utils.py 文件源码

def adler32(file):
    """
    An Adler-32 checksum is obtained by calculating two 16-bit checksums A and B and concatenating their bits into a 32-bit integer. A is the sum of all bytes in the stream plus one, and B is the sum of the individual values of A from each step.

    :returns: Hexified string, padded to 8 values.
    """

    # adler starting value is _not_ 0
    adler = 1L

    try:
        openFile = open(file, 'rb')
        for line in openFile:
            adler = zlib.adler32(line, adler)
    except:
        raise Exception('FATAL - could not get checksum of file %s' % file)

    # backflip on 32bit
    if adler < 0:
        adler = adler + 2 ** 32

    return str('%08x' % adler)