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#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