core: simplify Logger with C++11 features
refs #2146
Change-Id: I6ad9e7281c8a6b60c46b51de727bcddded42ba3d
diff --git a/core/logger.cpp b/core/logger.cpp
new file mode 100644
index 0000000..7d92aa3
--- /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