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CatOrNot/venv/lib/python3.6/site-packages/itsdangerous/encoding.py

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2018-12-11 00:32:28 +01:00
import base64
import string
import struct
from ._compat import text_type
from .exc import BadData
def want_bytes(s, encoding="utf-8", errors="strict"):
if isinstance(s, text_type):
s = s.encode(encoding, errors)
return s
def base64_encode(string):
"""Base64 encode a string of bytes or text. The resulting bytes are
safe to use in URLs.
"""
string = want_bytes(string)
return base64.urlsafe_b64encode(string).rstrip(b"=")
def base64_decode(string):
"""Base64 decode a URL-safe string of bytes or text. The result is
bytes.
"""
string = want_bytes(string, encoding="ascii", errors="ignore")
string += b"=" * (-len(string) % 4)
try:
return base64.urlsafe_b64decode(string)
except (TypeError, ValueError):
raise BadData("Invalid base64-encoded data")
# The alphabet used by base64.urlsafe_*
_base64_alphabet = (string.ascii_letters + string.digits + "-_=").encode("ascii")
_int64_struct = struct.Struct(">Q")
_int_to_bytes = _int64_struct.pack
_bytes_to_int = _int64_struct.unpack
def int_to_bytes(num):
return _int_to_bytes(num).lstrip(b"\x00")
def bytes_to_int(bytestr):
return _bytes_to_int(bytestr.rjust(8, b"\x00"))[0]