#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/time.h>

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

bool QUIT = false;
bool REMOVE_FILE = true; // remove file at end of job
string FILENAME = "junk.out";
uint32_t BUFF_SIZE = 20*1024;
uint32_t Nbuffs_written = 0;


#define _DBG__ cout<<__FILE__<<":"<<__LINE__<<endl
#define _DBG_  cout<<__FILE__<<":"<<__LINE__<<" "

//----------------------
// GetTime
//----------------------
double GetTime(void)
{
	struct itimerval itval;
	getitimer(ITIMER_REAL, &itval);
	
	double sec = (double)itval.it_value.tv_sec;
	double usec = (double)itval.it_value.tv_usec;
	
// 	struct timeval tv;
// 	gettimeofday(&tv, NULL);
// 
// 	double sec = (double)tv.tv_sec;
// 	double usec = (double)tv.tv_usec;
	
	return sec + (usec*1.0E-6);
}


//----------------------
// main
//----------------------
int main(int narg, char *argv[])
{
	// Initialize hi-res timer
	struct itimerval itval;
	itval.it_value.tv_sec = 1000;
	itval.it_value.tv_usec = 0;
	itval.it_interval.tv_sec = 10000000;
	itval.it_interval.tv_usec = 0;
	setitimer(ITIMER_REAL, &itval, NULL);

	// Open File
	ofstream ofs(FILENAME.c_str());
	if(!ofs.is_open()){
		cerr << "Unable to open file \""<<FILENAME<<"\" for writing!" << endl;
		exit(0);
	}
	
	// Allocate buffer
	char *buff = new char[BUFF_SIZE];

	// Write to file
	double start_time = GetTime();
	for(uint32_t i=0; i<50000; i++){
		
		ofs.write(buff, BUFF_SIZE);
		
		Nbuffs_written++;

	}	

	// Close file
	ofs.close();
	
	// MUST close file first since that flushes the buffers
	// which can take most of the time.
	double end_time = GetTime();
	double tdiff = (start_time - end_time);

	// Release buffer
	delete[] buff;

	// Optionally remove file
	if(REMOVE_FILE) remove(FILENAME.c_str());

	uint32_t MBwritten = ((BUFF_SIZE/1024)*Nbuffs_written)/1024;
	cout << MBwritten << " MB written in " << tdiff << " seconds";
	cout << "  = " << (double)MBwritten/tdiff << " MB/s" << endl;
	cout << "start_time=" << start_time << "  end_time=" << end_time << endl;

	return 0;
}