AyStar: Reduce redundant GetElement calls in BinaryHeap

src/pathfinder/npf/queue.cpp

@@ -80,26 +80,23 @@ bool BinaryHeap::Push(uint32 item, int priority)
 	}
 
 	/* Add the item at the end of the array */
-	this->GetElement(this->size + 1).priority = priority;
-	this->GetElement(this->size + 1).item = item;
+	BinaryHeapNode &new_item = this->GetElement(this->size + 1);
+	new_item.priority = priority;
+	new_item.item = item;
 	this->size++;
 
 	/* Now we are going to check where it belongs. As long as the parent is
 	 * bigger, we switch with the parent */
 	{
-		BinaryHeapNode temp;
-		int i;
-		int j;
-
-		i = this->size;
+		int i = this->size;
 		while (i > 1) {
 			/* Get the parent of this object (divide by 2) */
-			j = i / 2;
+			int j = i / 2;
 			/* Is the parent bigger than the current, switch them */
-			if (this->GetElement(i).priority <= this->GetElement(j).priority) {
-				temp = this->GetElement(j);
-				this->GetElement(j) = this->GetElement(i);
-				this->GetElement(i) = temp;
+			BinaryHeapNode &elem_i = this->GetElement(i);
+			BinaryHeapNode &elem_j = this->GetElement(j);
+			if (elem_i.priority <= elem_j.priority) {
+				std::swap(elem_i, elem_j);
 				i = j;
 			} else {
 				/* It is not, we're done! */
@@ -135,15 +132,13 @@ bool BinaryHeap::Delete(uint32 item, int priority)
 	/* Now the only thing we have to do, is resort it..
 	 * On place i there is the item to be sorted.. let's start there */
 	{
-		uint j;
-		BinaryHeapNode temp;
 		/* Because of the fact that Binary Heap uses array from 1 to n, we need to
 		 * increase i by 1
 		 */
 		i++;
 
 		for (;;) {
-			j = i;
+			uint j = i;
 			/* Check if we have 2 children */
 			if (2 * j + 1 <= this->size) {
 				/* Is this child smaller than the parent? */
@@ -158,9 +153,7 @@ bool BinaryHeap::Delete(uint32 item, int priority)
 
 			/* One of our children is smaller than we are, switch */
 			if (i != j) {
-				temp = this->GetElement(j);
-				this->GetElement(j) = this->GetElement(i);
-				this->GetElement(i) = temp;
+				std::swap(this->GetElement(i), this->GetElement(j));
 			} else {
 				/* None of our children is smaller, so we stay here.. stop :) */
 				break;
@@ -180,11 +173,11 @@ uint32 BinaryHeap::Pop()
 	if (this->size == 0) return UINT32_MAX;
 
 	/* The best item is always on top, so give that as result */
-	uint32 result = this->GetElement(1).item;
+	BinaryHeapNode result = this->GetElement(1);
 	/* And now we should get rid of this item... */
-	this->Delete(this->GetElement(1).item, this->GetElement(1).priority);
+	this->Delete(result.item, result.priority);
 
-	return result;
+	return result.item;
 }
 
 /**