/* 
 * Copyright (c) 2009 Peter J. Philipp 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 */
#include <sys/types.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>

int
main(void)
{
	DIR *dp;
	struct dirent *d;
	char **names, **names0;
	char buf[sizeof(int)];
	int count = 0;
	int i, rn, fd, *randomseed;;

	if ((dp = opendir(".")) == NULL) {
		perror("opendir");
		exit(1);
	}

	while ((d = readdir(dp)) != NULL) {
		count++;
	}

	rewinddir(dp);

	names = malloc((count + 1) * sizeof(char *));
	if (names == NULL) {
		perror("malloc");
		exit(1);	
	}

	names0 = malloc((count +1) * sizeof(char *));
	if (names0 == NULL) {
		perror("malloc");
		exit(1);	
	}

	count = 0;
	while ((d = readdir(dp)) != NULL) {
		names[count] = strdup(d->d_name);
		count++;
	}	
	
	names[count] = NULL;
	names0[count] = NULL;

	closedir(dp);
	
	if ((fd = open("/dev/random", O_RDONLY, 0)) < 0) {
		perror("open");
		exit(1);
	}
	if (read(fd, buf, sizeof(buf)) != sizeof(buf)) {
		perror("read");
		exit(1);
	}
	close(fd);

	randomseed = (int *)&buf;
	srand(*randomseed);
	
	for (i = 0; i < count; i++) {
		rn = rand() % count;

		while (names[rn] == NULL) {
			rn++;
			if (rn >= count) 
				rn = 0;
		}

		names0[i] = strdup(names[rn]);
		free(names[rn]);
		names[rn] = NULL;
	}
	for (i = 0; i < count; i++) {
		printf("%s\n", names0[i]);
	}

	exit(0);
}