diff options
Diffstat (limited to 'advtrains/helpers.lua')
| -rw-r--r-- | advtrains/helpers.lua | 50 |
1 files changed, 39 insertions, 11 deletions
diff --git a/advtrains/helpers.lua b/advtrains/helpers.lua index bef4903..6d22bc5 100644 --- a/advtrains/helpers.lua +++ b/advtrains/helpers.lua @@ -342,9 +342,10 @@ function advtrains.get_matching_conn(conn, nconns) return connlku[nconns][conn] end -function advtrains.random_id() +function advtrains.random_id(lenp) local idst="" - for i=0,5 do + local len = lenp or 6 + for i=1,len do idst=idst..(math.random(0,9)) end return idst @@ -476,6 +477,14 @@ end -- Metatable: local trackiter_mt = { + -- Internal State: + -- branches: A list of {pos, connid, limit} for where to restart + -- pos: The *next* position that the track iterator will return + -- bconnid: The connid of the connection of the rail at pos that points backward + -- tconns: The connections of the rail at pos + -- limit: the current limit + -- visited: a key-boolean table of already visited rails + -- get whether there are still unprocessed branches has_next_branch = function(self) return #self.branches > 0 @@ -491,13 +500,18 @@ local trackiter_mt = { self.tconns = adj_conns self.limit = br.limit - 1 self.visited[advtrains.encode_pos(br.pos)] = true + self.last_track_already_visited = false return br.pos, br.connid end, -- get the next track along the current branch, -- potentially adding branching tracks to the unprocessed branches list - -- returns status, track_pos, track_connid - -- status is true(ok), false(track has ended), nil(traversing limit has been reached) (when status~=true, track_pos and track_connid are nil) + -- returns track_pos, track_connid, track_backwards_connid + -- On error, returns nil, reason; reason is one of "track_end", "limit_hit", "already_visited" next_track = function(self) + if self.last_track_already_visited then + -- see comment below + return nil, "already_visited" + end local pos = self.pos if not pos then -- last run found track end. Return false @@ -507,12 +521,17 @@ local trackiter_mt = { if self.limit <= 0 then return nil, "limit_hit" end - if self.visited[advtrains.encode_pos(pos)] then - -- node was already seen. do not continue - return nil, "already_visited" - end -- select next conn (main conn to follow is the associated connection) + local old_bconnid = self.bconnid local mconnid = advtrains.get_matching_conn(self.bconnid, #self.tconns) + if self.visited[advtrains.encode_pos(pos)] then + -- node was already seen + -- Due to special requirements for the track section updater, return this first already visited track once + -- but do not process any further rails on this branch + -- The next call will then throw already_visited error + self.last_track_already_visited = true + return pos, mconnid, old_bconnid + end -- If there are more connections, add these to branches for nconnid,_ in ipairs(self.tconns) do if nconnid~=mconnid and nconnid~=self.bconnid then @@ -526,7 +545,16 @@ local trackiter_mt = { self.tconns = adj_conns self.limit = self.limit - 1 self.visited[advtrains.encode_pos(pos)] = true - return pos, mconnid + self.last_track_already_visited = false + return pos, mconnid, old_bconnid + end, + + add_branch = function(self, pos, connid) + table.insert(self.branches, {pos = pos, connid = connid, limit=self.limit}) + end, + + is_visited = function(self, pos) + return self.visited[advtrains.encode_pos(pos)] end, } @@ -569,8 +597,8 @@ while ti:has_next_branch() do repeat <do something with the track> if <track satisfies an abort condition> then break end --for example, when traversing should stop at TCBs this can check if there is a tcb here - ok, pos, connid = ti:next_track() - until not ok -- this stops the loop when either the track end is reached or the limit is hit + pos, connid = ti:next_track() + until not pos -- this stops the loop when either the track end is reached or the limit is hit -- while loop continues with the next branch ( diverging branch of one of the switches/crossings) until no more are left end |