queue.py

"""
@version: python3.6
@author: Fieldhunter
@contact: 1677532160yuan@gmail.com
@time: 2020-05-03
"""
import functools


"""
    Check if the code used to access the queue information,Decorator function.
    The purpose of simply adding code is to prevent queue from 
      being tampered with maliciously and to provide the API for developers.
"""
def check_code(func):
    @functools.wraps(func)
    def check(self, code):
        if code != 'adsf;{h3096j34ka`fd>&/edgb^45:6':
            raise Exception('code is wrong!')
        result = func(self, code)
        return result

    return check


class Sequential_queue():
    def __init__(self):
        self.__data = []
        self.__num = 0

    def add_data(self, element):
        self.__data.append(element)
        self.__num += 1

    def pop_data(self):
        if self.__data != []:
            last_data = self.__data[0]
            del self.__data[0]
            self.__num -= 1

            return last_data
        else:
            print("No data in queue")
            return None

    @check_code
    def return_basic_information(self, code):
        return self.__data, self.__num


# linked queue
class Link_Node():
    def __init__(self, num):
        self.data = num
        self.prev = None
        self.next = None


class Linked_queue():
    def __init__(self):
        self.__head = None
        self.__tail = None
        self.__num = 0

    def add_data(self, element):
        new_data = Link_Node(element)
        self.__num += 1
        if self.__tail == None:
            self.__head = self.__tail = new_data
        else:
            self.__head.prev = new_data
            new_data.next = self.__head
            self.__head = new_data

    def pop_data(self):
        if self.__tail == None:
            print("No data in queue")
            return None
        else:
            last_data = self.__tail.data
            self.__tail = self.__tail.prev
            self.__num -= 1
            if self.__tail == None:
                self.__head = None

            return last_data

    @check_code
    def return_basic_information(self, code):
        return self.__head, self.__tail, self.__num