#define _POSIX_C_SOURCE 200809L

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include <time.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <unistd.h>

#include "test.h"

#define T(f)

#define B(f) void f(int);

#include "tests.h"

#undef B

static int verbose = 1;

void error__(const char *n, int l, const char *s, ...) {

	fprintf(stderr, "use error in tests only\n");

}

static int N;

static unsigned long long start;

static unsigned long long dt;

//static unsigned long long bytes;

#define SEC  1000000000ULL

#define MAXN  500000000

static unsigned long long tic() {

	struct timespec ts;

	if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {

		fprintf(stderr, "bench: clock_gettime failed: %s\n", strerror(errno));

		return 0;

	}

	return ts.tv_sec*SEC + ts.tv_nsec;

}

void start_timer() {

	if (!start)

		start = tic();

}

void stop_timer() {

	if (start)

		dt += tic() - start;

	start = 0;

}

void reset_timer() {

	if (start)

		start = tic();

	dt = 0;

}

static int nextN() {

	unsigned long long n = dt/N;

	unsigned long long i;

	if (n)

		n = SEC/2/n;

	else

		n = SEC/2;

	n += n/2;

	if (n > N*100ULL)

		n = N*100ULL;

	else if (n <= N)

		n = N+1;

	if (n > MAXN)

		n = MAXN;

	/* round up to a nice number */

	for (i = 1; i < n; i *= 10);

	if (i/2 >= n)

		i /= 2;

	if (i/2 >= n)

		i /= 2;

	return i;

}

void vmstats() {

	FILE *f;

	char buf[256];

	int maj, min, in_heap=0;

	unsigned long l;

	size_t vm_size=0, vm_rss=0, vm_priv_dirty=0;

	f = fopen("/proc/self/smaps", "rb");

	if (f) while (fgets(buf, sizeof buf, f)) {

		if (sscanf(buf, "%*lx-%*lx %*s %*lx %x:%x %*lu %*s", &maj, &min)==2)

			in_heap = (!maj && !min && !strstr(buf, "---p") && (strstr(buf, "[heap]") || !strchr(buf, '[')));

		if (in_heap) {

			if (sscanf(buf, "Size: %lu", &l)==1) vm_size += l;

			else if (sscanf(buf, "Rss: %lu", &l)==1) vm_rss += l;

			else if (sscanf(buf, "Private_Dirty: %lu", &l)==1) vm_priv_dirty += l;

		}

	}

	if (f) fclose(f);

	fprintf(stderr, " %7zu virt %7zu res %7zu dirty", vm_size, vm_rss, vm_priv_dirty);

}

void stats() {

	if (dt/N > 100)

		fprintf(stderr, "%10d N %10llu ns/op   ", N, dt/N);

	else

		fprintf(stderr, "%10d N %13.2f ns/op", N, (double)dt/N);

	if (verbose)

		vmstats();

	fputc('\n', stderr);

}

static void run(const char *name, void (*f)(int)) {

	int p = fork();

	if (p) {

		int s;

		if (p<0 || wait(&s)<0 || !WIFEXITED(s) || WEXITSTATUS(s))

			fprintf(stderr, "benchmark %s failed\n", name);

		return;

	}

	fprintf(stderr, "%-32s", name);

	for (N=1; ; N=nextN()) {

		// TODO: fork at each iteration and pass N,dt..?

		reset_timer();

		start_timer();

		f(N);

		stop_timer();

//		fprintf(stderr, "%10d%12llu next: %d\n", N, dt, nextN());

		if (dt >= SEC/2 || N >= MAXN) {

			stats();

			exit(0);

		}

		if (N <= 0) {

			fprintf(stderr, "bench: fatal: N <= 0\n");

			exit(1);

		}

	}

}

int main() {

#define B(t) run(#t, t);

#include "tests.h"

	return 0;

}