36 lines
1.2 KiB
Python
36 lines
1.2 KiB
Python
# CER decoder
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from pyasn1.type import univ
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from pyasn1.codec.ber import decoder
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from pyasn1.compat.octets import oct2int
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from pyasn1 import error
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class BooleanDecoder(decoder.AbstractSimpleDecoder):
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protoComponent = univ.Boolean(0)
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def valueDecoder(self, fullSubstrate, substrate, asn1Spec, tagSet, length,
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state, decodeFun, substrateFun):
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head, tail = substrate[:length], substrate[length:]
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if not head or length != 1:
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raise error.PyAsn1Error('Not single-octet Boolean payload')
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byte = oct2int(head[0])
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# CER/DER specifies encoding of TRUE as 0xFF and FALSE as 0x0, while
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# BER allows any non-zero value as TRUE; cf. sections 8.2.2. and 11.1
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# in http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
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if byte == 0xff:
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value = 1
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elif byte == 0x00:
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value = 0
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else:
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raise error.PyAsn1Error('Unexpected Boolean payload: %s' % byte)
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return self._createComponent(asn1Spec, tagSet, value), tail
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tagMap = decoder.tagMap.copy()
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tagMap.update({
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univ.Boolean.tagSet: BooleanDecoder()
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})
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typeMap = decoder.typeMap
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class Decoder(decoder.Decoder): pass
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decode = Decoder(tagMap, decoder.typeMap)
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