dailycheckin/rsa/_compat.py
2020-12-08 13:31:25 +08:00

49 lines
1.5 KiB
Python

# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Python compatibility wrappers."""
from struct import pack
def byte(num: int) -> bytes:
"""
Converts a number between 0 and 255 (both inclusive) to a base-256 (byte)
representation.
:param num:
An unsigned integer between 0 and 255 (both inclusive).
:returns:
A single byte.
"""
return pack("B", num)
def xor_bytes(b1: bytes, b2: bytes) -> bytes:
"""
Returns the bitwise XOR result between two bytes objects, b1 ^ b2.
Bitwise XOR operation is commutative, so order of parameters doesn't
generate different results. If parameters have different length, extra
length of the largest one is ignored.
:param b1:
First bytes object.
:param b2:
Second bytes object.
:returns:
Bytes object, result of XOR operation.
"""
return bytes(x ^ y for x, y in zip(b1, b2))