Created and integrated levelized log

Change-Id: Ibfed76796a880bab2709b77b0c9540be7b75fad7
diff --git a/src/util/logging.cpp b/src/util/logging.cpp
new file mode 100644
index 0000000..b067c80
--- /dev/null
+++ b/src/util/logging.cpp
@@ -0,0 +1,71 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+* Copyright (c) 2016 Regents of the University of California.
+*
+* This file is part of the nTorrent codebase.
+*
+* nTorrent is free software: you can redistribute it and/or modify it under the
+* terms of the GNU Lesser General Public License as published by the Free Software
+* Foundation, either version 3 of the License, or (at your option) any later version.
+*
+* nTorrent 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 Lesser General Public License for more details.
+*
+* You should have received copies of the GNU General Public License and GNU Lesser
+* General Public License along with nTorrent, e.g., in COPYING.md file. If not, see
+* <http://www.gnu.org/licenses/>.
+*
+* See AUTHORS for complete list of nTorrent authors and contributors.
+*/
+
+
+#include "util/logging.hpp"
+
+#include <boost/date_time/posix_time/posix_time_types.hpp>
+#include <boost/log/core.hpp>
+#include <boost/log/expressions.hpp>
+#include <boost/log/sinks/text_file_backend.hpp>
+#include <boost/log/sources/record_ostream.hpp>
+#include <boost/log/sources/severity_logger.hpp>
+#include <boost/log/support/date_time.hpp>
+#include <boost/log/trivial.hpp>
+#include <boost/log/utility/setup/file.hpp>
+
+// ===== log macros =====
+namespace logging = boost::log;
+namespace src = boost::log::sources;
+namespace sinks = boost::log::sinks;
+namespace keywords = boost::log::keywords;
+namespace expr = boost::log::expressions;
+
+namespace ndn {
+namespace ntorrent {
+
+void LoggingUtil::init()
+{
+  logging::core::get()->set_filter
+  (
+      logging::trivial::severity >= SEVERITY_THRESHOLD
+  );
+
+  logging::add_file_log
+  (
+     keywords::file_name = "sample_%N.log",                                        // < file name pattern >
+     keywords::rotation_size = 10 * 1024 * 1024,                                   // < rotate files every 10 MiB... >
+     keywords::time_based_rotation = sinks::file::rotation_at_time_point(0, 0, 0), // < ...or at midnight >
+     keywords::format =                                                            // < log record format >
+     (
+       expr::stream
+           << expr::attr< unsigned int >("LineID")
+           << ": [" << expr::format_date_time< boost::posix_time::ptime >("TimeStamp", "%Y-%m-%d %H:%M:%S") << "]"
+           << ": <" << logging::trivial::severity
+           << "> " << expr::smessage
+    )
+  );
+}
+
+} // end ntorrent
+} // end ndn
+
+