Ap |U8* |utf16_to_utf8 |U8* p|U8 *d|I32 bytelen|I32 *newlen
Ap |U8* |utf16_to_utf8_reversed|U8* p|U8 *d|I32 bytelen|I32 *newlen
Ap |STRLEN |utf8_length |U8* s|U8 *e
-Ap |I32 |utf8_distance |U8 *a|U8 *b
+Ap |IV |utf8_distance |U8 *a|U8 *b
Ap |U8* |utf8_hop |U8 *s|I32 off
ApM |U8* |utf8_to_bytes |U8 *s|STRLEN *len
ApM |U8* |bytes_to_utf8 |U8 *s|STRLEN *len