Navigation static map

hi,

sorry for my english!

I want to create a offline routing for example like in shopping malls or in buildings. First i want to usw my own map (floor of building with doors, walls etc). For that i have do create a osm-xml file wiht josm right?

After creating that want to map the routing from my location to destination (from room a to room b). How can i do this without any gps, ibeacons, w-lan etc. Is there any api? I dont understand how after creating the xml file the path finding work. I mean there are doors, walls .. Is in the XML file (Map) a coordinates system ? Is there a easy way to just print the route or must i implement a a path finding algorithm by my own.

Like in this pic: File:OpenLevelUp_shopping_mall.png

Thx a lot for the answers.