Utf8.charpos

Available since: Gideros 2016.06

Description

convert UTF-8 position to byte offset. if only offset is given, return byte offset of this UTF-8 char index. if charpos and offset is given, a new charpos will calculate, by add/subtract UTF-8 char offset to current charpos. in all case, it return a new char position, and code point (a number) at this position.

(number) = utf8.charpos(s,charpos,offset)

's: (string) '
charpos: (number) optional
offset: (number) optional
Returns (number) return byte offset of this UTF-8 char index