base64.py 文件源码

def b16decode(s, casefold=False):
    """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.

    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.
    """
    s = _bytes_from_decode_data(s)
    if casefold:
        s = s.upper()
    if re.search(b'[^0-9A-F]', s):
        raise binascii.Error('Non-base16 digit found')
    return binascii.unhexlify(s)

#
# Ascii85 encoding/decoding
#