If you're willing to do some translation from JS to ObjC, then you might find this project helpful:
https://github.com/thelonious/svg-2d
Particularly, the path.js file which includes a parseData method, taking care of relative and absolute path commands.
https://github.com/thelonious/svg-2d/blob/master/shapes/path/Path.js
I should mention that I wrote this code years ago, but I have translated it to Java and C# and have used in professional products (can't share that code, unfortunately) and it seemed to work well in those environments as well.
HTH
Kevin
