add RRGraph object and basic check_rr_graph_obj() function

Author: tangxifan

vpr/src/util/rr_graph_obj_util.cpp

@@ -0,0 +1,30 @@
+/****************************************************************************
+ * This file include most-utilized functions that manipulate on the
+ * RRGraph object
+ ***************************************************************************/
+#include <tuple>
+#include "rr_graph_obj_util.h"
+
+/****************************************************************************
+ * Find the switches interconnecting two nodes
+ * Return a vector of switch ids
+ ***************************************************************************/
+std::vector<RRSwitchId> find_rr_graph_switches(const RRGraph& rr_graph,
+                                               const RRNodeId& from_node,
+                                               const RRNodeId& to_node) {
+    std::vector<RRSwitchId> switches;
+    std::vector<RREdgeId> edges = rr_graph.find_edges(from_node, to_node);
+    if (true == edges.empty()) {
+        /* edge is open, we return an empty vector of switches */
+        return switches;
+    }
+
+    /* Reach here, edge list is not empty, find switch id one by one
+     * and update the switch list
+     */
+    for (auto edge : edges) {
+        switches.push_back(rr_graph.edge_switch(edge));
+    }
+
+    return switches;
+}

vpr/src/util/rr_graph_obj_util.h

@@ -0,0 +1,14 @@
+#ifndef RR_GRAPH_OBJ_UTIL_H
+#define RR_GRAPH_OBJ_UTIL_H
+
+/* Include header files which include data structures used by
+ * the function declaration
+ */
+#include "rr_graph_obj.h"
+
+/* Get node-to-node switches in a RRGraph */
+std::vector<RRSwitchId> find_rr_graph_switches(const RRGraph& rr_graph,
+                                               const RRNodeId& from_node,
+                                               const RRNodeId& to_node);
+
+#endif