From 54db96be43bbb94f3d5193647be2f787a192f358 Mon Sep 17 00:00:00 2001
From: fonsinchen <fonsinchen@openttd.org>
Date: Sun, 20 Oct 2013 13:47:58 +0000
Subject: (svn r25891) -Feature: Use smallstack to allow for multiple next hops
 when loading and unloading.

---
 src/cargopacket.cpp | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

(limited to 'src/cargopacket.cpp')

diff --git a/src/cargopacket.cpp b/src/cargopacket.cpp
index 6a37cb488..9a1ba8568 100644
--- a/src/cargopacket.cpp
+++ b/src/cargopacket.cpp
@@ -421,7 +421,7 @@ void VehicleCargoList::SetTransferLoadPlace(TileIndex xy)
  * @param payment Payment object for registering transfers.
  * return If any cargo will be unloaded.
  */
-bool VehicleCargoList::Stage(bool accepted, StationID current_station, StationID next_station, uint8 order_flags, const GoodsEntry *ge, CargoPayment *payment)
+bool VehicleCargoList::Stage(bool accepted, StationID current_station, StationIDStack next_station, uint8 order_flags, const GoodsEntry *ge, CargoPayment *payment)
 {
 	this->AssertCountConsistency();
 	assert(this->action_counts[MTA_LOAD] == 0);
@@ -446,9 +446,24 @@ bool VehicleCargoList::Stage(bool accepted, StationID current_station, StationID
 			action = MTA_DELIVER;
 		} else if (force_transfer) {
 			action = MTA_TRANSFER;
-			cargo_next = ge->GetVia(cp->source, current_station, next_station);
-			assert((cargo_next != next_station || cargo_next == INVALID_STATION) &&
-					cargo_next != current_station);
+			/* We cannot send the cargo to any of the possible next hops and
+			 * also not to the current station. */
+			FlowStatMap::const_iterator flow_it(ge->flows.find(cp->source));
+			if (flow_it == ge->flows.end()) {
+				cargo_next = INVALID_STATION;
+			} else {
+				FlowStat new_shares = flow_it->second;
+				new_shares.ChangeShare(current_station, INT_MIN);
+				StationIDStack excluded = next_station;
+				while (!excluded.IsEmpty()) {
+					new_shares.ChangeShare(excluded.Pop(), INT_MIN);
+				}
+				if (new_shares.GetShares()->empty()) {
+					cargo_next = INVALID_STATION;
+				} else {
+					cargo_next = new_shares.GetVia();
+				}
+			}
 		} else {
 			/* Rewrite an invalid source station to some random other one to
 			 * avoid keeping the cargo in the vehicle forever. */
@@ -460,7 +475,7 @@ bool VehicleCargoList::Stage(bool accepted, StationID current_station, StationID
 				action = (accepted && cp->source != current_station) ? MTA_DELIVER : MTA_KEEP;
 			} else if (cargo_next == current_station) {
 				action = MTA_DELIVER;
-			} else if (cargo_next == next_station) {
+			} else if (next_station.Contains(cargo_next)) {
 				action = MTA_KEEP;
 			} else {
 				action = MTA_TRANSFER;
@@ -667,10 +682,14 @@ bool StationCargoList::ShiftCargo(Taction &action, StationID next)
  * @return Amount of cargo actually moved.
  */
 template <class Taction>
-uint StationCargoList::ShiftCargo(Taction action, StationID next, bool include_invalid)
+uint StationCargoList::ShiftCargo(Taction action, StationIDStack next, bool include_invalid)
 {
 	uint max_move = action.MaxMove();
-	if (this->ShiftCargo(action, next) && include_invalid && action.MaxMove() > 0) {
+	while (!next.IsEmpty()) {
+		this->ShiftCargo(action, next.Pop());
+		if (action.MaxMove() == 0) break;
+	}
+	if (include_invalid && action.MaxMove() > 0) {
 		this->ShiftCargo(action, INVALID_STATION);
 	}
 	return max_move - action.MaxMove();
@@ -735,10 +754,10 @@ uint StationCargoList::Truncate(uint max_move, StationCargoAmountMap *cargo_per_
  * @param max_move Maximum amount of cargo to reserve.
  * @param dest VehicleCargoList to reserve for.
  * @param load_place Tile index of the current station.
- * @param next_station Next station the loading vehicle will visit.
+ * @param next_station Next station(s) the loading vehicle will visit.
  * @return Amount of cargo actually reserved.
  */
-uint StationCargoList::Reserve(uint max_move, VehicleCargoList *dest, TileIndex load_place, StationID next_station)
+uint StationCargoList::Reserve(uint max_move, VehicleCargoList *dest, TileIndex load_place, StationIDStack next_station)
 {
 	return this->ShiftCargo(CargoReservation(this, dest, max_move, load_place), next_station, true);
 }
@@ -749,13 +768,13 @@ uint StationCargoList::Reserve(uint max_move, VehicleCargoList *dest, TileIndex
  * @param max_move Amount of cargo to load.
  * @param dest Vehicle cargo list where the cargo resides.
  * @param load_place The new loaded_at_xy to be assigned to packets being moved.
- * @param next_station Next station the loading vehicle will visit.
+ * @param next_station Next station(s) the loading vehicle will visit.
  * @return Amount of cargo actually loaded.
  * @note Vehicles may or may not reserve, depending on their orders. The two
  *       modes of loading are exclusive, though. If cargo is reserved we don't
  *       need to load unreserved cargo.
  */
-uint StationCargoList::Load(uint max_move, VehicleCargoList *dest, TileIndex load_place, StationID next_station)
+uint StationCargoList::Load(uint max_move, VehicleCargoList *dest, TileIndex load_place, StationIDStack next_station)
 {
 	uint move = min(dest->ActionCount(VehicleCargoList::MTA_LOAD), max_move);
 	if (move > 0) {
-- 
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