mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-27 15:01:08 +00:00
abf0909b68
According to CONTRIBUTING.md: "Algorithms in this repo should not be how-to examples for existing Python packages."
67 lines
2.3 KiB
Python
67 lines
2.3 KiB
Python
def base16_encode(data: bytes) -> str:
|
|
"""
|
|
Encodes the given bytes into base16.
|
|
|
|
>>> base16_encode(b'Hello World!')
|
|
'48656C6C6F20576F726C6421'
|
|
>>> base16_encode(b'HELLO WORLD!')
|
|
'48454C4C4F20574F524C4421'
|
|
>>> base16_encode(b'')
|
|
''
|
|
"""
|
|
# Turn the data into a list of integers (where each integer is a byte),
|
|
# Then turn each byte into its hexadecimal representation, make sure
|
|
# it is uppercase, and then join everything together and return it.
|
|
return "".join([hex(byte)[2:].zfill(2).upper() for byte in list(data)])
|
|
|
|
|
|
def base16_decode(data: str) -> bytes:
|
|
"""
|
|
Decodes the given base16 encoded data into bytes.
|
|
|
|
>>> base16_decode('48656C6C6F20576F726C6421')
|
|
b'Hello World!'
|
|
>>> base16_decode('48454C4C4F20574F524C4421')
|
|
b'HELLO WORLD!'
|
|
>>> base16_decode('')
|
|
b''
|
|
>>> base16_decode('486')
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Base16 encoded data is invalid:
|
|
Data does not have an even number of hex digits.
|
|
>>> base16_decode('48656c6c6f20576f726c6421')
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Base16 encoded data is invalid:
|
|
Data is not uppercase hex or it contains invalid characters.
|
|
>>> base16_decode('This is not base64 encoded data.')
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Base16 encoded data is invalid:
|
|
Data is not uppercase hex or it contains invalid characters.
|
|
"""
|
|
# Check data validity, following RFC3548
|
|
# https://www.ietf.org/rfc/rfc3548.txt
|
|
if (len(data) % 2) != 0:
|
|
raise ValueError(
|
|
"""Base16 encoded data is invalid:
|
|
Data does not have an even number of hex digits."""
|
|
)
|
|
# Check the character set - the standard base16 alphabet
|
|
# is uppercase according to RFC3548 section 6
|
|
if not set(data) <= set("0123456789ABCDEF"):
|
|
raise ValueError(
|
|
"""Base16 encoded data is invalid:
|
|
Data is not uppercase hex or it contains invalid characters."""
|
|
)
|
|
# For every two hexadecimal digits (= a byte), turn it into an integer.
|
|
# Then, string the result together into bytes, and return it.
|
|
return bytes(int(data[i] + data[i + 1], 16) for i in range(0, len(data), 2))
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|