pickletools.py 文件源码

def read_string4(f):
    r"""
    >>> import StringIO
    >>> read_string4(StringIO.StringIO("\x00\x00\x00\x00abc"))
    ''
    >>> read_string4(StringIO.StringIO("\x03\x00\x00\x00abcdef"))
    'abc'
    >>> read_string4(StringIO.StringIO("\x00\x00\x00\x03abcdef"))
    Traceback (most recent call last):
    ...
    ValueError: expected 50331648 bytes in a string4, but only 6 remain
    """

    n = read_int4(f)
    if n < 0:
        raise ValueError("string4 byte count < 0: %d" % n)
    data = f.read(n)
    if len(data) == n:
        return data
    raise ValueError("expected %d bytes in a string4, but only %d remain" %
                     (n, len(data)))