+}
+
+/** @brief remove the given edge from the given graph */
+void xbt_graph_free_edge(xbt_graph_t g, xbt_edge_t e,
+ void free_function(void *ptr))
+{
+ int idx;
+ int cursor = 0;
+ xbt_edge_t edge = NULL;
+
+ if ((free_function) && (e->data))
+ free_function(e->data);
+
+ xbt_dynar_foreach(g->edges, cursor, edge) {
+ if (edge == e) {
+ if (g->directed) {
+ idx = __xbt_find_in_dynar(edge->dst->in, edge);
+ xbt_dynar_remove_at(edge->dst->in, idx, NULL);
+ } else { /* only the out field is used */
+ idx = __xbt_find_in_dynar(edge->dst->out, edge);
+ xbt_dynar_remove_at(edge->dst->out, idx, NULL);
+ }
+
+ idx = __xbt_find_in_dynar(edge->src->out, edge);
+ xbt_dynar_remove_at(edge->src->out, idx, NULL);
+
+ xbt_dynar_cursor_rm(g->edges, &cursor);
+ free(edge);
+ break;
+ }
+ }
+}
+
+int __xbt_find_in_dynar(xbt_dynar_t dynar, void *p)
+{
+
+ int cursor = 0;
+ void *tmp = NULL;
+
+ xbt_dynar_foreach(dynar, cursor, tmp) {
+ if (tmp == p)
+ return cursor;
+ }
+ return -1;
+}
+
+/** @brief Retrieve the graph's nodes as a dynar */
+xbt_dynar_t xbt_graph_get_nodes(xbt_graph_t g)
+{
+ return g->nodes;
+}
+
+/** @brief Retrieve the graph's edges as a dynar */
+xbt_dynar_t xbt_graph_get_edges(xbt_graph_t g)
+{
+ return g->edges;
+}
+
+/** @brief Retrieve the node at the source of the given edge */
+xbt_node_t xbt_graph_edge_get_source(xbt_edge_t e)
+{
+
+ return e->src;
+}
+
+/** @brief Retrieve the node being the target of the given edge */
+xbt_node_t xbt_graph_edge_get_target(xbt_edge_t e)
+{
+ return e->dst;
+}
+
+
+/** @brief Set the weight of the given edge */
+void xbt_graph_edge_set_length(xbt_edge_t e, double length)
+{
+ e->length = length;
+
+}
+
+double xbt_graph_edge_get_length(xbt_edge_t e)
+{
+ return e->length;
+}
+
+
+/** @brief construct the adjacency matrix corresponding to the given graph
+ *
+ * The weights are the distances between nodes
+ */
+double *xbt_graph_get_length_matrix(xbt_graph_t g)
+{
+ int cursor = 0;
+ int in_cursor = 0;
+ int idx, i;
+ unsigned long n;
+ xbt_edge_t edge = NULL;
+ xbt_node_t node = NULL;
+ double *d = NULL;
+
+# define D(u,v) d[(u)*n+(v)]
+ n = xbt_dynar_length(g->nodes);
+
+ d = (double *) xbt_new0(double, n * n);
+
+ for (i = 0; i < n * n; i++) {
+ d[i] = -1.0;
+ }
+
+ xbt_dynar_foreach(g->nodes, cursor, node) {
+ in_cursor = 0;
+ D(cursor, cursor) = 0;
+
+ xbt_dynar_foreach(node->out, in_cursor, edge) {
+ if (edge->dst == node)
+ idx = __xbt_find_in_dynar(g->nodes, edge->src);
+ else /*case of undirected graphs */
+ idx = __xbt_find_in_dynar(g->nodes, edge->dst);
+ D(cursor, idx) = edge->length;
+ }
+ }
+
+# undef D
+
+ return d;
+}
+
+/** @brief Floyd-Warshall algorithm for shortest path finding
+ *
+ * From wikipedia:
+ *
+ * The Floyd–Warshall algorithm takes as input an adjacency matrix
+ * representation of a weighted, directed graph (V, E). The weight of a
+ * path between two vertices is the sum of the weights of the edges along
+ * that path. The edges E of the graph may have negative weights, but the
+ * graph must not have any negative weight cycles. The algorithm computes,
+ * for each pair of vertices, the minimum weight among all paths between
+ * the two vertices. The running time complexity is Θ(|V|3).
+ */
+void xbt_floyd_algorithm(xbt_graph_t g, double *adj, double *d,
+ xbt_node_t * p)
+{
+ int i, j, k;
+ unsigned long n;
+ n = xbt_dynar_length(g->nodes);
+
+# define D(u,v) d[(u)*n+(v)]
+# define P(u,v) p[(u)*n+(v)]
+
+ for (i = 0; i < n * n; i++) {
+ d[i] = adj[i];
+ }
+
+
+ for (i = 0; i < n; i++) {
+ for (j = 0; j < n; j++) {
+ if (D(i, j) != -1) {
+ P(i, j) = *((xbt_node_t *) xbt_dynar_get_ptr(g->nodes, i));
+ }
+ }
+ }
+
+ for (k = 0; k < n; k++) {
+ for (i = 0; i < n; i++) {
+ for (j = 0; j < n; j++) {
+ if ((D(i, k) != -1) && (D(k, j) != -1)) {
+ if ((D(i, j) == -1) || (D(i, j) > D(i, k) + D(k, j))) {
+ D(i, j) = D(i, k) + D(k, j);
+ P(i, j) = P(k, j);
+ }
+ }
+ }
+ }
+ }
+
+
+
+# undef P
+# undef D
+}
+
+/** @brief computes all-pairs shortest paths */
+xbt_node_t *xbt_graph_shortest_paths(xbt_graph_t g)
+{
+ xbt_node_t *p;
+ xbt_node_t *r;
+ int i, j, k;
+ unsigned long n;
+
+ double *adj = NULL;
+ double *d = NULL;
+
+# define P(u,v) p[(u)*n+(v)]
+# define R(u,v) r[(u)*n+(v)]
+
+ n = xbt_dynar_length(g->nodes);
+ adj = xbt_graph_get_length_matrix(g);
+ d = xbt_new0(double, n * n);
+ p = xbt_new0(xbt_node_t, n * n);
+ r = xbt_new0(xbt_node_t, n * n);
+
+ xbt_floyd_algorithm(g, adj, d, p);
+
+ for (i = 0; i < n; i++) {
+ for (j = 0; j < n; j++) {
+ k = j;
+
+ while ((P(i, k)) && (__xbt_find_in_dynar(g->nodes, P(i, k)) != i)) {
+ k = __xbt_find_in_dynar(g->nodes, P(i, k));
+ }
+
+ if (P(i, j)) {
+ R(i, j) = *((xbt_node_t *) xbt_dynar_get_ptr(g->nodes, k));
+ }
+ }
+ }
+# undef R
+# undef P
+
+ free(d);
+ free(p);
+ free(adj);
+ return r;
+}
+
+/** @brief Extract a spanning tree of the given graph */
+xbt_edge_t *xbt_graph_spanning_tree_prim(xbt_graph_t g)
+{
+ int tree_size = 0;
+ int tree_size_max = xbt_dynar_length(g->nodes) - 1;
+ xbt_edge_t *tree = xbt_new0(xbt_edge_t, tree_size_max);
+ xbt_edge_t e, edge;
+ xbt_node_t node = NULL;
+ xbt_dynar_t edge_list = NULL;
+ xbt_heap_t heap = xbt_heap_new(10, NULL);
+ int cursor;
+
+ xbt_assert0(!(g->directed),
+ "Spanning trees do not make sense on directed graphs");
+
+ xbt_dynar_foreach(g->nodes, cursor, node) {
+ node->xbtdata = NULL;
+ }
+
+ node = xbt_dynar_getfirst_as(g->nodes, xbt_node_t);
+ node->xbtdata = (void *) 1;
+ edge_list = node->out;
+ xbt_dynar_foreach(edge_list, cursor, e)
+ xbt_heap_push(heap, e, -(e->length));
+
+ while ((edge = xbt_heap_pop(heap))) {
+ if ((edge->src->xbtdata) && (edge->dst->xbtdata))
+ continue;
+ tree[tree_size++] = edge;
+ if (!(edge->src->xbtdata)) {
+ edge->src->xbtdata = (void *) 1;
+ edge_list = edge->src->out;
+ xbt_dynar_foreach(edge_list, cursor, e) {
+ xbt_heap_push(heap, e, -(e->length));
+ }
+ } else {
+ edge->dst->xbtdata = (void *) 1;
+ edge_list = edge->dst->out;
+ xbt_dynar_foreach(edge_list, cursor, e) {
+ xbt_heap_push(heap, e, -(e->length));
+ }
+ }
+ if (tree_size == tree_size_max)
+ break;
+ }
+
+ xbt_heap_free(heap);
+
+ return tree;
+}
+
+/** @brief Topological sort on the given graph
+ *
+ * From wikipedia:
+ *
+ * In graph theory, a topological sort of a directed acyclic graph (DAG) is
+ * a linear ordering of its nodes which is compatible with the partial
+ * order R induced on the nodes where x comes before y (xRy) if there's a
+ * directed path from x to y in the DAG. An equivalent definition is that
+ * each node comes before all nodes to which it has edges. Every DAG has at
+ * least one topological sort, and may have many.
+ */
+xbt_node_t *xbt_graph_topo_sort(xbt_graph_t g)
+{
+
+ xbt_node_t *sorted;
+ int cursor, idx;
+ xbt_node_t node;
+ unsigned long n;
+
+ n = xbt_dynar_length(g->nodes);
+ idx = n - 1;
+
+ sorted = xbt_malloc(n * sizeof(xbt_node_t));
+
+ xbt_dynar_foreach(g->nodes, cursor, node)
+ node->xbtdata = xbt_new0(int, 1);
+
+ xbt_dynar_foreach(g->nodes, cursor, node)
+ xbt_graph_depth_visit(g, node, sorted, &idx);
+
+ xbt_dynar_foreach(g->nodes, cursor, node) {
+ free(node->xbtdata);
+ node->xbtdata = NULL;
+ }
+
+ return sorted;
+}
+
+/** @brief First-depth graph traversal */
+void xbt_graph_depth_visit(xbt_graph_t g, xbt_node_t n,
+ xbt_node_t * sorted, int *idx)
+{
+ int cursor;
+ xbt_edge_t edge;
+
+ if (*((int *) (n->xbtdata)) == ALREADY_EXPLORED)
+ return;
+ else if (*((int *) (n->xbtdata)) == CURRENTLY_EXPLORING)
+ THROW0(0, 0, "There is a cycle");
+ else {
+ *((int *) (n->xbtdata)) = CURRENTLY_EXPLORING;
+
+ xbt_dynar_foreach(n->out, cursor, edge) {
+ xbt_graph_depth_visit(g, edge->dst, sorted, idx);
+ }
+
+ *((int *) (n->xbtdata)) = ALREADY_EXPLORED;
+ sorted[(*idx)--] = n;
+ }
+}
+
+/********************* Import and Export ******************/
+static xbt_graph_t parsed_graph = NULL;
+static xbt_dict_t parsed_nodes = NULL;
+
+static void *(*__parse_node_label_and_data) (xbt_node_t, const char *,
+ const char *) = NULL;
+static void *(*__parse_edge_label_and_data) (xbt_edge_t, const char *,
+ const char *) = NULL;
+
+static void __parse_graph_begin(void)
+{
+ DEBUG0("<graph>");
+ if (A_graphxml_graph_isDirected == A_graphxml_graph_isDirected_true)
+ parsed_graph = xbt_graph_new_graph(1, NULL);
+ else
+ parsed_graph = xbt_graph_new_graph(0, NULL);
+
+ parsed_nodes = xbt_dict_new();
+}
+
+static void __parse_graph_end(void)
+{
+ xbt_dict_free(&parsed_nodes);
+ DEBUG0("</graph>");
+}
+
+static void __parse_node(void)
+{
+ xbt_node_t node = xbt_graph_new_node(parsed_graph, NULL);
+
+ DEBUG1("<node name=\"%s\"/>", A_graphxml_node_name);
+ if (__parse_node_label_and_data)
+ node->data = __parse_node_label_and_data(node, A_graphxml_node_label,
+ A_graphxml_node_data);
+ xbt_graph_parse_get_double(&(node->position_x),
+ A_graphxml_node_position_x);
+ xbt_graph_parse_get_double(&(node->position_y),
+ A_graphxml_node_position_y);
+
+ xbt_dict_set(parsed_nodes, A_graphxml_node_name, (void *) node, NULL);
+}
+
+static void __parse_edge(void)
+{
+ xbt_edge_t edge = xbt_graph_new_edge(parsed_graph,
+ xbt_dict_get(parsed_nodes,
+ A_graphxml_edge_source),
+ xbt_dict_get(parsed_nodes,
+ A_graphxml_edge_target),
+ NULL);
+
+ if (__parse_edge_label_and_data)
+ edge->data = __parse_edge_label_and_data(edge, A_graphxml_edge_label,
+ A_graphxml_edge_data);
+
+ xbt_graph_parse_get_double(&(edge->length), A_graphxml_edge_length);
+
+ DEBUG3("<edge source=\"%s\" target=\"%s\" length=\"%f\"/>",
+ (char *) (edge->src)->data,
+ (char *) (edge->dst)->data, xbt_graph_edge_get_length(edge));
+}
+
+/** @brief Import a graph from a file following the GraphXML format */
+xbt_graph_t xbt_graph_read(const char *filename,
+ void *(node_label_and_data) (xbt_node_t,
+ const char *,
+ const char *),
+ void *(edge_label_and_data) (xbt_edge_t,
+ const char *,
+ const char *))
+{
+
+ xbt_graph_t graph = NULL;
+
+ __parse_node_label_and_data = node_label_and_data;
+ __parse_edge_label_and_data = edge_label_and_data;
+
+ xbt_graph_parse_reset_parser();
+
+ STag_graphxml_graph_fun = __parse_graph_begin;
+ ETag_graphxml_graph_fun = __parse_graph_end;
+ ETag_graphxml_node_fun = __parse_node;
+ ETag_graphxml_edge_fun = __parse_edge;
+
+ xbt_graph_parse_open(filename);
+ xbt_assert1((!xbt_graph_parse()), "Parse error in %s", filename);
+ xbt_graph_parse_close();
+
+ graph = parsed_graph;
+ parsed_graph = NULL;
+
+ return graph;
+}
+
+/** @brief Export the given graph in the GraphViz formatting for visualization */
+void xbt_graph_export_graphviz(xbt_graph_t g, const char *filename,
+ const char *(node_name) (xbt_node_t),
+ const char *(edge_name) (xbt_edge_t))
+{
+ int cursor = 0;
+ xbt_node_t node = NULL;
+ xbt_edge_t edge = NULL;
+ FILE *file = NULL;
+ const char *name = NULL;
+
+ file = fopen(filename, "w");
+ xbt_assert1(file, "Failed to open %s \n", filename);
+
+ if (g->directed)
+ fprintf(file, "digraph test {\n");
+ else
+ fprintf(file, "graph test {\n");
+
+ fprintf(file, " graph [overlap=scale]\n");
+
+ fprintf(file, " node [shape=box, style=filled]\n");
+ fprintf(file,
+ " node [width=.3, height=.3, style=filled, color=skyblue]\n\n");
+
+ xbt_dynar_foreach(g->nodes, cursor, node) {
+ fprintf(file, " \"%p\" ", node);
+ if ((node_name) && ((name = node_name(node))))
+ fprintf(file, "[label=\"%s\"]", name);
+ fprintf(file, ";\n");
+ }
+ xbt_dynar_foreach(g->edges, cursor, edge) {
+ if (g->directed)
+ fprintf(file, " \"%p\" -> \"%p\"", edge->src, edge->dst);
+ else
+ fprintf(file, " \"%p\" -- \"%p\"", edge->src, edge->dst);
+ if ((edge_name) && ((name = edge_name(edge))))
+ fprintf(file, "[label=\"%s\"]", name);
+ fprintf(file, ";\n");
+ }
+ fprintf(file, "}\n");
+ fclose(file);
+}
+
+/** @brief Export the given graph in the GraphXML format */
+void xbt_graph_export_graphxml(xbt_graph_t g, const char *filename,
+ const char *(node_name) (xbt_node_t),
+ const char *(edge_name) (xbt_edge_t),
+ const char *(node_data_print) (void *),
+ const char *(edge_data_print) (void *))
+{
+ int cursor = 0;
+ xbt_node_t node = NULL;
+ xbt_edge_t edge = NULL;
+ FILE *file = NULL;
+ const char *name = NULL;
+
+ file = fopen(filename, "w");
+ xbt_assert1(file, "Failed to open %s \n", filename);
+
+ fprintf(file, "<?xml version='1.0'?>\n");
+ fprintf(file, "<!DOCTYPE graph SYSTEM \"graphxml.dtd\">\n");
+ if (g->directed)
+ fprintf(file, "<graph isDirected=\"true\">\n");
+ else
+ fprintf(file, "<graph isDirected=\"false\">\n");
+ xbt_dynar_foreach(g->nodes, cursor, node) {
+ fprintf(file, " <node name=\"%p\" ", node);
+ if ((node_name) && ((name = node_name(node))))
+ fprintf(file, "label=\"%s\" ", name);
+ if ((node_data_print) && ((name = node_data_print(node->data))))
+ fprintf(file, "data=\"%s\" ", name);
+ fprintf(file, ">\n");
+ }
+ xbt_dynar_foreach(g->edges, cursor, edge) {
+ fprintf(file, " <edge source=\"%p\" target =\"%p\" ",
+ edge->src, edge->dst);
+ if ((edge_name) && ((name = edge_name(edge))))
+ fprintf(file, "label=\"%s\" ", name);
+ if (edge->length >= 0.0)
+ fprintf(file, "length=\"%g\" ", edge->length);
+ if ((edge_data_print) && ((name = edge_data_print(edge->data))))
+ fprintf(file, "data=\"%s\" ", name);
+ fprintf(file, ">\n");
+ }
+ fprintf(file, "</graph>\n");
+ fclose(file);