Update libs
This commit is contained in:
Antoine Bertin
@@ -0,0 +1,746 @@
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# BER decoder
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from pyasn1.type import tag, base, univ, char, useful, tagmap
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from pyasn1.codec.ber import eoo
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from pyasn1.compat.octets import oct2int, octs2ints
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from pyasn1 import error
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class AbstractDecoder:
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protoComponent = None
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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raise error.PyAsn1Error('Decoder not implemented for %s' % tagSet)
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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raise error.PyAsn1Error('Indefinite length mode decoder not implemented for %s' % tagSet)
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class AbstractSimpleDecoder(AbstractDecoder):
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def _createComponent(self, asn1Spec, tagSet, value=None):
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if asn1Spec is None:
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return self.protoComponent.clone(value, tagSet)
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elif value is None:
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return asn1Spec
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else:
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return asn1Spec.clone(value)
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class AbstractConstructedDecoder(AbstractDecoder):
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def _createComponent(self, asn1Spec, tagSet, value=None):
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if asn1Spec is None:
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return self.protoComponent.clone(tagSet)
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else:
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return asn1Spec.clone()
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class EndOfOctetsDecoder(AbstractSimpleDecoder):
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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return eoo.endOfOctets, substrate[:length]
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class ExplicitTagDecoder(AbstractSimpleDecoder):
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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return decodeFun(substrate[:length], asn1Spec, tagSet, length)
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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value, substrate = decodeFun(substrate, asn1Spec, tagSet, length)
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terminator, substrate = decodeFun(substrate)
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if terminator == eoo.endOfOctets:
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return value, substrate
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else:
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raise error.PyAsn1Error('Missing end-of-octets terminator')
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explicitTagDecoder = ExplicitTagDecoder()
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class IntegerDecoder(AbstractSimpleDecoder):
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protoComponent = univ.Integer(0)
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precomputedValues = {
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'\x00': 0,
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'\x01': 1,
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'\x02': 2,
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'\x03': 3,
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'\x04': 4,
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'\x05': 5,
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'\x06': 6,
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'\x07': 7,
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'\x08': 8,
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'\x09': 9,
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'\xff': -1,
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'\xfe': -2,
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'\xfd': -3,
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'\xfc': -4,
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'\xfb': -5
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}
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def _valueFilter(self, value):
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try:
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return int(value)
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except OverflowError:
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return value
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
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state, decodeFun):
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substrate = substrate[:length]
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if not substrate:
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raise error.PyAsn1Error('Empty substrate')
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if substrate in self.precomputedValues:
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value = self.precomputedValues[substrate]
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else:
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firstOctet = oct2int(substrate[0])
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if firstOctet & 0x80:
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value = -1
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else:
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value = 0
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for octet in substrate:
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value = value << 8 | oct2int(octet)
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value = self._valueFilter(value)
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return self._createComponent(asn1Spec, tagSet, value), substrate
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class BooleanDecoder(IntegerDecoder):
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protoComponent = univ.Boolean(0)
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def _valueFilter(self, value):
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if value:
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return 1
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else:
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return 0
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class BitStringDecoder(AbstractSimpleDecoder):
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protoComponent = univ.BitString(())
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
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state, decodeFun):
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substrate = substrate[:length]
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if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
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if not substrate:
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raise error.PyAsn1Error('Missing initial octet')
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trailingBits = oct2int(substrate[0])
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if trailingBits > 7:
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raise error.PyAsn1Error(
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'Trailing bits overflow %s' % trailingBits
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)
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substrate = substrate[1:]
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lsb = p = 0; l = len(substrate)-1; b = ()
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while p <= l:
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if p == l:
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lsb = trailingBits
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j = 7
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o = oct2int(substrate[p])
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while j >= lsb:
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b = b + ((o>>j)&0x01,)
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j = j - 1
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p = p + 1
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return self._createComponent(asn1Spec, tagSet, b), ''
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r = self._createComponent(asn1Spec, tagSet, ())
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(substrate)
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r = r + component
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return r, substrate
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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r = self._createComponent(asn1Spec, tagSet, '')
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(substrate)
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if component == eoo.endOfOctets:
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break
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r = r + component
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else:
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raise error.SubstrateUnderrunError(
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'No EOO seen before substrate ends'
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)
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return r, substrate
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class OctetStringDecoder(AbstractSimpleDecoder):
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protoComponent = univ.OctetString('')
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
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state, decodeFun):
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substrate = substrate[:length]
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if tagSet[0][1] == tag.tagFormatSimple: # XXX what tag to check?
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return self._createComponent(asn1Spec, tagSet, substrate), ''
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r = self._createComponent(asn1Spec, tagSet, '')
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(substrate)
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r = r + component
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return r, substrate
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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r = self._createComponent(asn1Spec, tagSet, '')
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(substrate)
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if component == eoo.endOfOctets:
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break
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r = r + component
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else:
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raise error.SubstrateUnderrunError(
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'No EOO seen before substrate ends'
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)
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return r, substrate
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class NullDecoder(AbstractSimpleDecoder):
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protoComponent = univ.Null('')
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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substrate = substrate[:length]
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r = self._createComponent(asn1Spec, tagSet)
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if substrate:
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raise error.PyAsn1Error('Unexpected substrate for Null')
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return r, substrate
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class ObjectIdentifierDecoder(AbstractSimpleDecoder):
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protoComponent = univ.ObjectIdentifier(())
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
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state, decodeFun):
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substrate = substrate[:length]
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if not substrate:
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raise error.PyAsn1Error('Empty substrate')
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oid = (); index = 0
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# Get the first subid
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subId = oct2int(substrate[index])
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oid = oid + divmod(subId, 40)
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index = index + 1
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substrateLen = len(substrate)
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while index < substrateLen:
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subId = oct2int(substrate[index])
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if subId < 128:
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oid = oid + (subId,)
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index = index + 1
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else:
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# Construct subid from a number of octets
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nextSubId = subId
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subId = 0
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while nextSubId >= 128 and index < substrateLen:
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subId = (subId << 7) + (nextSubId & 0x7F)
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index = index + 1
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nextSubId = oct2int(substrate[index])
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if index == substrateLen:
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raise error.SubstrateUnderrunError(
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'Short substrate for OID %s' % oid
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)
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subId = (subId << 7) + nextSubId
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oid = oid + (subId,)
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index = index + 1
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return self._createComponent(asn1Spec, tagSet, oid), substrate[index:]
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class RealDecoder(AbstractSimpleDecoder):
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protoComponent = univ.Real()
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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substrate = substrate[:length]
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if not length:
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raise error.SubstrateUnderrunError('Short substrate for Real')
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fo = oct2int(substrate[0]); substrate = substrate[1:]
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if fo & 0x40: # infinite value
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value = fo & 0x01 and '-inf' or 'inf'
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elif fo & 0x80: # binary enoding
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if fo & 0x11 == 0:
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n = 1
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elif fo & 0x01:
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n = 2
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elif fo & 0x02:
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n = 3
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else:
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n = oct2int(substrate[0])
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eo, substrate = substrate[:n], substrate[n:]
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if not eo or not substrate:
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raise error.PyAsn1Error('Real exponent screwed')
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e = 0
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while eo: # exponent
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e <<= 8
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e |= oct2int(eo[0])
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eo = eo[1:]
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p = 0
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while substrate: # value
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p <<= 8
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p |= oct2int(substrate[0])
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substrate = substrate[1:]
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if fo & 0x40: # sign bit
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p = -p
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value = (p, 2, e)
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elif fo & 0xc0 == 0: # character encoding
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try:
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if fo & 0x3 == 0x1: # NR1
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value = (int(substrate), 10, 0)
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elif fo & 0x3 == 0x2: # NR2
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value = float(substrate)
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elif fo & 0x3 == 0x3: # NR3
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value = float(substrate)
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else:
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raise error.SubstrateUnderrunError(
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'Unknown NR (tag %s)' % fo
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)
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except ValueError:
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raise error.SubstrateUnderrunError(
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'Bad character Real syntax'
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)
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elif fo & 0xc0 == 0x40: # special real value
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pass
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else:
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raise error.SubstrateUnderrunError(
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'Unknown encoding (tag %s)' % fo
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)
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return self._createComponent(asn1Spec, tagSet, value), substrate
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class SequenceDecoder(AbstractConstructedDecoder):
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protoComponent = univ.Sequence()
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def _getComponentTagMap(self, r, idx):
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try:
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return r.getComponentTagMapNearPosition(idx)
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except error.PyAsn1Error:
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return
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def _getComponentPositionByType(self, r, t, idx):
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return r.getComponentPositionNearType(t, idx)
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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substrate = substrate[:length]
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r = self._createComponent(asn1Spec, tagSet)
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idx = 0
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if not decodeFun:
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return r, substrate
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while substrate:
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asn1Spec = self._getComponentTagMap(r, idx)
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component, substrate = decodeFun(
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substrate, asn1Spec
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)
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idx = self._getComponentPositionByType(
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r, component.getEffectiveTagSet(), idx
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)
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r.setComponentByPosition(idx, component, asn1Spec is None)
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idx = idx + 1
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r.setDefaultComponents()
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r.verifySizeSpec()
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return r, substrate
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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r = self._createComponent(asn1Spec, tagSet)
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idx = 0
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while substrate:
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asn1Spec = self._getComponentTagMap(r, idx)
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if not decodeFun:
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return r, substrate
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component, substrate = decodeFun(substrate, asn1Spec)
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if component == eoo.endOfOctets:
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break
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idx = self._getComponentPositionByType(
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r, component.getEffectiveTagSet(), idx
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)
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r.setComponentByPosition(idx, component, asn1Spec is None)
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idx = idx + 1
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else:
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raise error.SubstrateUnderrunError(
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'No EOO seen before substrate ends'
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)
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r.setDefaultComponents()
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r.verifySizeSpec()
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return r, substrate
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class SequenceOfDecoder(AbstractConstructedDecoder):
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protoComponent = univ.SequenceOf()
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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substrate = substrate[:length]
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r = self._createComponent(asn1Spec, tagSet)
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asn1Spec = r.getComponentType()
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idx = 0
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(
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substrate, asn1Spec
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)
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r.setComponentByPosition(idx, component, asn1Spec is None)
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idx = idx + 1
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r.verifySizeSpec()
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return r, substrate
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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r = self._createComponent(asn1Spec, tagSet)
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asn1Spec = r.getComponentType()
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idx = 0
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(substrate, asn1Spec)
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if component == eoo.endOfOctets:
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break
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r.setComponentByPosition(idx, component, asn1Spec is None)
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idx = idx + 1
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else:
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raise error.SubstrateUnderrunError(
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'No EOO seen before substrate ends'
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)
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r.verifySizeSpec()
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return r, substrate
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class SetDecoder(SequenceDecoder):
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protoComponent = univ.Set()
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def _getComponentTagMap(self, r, idx):
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return r.getComponentTagMap()
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def _getComponentPositionByType(self, r, t, idx):
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nextIdx = r.getComponentPositionByType(t)
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if nextIdx is None:
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return idx
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else:
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return nextIdx
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class SetOfDecoder(SequenceOfDecoder):
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protoComponent = univ.SetOf()
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class ChoiceDecoder(AbstractConstructedDecoder):
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protoComponent = univ.Choice()
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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substrate = substrate[:length]
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r = self._createComponent(asn1Spec, tagSet)
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if not decodeFun:
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return r, substrate
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if r.getTagSet() == tagSet: # explicitly tagged Choice
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component, substrate = decodeFun(
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substrate, r.getComponentTagMap()
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)
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else:
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component, substrate = decodeFun(
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substrate, r.getComponentTagMap(), tagSet, length, state
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)
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if isinstance(component, univ.Choice):
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effectiveTagSet = component.getEffectiveTagSet()
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else:
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effectiveTagSet = component.getTagSet()
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r.setComponentByType(effectiveTagSet, component, 0, asn1Spec is None)
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return r, substrate
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indefLenValueDecoder = valueDecoder
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class AnyDecoder(AbstractSimpleDecoder):
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protoComponent = univ.Any()
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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if asn1Spec is None or \
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asn1Spec is not None and tagSet != asn1Spec.getTagSet():
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# untagged Any container, recover inner header substrate
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length = length + len(fullSubstrate) - len(substrate)
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substrate = fullSubstrate
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substrate = substrate[:length]
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return self._createComponent(asn1Spec, tagSet, value=substrate), ''
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def indefLenValueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet,
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length, state, decodeFun):
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if asn1Spec is not None and tagSet == asn1Spec.getTagSet():
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# tagged Any type -- consume header substrate
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header = ''
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else:
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# untagged Any, recover header substrate
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header = fullSubstrate[:-len(substrate)]
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r = self._createComponent(asn1Spec, tagSet, header)
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# Any components do not inherit initial tag
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asn1Spec = self.protoComponent
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if not decodeFun:
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return r, substrate
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while substrate:
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component, substrate = decodeFun(substrate, asn1Spec)
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if component == eoo.endOfOctets:
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break
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r = r + component
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else:
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raise error.SubstrateUnderrunError(
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'No EOO seen before substrate ends'
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)
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return r, substrate
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# character string types
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class UTF8StringDecoder(OctetStringDecoder):
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protoComponent = char.UTF8String()
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class NumericStringDecoder(OctetStringDecoder):
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protoComponent = char.NumericString()
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class PrintableStringDecoder(OctetStringDecoder):
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protoComponent = char.PrintableString()
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class TeletexStringDecoder(OctetStringDecoder):
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protoComponent = char.TeletexString()
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class VideotexStringDecoder(OctetStringDecoder):
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protoComponent = char.VideotexString()
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class IA5StringDecoder(OctetStringDecoder):
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protoComponent = char.IA5String()
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class GraphicStringDecoder(OctetStringDecoder):
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protoComponent = char.GraphicString()
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class VisibleStringDecoder(OctetStringDecoder):
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protoComponent = char.VisibleString()
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class GeneralStringDecoder(OctetStringDecoder):
|
||||
protoComponent = char.GeneralString()
|
||||
class UniversalStringDecoder(OctetStringDecoder):
|
||||
protoComponent = char.UniversalString()
|
||||
class BMPStringDecoder(OctetStringDecoder):
|
||||
protoComponent = char.BMPString()
|
||||
|
||||
# "useful" types
|
||||
class GeneralizedTimeDecoder(OctetStringDecoder):
|
||||
protoComponent = useful.GeneralizedTime()
|
||||
class UTCTimeDecoder(OctetStringDecoder):
|
||||
protoComponent = useful.UTCTime()
|
||||
|
||||
tagMap = {
|
||||
eoo.endOfOctets.tagSet: EndOfOctetsDecoder(),
|
||||
univ.Integer.tagSet: IntegerDecoder(),
|
||||
univ.Boolean.tagSet: BooleanDecoder(),
|
||||
univ.BitString.tagSet: BitStringDecoder(),
|
||||
univ.OctetString.tagSet: OctetStringDecoder(),
|
||||
univ.Null.tagSet: NullDecoder(),
|
||||
univ.ObjectIdentifier.tagSet: ObjectIdentifierDecoder(),
|
||||
univ.Enumerated.tagSet: IntegerDecoder(),
|
||||
univ.Real.tagSet: RealDecoder(),
|
||||
univ.Sequence.tagSet: SequenceDecoder(), # conflicts with SequenceOf
|
||||
univ.Set.tagSet: SetDecoder(), # conflicts with SetOf
|
||||
univ.Choice.tagSet: ChoiceDecoder(), # conflicts with Any
|
||||
# character string types
|
||||
char.UTF8String.tagSet: UTF8StringDecoder(),
|
||||
char.NumericString.tagSet: NumericStringDecoder(),
|
||||
char.PrintableString.tagSet: PrintableStringDecoder(),
|
||||
char.TeletexString.tagSet: TeletexStringDecoder(),
|
||||
char.VideotexString.tagSet: VideotexStringDecoder(),
|
||||
char.IA5String.tagSet: IA5StringDecoder(),
|
||||
char.GraphicString.tagSet: GraphicStringDecoder(),
|
||||
char.VisibleString.tagSet: VisibleStringDecoder(),
|
||||
char.GeneralString.tagSet: GeneralStringDecoder(),
|
||||
char.UniversalString.tagSet: UniversalStringDecoder(),
|
||||
char.BMPString.tagSet: BMPStringDecoder(),
|
||||
# useful types
|
||||
useful.GeneralizedTime.tagSet: GeneralizedTimeDecoder(),
|
||||
useful.UTCTime.tagSet: UTCTimeDecoder()
|
||||
}
|
||||
|
||||
# Type-to-codec map for ambiguous ASN.1 types
|
||||
typeMap = {
|
||||
univ.Set.typeId: SetDecoder(),
|
||||
univ.SetOf.typeId: SetOfDecoder(),
|
||||
univ.Sequence.typeId: SequenceDecoder(),
|
||||
univ.SequenceOf.typeId: SequenceOfDecoder(),
|
||||
univ.Choice.typeId: ChoiceDecoder(),
|
||||
univ.Any.typeId: AnyDecoder()
|
||||
}
|
||||
|
||||
( stDecodeTag, stDecodeLength, stGetValueDecoder, stGetValueDecoderByAsn1Spec,
|
||||
stGetValueDecoderByTag, stTryAsExplicitTag, stDecodeValue,
|
||||
stDumpRawValue, stErrorCondition, stStop ) = [x for x in range(10)]
|
||||
|
||||
class Decoder:
|
||||
defaultErrorState = stErrorCondition
|
||||
# defaultErrorState = stDumpRawValue
|
||||
defaultRawDecoder = AnyDecoder()
|
||||
def __init__(self, tagMap, typeMap={}):
|
||||
self.__tagMap = tagMap
|
||||
self.__typeMap = typeMap
|
||||
self.__endOfOctetsTagSet = eoo.endOfOctets.getTagSet()
|
||||
# Tag & TagSet objects caches
|
||||
self.__tagCache = {}
|
||||
self.__tagSetCache = {}
|
||||
|
||||
def __call__(self, substrate, asn1Spec=None, tagSet=None,
|
||||
length=None, state=stDecodeTag, recursiveFlag=1):
|
||||
fullSubstrate = substrate
|
||||
while state != stStop:
|
||||
if state == stDecodeTag:
|
||||
# Decode tag
|
||||
if not substrate:
|
||||
raise error.SubstrateUnderrunError(
|
||||
'Short octet stream on tag decoding'
|
||||
)
|
||||
|
||||
firstOctet = substrate[0]
|
||||
substrate = substrate[1:]
|
||||
if firstOctet in self.__tagCache:
|
||||
lastTag = self.__tagCache[firstOctet]
|
||||
else:
|
||||
t = oct2int(firstOctet)
|
||||
tagClass = t&0xC0
|
||||
tagFormat = t&0x20
|
||||
tagId = t&0x1F
|
||||
if tagId == 0x1F:
|
||||
tagId = 0
|
||||
while 1:
|
||||
if not substrate:
|
||||
raise error.SubstrateUnderrunError(
|
||||
'Short octet stream on long tag decoding'
|
||||
)
|
||||
t = oct2int(substrate[0])
|
||||
tagId = tagId << 7 | (t&0x7F)
|
||||
substrate = substrate[1:]
|
||||
if not t&0x80:
|
||||
break
|
||||
lastTag = tag.Tag(
|
||||
tagClass=tagClass, tagFormat=tagFormat, tagId=tagId
|
||||
)
|
||||
if tagId < 31:
|
||||
# cache short tags
|
||||
self.__tagCache[firstOctet] = lastTag
|
||||
if tagSet is None:
|
||||
if firstOctet in self.__tagSetCache:
|
||||
tagSet = self.__tagSetCache[firstOctet]
|
||||
else:
|
||||
# base tag not recovered
|
||||
tagSet = tag.TagSet((), lastTag)
|
||||
if firstOctet in self.__tagCache:
|
||||
self.__tagSetCache[firstOctet] = tagSet
|
||||
else:
|
||||
tagSet = lastTag + tagSet
|
||||
state = stDecodeLength
|
||||
if state == stDecodeLength:
|
||||
# Decode length
|
||||
if not substrate:
|
||||
raise error.SubstrateUnderrunError(
|
||||
'Short octet stream on length decoding'
|
||||
)
|
||||
firstOctet = oct2int(substrate[0])
|
||||
if firstOctet == 128:
|
||||
size = 1
|
||||
length = -1
|
||||
elif firstOctet < 128:
|
||||
length, size = firstOctet, 1
|
||||
else:
|
||||
size = firstOctet & 0x7F
|
||||
# encoded in size bytes
|
||||
length = 0
|
||||
lengthString = substrate[1:size+1]
|
||||
# missing check on maximum size, which shouldn't be a
|
||||
# problem, we can handle more than is possible
|
||||
if len(lengthString) != size:
|
||||
raise error.SubstrateUnderrunError(
|
||||
'%s<%s at %s' %
|
||||
(size, len(lengthString), tagSet)
|
||||
)
|
||||
for char in lengthString:
|
||||
length = (length << 8) | oct2int(char)
|
||||
size = size + 1
|
||||
state = stGetValueDecoder
|
||||
substrate = substrate[size:]
|
||||
if length != -1 and len(substrate) < length:
|
||||
raise error.SubstrateUnderrunError(
|
||||
'%d-octet short' % (length - len(substrate))
|
||||
)
|
||||
if state == stGetValueDecoder:
|
||||
if asn1Spec is None:
|
||||
state = stGetValueDecoderByTag
|
||||
else:
|
||||
state = stGetValueDecoderByAsn1Spec
|
||||
#
|
||||
# There're two ways of creating subtypes in ASN.1 what influences
|
||||
# decoder operation. These methods are:
|
||||
# 1) Either base types used in or no IMPLICIT tagging has been
|
||||
# applied on subtyping.
|
||||
# 2) Subtype syntax drops base type information (by means of
|
||||
# IMPLICIT tagging.
|
||||
# The first case allows for complete tag recovery from substrate
|
||||
# while the second one requires original ASN.1 type spec for
|
||||
# decoding.
|
||||
#
|
||||
# In either case a set of tags (tagSet) is coming from substrate
|
||||
# in an incremental, tag-by-tag fashion (this is the case of
|
||||
# EXPLICIT tag which is most basic). Outermost tag comes first
|
||||
# from the wire.
|
||||
#
|
||||
if state == stGetValueDecoderByTag:
|
||||
if tagSet in self.__tagMap:
|
||||
concreteDecoder = self.__tagMap[tagSet]
|
||||
else:
|
||||
concreteDecoder = None
|
||||
if concreteDecoder:
|
||||
state = stDecodeValue
|
||||
else:
|
||||
_k = tagSet[:1]
|
||||
if _k in self.__tagMap:
|
||||
concreteDecoder = self.__tagMap[_k]
|
||||
else:
|
||||
concreteDecoder = None
|
||||
if concreteDecoder:
|
||||
state = stDecodeValue
|
||||
else:
|
||||
state = stTryAsExplicitTag
|
||||
if state == stGetValueDecoderByAsn1Spec:
|
||||
if isinstance(asn1Spec, (dict, tagmap.TagMap)):
|
||||
if tagSet in asn1Spec:
|
||||
__chosenSpec = asn1Spec[tagSet]
|
||||
else:
|
||||
__chosenSpec = None
|
||||
else:
|
||||
__chosenSpec = asn1Spec
|
||||
if __chosenSpec is not None and (
|
||||
tagSet == __chosenSpec.getTagSet() or \
|
||||
tagSet in __chosenSpec.getTagMap()
|
||||
):
|
||||
# use base type for codec lookup to recover untagged types
|
||||
baseTagSet = __chosenSpec.baseTagSet
|
||||
if __chosenSpec.typeId is not None and \
|
||||
__chosenSpec.typeId in self.__typeMap:
|
||||
# ambiguous type
|
||||
concreteDecoder = self.__typeMap[__chosenSpec.typeId]
|
||||
elif baseTagSet in self.__tagMap:
|
||||
# base type or tagged subtype
|
||||
concreteDecoder = self.__tagMap[baseTagSet]
|
||||
else:
|
||||
concreteDecoder = None
|
||||
if concreteDecoder:
|
||||
asn1Spec = __chosenSpec
|
||||
state = stDecodeValue
|
||||
else:
|
||||
state = stTryAsExplicitTag
|
||||
elif tagSet == self.__endOfOctetsTagSet:
|
||||
concreteDecoder = self.__tagMap[tagSet]
|
||||
state = stDecodeValue
|
||||
else:
|
||||
state = stTryAsExplicitTag
|
||||
if state == stTryAsExplicitTag:
|
||||
if tagSet and \
|
||||
tagSet[0][1] == tag.tagFormatConstructed and \
|
||||
tagSet[0][0] != tag.tagClassUniversal:
|
||||
# Assume explicit tagging
|
||||
concreteDecoder = explicitTagDecoder
|
||||
state = stDecodeValue
|
||||
else:
|
||||
state = self.defaultErrorState
|
||||
if state == stDumpRawValue:
|
||||
concreteDecoder = self.defaultRawDecoder
|
||||
state = stDecodeValue
|
||||
if state == stDecodeValue:
|
||||
if recursiveFlag:
|
||||
decodeFun = self
|
||||
else:
|
||||
decodeFun = None
|
||||
if length == -1: # indef length
|
||||
value, substrate = concreteDecoder.indefLenValueDecoder(
|
||||
fullSubstrate, substrate, asn1Spec, tagSet, length,
|
||||
stGetValueDecoder, decodeFun
|
||||
)
|
||||
else:
|
||||
value, _substrate = concreteDecoder.valueDecoder(
|
||||
fullSubstrate, substrate, asn1Spec, tagSet, length,
|
||||
stGetValueDecoder, decodeFun
|
||||
)
|
||||
if recursiveFlag:
|
||||
substrate = substrate[length:]
|
||||
else:
|
||||
substrate = _substrate
|
||||
state = stStop
|
||||
if state == stErrorCondition:
|
||||
raise error.PyAsn1Error(
|
||||
'%r not in asn1Spec: %r' % (tagSet, asn1Spec)
|
||||
)
|
||||
return value, substrate
|
||||
|
||||
decode = Decoder(tagMap, typeMap)
|
||||
|
||||
# XXX
|
||||
# non-recursive decoding; return position rather than substrate
|
||||
Reference in New Issue
Block a user