Diff: timer.h

Revision:

0:ee91220d7bea

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/timer.h	Tue Nov 30 23:53:06 2010 +0000
@@ -0,0 +1,126 @@
+#ifndef TIMER_H
+#define TIMER_H
+
+#include <ctime>
+#include <iostream>
+#include <iomanip>
+
+class timer
+{
+ friend std::ostream& operator<<(std::ostream& os, timer& t);
+
+ private:
+  bool running;
+  clock_t start_clock;
+  time_t start_time;
+  double acc_time;
+
+  double elapsed_time();
+
+ public:
+  // 'running' is initially false.  A timer needs to be explicitly started
+  // using 'start' or 'restart'
+  timer() : running(false), start_clock(0), start_time(0), acc_time(0) { }
+
+  void start(const char* msg = 0);
+  void restart(const char* msg = 0);
+  void stop(const char* msg = 0);
+  void check(const char* msg = 0);
+
+}; // class timer
+
+//===========================================================================
+// Return the total time that the timer has been in the "running"
+// state since it was first "started" or last "restarted".  For
+// "short" time periods (less than an hour), the actual cpu time
+// used is reported instead of the elapsed time.
+
+inline double timer::elapsed_time()
+{
+  time_t acc_sec = time(0) - start_time;
+  if (acc_sec < 3600)
+    return (clock() - start_clock) / (1.0 * CLOCKS_PER_SEC);
+  else
+    return (1.0 * acc_sec);
+
+} // timer::elapsed_time
+
+//===========================================================================
+// Start a timer.  If it is already running, let it continue running.
+// Print an optional message.
+
+inline void timer::start(const char* msg)
+{
+  // Print an optional message, something like "Starting timer t";
+  if (msg) std::cout << msg << std::endl;
+
+  // Return immediately if the timer is already running
+  if (running) return;
+
+  // Set timer status to running and set the start time
+  running = true;
+  start_clock = clock();
+  start_time = time(0);
+
+} // timer::start
+
+//===========================================================================
+// Turn the timer off and start it again from 0.  Print an optional message.
+
+inline void timer::restart(const char* msg)
+{
+  // Print an optional message, something like "Restarting timer t";
+  if (msg) std::cout << msg << std::endl;
+
+  // Set timer status to running, reset accumulated time, and set start time
+  running = true;
+  acc_time = 0;
+  start_clock = clock();
+  start_time = time(0);
+
+} // timer::restart
+
+//===========================================================================
+// Stop the timer and print an optional message.
+
+inline void timer::stop(const char* msg)
+{
+  // Print an optional message, something like "Stopping timer t";
+  if (msg) std::cout << msg << std::endl;
+
+  // Compute accumulated running time and set timer status to not running
+  if (running) acc_time += elapsed_time();
+  running = false;
+
+} // timer::stop
+
+//===========================================================================
+// Print out an optional message followed by the current timer timing.
+
+inline void timer::check(const char* msg)
+{
+  // Print an optional message, something like "Checking timer t";
+  if (msg) std::cout << msg << " : ";
+
+  std::cout << "Elapsed time [" << std::setiosflags(std::ios::fixed)
+            << std::setprecision(2)
+            << acc_time + (running ? elapsed_time() : 0) << "] seconds\n";
+
+} // timer::check
+
+//===========================================================================
+// Allow timers to be printed to ostreams using the syntax 'os << t'
+// for an ostream 'os' and a timer 't'.  For example, "cout << t" will
+// print out the total amount of time 't' has been "running".
+
+inline std::ostream& operator<<(std::ostream& os, timer& t)
+{
+  os << std::setprecision(2) << std::setiosflags(std::ios::fixed)
+    << t.acc_time + (t.running ? t.elapsed_time() : 0);
+  return os;
+}
+
+//===========================================================================
+
+#endif // TIMER_H
+