[MIRROR] Transit space refactor (#7130)

* Transit space refactor

* Update bitfields.dm

code/modules/mapping/space_management/space_reservation.dm

@@ -0,0 +1,70 @@
+
+//Yes, they can only be rectangular.
+//Yes, I'm sorry.
+/datum/turf_reservation
+	var/list/reserved_turfs = list()
+	var/bottom_left_coords[3]
+	var/top_right_coords[3]
+	var/wipe_reservation_on_release = TRUE
+	var/turf_type = /turf/open/space
+
+/datum/turf_reservation/transit
+	turf_type = /turf/open/space/transit
+
+/datum/turf_reservation/proc/Release()
+	var/v = reserved_turfs.Copy()
+	for(var/i in reserved_turfs)
+		reserved_turfs -= i
+		SSmapping.used_turfs -= i
+	SSmapping.reserve_turfs(v)
+
+/datum/turf_reservation/proc/Reserve(width, height, zlevel)
+	if(width > world.maxx || height > world.maxy)
+		return FALSE
+	var/list/avail = SSmapping.unused_turfs["[zlevel]"]
+	var/turf/BL
+	var/turf/TR
+	var/list/turf/final = list()
+	var/passing = FALSE
+	for(var/i in avail)
+		CHECK_TICK
+		BL = i
+		if(!(BL.flags_1 & UNUSED_RESERVATION_TURF_1))
+			continue
+		if(BL.x + width > world.maxx || BL.y + height > world.maxy)
+			continue
+		TR = locate(BL.x + width, BL.y + height, BL.z)
+		if(!(TR.flags_1 & UNUSED_RESERVATION_TURF_1))
+			continue
+		final = block(BL, TR)
+		if(!final)
+			continue
+		passing = TRUE
+		for(var/I in final)
+			var/turf/checking = I
+			if(!(checking.flags_1 & UNUSED_RESERVATION_TURF_1))
+				passing = FALSE
+				break
+		if(!passing)
+			continue
+		break
+	if(!passing || !istype(BL) || !istype(TR))
+		return FALSE
+	bottom_left_coords = list(BL.x, BL.y, BL.z)
+	top_right_coords = list(TR.x, TR.y, TR.z)
+	for(var/i in final)
+		var/turf/T = i
+		reserved_turfs |= T
+		T.flags_1 &= ~UNUSED_RESERVATION_TURF_1
+		SSmapping.unused_turfs["[T.z]"] -= T
+		SSmapping.used_turfs[T] = src
+		T.ChangeTurf(turf_type, turf_type)
+	return TRUE
+
+/datum/turf_reservation/New()
+	LAZYADD(SSmapping.turf_reservations, src)
+
+/datum/turf_reservation/Destroy()
+	Release()
+	LAZYREMOVE(SSmapping.turf_reservations, src)
+	return ..()