The street navigation is trivial by itself, it is simple lookup in the geocode database.
This is implemented in public_html/parse.pl

The relatively nontrivial thing is conversion of OSM xml file into the database of addresses. 
Here I can at least boast relatively fast conversion to sqlite (belarus.osm is converted in 11min), this is done
using little memory (about 20M, mostly the size of perl interpreter).

converters:
convertdb/osm2sqlite.pl (converts xml into generic sqlite database containing all the info from the initial table).
convertdb/osmsql2geocodesql.pl (make database of coordinates linked to addresses). This will be rewritten. However, it is also fast
(for Minsk, takes few seconds)