c++底层uft8和bytes转换

http://www.nubaria.com/en/blog/?p=289

http://en.cppreference.com/w/cpp/string/multibyte/wcstombs

http://jianshusoft.blog.51cto.com/2380869/808356

http://utf8everywhere.org/

http://blog.csdn.net/sunmenggmail/article/details/8935425

http://shitouer.cn/2013/04/google-protocol-buffers-encoding/

http://www.cnblogs.com/hewei2012/p/3374147.html

http://www.lemoda.net/c/iconv-example/iconv-example.html