Examples 

94#: -------- 

95#: Decode DER serialisation without ASN.1 schema 

96#: 

97#: .. code-block:: pycon 

98#: 

99#: >>> s, _ = decode(b'0\t\x02\x01\x01\x02\x01\x02\x02\x01\x03') 

100#: >>> str(s) 

101#: SequenceOf: 

102#: 1 2 3 

103#: 

104#: Decode DER serialisation with ASN.1 schema 

105#: 

106#: .. code-block:: pycon 

107#: 

108#: >>> seq = SequenceOf(componentType=Integer()) 

109#: >>> s, _ = decode(b'0\t\x02\x01\x01\x02\x01\x02\x02\x01\x03', asn1Spec=seq) 

110#: >>> str(s) 

111#: SequenceOf: 

112#: 1 2 3 

113#: 

114decode = Decoder() 

115 

116def __getattr__(attr: str): 

117 if newAttr := {"tagMap": "TAG_MAP", "typeMap": "TYPE_MAP"}.get(attr): 

118 warnings.warn(f"{attr} is deprecated. Please use {newAttr} instead.", DeprecationWarning) 

119 return globals()[newAttr] 

120 raise AttributeError(attr)