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https://github.com/hastagAB/Awesome-Python-Scripts.git
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76 lines
2.7 KiB
Python
76 lines
2.7 KiB
Python
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from __future__ import print_function
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import os
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import string
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import argparse
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try:
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maketrans = string.maketrans # python2
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except AttributeError:
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maketrans = str.maketrans # python3
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def caeser_cipher(string_: str, offset: int, decode: bool, file_: string) -> None:
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""" Caeser Cipher implementation, reads file or string. Also decodes.
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Default implementation is ROT13 encoding.
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To decode, specify the same offset you used to encode and your ciphertext / file.
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:param string_: string to encode / decode
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:param offset: # of chars to rotate by
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:param decode: decode instead of encode
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:param file_: file to read in then encode/decode
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"""
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if file_ and os.path.exists(file_):
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with open(file_, 'r') as f:
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string_ = f.read()
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if decode:
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offset *= -1
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lower_offset_alphabet = string.ascii_lowercase[offset:] + string.ascii_lowercase[:offset]
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lower_translation_table = maketrans(string.ascii_lowercase, lower_offset_alphabet)
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upper_offset_alphabet = string.ascii_uppercase[offset:] + string.ascii_uppercase[:offset]
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upper_translation_table = maketrans(string.ascii_uppercase, upper_offset_alphabet)
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lower_converted = string_.translate(lower_translation_table)
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final_converted = lower_converted.translate(upper_translation_table)
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if file_:
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extension = 'dec' if decode else 'enc'
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with open("{}.{}".format(file_, extension), 'w') as f:
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print(final_converted, file=f)
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else:
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print(final_converted)
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def check_offset_range(value: int) -> int:
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""" Validates that value is in the allowable range.
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:param value: integer to validate
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:return: valid integer
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:raises: argparse.ArgumentTypeError
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"""
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value = int(value)
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if value < -25 or value > 25:
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raise argparse.ArgumentTypeError("{} is an invalid offset".format(value))
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return value
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if __name__ == '__main__':
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parser = argparse.ArgumentParser(description="Simple Caeser Cipher [En,De]coder")
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parser.add_argument('-d', '--decode', action='store_true', dest='decode',
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help='decode ciphertext (offset should equal what was used to encode)', default=False)
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parser.add_argument('-o', '--offset', dest='offset', default=13, type=check_offset_range,
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help='number of characters to shift')
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group = parser.add_mutually_exclusive_group(required=True)
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group.add_argument('-f', '--file', dest='file', help='file to encode', default=None)
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group.add_argument('-s', '--string', dest='string', help='string to encode', default=None)
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args = parser.parse_args()
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caeser_cipher(args.string, args.offset, args.decode, args.file)
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