omnihash.py 文件源码

def make_digesters(fpath, families, include_CRCs=False):
    """
    Create and return a dictionary of all our active hash algorithms.

    Each digester is a 2-tuple ``( digester.update_func(bytes), digest_func(digester) -> int)``.
    """
    ## TODO: simplify digester-tuple API, ie: (digester, update_func(d), digest_func(d))

    families = set(f.upper() for f in families)
    digesters = OrderedDict()

    digesters['LENGTH'] = (LenDigester(), LenDigester.digest)

    # Default Algos
    for algo in sorted(hashlib.algorithms_available):
        # algorithms_available can have duplicates
        aname = algo.upper()
        if aname not in digesters and is_algo_in_families(aname, families):
            digesters[aname] = (hashlib.new(algo), lambda d: d.hexdigest())

    # CRC
    if include_CRCs:
        for name in sorted(crcmod._crc_definitions_by_name):
            crc_name = crcmod._crc_definitions_by_name[name]['name']
            aname = crc_name.upper()
            if is_algo_in_families(aname, families):
                digesters[aname] = (crcmod.PredefinedCrc(crc_name),
                                    lambda d: hex(d.crcValue))

    add_git_digesters(digesters, fpath)

    ## Append plugin digesters.
    #
    digesters.update(known_digesters)
    for digester in list(digesters.keys()):
        if not is_algo_in_families(digester.upper(), families):
            digesters.pop(digester, None)

    return digesters