/*
 * Copyright (c) 2007 Red Hat, Inc.
 * All Rights Reserved.
 *
 * Written by Eric Sandeen <sandeen@redhat.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/*
 * stress & time sequential deep directory creation
 */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>


/* max 32 path components */
/* contains the current, steadily increasing, path components */

int pathvals[32];

/* full path creates we've completed */

unsigned long long pathcounter = 0;

/*
 * depth controls recursion
 * path gets appended during recursion
 * max is the max value of any component
 */

int update_pathvals(int dir_depth, int max_subdirs)
{
	int i;
	unsigned long long counter = pathcounter;

	// printf("update_pathvals\n");	
	for (i = dir_depth - 1; i >= 0; i--) {
		pathvals[i] = counter % max_subdirs;
		counter = counter / max_subdirs;
		// printf("pathvals[%d] is %03x\n", i, pathvals[i]);
	}
	pathcounter++;
}

int makepath(int dir_depth, int max_subdirs)
{
	int i;
	int dirname_len = 3;
	char path[4096] = ".";		/* MAXPATHLEN? */
	char component[128] = "";	/* MAXNAMELEN? */

	/* for now hardcode dirname len to 3, i.e. max 4096 subdirs */
	for (i = 0; i < dir_depth; i++) {
		sprintf(component, "/%0*x", dirname_len, pathvals[i]);
		// printf("component %s\n", component);
		strcat(path, component);
		/* would be mkdir */
		mkdir(path, 0777);
		// printf("mkdir %s\n", path);
	}
	return 0;
}

int main(int argc, char *argv[])
{

	int i, j;
	int dir_depth = 6;		/* maximum dir components */
	int max_subdirs = 4096;	/* max subdirs of any dir */

	int iter_size = 32768;		/* how often do we check elapsed time */
	int iterations = 100;		/* and how many times we do it */
	struct timeval start_time, end_time;

	/* if dir_depth * max_subdirs < batch_size * batches we'll wrap... */

	for (i = 0; i < iterations; i++) {
		double elapsed;
		gettimeofday(&start_time, NULL);
		for (j = 0; j < iter_size; j++) {
			update_pathvals(dir_depth, max_subdirs);
			makepath(dir_depth, max_subdirs);
		}

		gettimeofday(&end_time, NULL);
		elapsed = 1000000ULL * (end_time.tv_sec - start_time.tv_sec) +
			  (end_time.tv_usec - start_time.tv_usec);
		printf("iter %d: %lf sec\n", i, elapsed / 1000000);
	}

	return 0;
}