说明：  PB位操作源码。PB本身没有提供位操作的函数，由于加密等需要，很不方便，这个源码解决了这个问题。供大家参考。
(PB-bit operating source. PB-bit operation itself did not provide the function, as a result of encryption, such as needs, very inconvenient, this source solved the problem. For your reference.)