+}
+
+/** @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)
+{