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

#define SAMPLES	1000

static double samples[SAMPLES];
static const char prog[] = "/-\\|";

#define NS 1000000000

int main(int argc, char **argv)
{
	int i, iter;
	struct timespec start, end;
	struct timespec sleep;
	double base;

	if (argc < 2) 
		base = .1;
	else
		base = strtod(argv[1], NULL);

	iter = 20 / base;
	if (iter > SAMPLES)
		iter = SAMPLES;

	fprintf(stderr, "%d iterations at %f sec\n", iter, base);

	sleep.tv_sec = 0;
	sleep.tv_nsec = base * NS;

	while (sleep.tv_nsec >= NS) {
		sleep.tv_sec++;
		sleep.tv_nsec -= NS;
	}

	for(i = 0; i < iter; i++) {
		double delta;

		fprintf(stderr, "%c\b", prog[i % (sizeof(prog)-1)]);
		clock_gettime(CLOCK_MONOTONIC, &start);
		nanosleep(&sleep, NULL);
		clock_gettime(CLOCK_MONOTONIC, &end);

		delta = (end.tv_sec * NS + end.tv_nsec) -
			(start.tv_sec * NS + start.tv_nsec);

		samples[i] = delta - (base * NS);
	}

	for(i = 0; i < iter; i++)
		printf("%f\n", samples[i] / NS);

	return 0;
}