The B2PF library is a set of C functions that process character strings in languages such as Arabic, where the characters change their shapes depending on their neighbours within words. B2PF reads input encoded as Unicode base characters. It converts characters that form words to the appropriate presentation forms according to a set of externally-supplied rules. A set of rules for Arabic script are supplied.
B2PF can process UTF-8, UTF-16, or UTF-32 input. It can handle left-to-right or right-to-left input and convert the output if required.
You can read the B2PF documentation from the here.