fix ArrayList_Shift for args (al, 0, -1)

As a result, this should fix #1051.

winpr/libwinpr/utils/collections/ArrayList.c

@@ -148,7 +148,7 @@ void ArrayList_Shift(wArrayList* arrayList, int index, int count)
 	}
 	else if (count < 0)
 	{
-		MoveMemory(&arrayList->array[index + count], &arrayList->array[index], (arrayList->size - index) * sizeof(void*));
+		MoveMemory(&arrayList->array[index], &arrayList->array[index - count], (arrayList->size + count) * sizeof(void*));
 		arrayList->size += count;
 	}
 }

winpr/libwinpr/utils/test/TestArrayList.c

@@ -7,11 +7,13 @@ int TestArrayList(int argc, char* argv[])
 {
 	int index;
 	int count;
+	size_t val;
 	wArrayList* arrayList;
+	const int elemsToInsert = 10;
 
 	arrayList = ArrayList_New(TRUE);
 
-	for (index = 0; index < 10; index++)
+	for (index = 0; index < elemsToInsert; index++)
 	{
 		ArrayList_Add(arrayList, (void*) (size_t) index);
 	}
@@ -43,6 +45,26 @@ int TestArrayList(int argc, char* argv[])
 	if (index != 6)
 		return -1;
 
+	for (index = 0; index < elemsToInsert; index++) {
+		val = (size_t)ArrayList_GetItem(arrayList, 0);
+		ArrayList_RemoveAt(arrayList, 0);
+		if (val != index)
+		{
+			printf("ArrayList: shifted %d entries, expected value %d, got %d\n", index, index, val);
+			return -1;
+		}
+	}
+
+	index = ArrayList_IndexOf(arrayList, (void*) (size_t) elemsToInsert, -1, -1);
+	printf("ArrayList index: %d\n", index);
+	if (index != -1)
+		return -1;
+
+	count = ArrayList_Count(arrayList);
+	printf("ArrayList count: %d\n", count);
+	if (count != 0)
+		return -1;
+
 	ArrayList_Clear(arrayList);
 	ArrayList_Free(arrayList);