Output log for unused altRouteNames

[michihdeu]

We already have unusedaltlabels.log but an unusedaltroutenames.log would help to eliminate leftover.

[yakra]

First create an unused_alt_route_names set for each Route, much like the existing unused_alt_labels. Populate it during Route construction, when the alt_route_names list is created. Then, either:

• During .list processing, every time a Region+Name combo is matched, remove it from the unused_alt_route_names set. For primary names, we're just removing something that's already not there. :) This is the simpler-to-code option.
• Create two route_hash tables, one for primary names and one for AltRouteNames. When a lookup in the primary table fails, check the alt table. When an AltRouteName match is found, remove it from the set.
  • Faster where, for the 99.82% of good .list lines not using AltRouteNames, we're not searching for a nonexistent primary name in the unused_alt_route_names set.
  • A tiny bit slower in the 0.18% of cases where AltRouteNames are involved, because we're looking up these entries in two hash tables instead of one, and in Unknown region/highway combo cases (which number 3.6x as many).
    Counterbalanced to whatever degree by the primary name lookups being a tiny bit faster due to using a smaller set.
  • For another potential speedup, this enables us to remove the existing alt_route_names list (which would also save some RAM).
    • Right now, every time we find a region/highway match, we iterate through the alt_route_names list until a match is found, to add the deprecated route name ... -> canonical name note to the user log.
    • No iterating; instead, just add the note to the log as soon as a match is found via the alt_route_hash table.

[yakra]

I think it would be useful to have lists of both unused and in-use AltRouteNames.

[yakra]

I think it would be useful to have lists of both unused and in-use AltRouteNames.

In-use AltRouteNames is a bit questionable. More useful would be a .log of all in-use .list names, whether primary or alternate.

[yakra]

Similar to "option 2" for waypoint labels, .list names will be flagged as in-use:

• only if the entire.list line, both waypoint labels included, is valid and credits a traveler with non-zero distance traveled.
• a valid region/route combo alone is not sufficient.