Given a position p with a UTF-8 encoded string str, find the start
of the previous UTF-8 character starting before p. Returns NULL if no
UTF-8 characters are present in str before p.
p does not have to be at the beginning of a UTF-8 character. No check
is made to see if the character found is actually valid other than
it starts with an appropriate byte.
Parameters
str: string
pointer to the beginning of a UTF-8 encoded string
Given a position
pwith a UTF-8 encoded stringstr, find the start of the previous UTF-8 character starting beforep. ReturnsNULLif no UTF-8 characters are present instrbeforep.pdoes not have to be at the beginning of a UTF-8 character. No check is made to see if the character found is actually valid other than it starts with an appropriate byte.