md5sum_snippet

import hashlib


def gen_hash(file, chunk_size=512*1024**1, hash_algorithm='md5'):
    """
    file: str | pathobj
    chunk_size: 512KiB | int
    hash_algorithm: 'md5' | hashlib.algorithms_available

    Reads the file chunked and update the hash.

    returns: hash object
    """
    hasher = hashlib.new(hash_algorithm)
    chunk = bytearray(chunk_size)
    view = memoryview(chunk)
    with open(file, 'rb') as fd:
        while True:
            last = fd.readinto(chunk)
            if not last:
                break
            hasher.update(view[:last])
    return hasher