add executor and test
diff --git a/src/executor.cc b/src/executor.cc
new file mode 100644
index 0000000..15d54d1
--- /dev/null
+++ b/src/executor.cc
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2013 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "executor.h"
+
+using namespace std;
+using namespace boost;
+
+Executor::Executor(int poolSize)
+{
+ for (int i = 0; i < poolSize; i++)
+ {
+ m_group.create_thread(bind(&Executor::run, this));
+ }
+}
+
+Executor::~Executor()
+{
+ m_group.interrupt_all();
+}
+
+void
+Executor::execute(const Job &job)
+{
+ Lock lock(m_mutex);
+ bool queueWasEmpty = m_queue.empty();
+ m_queue.push_back(job);
+
+ // notify working threads if the queue was empty
+ if (queueWasEmpty)
+ {
+ m_cond.notify_one();
+ }
+}
+
+int
+Executor::poolSize()
+{
+ return m_group.size();
+}
+
+int
+Executor::jobQueueSize()
+{
+ Lock lock(m_mutex);
+ return m_queue.size();
+}
+
+void
+Executor::run()
+{
+ while(true)
+ {
+ Job job = waitForJob();
+
+ job();
+ }
+}
+
+Executor::Job
+Executor::waitForJob()
+{
+ Lock lock(m_mutex);
+
+ // wait until job queue is not empty
+ while (m_queue.empty())
+ {
+ m_cond.wait(lock);
+ }
+
+ Job job = m_queue.front();
+ m_queue.pop_front();
+ return job;
+}
diff --git a/src/executor.h b/src/executor.h
new file mode 100644
index 0000000..bda46b4
--- /dev/null
+++ b/src/executor.h
@@ -0,0 +1,77 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2013 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef EXECUTOR_H
+#define EXECUTOR_H
+
+#include <boost/function.hpp>
+#include <boost/thread/condition_variable.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/locks.hpp>
+#include <boost/thread/thread.hpp>
+#include <deque>
+
+/* A very simple executor to execute submitted tasks immediately or
+ * in the future (depending on whether there is idle thread)
+ * A fixed number of threads are created for executing tasks;
+ * The policy is FIFO
+ * No cancellation of submitted tasks
+ */
+
+class Executor
+{
+public:
+ typedef boost::function<void ()> Job;
+
+ Executor(int poolSize);
+ ~Executor();
+
+ // execute the job immediately or sometime in the future
+ void
+ execute(const Job &job);
+
+ int
+ poolSize();
+
+// only for test
+ int
+ jobQueueSize();
+
+private:
+ void
+ run();
+
+ Job
+ waitForJob();
+
+private:
+ typedef std::deque<Job> JobQueue;
+ typedef boost::mutex Mutex;
+ typedef boost::unique_lock<Mutex> Lock;
+ typedef boost::condition_variable Cond;
+ typedef boost::thread Thread;
+ typedef boost::thread_group ThreadGroup;
+ JobQueue m_queue;
+ Mutex m_mutex;
+ Cond m_cond;
+ ThreadGroup m_group;
+};
+#endif // EXECUTOR_H