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src/util/log/Log.h

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+// Copyright 2017, University of Freiburg,
+// Chair of Algorithms and Data Structures.
+// Authors: Patrick Brosi <brosi@informatik.uni-freiburg.de>
+
+#ifndef UTIL_LOG_LOG_H_
+#define UTIL_LOG_LOG_H_
+
+#include <chrono>
+#include <iomanip>
+#include <iostream>
+
+#define VDEBUG 4
+#define DEBUG 3
+#define INFO 2
+#define WARN 1
+#define ERROR 0
+
+#ifndef LOGLEVEL
+#define LOGLEVEL 2
+#endif
+
+// compiler will optimize statement away if x > LOGLEVEL
+#define LOG(x) if (x <= LOGLEVEL) util::Log<x>().log()
+
+using std::setfill;
+using std::setw;
+using namespace std::chrono;
+
+namespace util {
+
+static const char* LOGS[] = {"ERROR", "WARN ", "INFO ", "DEBUG", "DEBUG"};
+
+template <char LVL>
+class Log {
+ public:
+  Log() { if (LVL == ERROR) os = &std::cerr; else os = &std::cout; }
+  ~Log() { (*os) << std::endl; }
+  std::ostream& log() { return ts() << LOGS[(size_t)LVL] << ": "; }
+
+ private:
+  std::ostream* os;
+  std::ostream& ts() {
+    char tl[20];
+    auto n = system_clock::now();
+    time_t tt = system_clock::to_time_t(n);
+    int m = duration_cast<milliseconds>(n-time_point_cast<seconds>(n)).count();
+    struct tm t = *localtime(&tt);
+    strftime(tl, 20, "%Y-%m-%d %H:%M:%S", &t);
+    return (*os) << "[" << tl << "." << setfill('0') << setw(3) << m << "] ";
+  }
+};
+}
+
+#endif  // UTIL_LOG_LOG_H_