4 files changed, 108 insertions, 57 deletions

diff --git a/src/testbed/Makefile.am b/src/testbed/Makefile.am
index a08f320b8..130014836 100644
--- a/src/testbed/Makefile.am
+++ b/src/testbed/Makefile.am
@@ -65,7 +65,7 @@ libgnunettestbed_la_SOURCES = \
   testbed_api_statistics.c \
   testbed_api_testbed.c \
   testbed_api_test.c \
-  testbed_api_topology.c
+  testbed_api_topology.c testbed_api_topology.h
 libgnunettestbed_la_LIBADD = $(XLIB) \
  $(top_builddir)/src/core/libgnunetcore.la \
  $(top_builddir)/src/statistics/libgnunetstatistics.la \
diff --git a/src/testbed/testbed_api_testbed.c b/src/testbed/testbed_api_testbed.c
index cfe6370ea..a7e15dc6b 100644
--- a/src/testbed/testbed_api_testbed.c
+++ b/src/testbed/testbed_api_testbed.c
@@ -29,6 +29,7 @@
 #include "gnunet_testbed_service.h"
 #include "testbed_api_peers.h"
 #include "testbed_api_hosts.h"
+#include "testbed_api_topology.h"
 
 /**
  * Generic loggins shorthand
@@ -672,38 +673,8 @@ GNUNET_TESTBED_run (const char *host_filename,
     }
     else if (0 == strcasecmp (topology, "2D_TORUS"))
     {
-      double sq;
-      unsigned int sq_floor;
-      unsigned int rows;
-      unsigned int *rows_len;
-      unsigned int x;
-      unsigned int y;
-      unsigned int n;
-
       rc->topology = GNUNET_TESTBED_TOPOLOGY_2D_TORUS;
-      sq = sqrt ((double) num_peers);
-      sq = floor (sq);
-      sq_floor = (unsigned int) sq;
-      rows = (sq_floor + 1);
-      rows_len = GNUNET_malloc (sizeof (unsigned int) * rows);
-      for (y = 0; y < rows - 1; y++)
-        rows_len[y] = sq_floor;
-      n = sq_floor * sq_floor;
-      GNUNET_assert (n <= num_peers);
-      rc->num_oc = 2 * n;
-      x = 0;
-      y = 0;
-      while (n < num_peers)
-      {
-        if (x < y)
-          rows_len[rows - 1] = ++x;
-        else
-          rows_len[y++]++;
-        n++;
-      }
-      rc->num_oc += (x < 2) ? x : 2 * x;
-      rc->num_oc += (y < 2) ? y : 2 * y;
-      GNUNET_free (rows_len);
+      rc->num_oc = GNUNET_TESTBED_2dtorus_calc_links (num_peers, NULL, NULL);
     }
     else
       LOG (GNUNET_ERROR_TYPE_WARNING,
diff --git a/src/testbed/testbed_api_topology.c b/src/testbed/testbed_api_topology.c
index effc428e8..9c62502c4 100644
--- a/src/testbed/testbed_api_topology.c
+++ b/src/testbed/testbed_api_topology.c
@@ -28,6 +28,7 @@
 #include "testbed_api.h"
 #include "testbed_api_peers.h"
 #include "testbed_api_operations.h"
+#include "testbed_api_topology.h"
 
 /**
  * Generic loggins shorthand
@@ -232,49 +233,81 @@ gen_topo_ring (struct TopologyContext *tc)
 
 
 /**
- * Generates ring topology
+ * Returns the number of links that are required to generate a 2d torus for the
+ * given number of peers. Also returns the arrangment (number of rows and the
+ * length of each row)
  *
- * @param tc the topology context
+ * @param num_peers number of peers
+ * @param rows number of rows in the 2d torus. Can be NULL
+ * @param rows_len the length of each row. This array will be allocated
+ *          fresh. The caller should free it. Can be NULL
  */
-static void
-gen_topo_2dtorus (struct TopologyContext *tc)
+unsigned int
+GNUNET_TESTBED_2dtorus_calc_links (unsigned int num_peers,
+                                   unsigned int *rows,
+                                   unsigned int **rows_len)
 {
   double sq;
   unsigned int sq_floor;
-  unsigned int rows;
-  unsigned int *rows_len;
+  unsigned int _rows;
+  unsigned int *_rows_len;
   unsigned int x;
   unsigned int y;
-  unsigned int num_peers;
+  unsigned int _num_peers;
   unsigned int cnt;
-  unsigned int offset;
-
-  sq = sqrt (tc->num_peers);
+  
+  sq = sqrt (num_peers);
   sq = floor (sq);
   sq_floor = (unsigned int) sq;
-  rows = (sq_floor + 1);
-  rows_len = GNUNET_malloc (sizeof (unsigned int) * rows);
-  for (y = 0; y < rows - 1; y++)
-    rows_len[y] = sq_floor;
-  num_peers = sq_floor * sq_floor;
-  GNUNET_assert (num_peers <= tc->num_peers);
-  tc->link_array_size = 2 * num_peers;
+  _rows = (sq_floor + 1);
+  _rows_len = GNUNET_malloc (sizeof (unsigned int) * _rows);  
+  for (y = 0; y < _rows - 1; y++)
+    _rows_len[y] = sq_floor;
+  _num_peers = sq_floor * sq_floor;
+  cnt = 2 * _num_peers;
   x = 0;
   y = 0;
-  while (num_peers < tc->num_peers)
+  while (_num_peers < num_peers)
   {
     if (x < y)
-      rows_len[rows - 1] = ++x;
+      _rows_len[_rows - 1] = ++x;
     else
-      rows_len[y++]++;
-    num_peers++;
+      _rows_len[y++]++;
+    _num_peers++;
   }
-  tc->link_array_size += (x < 2) ? x : 2 * x;
-  tc->link_array_size += (y < 2) ? y : 2 * y;
+  cnt += (x < 2) ? x : 2 * x;
+  cnt += (y < 2) ? y : 2 * y;
+  if (0 == _rows_len[_rows - 1])
+    _rows--;
+  if (NULL != rows)
+    *rows = _rows;
+  if (NULL != rows_len)
+    *rows_len = _rows_len;
+  else
+    GNUNET_free (_rows_len);
+  return cnt;
+}
+
+
+/**
+ * Generates ring topology
+ *
+ * @param tc the topology context
+ */
+static void
+gen_topo_2dtorus (struct TopologyContext *tc)
+{
+  unsigned int rows;
+  unsigned int *rows_len;
+  unsigned int x;
+  unsigned int y;
+  unsigned int cnt;
+  unsigned int offset;
+
+  tc->link_array_size = GNUNET_TESTBED_2dtorus_calc_links (tc->num_peers, &rows,
+                                                           &rows_len);
   tc->link_array = GNUNET_malloc (sizeof (struct OverlayLink) *
                                   tc->link_array_size);
-  if (0 == rows_len[rows - 1])
-    rows--;
   cnt = 0;
   offset = 0;
   for (y = 0; y < rows; y++)
diff --git a/src/testbed/testbed_api_topology.h b/src/testbed/testbed_api_topology.h
new file mode 100644
index 000000000..b5ae8ce44
--- /dev/null
+++ b/src/testbed/testbed_api_topology.h
@@ -0,0 +1,47 @@
+/*
+      This file is part of GNUnet
+      (C) 2008--2012 Christian Grothoff (and other contributing authors)
+
+      GNUnet is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published
+      by the Free Software Foundation; either version 3, or (at your
+      option) any later version.
+
+      GNUnet is distributed in the hope that it will be useful, but
+      WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+      General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with GNUnet; see the file COPYING.  If not, write to the
+      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+      Boston, MA 02111-1307, USA.
+ */
+
+/**
+ * @file testbed/testbed_api_topology.h
+ * @brief header for intra library exported functions
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in> 
+ */
+
+#ifndef TESTBED_API_TOPOLOGY_H
+#define TESTBED_API_TOPOLOGY_H
+
+/**
+ * Returns the number of links that are required to generate a 2d torus for the
+ * given number of peers. Also returns the arrangment (number of rows and the
+ * length of each row)
+ *
+ * @param num_peers number of peers
+ * @param rows number of rows in the 2d torus. Can be NULL.
+ * @param rows_len the length of each row. This array will be allocated
+ *          fresh. The caller should free it. Can be NULL.
+ */
+unsigned int
+GNUNET_TESTBED_2dtorus_calc_links (unsigned int num_peers,
+                                   unsigned int *rows,
+                                   unsigned int **rows_len);
+
+#endif  
+/* end of  testbed_api_topology.h */
+