Modified the connectivity finding search routine so that it does

not crash if too many unprocessed areas get queued up.  Also modified
it to prune entries that match one of the last five entries created
before searching the current tile.  However, it is not clear that
that makes any significant difference to the run time, and it needs
to be analyzed vs. the number of entries to check against.

database/DBconnect.c

@@ -88,6 +88,7 @@ struct conSrArg2
 
     conSrArea		*csa2_list;	/* List of areas to process */
     int			csa2_top;	/* Index of next area to process */
+    int			csa2_lasttop;	/* Previous top index */
     int			csa2_size;	/* Max. number bins in area list */
 };
 
@@ -654,7 +655,7 @@ dbcUnconnectFunc(tile, clientData)
  *	connectivity between them.
  *
  * Results:
- *	Always 0.
+ *	Return 0 normally, 1 if list size exceeds integer bounds.
  *
  * Side effects:
  *	Adds a label to the destination definition "def".
@@ -740,7 +741,7 @@ dbcConnectLabelFunc(scx, lab, tpath, csa2)
 		if ((slab->lab_flags & PORT_NUM_MASK) == lidx)
 		{
 		    Rect newarea;
-		    int pNum;
+		    int i, pNum;
 
 		    // Do NOT go searching on labels connected to space!
 		    if (slab->lab_type == TT_SPACE) continue;
@@ -763,24 +764,34 @@ dbcConnectLabelFunc(scx, lab, tpath, csa2)
 		    newarea.r_ybot--;
 		    newarea.r_ytop++;
 
+    		    /* Check if any of the last 5 entries has the same type and	*/
+    		    /* area.  If so, don't duplicate the existing entry.	*/
+
+		    for (i = csa2->csa2_lasttop; i > csa2->csa2_lasttop - 5; i--)
+			if (connectMask == csa2->csa2_list[i].connectMask)
+			    if (GEO_SURROUND(&csa2->csa2_list[i].area, &newarea))
+				return 0;
+
 		    /* Register the area and connection mask as needing to be processed */
 
 		    if (++csa2->csa2_top == csa2->csa2_size)
 		    {
+			conSrArea *newlist;
+			int newSize, newTotal;
+
 			/* Reached list size limit---need to enlarge the list	   */
 			/* Double the size of the list every time we hit the limit */
 
-			conSrArea *newlist;
+			newSize = csa2->csa2_size * 2;
-			int i, lastsize = csa2->csa2_size;
+			newTotal = newSize * sizeof(conSrArea);
+			if (newTotal <= 0) return 1;
 
-			csa2->csa2_size *= 2;
+			newlist = (conSrArea *)mallocMagic((size_t)newTotal);
-
-			newlist = (conSrArea *)mallocMagic(csa2->csa2_size
-					* sizeof(conSrArea));
 			memcpy((void *)newlist, (void *)csa2->csa2_list,
-					(size_t)lastsize * sizeof(conSrArea));
+					(size_t)csa2->csa2_size * sizeof(conSrArea));
 			freeMagic((char *)csa2->csa2_list);
 			csa2->csa2_list = newlist;
+			csa2->csa2_size = newSize;
 		    }
 
 		    csa2->csa2_list[csa2->csa2_top].area = newarea;
@@ -811,7 +822,8 @@ dbcConnectLabelFunc(scx, lab, tpath, csa2)
  *	catecorner tiles from being considered as connected.
  *
  * Results:
- *	Always returns 0 to keep the search from aborting.
+ *	Returns 0 normally to keep the search from aborting;  returns 1
+ *	if allocation of list failed due to exceeding integer bounds.
  *
  * Side effects:
  *	Adds paint to the destination definition.
@@ -835,7 +847,7 @@ dbcConnectFunc(tile, cx)
     SearchContext scx2;
     TileType loctype = TiGetTypeExact(tile);
     TileType dinfo = 0;
-    int pNum = cx->tc_plane;
+    int i, pNum = cx->tc_plane;
     CellDef *def;
 
     TiToRect(tile, &tileArea);
@@ -948,6 +960,16 @@ dbcConnectFunc(tile, cx)
 	newarea.r_xtop += 1;
     }
 
+    /* Check if any of the last 5 entries has the same type and	*/
+    /* area.  If so, don't duplicate the existing entry.	*/
+    /* (NOTE:  Connect masks are all from the same table, so	*/
+    /* they can be compared by address, no need for TTMaskEqual)*/
+
+    for (i = csa2->csa2_lasttop; i > csa2->csa2_lasttop - 5; i--)
+	if (connectMask == csa2->csa2_list[i].connectMask)
+	    if (GEO_SURROUND(&csa2->csa2_list[i].area, &newarea))
+		return 0;
+
     /* Register the area and connection mask as needing to be processed */
 
     if (++csa2->csa2_top == csa2->csa2_size)
@@ -956,15 +978,19 @@ dbcConnectFunc(tile, cx)
 	/* Double the size of the list every time we hit the limit */
 
 	conSrArea *newlist;
-	int i, lastsize = csa2->csa2_size;
+	int newSize, newTotal;
 
-	csa2->csa2_size *= 2;
+	newSize = csa2->csa2_size * 2;
+	newTotal = newSize * sizeof(conSrArea);
 
-	newlist = (conSrArea *)mallocMagic((size_t)(csa2->csa2_size) * sizeof(conSrArea));
+	if (newTotal <= 0) return 1;	/* Exceeded integer bounds */
+
+	newlist = (conSrArea *)mallocMagic((size_t)newTotal);
 	memcpy((void *)newlist, (void *)csa2->csa2_list,
-			(size_t)lastsize * sizeof(conSrArea));
+			(size_t)csa2->csa2_size * sizeof(conSrArea));
 	freeMagic((char *)csa2->csa2_list);
 	csa2->csa2_list = newlist;
+	csa2->csa2_size = newSize;
     }
 
     csa2->csa2_list[csa2->csa2_top].area = newarea;
@@ -1054,10 +1080,12 @@ DBTreeCopyConnect(scx, mask, xMask, connect, area, doLabels, destUse)
     csa2.csa2_list = (conSrArea *)mallocMagic(CSA2_LIST_START_SIZE
 			* sizeof(conSrArea));
     csa2.csa2_top = -1;
+    csa2.csa2_lasttop = -1;
 
     DBTreeSrTiles(scx, mask, xMask, dbcConnectFunc, (ClientData) &csa2);
     while (csa2.csa2_top >= 0)
     {
+	int result;
         char pathstring[FLATTERMSIZE];
         TerminalPath tpath;
 
@@ -1069,12 +1097,21 @@ DBTreeCopyConnect(scx, mask, xMask, connect, area, doLabels, destUse)
 	scx->scx_area = csa2.csa2_list[csa2.csa2_top].area;
 	newtype = csa2.csa2_list[csa2.csa2_top].dinfo;
 	csa2.csa2_top--;
+	csa2.csa2_lasttop = csa2.csa2_top;
 
 	if (newtype & TT_DIAGONAL)
-	    DBTreeSrNMTiles(scx, newtype, newmask, xMask, dbcConnectFunc,
+	    result = DBTreeSrNMTiles(scx, newtype, newmask, xMask, dbcConnectFunc,
 			(ClientData) &csa2);
 	else
-	    DBTreeSrTiles(scx, newmask, xMask, dbcConnectFunc, (ClientData) &csa2);
+	    result = DBTreeSrTiles(scx, newmask, xMask, dbcConnectFunc,
+			(ClientData) &csa2);
+
+	if (result != 0)
+	{
+	    TxError("Connectivity search exceeded memory limit and stopped;"
+			"  incomplete result.\n");
+	    break;
+	}
 
 	/* Check the source def for any labels belonging to this        */
 	/* tile area and plane, and add them to the destination.        */
@@ -1107,8 +1144,12 @@ DBTreeCopyConnect(scx, mask, xMask, connect, area, doLabels, destUse)
 	}
 	if (doLabels == SEL_SIMPLE_LABELS) tpath.tp_first = NULL;
 	if (doLabels != SEL_NO_LABELS)
-	    DBTreeSrLabels(scx, newmask, xMask, &tpath, searchtype,
+	    if (DBTreeSrLabels(scx, newmask, xMask, &tpath, searchtype,
-			dbcConnectLabelFunc, (ClientData) &csa2);
+			dbcConnectLabelFunc, (ClientData) &csa2) != 0)
+	    {
+		TxError("Connection search hit memory limit and stopped.\n");
+		break;
+	    }
     }
     freeMagic((char *)csa2.csa2_list);