Hacky fix to ware_t good amount overflow when viewing a stop informat…

…ion window set to list in "via (amount)" order.

If a single via destination had more than 8,388,607 units heading to it an arithmetic overflow would occur causing total unit count to be reported incorrectly. This fix prevents packet mergers once logical amount limits are reached hence keeping counting correct at the cost of duplicate listings.

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@8677 8aca7d54-2c30-db11-9de9-000461428c89

freight_list_sorter.cc

@@ -88,13 +88,21 @@ bool freight_list_sorter_t::compare_ware(ware_t const& w1, ware_t const& w2)
 
 
 
-void freight_list_sorter_t::add_ware_heading( cbuffer_t &buf, uint32 sum, uint32 max, const ware_t *ware, const char *what_doing )
+void freight_list_sorter_t::add_ware_heading( cbuffer_t &buf, uint64 sum, uint32 max, const ware_t *ware, const char *what_doing )
 {
+	uint32 const max_display = ~0;
+
 	// not the first line?
 	if(  buf.len() > 0  ) {
 		buf.append("\n");
 	}
-	buf.printf("%u", sum);
+
+	if (sum > max_display) {
+		buf.printf(">%u", max_display);
+	} else {
+		buf.printf("%u", (uint32)sum);
+	}
+
 	if(  max != 0  ) {
 		// convois
 		buf.printf("/%u", max);
@@ -122,23 +130,28 @@ void freight_list_sorter_t::sort_freight(vector_tpl<ware_t> const& warray, cbuff
 			continue;
 		}
 		wlist[pos] = ware;
+		ware_t & current_good = wlist[pos];
 		// for the sorting via the number for the next stop we unify entries
 		if(  sort_mode == by_via_sum  ) {
 			// only add it, if there is not another thing waiting with the same via but another destination
 			for(  int i=0;  i<pos;  i++  ) {
 				ware_t& wi = wlist[i];
-				if(  wi.get_index()==ware.get_index()  &&  wi.get_zwischenziel()==ware.get_zwischenziel()  ) {
+				if(  wi.get_index()==ware.get_index()  &&  wi.get_zwischenziel()==ware.get_zwischenziel()  && !wi.is_goods_amount_maxed()  ) {
 					if(  wi.get_zwischenziel().is_bound()  ) {
 						if(  (  wi.get_ziel()==wi.get_zwischenziel() )==( ware.get_ziel()==ware.get_zwischenziel() ) ) {
-							wi.menge += ware.menge;
-							--pos;
+							current_good.menge = wi.add_goods(ware.menge);
+							if (current_good.menge == 0) {
+								--pos;
+							}
 							break;
 						}
 					}
 					else {
 						if(  wi.get_ziel() == ware.get_ziel()  ) {
-							wi.menge += ware.menge;
-							--pos;
+							current_good.menge = wi.add_goods(ware.menge);
+							if (current_good.menge == 0) {
+								--pos;
+							}
 							break;
 						}
 					}
@@ -174,7 +187,7 @@ void freight_list_sorter_t::sort_freight(vector_tpl<ware_t> const& warray, cbuff
 
 			ware_t const& ware = wlist[j];
 			if(  last_goods_index!=ware.get_index()  &&  last_ware_catg!=ware.get_catg()  ) {
-				sint32 sum = 0;
+				uint64 sum = 0;
 				last_goods_index = ware.get_index();
 				last_ware_catg = (ware.get_catg()!=0) ? ware.get_catg() : -1;
 				for(  int i=j;  i<pos;  i++  ) {

freight_list_sorter.h

@@ -26,7 +26,7 @@ class freight_list_sorter_t
 
 	static bool compare_ware(ware_t const& w1, ware_t const& w2);
 
-	static void add_ware_heading( cbuffer_t &buf, uint32 sum, uint32 max, const ware_t *ware, const char *what_doing );
+	static void add_ware_heading( cbuffer_t &buf, uint64 sum, uint32 max, const ware_t *ware, const char *what_doing );
 };
 
 

simutrans/history.txt

@@ -1,3 +1,4 @@
+    FIX: The stop information window in "via (amount)" order will no longer count incorrectly when more than 8,388,607 units are headed to a single destination
     FIX: SDL2 build running on Windows 10 in fullscreen mode now minimizes and maximizes responsively
 	CHG: gui overhaul: automatic placement and size calculation of elements
 	ADD: use animated water graphics on shores

simware.cc

@@ -25,7 +25,7 @@
 
 const goods_desc_t *ware_t::index_to_desc[256];
 
-
+uint32 const ware_t::MAXIMUM_GOOD_AMOUNT = (1 << 23) - 1;
 
 ware_t::ware_t() : ziel(), zwischenziel(), zielpos(-1, -1)
 {
@@ -185,3 +185,18 @@ sint64 ware_t::calc_revenue(const goods_desc_t* desc, waytype_t wt, sint32 speed
 	// take the larger of both
 	return desc->get_value() * (grundwert128 > grundwert_bonus ? grundwert128 : grundwert_bonus);
 }
+
+uint32 ware_t::add_goods(uint32 const number) {
+	goods_amount_limit_t const sum = menge + number;
+	if (sum > MAXIMUM_GOOD_AMOUNT) {
+		menge = MAXIMUM_GOOD_AMOUNT;
+		return sum - MAXIMUM_GOOD_AMOUNT;
+	}
+
+	menge = sum;
+	return 0;
+}
+
+bool ware_t::is_goods_amount_maxed() {
+	return (goods_amount_limit_t)menge == MAXIMUM_GOOD_AMOUNT;
+}

simware.h

@@ -19,6 +19,12 @@ class ware_t
 	static const goods_desc_t *index_to_desc[256];
 
 public:
+	// Type used to specify goods limit, including handling potential overflow from addition.
+	typedef uint32 goods_amount_limit_t;
+
+	// Maximum number of goods per ware package. Limited by the bit field used.
+	static goods_amount_limit_t const MAXIMUM_GOOD_AMOUNT;
+
 	/// type of good, used as index into goods-types array
 	uint32 index: 8;
 
@@ -121,6 +127,20 @@ class ware_t
 	 * @param speedkmh actual achieved speed in km/h
 	 */
 	static sint64 calc_revenue(const goods_desc_t* desc, waytype_t wt, sint32 speedkmh);
+
+	/**
+	 * Adds the number of goods to this goods packet.
+	 * Number of goods must be less than or equal to MAXIMUM_GOOD_AMOUNT.
+	 * @param number The number of goods to add to this packet.
+	 * @return Any excess goods that could not be added, eg due to logical limits.
+	 */
+	uint32 add_goods(uint32 const number);
+
+	/**
+	 * Checks if the goods amount is maxed.
+	 * @return If goods amount is maxed out so no more goods can be added.
+	 */
+	bool is_goods_amount_maxed();
 };
 
 #endif