[MIRROR] [READY]Astar improvement (#5646)

* [READY]Astar improvement (#34713)

Improvements to A* via using bitflags to find directions and caching already checked directions so we don't recheck them.

* [READY]Astar improvement

code/controllers/subsystem/pathfinder.dm

@@ -0,0 +1,38 @@
+SUBSYSTEM_DEF(pathfinder)
+	name = "pathfinder"
+	init_order = INIT_ORDER_PATH
+	flags = SS_NO_FIRE
+	var/lcount = 10
+	var/run
+	var/free
+	var/list/flow
+	var/static/space_type_cache
+
+/datum/controller/subsystem/pathfinder/Initialize()
+	space_type_cache = typecacheof(/turf/open/space)
+	run = 0
+	free = 1
+	flow = new()
+	flow.len=lcount
+
+/datum/controller/subsystem/pathfinder/proc/getfree(atom/M)
+	if(run < lcount)
+		run += 1
+		while(flow[free])
+			CHECK_TICK
+			free = (free % lcount) + 1
+		var/t = addtimer(CALLBACK(SSpathfinder, /datum/controller/subsystem/pathfinder.proc/toolong, free), 150, TIMER_STOPPABLE)
+		flow[free] = t
+		flow[t] = M
+		return free
+	else
+		return 0
+
+/datum/controller/subsystem/pathfinder/proc/toolong(l)
+	log_game("Pathfinder route took longer than 150 ticks, src bot [flow[flow[l]]]")
+	found(l)
+
+/datum/controller/subsystem/pathfinder/proc/found(l)
+	deltimer(flow[l])
+	flow[l] = null
+	run -= 1