Find and Replace Japanese characters in pdf file on iPhone

Hi eveybody !

I want to find and replace Japanese characters in pdf on iPhone.

I using zlib to deflate stream - endstream block and extract text.It's work fine with latin-text.

But when i work with japanese characters , I don't know how to do it ?

I decode a sample japanese pdf file, and I know that each Japanese characters are performances as hex string : "<01b7><0e230a23>..."

But i don't know how to convert Japanese characters to the hex string like that.

Can evrybody help me?

Thanks!