* gets unicode character at byte position @a p of UTF-8 encoded @a text, then advances @a p to the next character.
* @throws std::runtime_error if decoding fails.
* See unicode standard section 3.10 table 3-5 and 3-6 for details.
* gets unicode character at byte position @a p of UTF-8 encoded @a text, then advances @a p to the next character.
* @throws std::runtime_error if decoding fails.
* See unicode standard section 3.10 table 3-5 and 3-6 for details.