26 lines
800 B
Python
26 lines
800 B
Python
from typing import Union
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def der_encode(value: int) -> bytes:
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# max() to have minimum length of 1
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value_bytes = value.to_bytes(max(1, (value.bit_length() + 7) // 8), 'big')
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if value >= 0x80:
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value_bytes = (0x80 | len(value_bytes)).to_bytes(1, 'big') + value_bytes
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return value_bytes
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def format_tlv(tag: int, value: Union[int, str, bytes]) -> bytes:
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if isinstance(value, int):
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# max() to have minimum length of 1
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value = value.to_bytes(max(1, (value.bit_length() + 7) // 8), 'big')
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elif isinstance(value, str):
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value = value.encode()
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assert isinstance(value, bytes), f"Unhandled TLV formatting for type : {type(value)}"
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tlv = bytearray()
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tlv += der_encode(tag)
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tlv += der_encode(len(value))
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tlv += value
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return tlv
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