def pretty_size(size):
    if size >= 1024*1024*1024:
        return "%.1f GiB" % round(size/1024/1024/1024.0)
    elif size >= 1024*1024:
        return "%.1f MiB" % round(size/1024/1024.0)
    elif size >= 1024:
        return "%.1f KiB" % round(size/1024.0)
    else:
        return "%u B" % size


def format_disk_space(size):
    """ Convert bytes to a human readable format.
        Returns a tuple, for example (20,"MiB") """

    if size >= 1024*1024*1024:
        return ("%.1f"%round(size/1024/1024/1024.0),"GiB")
    elif size >= 1024*1024:
        return ("%.1f"%round(size/1024/1024.0),"MiB")
    elif size >= 1024:
        return ("%.1f"%round(size/1024.0),"KiB")
    else:
        return ("%u"%size,"B")