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