diff --git a/core/logger.cpp b/core/logger.cpp
new file mode 100644
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--- /dev/null
+++ b/core/logger.cpp
@@ -0,0 +1,65 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California,
+ *                      Arizona Board of Regents,
+ *                      Colorado State University,
+ *                      University Pierre & Marie Curie, Sorbonne University,
+ *                      Washington University in St. Louis,
+ *                      Beijing Institute of Technology,
+ *                      The University of Memphis
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD 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 of the License, or (at your option) any later version.
+ *
+ * NFD 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
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "logger.hpp"
+#include <ndn-cxx/util/time.hpp>
+#include <cinttypes>
+#include <cstdio>
+#include <type_traits>
+
+namespace nfd {
+
+Logger::Logger(const std::string& name, LogLevel level)
+  : m_moduleName(name)
+  , m_enabledLogLevel(level)
+{
+}
+
+const char*
+Logger::now()
+{
+  using namespace ndn::time;
+
+  static const microseconds::rep ONE_SECOND = 1000000;
+  microseconds::rep microsecondsSinceEpoch = duration_cast<microseconds>(
+                                             system_clock::now().time_since_epoch()).count();
+
+  // 10 (whole seconds) + '.' + 6 (fraction) + '\0'
+  static char buffer[10 + 1 + 6 + 1];
+  BOOST_ASSERT_MSG(microsecondsSinceEpoch / ONE_SECOND <= 9999999999L,
+                   "whole seconds cannot fit in 10 characters");
+
+  static_assert(std::is_same<microseconds::rep, int_least64_t>::value,
+                "PRIdLEAST64 is incompatible with microseconds::rep");
+  std::snprintf(buffer, sizeof(buffer), "%" PRIdLEAST64 ".%06" PRIdLEAST64,
+                microsecondsSinceEpoch / ONE_SECOND,
+                microsecondsSinceEpoch % ONE_SECOND);
+
+  // It's okay to return a statically allocated buffer, because Logger::now() is invoked
+  // only once per log macro.
+  return buffer;
+}
+
+} // namespace nfd