generator.py 文件源码

def _make_boundary(text=None):
    # Craft a random boundary.  If text is given, ensure that the chosen
    # boundary doesn't appear in the text.
    token = random.randrange(sys.maxint)
    boundary = ('=' * 15) + (_fmt % token) + '=='
    if text is None:
        return boundary
    b = boundary
    counter = 0
    while True:
        cre = re.compile('^--' + re.escape(b) + '(--)?$', re.MULTILINE)
        if not cre.search(text):
            break
        b = boundary + '.' + str(counter)
        counter += 1
    return b