# HG changeset patch
# User bjarni
# Date 1131137523 0
# Node ID ad75080afea4bdab154952d6f5fc9dc34e54ae46
# Parent  d69238b81415e65ca682c0889e7ceaca30caf16d
(svn r3136) -Fix: [autoreplace] all cargo in engines that consists of more than one vehicle will try to move cargo from all vehicles
	currently this applies to planes and multiheaded train engines (no more lost airmail)
	added GetNextEnginePart() that returns the next vehicle in an engine nomatter what type it is
	when more types of multivehicle engines are added, they will have to be added here too or autoreplace will not remove all cargo

diff -r d69238b81415 -r ad75080afea4 train_cmd.c
--- a/train_cmd.c	Fri Nov 04 16:12:48 2005 +0000
+++ b/train_cmd.c	Fri Nov 04 20:52:03 2005 +0000
@@ -961,7 +961,7 @@
  * engine is 'started', first 'close' that before 'closing' our
  * searched engine
  */
-static Vehicle *GetRearEngine(const Vehicle *v, EngineID engine)
+Vehicle *GetRearEngine(const Vehicle *v, EngineID engine)
 {
 	Vehicle *u;
 	int en_count = 1;
diff -r d69238b81415 -r ad75080afea4 vehicle.c
--- a/vehicle.c	Fri Nov 04 16:12:48 2005 +0000
+++ b/vehicle.c	Fri Nov 04 20:52:03 2005 +0000
@@ -1446,6 +1446,32 @@
 	}
 }
 
+/*
+ * This function returns the next vehicle in an engine that consists of more than one vehicle
+ * This is planes, multiheaded train engines and so on. It's NOT whole trains as it is only the engines, that are linked together
+ */
+static Vehicle *GetNextEnginePart(Vehicle *v)
+{
+	switch (v->type) {
+		case VEH_Train:
+		{
+			const RailVehicleInfo *rvi = RailVehInfo(v->engine_type);
+			if (rvi->flags & RVI_MULTIHEAD)
+				return GetRearEngine(v, v->engine_type);
+		}
+			break;
+		case VEH_Aircraft:
+			return v->next;
+			break;
+		case VEH_Road:
+		case VEH_Ship:
+			break;
+		default: NOT_REACHED();
+	}
+	return NULL;
+}
+
+
 /** Clone a vehicle. If it is a train, it will clone all the cars too
 * @param x,y depot where the cloned vehicle is build
 * @param p1 the original vehicle's index
@@ -1525,6 +1551,37 @@
 	return total_cost;
 }
 
+/*
+ * move the cargo from one engine to another if possible
+ */
+static void MoveVehicleCargo(Vehicle *dest, Vehicle *source)
+{
+	Vehicle *v = dest;
+	int units_moved;
+
+	do {
+		do {
+			if (source->cargo_type != dest->cargo_type)
+				continue;	// cargo not compatible
+
+			if (dest->cargo_count == dest->cargo_cap)
+				continue;	// the destination vehicle is already full
+
+			units_moved = min(source->cargo_count, dest->cargo_cap - dest->cargo_count);
+			source->cargo_count -= units_moved;
+			dest->cargo_count   += units_moved;
+			dest->cargo_source   = source->cargo_source;
+
+			// copy the age of the cargo
+			dest->cargo_days   = source->cargo_days;
+			dest->day_counter  = source->day_counter;
+			dest->tick_counter = source->tick_counter;
+
+		} while (source->cargo_count > 0 && (dest = GetNextEnginePart(dest)) != NULL);
+		dest = v;
+	} while ((source = GetNextEnginePart(source)) != NULL);
+}
+
 /* Replaces a vehicle (used to be called autorenew)
  * This function is only called from MaybeReplaceVehicle(), which is the next one
  * Must be called with _current_player set to the owner of the vehicle
@@ -1535,7 +1592,7 @@
 static int32 ReplaceVehicle(Vehicle **w, byte flags)
 {
 	int32 cost;
-	const Vehicle *old_v = *w;
+	Vehicle *old_v = *w;
 	const Player *p = GetPlayer(old_v->owner);
 	EngineID new_engine_type;
 	const UnitID cached_unitnumber = old_v->unitnumber;
@@ -1560,17 +1617,7 @@
 			}
 		}
 
-		/* move the cargo to the new vehicle */
-		if (old_v->cargo_type == new_v->cargo_type && old_v->cargo_count != 0) {
-			// move the cargo to the new vehicle
-			new_v->cargo_count = min(old_v->cargo_count, new_v->cargo_cap);
-			new_v->cargo_source = old_v->cargo_source;
-
-			// copy the age of the cargo
-			new_v->cargo_days = old_v->cargo_days;
-			new_v->day_counter = old_v->day_counter;
-			new_v->tick_counter = old_v->tick_counter;
-		}
+		MoveVehicleCargo(new_v, old_v);
 
 		if (old_v->type == VEH_Train && old_v->u.rail.first_engine != INVALID_VEHICLE) {
 			/* this is a railcar. We need to move the car into the train
diff -r d69238b81415 -r ad75080afea4 vehicle.h
--- a/vehicle.h	Fri Nov 04 16:12:48 2005 +0000
+++ b/vehicle.h	Fri Nov 04 20:52:03 2005 +0000
@@ -325,6 +325,7 @@
 void CheckVehicleBreakdown(Vehicle *v);
 void AgeVehicle(Vehicle *v);
 void VehicleEnteredDepotThisTick(Vehicle *v);
+Vehicle *GetRearEngine(const Vehicle *v, EngineID engine);
 
 void BeginVehicleMove(Vehicle *v);
 void EndVehicleMove(Vehicle *v);