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reset the xbtdata at the and of topologicalsort (forgotten)
[simgrid.git] / src / xbt / graph.c
index 71ee5b5..34e454b 100644 (file)
@@ -1,12 +1,9 @@
-
-
 /*     $Id$     */
 
-
 /* a generic graph library.                                                 */
 
-/* Copyright (c) 2006 Darina Dimitrova, Arnaud Legrand. 
-   All rights reserved.                  */
+/* Copyright (c) 2006 Darina Dimitrova, Arnaud Legrand.                     */
+/* All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 #include "graph_private.h"
 #include "xbt/graphxml_parse.h"
 #include "xbt/dict.h"
+#include "xbt/heap.h"
+
+
+
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(graph, xbt, "Graph");
+
 
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(graph,xbt,"Graph");
 
 /** Constructor
  * \return a new graph
  */
 xbt_graph_t xbt_graph_new_graph(unsigned short int directed, void *data)
 {
-  xbt_graph_t graph=NULL;
-  graph=xbt_new0(struct xbt_graph,1);
-  graph->directed=directed;
-  graph->data=data;
-  graph->nodes= xbt_dynar_new(sizeof(xbt_node_t), free);
-  graph->edges= xbt_dynar_new(sizeof(xbt_edge_t), free);
+  xbt_graph_t graph = NULL;
+  graph = xbt_new0(struct xbt_graph, 1);
+  graph->directed = directed;
+  graph->data = data;
+  graph->nodes = xbt_dynar_new(sizeof(xbt_node_t), NULL);
+  graph->edges = xbt_dynar_new(sizeof(xbt_edge_t), NULL);
 
   return graph;
 }
 
 xbt_node_t xbt_graph_new_node(xbt_graph_t g, void *data)
 {
-  xbt_node_t node=NULL;
-  node=xbt_new0(struct xbt_node,1);
-  node->data=data;
-  node->in=xbt_dynar_new(sizeof(xbt_node_t), free);
-  node->out=xbt_dynar_new(sizeof(xbt_node_t), free);
-  xbt_dynar_push(g->nodes,&node);  
+  xbt_node_t node = NULL;
+  node = xbt_new0(struct xbt_node, 1);
+  node->data = data;
+  node->in = xbt_dynar_new(sizeof(xbt_edge_t), NULL);
+  node->out = xbt_dynar_new(sizeof(xbt_edge_t), NULL);
+  node->position_x = -1.0;
+  node->position_y = -1.0;
+
+  xbt_dynar_push(g->nodes, &node);
 
   return node;
 }
 
 
 xbt_edge_t xbt_graph_new_edge(xbt_graph_t g,
-                            xbt_node_t src, xbt_node_t dst, void *data)
+                             xbt_node_t src, xbt_node_t dst, void *data)
 {
-  xbt_edge_t edge=NULL;
-
-  edge=xbt_new0(struct xbt_edge,1);
-  xbt_dynar_push(src->out,&edge); 
-  xbt_dynar_push(dst->in,&edge); 
-  edge->data=data;
-  edge->src=src;
-  edge->dst=dst;
-  if(!g->directed) 
-   {
-     xbt_dynar_push(src->in,&edge); 
-     xbt_dynar_push(dst->out,&edge); 
-   }
+  xbt_edge_t edge = NULL;
+
+  edge = xbt_new0(struct xbt_edge, 1);
+  xbt_dynar_push(src->out, &edge);
+  if (g->directed) 
+    xbt_dynar_push(dst->in, &edge);
+  else /* only the "out" field is used */
+    xbt_dynar_push(dst->out, &edge);
+
+  edge->data = data;
+  edge->src = src;
+  edge->dst = dst;
+  if (!g->directed) 
+    {
+      xbt_dynar_push(src->in, &edge);
+      xbt_dynar_push(dst->out, &edge);
+    }
 
- xbt_dynar_push(g->edges,&edge);
 
- return edge; 
+  xbt_dynar_push(g->edges, &edge);
+
+  return edge;
 }
 
 
@@ -78,88 +90,133 @@ xbt_edge_t xbt_graph_new_edge(xbt_graph_t g,
  * Free the graph structure. 
  */
 void xbt_graph_free_graph(xbt_graph_t g,
-                         void node_free_function(void * ptr),
-                         void edge_free_function(void * ptr),
-                         void graph_free_function(void * ptr))
-{ 
-  int cursor; 
-  xbt_node_t node=NULL; 
+                         void node_free_function(void *ptr),
+                         void edge_free_function(void *ptr),
+                         void graph_free_function(void *ptr))
+{
+  int cursor = 0;
+  xbt_node_t node = NULL;
+  xbt_edge_t edge = NULL;
 
-  xbt_dynar_foreach(g->nodes,cursor,node)
-    xbt_graph_free_node(g,node,node_free_function);
 
-  xbt_assert0(!xbt_dynar_length(g->edges),
-             "Damnit, there are some remaining edges!");
+  xbt_dynar_foreach(g->nodes, cursor, node)
+    {
+      xbt_dynar_free(&(node->out));
+      xbt_dynar_free(&(node->in));
+      if(node_free_function)
+       node_free_function(node->data);
+    }
 
+  xbt_dynar_foreach(g->edges, cursor, edge) 
+    {
+      if(edge_free_function)
+       edge_free_function(edge->data);
+    }
+
+  xbt_dynar_foreach(g->nodes, cursor, node)
+    free(node);
   xbt_dynar_free(&(g->nodes));
+
+  xbt_dynar_foreach(g->edges, cursor, edge)
+    free(edge);
   xbt_dynar_free(&(g->edges));
-  fprintf(stderr,"%s","after free containers\n");    
 
+  free(g);
 
   return;
 }
 
-void xbt_graph_free_node(xbt_graph_t g, xbt_node_t n, void free_function(void * ptr))
-{ 
-  int cursor; 
-  xbt_node_t node=NULL;
 
-  if ((free_function)&&(n->data))
-    free_function(n->data);
 
-  xbt_dynar_free_container(&(n->in));
+void xbt_graph_free_node(xbt_graph_t g, xbt_node_t n,
+                        void_f_pvoid_t * node_free_function,
+                        void_f_pvoid_t * edge_free_function)
+{
+  unsigned long nbr;
+  int i;
+  int cursor = 0;
+  xbt_node_t node = NULL;
+  xbt_edge_t edge = NULL;
+
+  nbr = xbt_dynar_length(g->edges);
+  cursor=0;
+  for (i = 0; i < nbr; i++)
+    {
+      xbt_dynar_cursor_get(g->edges, &cursor, &edge);
+        
+      if ((edge->dst == n) || (edge->src == n))
+       {
+         xbt_graph_free_edge(g, edge, edge_free_function);
+       } 
+      else xbt_dynar_cursor_step( g->edges, &cursor);   
+    }
+
+
+ if ((node_free_function) && (n->data))
+    node_free_function(n->data);
 
-  xbt_dynar_free_container(&(n->out));
-  xbt_dynar_foreach(g->nodes,cursor,node)
+  cursor = 0;
+  xbt_dynar_foreach(g->nodes, cursor, node)
     {
-      if (node==n)
-       xbt_dynar_cursor_rm(g->nodes,&cursor);   
-      
+      if (node == n)
+       xbt_dynar_cursor_rm(g->nodes, &cursor);
+
     }
+
   return;
-   
 }
-void xbt_graph_free_edge(xbt_graph_t g, xbt_edge_t e, void free_function(void * ptr))
+
+void xbt_graph_free_edge(xbt_graph_t g, xbt_edge_t e,
+                        void free_function(void *ptr))
 {
-   int cursor=0; 
-   xbt_edge_t edge=NULL;
-   xbt_node_t node=NULL;
-   xbt_node_t temp=NULL;
-   
-   if ((free_function)&&(e->data))
-     free_function(e->data);
-   xbt_dynar_foreach(g->nodes,cursor,node)
-     {
-       if (node==e->src)
-        xbt_dynar_pop(node->out,temp);
-       if (g->directed)
-        xbt_dynar_pop(node->in,temp);
-        
-     }
-   node=NULL;
-   cursor=0;
-   xbt_dynar_foreach(g->nodes,cursor,node)
-     {
-        if (node==e->dst)
-         xbt_dynar_pop(node->in,temp);
-       if (g->directed)
-         xbt_dynar_pop(node->out,temp);
-        
-     }
-   cursor=0;
-   xbt_dynar_foreach(g->edges,cursor,edge)
-     if (edge==e) 
-       {
-        xbt_dynar_cursor_rm(g->edges,&cursor);
-        break;
-       }
-   
+  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;
 }
 
 xbt_dynar_t xbt_graph_get_nodes(xbt_graph_t g)
 {
   return g->nodes;
 }
+
 xbt_dynar_t xbt_graph_get_edges(xbt_graph_t g)
 {
   return g->edges;
@@ -167,31 +224,22 @@ xbt_dynar_t xbt_graph_get_edges(xbt_graph_t g)
 
 xbt_node_t xbt_graph_edge_get_source(xbt_edge_t e)
 {
-  
+
   return e->src;
 }
+
 xbt_node_t xbt_graph_edge_get_target(xbt_edge_t e)
 {
   return e->dst;
 }
-int xbt_get_node_index(xbt_graph_t g, xbt_node_t n)
-{
 
-  int cursor=0;
-  xbt_node_t tmp;
-  xbt_dynar_foreach(g->nodes,cursor,tmp)
-    {
-      if (tmp==n)
-       break;
-    }
-  return (cursor-1);
-}
 
-void  xbt_graph_edge_set_length(xbt_edge_t e, double length)
+void xbt_graph_edge_set_length(xbt_edge_t e, double length)
 {
-  e->length=length;
-  
+  e->length = length;
+
 }
+
 double xbt_graph_edge_get_length(xbt_edge_t e)
 {
   return e->length;
@@ -201,208 +249,406 @@ double xbt_graph_edge_get_length(xbt_edge_t e)
 /*construct the adjacency matrix corresponding to a graph,
   the weights are the distances between nodes
  */
-doublexbt_graph_get_length_matrix(xbt_graph_t g)
+double *xbt_graph_get_length_matrix(xbt_graph_t g)
 {
- fprintf(stderr,"%s","START GET LENGTHS\n" );
- int cursor = 0;
+  int cursor = 0;
   int in_cursor = 0;
-  int idx,i;
+  int  idx,i;
   unsigned long n;
   xbt_edge_t edge = NULL;
-  xbt_node_t node;
-  double* d=NULL;
+  xbt_node_t node=NULL;
+  double *d = NULL;
 
- # define D(u,v) d[(u)*n+(v)] 
- n = xbt_dynar_length(g->nodes);
+# define D(u,v) d[(u)*n+(v)]
 n = xbt_dynar_length(g->nodes);
 
-  d = (double*)xbt_malloc(n*n*(sizeof(double)));
+  d = (double *) xbt_new0(double, n*n);
 
-  for (i=0;i<n*n;i++)
+  for (i = 0; i < n * n; i++)
     {
-         d[i]=-1.0;
+      d[i] = -1.0;
     }
-
-
-  xbt_dynar_foreach(g->nodes,cursor,node)
-    {fprintf(stderr,"CURSOR:      %d\n",cursor );
-      in_cursor=0;
-      D(cursor-1,cursor-1)=0;
-      xbt_dynar_foreach(node->in,in_cursor,edge)
-       {fprintf(stderr,"EDGE IN:      %s\n",(char*)edge->data );
-fprintf(stderr,"EDGE DST:      %s\n",(char*)edge->dst->data );
-         idx = xbt_get_node_index(g,edge->dst);
- fprintf(stderr,"IDX: %d\n",idx );
-fprintf(stderr,"EDGE ADR: %x\n",(int)edge );
-fprintf(stderr,"EDGE LENGTH: %le\n", edge->length );
-         D(cursor-1,idx) = edge->length;
+  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;
        }
     }
- fprintf(stderr,"BEFORE RETURN\n" );
+
 # undef D
 
-return d; 
+  return d;
 }
 
- /*  calculate all-pairs shortest paths */
-/*   the shortest distance between node  i and j are stocked in  distances[i][j] */
-void xbt_floyd_algorithm(xbt_graph_t g, double* adj,double* d,  xbt_node_t* p)
+
+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);
+  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++)
+  for (i = 0; i < n * n; i++)
     {
-      d[i]=adj[i];
+      d[i] = adj[i];
     }
-  for(i=0;i<n;i++)
+
+
+  for (i = 0; i < n; i++)
     {
-      for(j=0;j<n;j++)
+      for (j = 0; j < n; j++)
        {
-         if(D(i,j)!=-1) P(i,j)=xbt_dynar_get_ptr (g->nodes,i) ;
+         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 (k = 0; k < n; k++)
     {
-      for(i=0;i<n;i++)
+      for (i = 0; i < n; i++)
        {
-         for(j=0;j<n;j++)
+         for (j = 0; j < n; j++)
            {
-             if((D(i,k)!=-1) && (D(k,j)!=-1))
+             if ((D(i, k) != -1) && (D(k, j) != -1))
                {
-                 if((D(i,j)==-1) || (D(i,j) > D(i,k)+D(k,j)))
+                 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);
+                     D(i, j) = D(i, k) + D(k, j);
+                     P(i, j) = P(k, j);
                    }
                }
            }
        }
     }
+
+
+
 # undef P
 # undef D
 }
 
 /*computes all-pairs shortest paths*/
-xbt_node_txbt_graph_shortest_paths(xbt_graph_t g)
+xbt_node_t *xbt_graph_shortest_paths(xbt_graph_t g)
 {
-  xbt_node_tp;
xbt_node_t* r;
int i,j,k;
- unsigned long  n; 
-  double* adj=NULL;
double* d=NULL;
+  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); 
- xbt_floyd_algorithm(g,adj,d,p);
+  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));
+           }
 
- for(i=0;i<n;i++)
-   {
-     for(j=0;j<n;j++)
-       {
-        k=j;
-        while((P(i,k))&&( xbt_get_node_index(g,P(i,k))!=i))
-          { 
-            k =  xbt_get_node_index(g,P(i,k));
-          }
-        if(P(i,j)) 
-          {
-            R(i,j)=(xbt_node_t)xbt_dynar_get_ptr(g->nodes,k);
-          }
-       }
-   }
+         if (P(i, j))
+           {
+             R(i, j) = *((xbt_node_t*) xbt_dynar_get_ptr(g->nodes, k));
+           }
+       }
+    }
 # undef R
 # undef P
 
-   xbt_free(d);
-   xbt_free(p);
- return r;
+  free(d);
+  free(p);
+  free(adj);
+  return r;
+}
+
+
+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;
+}
+
+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) 
+   {
+    node->xbtdata = NULL;
+   }     
+  return sorted; 
+
+
+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;
+    }       
 }
 
-static xbt_graph_t parsed_graph=NULL;
-static xbt_dict_t parsed_nodes=NULL;
-static xbt_dict_t parsed_edges=NULL; 
-     
 
-static void  __parse_graph_begin(void)
+/********************* 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)
+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,(void*)A_graphxml_node_name);
+  xbt_node_t node =
+      xbt_graph_new_node(parsed_graph, NULL);
 
- xbt_dict_set( parsed_nodes,A_graphxml_node_name, (void *)node, free); 
-  
- DEBUG1("<node label=\"%s\"/>",(char*)(node->data));
+  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),
-                                      (void*) A_graphxml_edge_name);
-
- xbt_dict_set( parsed_edges,A_graphxml_edge_name, (void *)edge, free);
- xbt_graph_edge_set_length(edge,atof(A_graphxml_edge_length));
-  DEBUG4("<edge name=\"%s\"  source=\"%s\" target=\"%s\" length=\"%f\"/>",
-        (char*)edge->data,
-        (char*)(edge->src)->data,
-        (char*)(edge->dst)->data,
+  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));
 }
 
-xbt_graph_t xbt_graph_read(const char *filename)
-{ 
-  xbt_graph_t graph = xbt_graph_new_graph(1,NULL);
+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*))
+{
 
-  parsed_graph = graph;
-  parsed_nodes= xbt_dict_new();
-  parsed_edges= xbt_dict_new();
+  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_assert1((!xbt_graph_parse()), "Parse error in %s", filename);
   xbt_graph_parse_close();
 
+  graph = parsed_graph;
   parsed_graph = NULL;
+
   return graph;
 }
-void xbt_graph_export_surfxml(xbt_graph_t g,
-                             const char *filename,
-                             const char *(node_name)(xbt_node_t),
-                             const char *(edge_name)(xbt_edge_t)
-                             )
+
+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);
+}
+
+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);
 }
 
-/* ./xbt/graphxml_usage xbt/graph.xml --xbt-log=graph.thres=debug */