- /* (3) find the common father.
- * Before that, index_src and index_dst may be different, they both point to nullptr in path_src/path_dst
- * So we move them down simultaneously as long as they point to the same content.
- */
- do {
- current_src = path_src[--index_src];
- current_dst = path_dst[--index_dst];
- } while (index_src > 0 && index_dst > 0 && current_src == current_dst);
-
- /* (4) if we did not find a difference (index_src or index_dst went to 0), both elements are in the same AS */
- if (current_src == current_dst)
- father = current_src;
- else // we found a difference
- father = path_src[index_src + 1];
-
- /* (5) result generation */
- *common_ancestor = father; /* the common father of src and dst */
- *src_ancestor = current_src; /* the first different father of src */
- *dst_ancestor = current_dst; /* the first different father of dst */
- #undef ROUTING_HIERARCHY_MAXDEPTH
+ /** @brief Get the common ancestor and its first children in each line leading to src and dst
+ *
+ * After this call, common_ancestor, src_ancestor and dst_ancestor are set as follows.
+ * @verbatim
+ * platform root
+ * |
+ * ...
+ * |
+ * common_ancestor
+ * / \
+ * / \
+ * / \
+ * / \
+ * src_ancestor dst_ancestor
+ * | |
+ * ... ... <-- possibly long pathes
+ * | |
+ * src dst
+ * @endverbatim
+ */
+ static void find_common_ancestors(NetCard* src, NetCard* dst,
+ /* OUT */ AsImpl** common_ancestor, AsImpl** src_ancestor, AsImpl** dst_ancestor)
+ {
+#define ROUTING_HIERARCHY_MAXDEPTH 32 /* increase if it is not enough */
+ AsImpl* path_src[ROUTING_HIERARCHY_MAXDEPTH];
+ AsImpl* path_dst[ROUTING_HIERARCHY_MAXDEPTH];
+ int index_src = 0;
+ int index_dst = 0;
+ AsImpl* current_src;
+ AsImpl* current_dst;
+ AsImpl* father;
+
+ /* (1) find the path to root of src and dst*/
+ AsImpl* src_as = src->containingAS();
+ AsImpl* dst_as = dst->containingAS();
+
+ xbt_assert(src_as, "Host %s must be in an AS", src->name());
+ xbt_assert(dst_as, "Host %s must be in an AS", dst->name());
+
+ /* (2) find the path to the root routing component */
+ for (AsImpl* current = src_as; current != nullptr; current = static_cast<AsImpl*>(current->father())) {
+ xbt_assert(index_src < ROUTING_HIERARCHY_MAXDEPTH,
+ "ROUTING_HIERARCHY_MAXDEPTH should be increased for element %s", src->name());
+ path_src[index_src++] = current;
+ }
+ for (AsImpl* current = dst_as; current != nullptr; current = static_cast<AsImpl*>(current->father())) {
+ xbt_assert(index_dst < ROUTING_HIERARCHY_MAXDEPTH, "ROUTING_HIERARCHY_MAXDEPTH should be increased for path_dst");
+ path_dst[index_dst++] = current;