--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/gov/nasa/jpf/listener/StateCountEstimator.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed under the
+ * Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ *        http://www.apache.org/licenses/LICENSE-2.0. 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and 
+ * limitations under the License.
+ */
+package gov.nasa.jpf.listener;
+
+import gov.nasa.jpf.Config;
+import gov.nasa.jpf.ListenerAdapter;
+import gov.nasa.jpf.search.Search;
+import gov.nasa.jpf.vm.ChoiceGenerator;
+import gov.nasa.jpf.vm.VM;
+import gov.nasa.jpf.vm.Path;
+import gov.nasa.jpf.vm.Transition;
+
+import java.io.PrintWriter;
+import java.util.Formatter;
+
+/**
+ * From already visited states, estimates the total number of states by the branching factor.
+ */
+
+public class StateCountEstimator extends ListenerAdapter
+{
+   private final PrintWriter   m_out;
+   private final StringBuilder m_buffer    = new StringBuilder();
+   private final Formatter     m_formatter = new Formatter(m_buffer);
+   private final int           m_logPeriod;
+   private       double        m_lastPercent;
+   private       long          m_nextLog;
+   private       long          m_startTime;
+
+   public StateCountEstimator(Config config)
+   {
+      m_out       = new PrintWriter(System.out, true);
+      m_logPeriod = config.getInt("jpf.state_count_estimator.log_period", 0);
+   }
+
+   @Override
+   public void searchStarted(Search search)
+   {
+      m_nextLog     = 0;
+      m_lastPercent = 0.0;
+      m_startTime   = System.currentTimeMillis();
+   }
+
+   @Override
+   public void searchFinished(Search search)
+   {
+      log(search);
+   }
+
+   @Override
+   public void stateProcessed(Search search)
+   {
+      if (m_nextLog > System.currentTimeMillis())
+         return;
+      
+      if (log(search))
+         m_nextLog = m_logPeriod + System.currentTimeMillis();
+   }
+
+   private boolean log(Search search)
+   {
+      VM vm;
+      Path path;
+      Transition trans;
+      ChoiceGenerator cg;
+      double percent, delta;
+      long currentState, expectedState, currentTime, expectedTime;
+      int i, size, processed;
+
+      vm       = search.getVM();
+      path      = vm.getPath();
+      size      = path.size();
+      percent   = 0.0;
+      delta     = 1.0;
+      processed = 0;
+      
+      for (i = 0; i < size; i++)
+      {
+         trans      = path.get(i);
+         cg         = trans.getChoiceGenerator();
+         delta     /= cg.getTotalNumberOfChoices();
+         processed  = cg.getProcessedNumberOfChoices() - 1;
+         percent   += delta * processed;
+      }
+      
+      if (size == 0)
+         percent = 1.0;
+      
+      if (m_lastPercent > percent)  // Sometimes a state is declared as processed but doesn't show up in the path so the percentage appears to go backwards.
+         return(false);
+      
+      m_lastPercent = percent;
+         
+      currentState  = vm.getStateCount();
+      expectedState = (long) (currentState / percent);
+      
+      currentTime   = System.currentTimeMillis() - m_startTime;
+      expectedTime  = (long) (currentTime / percent);
+      
+      m_formatter.format("State:  %,d / %,d (%g%%)    Time:  ", currentState, expectedState, 100.0 * percent);
+      
+      formatTime(expectedTime);
+      m_buffer.append(" - ");
+      formatTime(currentTime);
+      m_buffer.append(" = ");
+      formatTime(expectedTime - currentTime);
+
+      m_out.println(m_buffer.toString());
+      m_buffer.setLength(0);
+      
+      return(true);
+   }
+
+   private void formatTime(long time)
+   {
+      long days, hours, minutes, seconds;
+      boolean commit;
+
+      seconds = time / 1000;
+      minutes = seconds / 60;
+      hours   = minutes / 60;
+      days    = hours / 24;
+
+      seconds %= 60;
+      minutes %= 60;
+      hours   %= 24;
+
+      commit = false;
+
+      if ((commit) || (days != 0))
+      {
+         commit = true;
+         m_buffer.append(days);
+         m_buffer.append(' ');
+      }
+
+      if ((commit) || (hours != 0))
+      {
+         if ((commit) && (hours < 10))
+            m_buffer.append('0');
+
+         m_buffer.append(hours);
+         m_buffer.append(':');
+         commit = true;
+      }
+
+      if ((commit) || (minutes != 0))
+      {
+         if ((commit) && (minutes < 10))
+            m_buffer.append('0');
+
+         m_buffer.append(minutes);
+         m_buffer.append(':');
+         commit = true;
+      }
+
+      if ((commit) && (seconds < 10))
+         m_buffer.append('0');
+
+      m_buffer.append(seconds);
+   }
+}