https://zhuanlan.zhihu.com/p/28009037
https://blog.csdn.net/hejjunlin/article/details/71976574
https://blog.csdn.net/zfgogo/article/details/52439849
https://www.jianshu.com/p/62bde41cf1a5
http://www.voidcn.com/article/p-nurywfzr-bor.html
https://blog.csdn.net/sha1996118/article/details/79717471
原文：https://www.cnblogs.com/tc310/p/11216174.html