import hashlib
from io import BytesIO


def calc_hash_of_bytes(buf: BytesIO):
    """ calculate the hash of the file """

    algo = hashlib.sha1()

    buffer_size = 65536
    buffer_size = buffer_size * 1024 * 1024

    while True:
        data = buf.read(buffer_size)
        if not data:
            break
        algo.update(data)

    hex = algo.hexdigest()

    return hex


def calc_hash_of_file(file):
    """ calculate the hash of the file """

    #read file
    with open(file, 'rb') as fh:
        buf = BytesIO(fh.read())

    hex = calc_hash_of_bytes(buf)

    return hex