lib/graph.h

   1 /*
   2  * Graph data structure.
   3  *
   4  * --
   5  * Copyright (C) 2016 Cumulus Networks, Inc.
   6  *
   7  * This file is part of GNU Zebra.
   8  *
   9  * GNU Zebra is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the
  11  * Free Software Foundation; either version 2, or (at your option) any
  12  * later version.
  13  *
  14  * GNU Zebra is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; see the file COPYING; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #ifndef _ZEBRA_COMMAND_GRAPH_H
  25 #define _ZEBRA_COMMAND_GRAPH_H
  26
  27 #include <stdbool.h>
  28 #include "vector.h"
  29
  30 struct graph {
  31         vector nodes;
  32 };
  33
  34 struct graph_node {
  35         vector from; // nodes which have edges to this node
  36         vector to;   // nodes which this node has edges to
  37
  38         void *data;              // node data
  39         void (*del)(void *data); // deletion callback
  40 };
  41
  42 struct graph *graph_new(void);
  43
  44 /**
  45  * Creates a new node.
  46  *
  47  * @struct graph the graph this node exists in
  48  * @param[in] data this node's data
  49  * @param[in] del data deletion callback
  50  * @return the new node
  51  */
  52 struct graph_node *graph_new_node(struct graph *graph, void *data,
  53                                   void (*del)(void *));
  54
  55 /**
  56  * Deletes a node.
  57  *
  58  * Before deletion, this function removes all edges to and from this node from
  59  * any neighbor nodes.
  60  *
  61  * If *data and *del are non-null, the following call is made:
  62  *   (*node->del) (node->data);
  63  *
  64  * @param[in] graph the graph this node belongs to
  65  * @param[out] node pointer to node to delete
  66  */
  67 void graph_delete_node(struct graph *graph, struct graph_node *node);
  68
  69 /**
  70  * Makes a directed edge between two nodes.
  71  *
  72  * @param[in] from
  73  * @param[in] to
  74  * @return to
  75  */
  76 struct graph_node *graph_add_edge(struct graph_node *from,
  77                                   struct graph_node *to);
  78
  79 /**
  80  * Removes a directed edge between two nodes.
  81  *
  82  * @param[in] from
  83  * @param[in] to
  84  */
  85 void graph_remove_edge(struct graph_node *from, struct graph_node *to);
  86
  87 /**
  88  * Deletes a graph.
  89  * Calls graph_delete_node on each node before freeing the graph struct itself.
  90  *
  91  * @param graph the graph to delete
  92  */
  93 void graph_delete_graph(struct graph *graph);
  94
  95 /*
  96  * Finds a node in the graph.
  97  *
  98  * @param[in] graph the graph to search in
  99  * @param[in] data the data to key off
 100  * @return the first graph node whose data pointer matches `data`
 101  */
 102 struct graph_node *graph_find_node(struct graph *graph, void *data);
 103
 104
 105 /*
 106  * Determines whether two nodes have a directed edge between them.
 107  *
 108  * @param from
 109  * @param to
 110  * @return whether there is a directed edge from `from` to `to`.
 111  */
 112 bool graph_has_edge(struct graph_node *from, struct graph_node *to);
 113
 114 #endif /* _ZEBRA_COMMAND_GRAPH_H */