UTF-8

http://code.alexreisner.com/articles/character-encoding.html

对于以UTF-8编码的字节：

if it starts with 0	it’s an ASCII character
if it starts with 10	it’s a continuation of a multi-byte character
if it starts with 110	it’s the first byte of a 2-byte character
if it starts with 1110	it’s the first byte of a 3-byte character
if it starts with 11110	it’s the first byte of a 4-byte character