1 files changed, 127 insertions, 0 deletions
diff --git a/src/vppinfra/graph.h b/src/vppinfra/graph.h
new file mode 100644
index 00000000000..1c26118f76c
--- /dev/null
+++ b/src/vppinfra/graph.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_clib_graph_h
+#define included_clib_graph_h
+
+#include <vppinfra/format.h>
+#include <vppinfra/hash.h>
+#include <vppinfra/pool.h>
+
+/* Generic graphs. */
+typedef struct
+{
+  /* Next node along this link. */
+  u32 node_index;
+
+  /* Other direction link index to reach back to current node. */
+  u32 link_to_self_index;
+
+  /* Distance to next node. */
+  u32 distance;
+} graph_link_t;
+
+/* Direction on graph: either next or previous. */
+typedef struct
+{
+  /* Vector of links. */
+  graph_link_t *links;
+
+  /* Hash mapping node index to link which visits this node. */
+  uword *link_index_by_node_index;
+} graph_dir_t;
+
+always_inline void
+graph_dir_free (graph_dir_t * d)
+{
+  vec_free (d->links);
+  hash_free (d->link_index_by_node_index);
+}
+
+always_inline graph_link_t *
+graph_dir_get_link_to_node (graph_dir_t * d, u32 node_index)
+{
+  uword *p = hash_get (d->link_index_by_node_index, node_index);
+  return p ? vec_elt_at_index (d->links, p[0]) : 0;
+}
+
+always_inline uword
+graph_dir_add_link (graph_dir_t * d, u32 node_index, u32 distance)
+{
+  graph_link_t *l;
+  ASSERT (!graph_dir_get_link_to_node (d, node_index));
+  vec_add2 (d->links, l, 1);
+  l->node_index = node_index;
+  l->distance = distance;
+  hash_set (d->link_index_by_node_index, node_index, l - d->links);
+  return l - d->links;
+}
+
+always_inline void
+graph_dir_del_link (graph_dir_t * d, u32 node_index)
+{
+  graph_link_t *l = graph_dir_get_link_to_node (d, node_index);
+  uword li = l - d->links;
+  uword n_links = vec_len (d->links);
+
+  ASSERT (l != 0);
+  hash_unset (d->link_index_by_node_index, node_index);
+  n_links -= 1;
+  if (li < n_links)
+    d->links[li] = d->links[n_links];
+  _vec_len (d->links) = n_links;
+}
+
+typedef struct
+{
+  /* Nodes we are connected to plus distances. */
+  graph_dir_t next, prev;
+} graph_node_t;
+
+typedef struct
+{
+  /* Pool of nodes. */
+  graph_node_t *nodes;
+
+  void *opaque;
+
+  format_function_t *format_node;
+} graph_t;
+
+/* Set link distance, creating link if not found. */
+u32 graph_set_link (graph_t * g, u32 src, u32 dst, u32 distance);
+
+always_inline void
+graph_set_bidirectional_link (graph_t * g, u32 src, u32 dst, u32 distance)
+{
+  graph_set_link (g, src, dst, distance);
+  graph_set_link (g, dst, src, distance);
+}
+
+void graph_del_link (graph_t * g, u32 src, u32 dst);
+uword graph_del_node (graph_t * g, u32 src);
+
+unformat_function_t unformat_graph;
+format_function_t format_graph;
+format_function_t format_graph_node;
+
+#endif /* included_clib_graph_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */