Human-readable Size

human_size.py

def readable_size(byte_size: int, base: int = 10, decimals: int = 1):
    """
    Given the size of an object in bytes, returns a human-readable alternative.
    For ex:
        >>> readable_size(44000000)
        42.0 MB

    Supports sizes up to 1024 yobibytes in Binary or 1000 yottabytes in Decimal SI.

    Inspired by the following StackOverflow questions:
     - https://stackoverflow.com/questions/1094841/get-human-readable-version-of-file-size
     - https://stackoverflow.com/questions/3758606/how-can-i-convert-byte-size-into-a-human-readable-format-in-java

    :param byte_size: the size of the object in bytes
    :param base: optional int, either 2 for Binary or 10 for Decimal SI. Binary is the default.
    :param decimals: optional int, specify the number of significant digits to return
    :return: str formatted with the maximum possible units and the suffix, like '50.0 MiB'
    """
    if base == 2:
        unit, pre = 2 ** 10, 'kMGTPEZY'
    elif base == 10:
        unit, pre = 10 ** 3, 'KMGTPEZY'
    else:
        raise ValueError('Base must either be 10 or 2; given: {0}'.format(base))

    abs_bytes = abs(byte_size)
    if abs_bytes < unit:
        return '{0:.1f} B'.format(byte_size)

    exp = int(math.log(abs_bytes) / math.log(unit))

    th = math.ceil(math.pow(unit, exp) * (unit - 0.05))
    if exp < 6 and abs_bytes >= th - (51 if (th & 0xFFF) == 0xD00 else 0):
        exp += 1

    suffix = pre[exp - 1]

    # Discard significant digits to improve floating point precision of really large values when printing
    if exp > 4:
        byte_size /= unit
        exp -= 1

    return '{0:.{3}f} {1}{2}B'.format(byte_size / math.pow(unit, exp), suffix, 'i' if base == 2 else '', decimals)