util.py 文件源码

def optimal_data_chunks(data, minimum=4):
    """
    An iterator returning QRData chunks optimized to the data content.

    :param minimum: The minimum number of bytes in a row to split as a chunk.
    """
    data = to_bytestring(data)
    re_repeat = (
        six.b('{') + six.text_type(minimum).encode('ascii') + six.b(',}'))
    num_pattern = re.compile(six.b('\d') + re_repeat)
    num_bits = _optimal_split(data, num_pattern)
    alpha_pattern = re.compile(
        six.b('[') + re.escape(ALPHA_NUM) + six.b(']') + re_repeat)
    for is_num, chunk in num_bits:
        if is_num:
            yield QRData(chunk, mode=MODE_NUMBER, check_data=False)
        else:
            for is_alpha, sub_chunk in _optimal_split(chunk, alpha_pattern):
                if is_alpha:
                    mode = MODE_ALPHA_NUM
                else:
                    mode = MODE_8BIT_BYTE
                yield QRData(sub_chunk, mode=mode, check_data=False)