logger initial commit

examples/c++/logger.cxx

@@ -0,0 +1,17 @@
+#include "upm_logger.hpp"
+
+using namespace upm;
+
+int main()
+{
+
+  UPM_LOGGER::getLogLevel() = LOG_ERROR;
+
+  UPM_LOGGER().get(LOG_WARNING) << "a loop with 4 iterations";
+
+  for (int i = 0; i < 4; ++i) {
+    UPM_LOGGER().get(LOG_DEBUG) << "i = " << i;
+  }
+
+  return 0;
+}

include/upm_logger.hpp

@@ -0,0 +1,84 @@
+#pragma once
+
+#include <sstream>
+#include <string>
+#include <chrono>
+#include <stdio.h>
+
+namespace upm {
+
+  enum UpmLogLevel {
+      LOG_ERROR,
+      LOG_WARNING,
+      LOG_INFO,
+      LOG_DEBUG,
+      NA
+  };
+
+  static const std::string logLevelNames[] = {
+    "ERROR",
+    "WARNING",
+    "INFO",
+    "DEBUG",
+    ""
+  };
+
+  class UPM_LOGGER {
+  public:
+    UPM_LOGGER();
+    virtual ~UPM_LOGGER();
+    std::ostringstream& get(UpmLogLevel level = LOG_INFO);
+    static UpmLogLevel& getLogLevel();
+  protected:
+    std::ostringstream os;
+  private:
+    UPM_LOGGER(const UPM_LOGGER&);
+    UPM_LOGGER& operator=(const UPM_LOGGER&);
+  private:
+    UpmLogLevel logLevel;
+
+  public:
+    static const std::string& getLogLevelName(UpmLogLevel level)
+    {
+      if (level < LOG_ERROR || level >= NA) {
+        return NULL;
+      }
+
+      return logLevelNames[level];
+    }
+  };
+
+  UPM_LOGGER::UPM_LOGGER() {}
+
+
+  UpmLogLevel& UPM_LOGGER::getLogLevel()
+  {
+    static UpmLogLevel reportingLevel = LOG_DEBUG;
+    return reportingLevel;
+  }
+
+  std::ostringstream& UPM_LOGGER::get(UpmLogLevel level)
+  {
+    using namespace std::chrono;
+
+    os << "- " << duration_cast<milliseconds>
+      (system_clock::now().time_since_epoch()).count();
+    os << " " << getLogLevelName(level) << ": ";
+    os << std::string(level > LOG_DEBUG ? level - LOG_DEBUG : 0, '\t');
+    logLevel = level;
+
+    return os;
+  }
+
+  UPM_LOGGER::~UPM_LOGGER()
+  {
+    if (logLevel >= UPM_LOGGER::getLogLevel()) {
+      os << std::endl;
+      fprintf(stderr, "%s", os.str().c_str());
+      fflush(stderr);
+    }
+  }
+
+}
+
+