# HG changeset patch
# User Balazs Dezso <deba@inf.elte.hu>
# Date 1224281122 -7200
# Node ID 96f7cc46c91cda1928a772df0c3b5f71b58a059d
# Parent  6dbd5184c6a99e936a7de899e64c114e30c0f94f
Porting nauty reader function from SVN #3509

diff -r 6dbd5184c6a9 -r 96f7cc46c91c lemon/Makefile.am
--- a/lemon/Makefile.am	Sun Oct 12 19:35:48 2008 +0100
+++ b/lemon/Makefile.am	Sat Oct 18 00:05:22 2008 +0200
@@ -35,6 +35,7 @@
 	lemon/list_graph.h \
 	lemon/maps.h \
 	lemon/math.h \
+	lemon/nauty_reader.h \
 	lemon/path.h \
         lemon/random.h \
 	lemon/smart_graph.h \
diff -r 6dbd5184c6a9 -r 96f7cc46c91c lemon/nauty_reader.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lemon/nauty_reader.h	Sat Oct 18 00:05:22 2008 +0200
@@ -0,0 +1,120 @@
+/* -*- mode: C++; indent-tabs-mode: nil; -*-
+ *
+ * This file is a part of LEMON, a generic C++ optimization library.
+ *
+ * Copyright (C) 2003-2008
+ * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
+ * (Egervary Research Group on Combinatorial Optimization, EGRES).
+ *
+ * Permission to use, modify and distribute this software is granted
+ * provided that this copyright notice appears in all copies. For
+ * precise terms see the accompanying LICENSE file.
+ *
+ * This software is provided "AS IS" with no warranty of any kind,
+ * express or implied, and with no claim as to its suitability for any
+ * purpose.
+ *
+ */
+
+#ifndef LEMON_NAUTY_READER_H
+#define LEMON_NAUTY_READER_H
+
+#include <vector>
+#include <iostream>
+#include <string>
+
+/// \ingroup io_group
+///
+/// @defgroup nauty_group NAUTY format
+///
+/// \brief Read \e Nauty format
+///
+/// Tool to read graphs from \e Nauty format data
+
+/// \ingroup nauty_group
+/// \file
+/// \brief Nauty file reader.
+namespace lemon {
+
+  /// \ingroup nauty_group
+  ///
+  /// \brief Nauty file reader
+  ///
+  /// The \e geng program is in the \e gtools suite of the nauty
+  /// package. This tool can generate all non-isomorphic undirected
+  /// graphs with given node number from several classes (for example,
+  /// general, connected, biconnected, triangle-free, 4-cycle-free,
+  /// bipartite and graphs with given edge number and degree
+  /// constraints). This function reads a \e nauty \e graph6 \e format
+  /// line from the given stream and builds it in the given graph.
+  ///
+  /// The site of nauty package: http://cs.anu.edu.au/~bdm/nauty/
+  ///
+  /// For example, the number of all non-isomorphic connected graphs
+  /// can be computed with following code.
+  ///\code
+  /// int num = 0;
+  /// SmartGraph graph;
+  /// while(readNauty(std::cin, graph)) {
+  ///   PlanarityChecking<SmartUGraph> pc(graph);
+  ///   if (pc.run()) ++num;
+  /// }
+  /// std::cout << "Number of planar graphs: " << num << std::endl;
+  ///\endcode
+  ///
+  /// The nauty files are quite huge, therefore instead of the direct
+  /// file generation the pipelining is recommended.
+  ///\code
+  /// ./geng -c 10 | ./num_of_pg
+  ///\endcode
+  template <typename Graph>
+  std::istream& readNauty(std::istream& is, Graph& graph) {
+    graph.clear();
+
+    std::string line;
+    if (getline(is, line)) {
+      int index = 0;
+
+      int n;
+
+      if (line[index] == '>') {
+        index += 10;
+      }
+
+      char c = line[index++]; c -= 63;
+      if (c != 63) {
+        n = int(c);
+      } else {
+        c = line[index++]; c -= 63;
+        n = (int(c) << 12);
+        c = line[index++]; c -= 63;
+        n |= (int(c) << 6);
+        c = line[index++]; c -= 63;
+        n |= int(c);
+      }
+
+      std::vector<typename Graph::Node> nodes;
+      for (int i = 0; i < n; ++i) {
+        nodes.push_back(graph.addNode());
+      }
+
+      int bit = -1;
+      for (int j = 0; j < n; ++j) {
+        for (int i = 0; i < j; ++i) {
+          if (bit == -1) {
+            c = line[index++]; c -= 63;
+            bit = 5;
+          }
+          bool b = (c & (1 << (bit--))) != 0;
+
+          if (b) {
+            graph.addEdge(nodes[i], nodes[j]);
+          }
+        }
+      }
+    }
+    return is;
+  }
+}
+
+#endif