title: How to decode a multibyte utf8 string? (C++)
body: <p>I'm trying to build a set of helper functions for decoding and modifying multibyte utf-8 strings. For example, finding the amount of characters in the string, and finding the byte offset of a particular character.</p>
  
  <p>I've been looking for a solution for a while, but haven't been able to figure it out.
  If anyone could show me a cross platform and portable way to do this only using the STL
  I would really appreciate it. Also if there is a c++11 way to do it I'm open to that as well.</p>