Function b16decode

Lib/base64.py:281–302

Decode the Base16 encoded bytes-like object or ASCII string s. Optional casefold is a flag specifying whether a lowercase alphabet is acceptable as input. For security purposes, the default is False. ignorechars should be a byte string containing characters to ignore from the inpu

(s, casefold=False, *, ignorechars=b'')

def b16decode(s, casefold=False, *, ignorechars=b''):
    """Decode the Base16 encoded bytes-like object or ASCII string s.

    Optional casefold is a flag specifying whether a lowercase alphabet is
    acceptable as input.  For security purposes, the default is False.

    ignorechars should be a byte string containing characters to ignore
    from the input.

    The result is returned as a bytes object.  A binascii.Error is raised if
    s is incorrectly padded or if there are non-alphabet characters present
    in the input.
    """
    if not casefold:
        s = _bytes_from_decode_data(s)
        if not isinstance(ignorechars, bytes):
            ignorechars = bytes(memoryview(ignorechars))
        for b in b'abcdef':
            if b in s and b not in ignorechars:
                raise binascii.Error('Non-base16 digit found')
        s = s.translate(None, delete=b'abcdef')
    return binascii.unhexlify(s, ignorechars=ignorechars)

#
# Ascii85 encoding/decoding